Smeer Durani, Neeraja Mathur, D.S.R.Murty

Chemistry laboratory,
Atomic Minerals Directorate for Exploration and Research,
Begumpet, Hyderabad-500016

Abstract

A simple, convenient and rapid dissolution method resulting in a single solution for determination of major impurities in hi-tech minerals is described. Six mineral samples i.e., ilmenite, rutile, garnet, zircon, monazite and sillimanite were dissolved by microwave assisted digestion procedures and major element impurities such as Al, Fe, Ca, Mg, Mn, Na, K, P were determined by Flame AAS & UV-VIS spectrophotometry. The validity / performance of Microwave assisted digestion (MDS) method was compared with the conventional analytical methods of hot plate digestion / fusion. MDS requires only two hours of sample dissolution time, much shorter than required for conventional digestion in an open vessel and also results in very less amount of dissolved salts. The recoveries were in the range of 85 – 110%.

Keywords: Chemical characterization; Refractory minerals; Flame-AAS; Microwave digestion

A NEW SAMPLE DECOMPOSITION PROCEDURE FOR THE BARYTE BEARING ROCKS AND PEGMATITE MINERALS: ELEMENTAL CHARACTERISATION USING ICP-AES AND FAAS

A. Premadas and Anitha Mary Thomas

Chemistry Laboratory, Southern Region
Atomic Minerals Directorate for Exploration and Research
Department of Atomic Energy, Nagarbhavi, Bangalore-560072, India.
apremadas.amd@gov.in

Abstract

This paper proposes a new sample decomposition procedure for the baryte bearing rocks and baryte bearing pegmatite refractory minerals for the preparation of a single sample solution. Samples are completely decomposed by fusion with a mixture of di-sodium hydrogen phosphate and di-hydrogen sodium phosphate, the cooled melt is completely extracted in distilled water. The solution after suitable dilution is used for the ICP-AES and FAAS estimation of essentially Ba, Ti, Al, Fe, Mn, Ca, and Mg and also some other elements like Sr, Cr, Mo, V, Nb and Ta. Uranium is determined by the laser fluorimetric method. A lithium meta-borate fusion for the sample decomposition is also optimized. The results obtained by the two methods are compared with the conventional acid digestion and sodium carbonate fusion. Validity of the proposed method is established by analyzing some Canadian Certified Reference samples like SY-2, SY-3, SO-2, MRG-1 and FeR-1 doped with milligram quantities of barium sulphate and synthetic samples prepared from high purity oxides. The proposed procedure is simple, accurate and precise.

Keywords: Baryte bearing rocks; Elemental characterization; ICP-AES; FAAS; Sample decomposition

A RAPID DISSOLUTION PROCEDURE FOR THE FLUORIMETRIC DETERMINATION OF URANIUM IN CALCRETE SAMPLES OF
WESTERN RAJASTHAN

A. Thangaraj, M.K. Ganguly, P.N. Bangroo, K.Ramesh Kumar and L. K. Nanda

Western Region, Atomic Minerals Directorate for Exploration and Research,
Department of Atomic Energy, Jaipur

Abstract

The calcrete samples in Rajasthan have shown positive uranium concentration in a set of samples in Lachhri area. Since these samples contain high calcium, the opening of the samples by hydrofluoric acid becomes difficult due to formation of insoluble calcium and magnesium fluorides. In order to circumvent this problem, boric acid was used along with nitric acid to break the fluorides and remove fluoride. The recovery of uranium in the presence of boric acid was studied and found to be quantitative. Based on this a procedure of sample opening of calcrete samples and estimation of uranium is presented in this work.

Keywords: Determination; Uranium; Fluorimeter; Ca-rich samples

RAPID DECOMPOSITION AND DISSOLUTION OF TIN SLAG SAMPLES FOR DIRECT DETERMINATION OF URANIUM BY LASER INDUCED FLUORIMETRY

P.L. Mahanta, G. Chakrapani*, R. Radhamani and P. Murugesan

Chemistry Laboratory, Atomic Minerals Directorate for Exploration and Research Central Region, Nagpur-440001
*chakrapanigotur@yahoo.com

Abstract

A simple and rapid decomposition method has been developed for application to dissolution of tin slag samples for determination of uranium at ppm levels by Laser Induced Fluorimetry. Tin slag samples were treated with HF and HClO₄, fumed to dryness, fused with flux (Sodium dihydrogen orthophosphate and di-sodium hydrogen ortho phosphate in the ratio 1:1) and dissolved in distilled water for the analysis of uranium by laser induced fluorimetry (LIF). The main advantage of this method is sample decomposition is simple, no separation stage is involved and analysis could be carried out directly. The flux (phosphate mixture) used for decomposition itself acts as fluorescence enhancing buffer unlike other complexing agents like Oxalic, Tartaric and Citric acids (used in various sample decomposition procedures involving variety of fluxes) as these reagents acts as strong quenchers of uranium fluorescence and hence separation is required before analysis. The accuracy of the method is evaluated by analyzing synthetic samples and comparing the values obtained by present method with pellet fluorimetry. In both the cases the results obtained are well within the experimental error. The RSD of the method is ± 10% at 100 ppm level. The method is successfully applied to numerous tin slag samples received from Rare Metal and Rare Earth Investigation Groups.

Keywords: Uranium, Tin slag, Phosphate flux, Laser Fluorimetry.

DEVELOPMENT OF METHOD FOR RAPID DIGESTION OF SILICEOUS URANIUM ORES OF SINGHBHUM SHEAR ZONE

S.K. Singh and *A.K. Singh

Control Research and Development Department,
Uranium Corporation of India Limited, Turamdih
*anand_ucil@rediffmail.com

Abstract

Singhbhum shear zone (SSZ) of Jharkhand state is known as the treasure house of many minerals of economic importance. The zone also hosts the lion’s share of Indian uranium reserves spread in a number of small to medium deposits. Jaduguda, the first uranium deposit to be discovered in the country is located almost at the centre of this 180 km long shear zone. The host rock of the uranium-mineralized sector of SSZ is rich in silica content and its digestion by conventional open vessel digestion method is very tedious and time-consuming. It calls for the development of a rapid and effective method for digestion of this type of ore. Experiments were carried out to digest the siliceous uranium ores by Microwave digester and the method has now been standardized for regular application.

Keywords: Uranium ore; Siliceous; Conventional digestion; Microwave digester
*Corresponding author:

A SIMPLE, RAPID AND ACCURATE DETERMINATION OF URANIUM IN MONAZITE MINERAL, Th AND REE-RICH MATRIX USING LASER FLUORIMETER AND ICP-AES

A.Premadas*, Nishma Ojha and Dhilshathu Beegam

Chemistry Laboratory, Southern Region
Atomic Minerals Directorate for Exploration and Research
Department of Atomic Energy, Nagarabhavi, Bangalore-560072, India.
*apremadas.amd@gov.in

Abstract

An accurate, simple, rapid and direct laser fluorimetric determination of trace level of uranium in monazite mineral, thorium and rare earth elements rich matrix is reported with a determination limit of 1µg g-1 uranium in ThO2 matrix using laser fluorimeter. Sample solution is prepared by fusing the sample with a mixture of Na₄P₂O₇ and NaH₂PO₄ and the solution is prepared in distilled water, and few drops of hydrogen peroxide were added in case of monazite mineral. Suitable aliquot is taken for the direct laser fluorimetric determination of uranium using sodium pyrophosphate solution (pH ~ 7) as fluorescence enhancing reagent. Unlike in the pellet fluorimetric determination of uranium, fluorescence quenching is not observed either due to thorium or rare earth elements in the concentration range studied (5-200 µg ml^-1) by this method. Analytical problems encountered in the determination of uranium in monazite mineral by the pellet fluorimetric method after the ethyl acetate solvent extraction separation is also discussed. A spectral interference-free ICP-AES uranium determination procedure in monazite mineral is optimized after the solvent extraction separation of uranium from acidified sodium polyphosphate medium using ethyl acetate, tri-n-butyl phosphate (TBP) and tri-n-octyl phosphine oxide (TOPO) as individual extractant. The proposed uranium determination methods are validated by estimating uranium in (i) monazite in-house reference sample (ii) synthetic sample prepared by mixing high purity oxides of Th and some REE, doped with known trace amounts of uranium and, (iii) by the standard addition technique. The laser fluorimetric determination is used for the determination of uranium at trace level, and ICP-AES at the percentage level. The RSD of the method at 1µg g-1 uranium in ThO2 matrix is 7% (n=4) and at 0.35% uranium in monazite mineral RSD is 4% (n=4) using ICP-AES.

Keywords: Determination, Uranium, Thorium matrix, REE matrix; Laser fluorimeter
*corresponding author

ANION EXCHNAGE SEPARATION OF TRACE LEVEL OF THORIUM AND URANIUM FROM ZIRCONIUM MATRIX: ICP-AES AND LASER FLUORIMETRIC DETERMINATION OF URANIUM AND THORIUM IN ZIRCON MINERAL

A. Premadas and B. Gomathyamma

Chemistry Laboratory, Southern Region
Atomic Minerals Directorate for Exploration and Research
Department of Atomic Energy, Nagarabhavi, Bangalore-560072, India.
apremadas.amd@gov.in

Abstract

A simple, selective and quantitative anion exchange separation procedure for Th and U at trace level from Zr-rich matrix has been developed. Both Th and U are adsorbed on an anion exchanger, Dowex-1 X8, (100-200 mesh size) quantitatively, leaving the Zr un-adsorbed, facilitating the complete separation of Th and U from Zr-rich matrix, thus providing an interference-free ICP-AES determination of Th and U at trace level. The procedure is applied to zircon mineral sample. A simple, rapid and direct laser fluorimetric determination of U in zircon sample is also developed, and the tolerance level of Zr and oxalate salts are quantified. The proposed methods are accurate and the reproducible.

Keywords: Anion-exchange separation; Uranium and Thorium determination;
Zr - rich samples; ICP-AES; Laser fluorimetry

DIRECT URANIUM ESTIMATION IN
GEOLOGICAL SAMPLES WITH HPGe DETECTOR

N.Rupa, V.Koteswara Rao, A.A.P.S.R.Acharyulu, S.K.Rohatgi, G.B.Rout, S.S.Raghuwanshi

Atomic Minerals Directorate for Exploration and Research,
Department of Atomic Energy Begumpet Hyderabad - 500 629

Abstract

Estimation of Uranium in geological rock samples, is carried out by gamma ray spectrometry measuring 1.76 MeV gamma emitted by daughter product ²¹⁴Bi of the Uranium series with an assumption that Uranium series is in equilibrium with its daughter products. In present attempt, estimation of Uranium has been done by measuring 63.3 keV and 92.38 keV gamma rays emitted by nuclide ²³⁴Th (immediate daughter product of ²³⁸U) using High Purity Germanium detector. Interestingly this technique does not need apriori any conditions of equilibrium or disequilibrium in the Uranium series - an advantage.

Keywords: Uranium; Direct estimation; HPGe detector; Geological samples

DETERMINATION OF URANIUM CONCENTRATION AND FREE ACID IN URANYL NITRATE SOLUTIONS BY TWO-END POINT pH TITRATION

Binoj Nair, P. Shanmugavelu, T.M. Sudhakar and S.Sarkar

Analytical Control Laboratory, Chemical Technology Group,
Bhabha Atomic Research Centre, Mumbai, India

Abstract

A simple analytical method has been described for measuring the free acidity and uranium concentration in uranium bearing process stream samples for uranium refining industry. The method involves acid-base titration using standardised NaOH as titrant at two pre-set end points i.e. pH-3 and pH-4, which corresponds to the free acid and the hydrolyzing reaction of uranium. The volume of titrant consumed in back titration can be calculated to yield the free acidity and uranium concentration of the sample aliquot. The calibration is performed using a standard uranyl nitrate solution where the uranium concentration is 30 g/L with a free acidity of 0.3 N. Relative standard deviation of less than 2 % has been obtained for both uranium and free acidity measurements by the proposed method. The results are compared with those obtained by potentiometry and the results are found to be satisfactory.

Keywords: Determination; Uranium; free acid; pH titration; uranyl nitrate solution

ESTIMATION OF LOW LEVELS OF URANIUM IN ACTIVE EFFLUENTS AND SOLID WASTE FROM URANIUM PROCESSING FACILITIES USING AUTOMATIC VOLUMETRIC ANALYZER

Shanmugavelu.P, Prabhakar.M.S, Pavithran. M.V., Sudhakar. T.M and Sarkar.S

Analytical Control Laboratory, Chemical Technology Group,
Bhabha Atomic Research Centre, Mumbai, India

Abstract

A simple, fast and accurate analytical method for estimating low level of uranium in active effluents and solid waste originating from uranium processing industries is described here. The method involves complete automation of analysis using computer controlled titrator as per standard Davis & Gray volumetric method. The method is tested for its performance and validated by analyzing different standard solutions. It is found that samples having uranium concentration above 200 ppm can be analysed with the acceptable limit of precision and accuracy.

Keywords: Estimation; Uranium; Effluents; Automatic volumetric analyzer.

ANALYSIS OF URANIUM – A COMPARATIVE STUDY USING ICP-MS
AND LASER FLUORIMETRY

Shailaja Pandey, Niyoti S. Shenoy and Sanjukta A. Kumar

Analytical Chemistry Division, Bhabha Atomic Research Centre,
Mumbai 400085, India

Abstract

Uranium in ultratrace level has been determined in seawater using ICP-MS and Laser Fluorimetry. A matrix separation is carried out using Poly Hydroxamic Acid as solid phase extractant in the case of ICP-MS to remove the high salt content. In laser fluorimetry a nitric acid treatment was done to eliminate the quenching effect. The values obtained by both the techniques are in good agreement.

Keywords: ICP-MS; Laser Fluorimetry, Uranium analysis

TRACE ELEMENT ANALYSIS OF URANIUM SAMPLES:
ROUTINE ANALYSIS METHODOLOGY

S.Chandramouleeswaran and J.C.Upadya

Analytical Chemistry Division,
Bhabha Atomic Research Centre, Trombay, Mumbai 400 085

Abstract

The analysis of trace levels of iron and aluminium in uranium are routinely carried out and around 1900 samples have been analyzed over the last five years. The matrix is removed by solvent extraction method using tributyl phosphate (TBP). The separated aqueous phase containing iron and aluminium were analyzed using both spectrophotometry and ICP-AES. The spectrophotometric method has a detection limit of 0.04 µg/ mL whereas that for ICP-AES is 0.1 µg/ mL. Because of the large sample throughput, the use of ICP-AES is more suited for the regular analysis.

Keywords: Iron; Aluminium; Uranium samples; Tri-n-butyl phosphate; ICP-AES;
Spectrophotometry

DETERMINATION OF %²³⁵U IN DEPLETED URANIUM SAMPLES USING NAI(TL)-GAMMA RAY SPECTROMETER IN COMBINATION WITH REDOX TITRIMETRY

R. Vasantha, U. Bharati Misra, B. Narasimha Murty and R.B. Yadav

Control Laboratory, Nuclear Fuel Complex, Hyderabad, India- 500 062

Abstract

The present paper describes an analytical method based on combination of Gamma Ray Spectrometry cum Redox Titrimetry to determine the content of ²³⁵U in depleted uranium materials. The content of in depleted uranium samples is calculated by measuring the count rates pertaining to photo peak of 185.7 keV of sample solution and that of the natural uranium standard solution having the same concentration of uranium. The count rates are measured by using gamma ray spectrometer equipped with a NaI(Tl) detector and the concentration of uranium in the solutions is determined by redox titrimetric method. The variance in the calculated content of ^%235U is expressed in terms of variance in the count rates at the 185.7 keV photo peak pertaining to sample and natural uranium standard solutions using the basic statistical concept of propagation of errors. The present method in determination of ^%235U has relative standard deviation of 1% (n=10) at 0.590 % ²³⁵U in depleted uranium samples. The content of ^%235U determined in various uranium dioxide powders of depleted uranium material using the present method are compared well with those values obtained by thermal ionization mass spectrometry.

Keywords: Depleted uranium; Redox titration; Gamma ray spectrometer

DIFFERENTIAL PULSE POLAROGRAPHIC DETERMINATION
OF URANIUM IN LEACH LIQUORS

A. A. Patwardhan

Chemistry Laboratory, Atomic Minerals Directorate for Exploration and Research,
Central Region, AMD Complex, Civil Lines, Nagpur-440 001

Abstract

Leaching of Uranium ores is an initial and intrinsic step towards its beneficiation and conversion into nuclear fuel .The “leach liquors” are the process solutions produced during the beneficiation operation and require frequent and rapid monitoring for their uranium content. However, most of the existing analytical procedures viz. fluorimetric technique and ICP-AES require pre-separation of uranium owing to possible matrix interferences.

Present communication describes a direct (without any pre- separation), rapid and selective method for determination of uranium in leach liquors by Differential Pulse Polarography. A mixture of Sulphuric acid (0.05M) and ascorbic acid (2%w/v) has been used as supporting electrolyte. Uranium, under the conditions, exhibits a reduction peak at – 0.228 v. Vs Ag/AgCl reference electrode. The lowest limit of quantitation achieved by the proposed method is 5 ppm of U₃O₈ (RSD + 3%) in presence of large amount of iron(U :Fe ratio =1: 10000)

The two major advantages of the proposed method are (i) absence of any separation or pre-concentration step and (ii) the use of 0.05 M H₂SO₄ as supporting electrolyte, which, is the very medium used as leaching agent in the acid leaching of uranium ores. Other experimental parameters viz. effect of supporting electrolyte, effect of ascorbic acid concentration ,effect of presence of other ions, possibility of simultaneous determination of other cations etc. has also been studied in detail . Routine samples of leach liquors received were analysed by the proposed method, and the method has been validated by analysing international rock standards namely SY-2 and SY-3.

Keywords: Uranium; Leach liquors; Differential Pulse Polarography; Ascorbic acid; Sulphuric acid.

COMPARISON OF CLASSICAL AND INSTRUMENTAL TECHNIQUES FOR THE ANALYSIS OF HIGH GRADE URANIUM ORES AND PROCESS SAMPLES

N. Balachandran, R. R. Venkitakrishnan and A. S. Navale

Mineral Processing Division, BARC, AMD Complex, Hyderabad

Abstract

The uranium content in Indian uranium ores is quite low. The analysis of uranium in these ores is commonly carried out by pellet fluorimetriy. Recently, a high grade uranium ore sample was received in our laboratory having uranium content more than 20%. The process stream samples from this ore also are high in uranium content. The classical methods like volumetry and gravimetry are employed for analysis of such high grade samples. But these classical methods are time consuming and sample throughput is considerably low. Studies were carried out to adopt pellet fluorimetric technique for such high grade ore and compare the results with those from classical methods. The results showed that it is possible to obtain results comparable to the classical methods and that the fluorimetric method can be applied to the analysis of both high and low grade samples without loss in accuracy.

Keywords: Uranium estimation; Fluorimetry; Spectrophotometry; Gravimetry;
Uranium ores.

A RAPID METHOD FOR DETERMINATION OF TRACE ELEMENTS IN HYDROGEOCHEMICAL SAMPLES AND SALINE WATERS USING ICP – AES AFTER COPPER – DIETHYLDITHIOCARBAMATE CO-PRECIPITATION

Roopa Bose and K.Satyanarayana

Chemistry Laboratory,Southern Region,
Atomic Minerals Directorate for Exploration and Research,
AMD Complex,Nagarbhavi,Bangalore.

Abstract

A method for the determination of trace amounts of Bi, Cd, Co, Cr, Hf, Ni, Pb, Th, Zn and Zr in hydrogeochemical samples and saline waters by Inductively Coupled Plasma Atomic Emission Spectrometry after co-precipitation by using diethyldithiocarbamate as a chelating agent and copper as a carrier element is described. Different factors including pH of the sample solution, chelating agent conc., carrier element conc. and time of contact were optimized for achieving quantitative recovery of the traces at µgl-1 levels. The method developed was applied for estimation of traces in hydrogeochemical samples received from different field areas pertaining to uranium exploration programmes. The optimized procedure was also successfully applied to recover trace elements from spiked samples of reconstituted sea water at 5 – 10 µgl^-1 conc.

The recoveries varied from 98 % to 105 % according to the trace elements determined except in the case of Bi where the recovery was varied between 85% to 88%. The limits of determination by the proposed method in natural water samples are 5 µgl^-1 for Bi and Hf; 4 µgl^-1 for Pb and Th; 2 µgl^-1 for Co, Ni, Zr and 1 µgl^-1 for Cd, Cr and Zn by ICP - AES. By flame AAS the limits of determination were 6 µgl^-1 for Pb; 3 µgl^-1 for Co and Ni; 1 µgl^-1 for Cd and 0.5 µgl^-1 for Zn. The RSD of the present procedure as a whole ( n = 3) is about 6 – 8% at 5 µgl^-1 level.

Keywords: Co-precipitation; Sodium diethyldithiocarbamate; Water samples; ICP-AES

SELECTIVE METHOD FOR DETERMINATION OF PESTICIDE RESIDUES IN ENVIRONMENTAL WATER SAMPLES USING CAPILLARY GAS CHROMATOGRAPH AND MASS SPECTROMETRY

K. Rama Mohan*, A. Keshav Krishna, N. N. Murthy, A. Santosh Kumar, G. Machender

Environmental Geochemistry Division, National Geophysical Research Institute
(Council of Scientific & Industrial Research, India)
Uppal Road, Hyderabad 500606, India
*krmohan@ngri.res.in

Abstract

A selective method for the determination of organochlorine pesticide (OCP) residues in water samples was reported. Liquid-Liquid-Extraction (LLE) method was evaluated in optimizing the extraction procedure for the analysis of pesticides. Florisil column chromatography was adopted for clean-up the extracts. The dichloromethane gave the best results of all the extracting solvents used. The percentage of recoveries ranged from 90.12±7.12 (Dieldrin) to 101.25±2.84% (d-BHC). The Limits of detection for the OCPs vary between 0.4 and 1.6µg/l. The residues were determined by gas chromatographic separation and GC quadrupole–MS detection. The determination of 16 OCPs was achieved in about 23 min. The LLE method was applied to groundwater samples collected from Kazipalli Industrial Area, Hyderabad that receives run-offs from agricultural lands and effluents from industries. The levels of OCPs levels detected ranged from 0.5 (Dieldrin) to 111.6µg/l (d-BHC) which include some endocrine disrupting pesticides.

Keywords: Determination; Organochlorine pesticide (OCP); GC-MS; Water samples

*Corresponding author

SURFACE TENSION OF WATER, SATURATED (0-100%) WITH
TRI-n-BUTYL PHOSPHATE AT 298.15 K

Shekhar Kumar*, Rajnish Kumar and S.B. Koganti

Reprocessing Research and Development Division
Reprocessing Group, IGCAR, Kalpakkam 603102, India
*shekhar@igcar.gov.in

Abstract

The surface tension of water with varying concentration of TBP (0-100% saturation) was measured at 298.15 K and 0.1 MPa. The experimental data could be modeled by the Tamura’s method. However for modeling of experimental data by Szyszkowski equation, need for a correction in the basic equation was observed as the “constant” ac was found to be composition dependent for the TBP-water system. An extended Szyszkowski equation has been proposed in this work, possibly for the first time in literature.

Keywords: Surface tension; Water-Tri-n-butyl phosphate; Szyszkowski equation
*Corresponding Author

ASSESSMENT OF MOISTURE CONTENT IN THE STEAM GENERATED BY STEAM GENERATOR OF A NUCLEAR POWER PLANT BY DETERMINING THE SODIUM CONTENT IN THE CONDENSATE BY FLAME EMISSION SPECTROMETER

P.K.Pal and R.C.Bohra

Rajasthan Atomic Power Station, Kota, Rajasthan

Abstract

This paper describes a procedure to assess the content of moisture indirectly in the steam generated by a steam generated used in a nuclear power plant which is an important parameter for the smooth functioning of the steam generator. The procedure involves generation of steam with use of boiler water containing known quantity of sodium followed by the determination of content of sodium in the condensate water using flame emission technique. As the moisture content in the steam can result only due to carry over of the boiler water containing sodium, the presence of sodium in the water condensate which otherwise would have been nil is an indirect measure of moisture content in the steam. Thus, the fraction of moisture content in the steam is simply the ratio of contents of content of sodium in the water condensate to content of sodium in the boiler water.

Keywords: Moisture content; Determination; Sodium in condensate; Flame emission spectrometer

SYNTHESIS OF IMMOBILIZED USED GREEN TEA LEAVES ON SILICA GEL AND ITS APPLICATION IN SEPARATION / PRE CONCENTRATION OF URANIUM AND TRACE ELEMENTS IN HYDROGEOCHEMICAL SAMPLES

Vijay Kumar, Satya Prakash and P.N. Bangroo

Chemistry Laboratory, Western Region, Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Jaipur

Abstract

A simple and sensitive method has been developed for the separation and pre concentration of trace elements like copper, cobalt, nickel, zinc and uranium by means of Used Green Tea Leaves (UGTLs), immobilized over the silica gel using a 25mm x 10mm sorbent column. The pre concentrated elements have been determined by Inductively Coupled Plasma-Optical Emission Spectrometer (Jobin Yuon, Horiba Ultima2), Flame Atomic Absorption Spectrometer (Analytik Jena novAA 300)and uranium by Fluorimeter (model Galvanek and Morrison) /Laser Induced Fluorimeter (Fabricated by RRCAT, Indore).The pre concentration studies have been carried out at different pH (2-7) conditions so as to arrive at optimization and the quantitative recovery of analytes by eluting with 1 mol/L of HCl solution at the flow rate of 1.5 ml/min. The validity of the method was checked with synthetic mixture and standard addition technique. The method has been tested in a number of effluents and hydrogeochemical samples. Accuracy achieved was ±10% at 10ppb level for trace elements and 0.1ppb for uranium with the enrichment factor of 10.

Keywords: Preconcentration; Immobilized; Silica gel; Uranium; Hydrogeochemical samples

A RAPID METHOD FOR MAJOR AND TRACE ELEMENT DETERMINATION IN WATERS USING PLASMA EMSSION SPECTROMETRY

Smeer Durani and D. S. R. Murty

Atomic Minerals Directorate for Exploration and Research,
Department of Atomic Energy, Begumpet, Hyderabad-500016

Abstract

For hydrogeochemical exploration studies, water plays a key role as the mediator of many processes, as well as being the principle medium for the solubilisation and transport of material. Hence, its composition is intensively studied for geochemical interpretation. Direct analysis of water is the simplest application of ICP-OES in practice. A large number of hydrogeochemical samples are analysed for major and trace elements. Quick analytical feed back for field interpretation is required. Therefore, an Inductively Coupled Plasma Optical emission spectrometry is used for multi elemental determination of major and trace elements without pre-concentration. The present equipment utilized has advantage of low detection limits, excellent sensitivity and high sample throughput.

Keywords: Determination; Hydrogeochemical samples; ICP-OES; Trace elements

DETERMINATION OF INDIUM IN NIOBATE/ TANTALATE AND
GEOLOGICAL SAMPLES BY ICP- AES AFTER ACID HYDROLYSIS
SEPARATION AND SOLVENT EXTRACTION

K.Satyanarayana¹, Bincy Cyriac¹ and Smeer Durani²

¹ Chemistry Laboratory, AMD, SR, Nagarabhavi, Bangalore – 72 &
² Chemistry Laboratory, AMD, Complex, Begumpet, Hyderabad – 500 629.

Abstract

A simple, precise and accurate solvent extraction method is described for the separation and estimation of Indium in geological materials. Solvent extraction of Indium from 6 M HCl medium using tri-n-butyl phosphate, selectively separates Indium from accompanying elements in different type of geological samples. Acid hydrolysis of Nb/Ta samples separates Indium from major matrix elements like Nb and Ta. The remaining elements do not influence the selective extraction and preconcentration of In and its subsequent determination by ICP-AES or flame AAS. The silica rich geological samples are decomposed by HF-H₂SO₄-HCl treatment followed by dissolution in 6M HCl before applying solvent extraction procedure. In Nb/Ta type of samples, Indium was separated from Nb and Ta by acid hydrolysis, involving fusion with Na₂O₂, dissolution in HCl followed by NH₄OH precipitation and hydrolysis in HCl. The oxychloride precipitates of Nb and Ta are filtered off and subjected to solvent extraction using TBP. The proposed method has been applied to some international reference standards (IGS-33 and ASK-3) and to some Nb/Ta type samples and the results are compared by ICP-AES as well flame AAS techniques. The method is simple, rapid and accurate showing a relative standard deviation of 2% (at 170 µg/g) to 7.0% (at 16 µg/g ) and the method can be applied down to 1 µg/g .

Keywords : Indium; Geological materials; Niobate-Tantalate; acid hydrolysis; solvent extraction; ICP-AES.

DETERMINATION OF As, Se AND Mo IN GEOLOGICAL SAMPLES
BY ICP-AES AFTER SULFIDE CO-PRECIPITATION AND
PRECONCENTRATION USING Cu AS CARRIER

K. Satyanarayana, Usha Nathan and A.K. Rai

Chemistry Laboratory, Southern Region
Atomic Minerals Directorate for Exploration and Research
Department of Atomic Energy, Nagarabhavi, Bangalore-560072, India.

Abstract

A simple and rapid inductively coupled plasma atomic emission spectrometric method for the determination of As, Se and Mo in a variety of geological materials is described. The samples are treated with a mixture of acids like HF, HNO₃, HClO₄ and H₂SO₄. Copper carrier solution is added to the clear solution to act as a co-precipitant before the addition of sodium sulfide solution in 10% v/v HCl solution. The precipitates are dissolved in aqua-regia and H₂SO₄ with final dissolution in 10% v/v H₂SO₄ acid solution and is aspirated into the plasma for optical emission measurements. The method is accurate and precise, offering a relative standard deviation ranging from 2-7.0 % for all the three elements studied. The method was applied to different types of international reference standards, viz., SY-3, FER-1, FER-2, SO-2, SO-3, SO-4, ASK-2, and ASK-3 besides some geological materials including iron rich pit samples, pyrite rich and limestone samples for all the elements and measured at their most sensitive emission lines viz.193.759nm for As(I), 196.090nm for Se(I), and 202.030nm for Mo(II). The values obtained are compared well with the certified values for all the three elements. The method allows the determination of As, Se and Mo down to 1µg/gm in different types of geological samples.

Keywords: Arsenic, Selenium and Molybdenum determination; Geological materials; Preconcentration; Inductively coupled plasma atomic emission spectrometry

ANALYSIS OF Cm-247 SUPERCAST ALLOY FOR Au, Hg, In and Pd by ICP-AES

G. Satyanarayana, R. Ethiraj, Y. Balaji Rao* and R.B. Yadav
Control Laboratory, Nuclear Fuel Complex, Department of Atomic Energy,
ECIL Post, Hyderabad 500062
*ybr@nfc.gov.in

Abstract

The present paper discusses a new method developed for estimation of Gold (Au), Mercury (Hg), Indium (In) and Palladium (Pd) in Nickel based Cm-247 super alloy by Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). The present procedure employs the dissolution of alloy in a mixture of Sulphuric acid, Nitric acid and HF and subsequent analysis by sequential ICP-AES (Model JY Ultima 2C HR, France).This procedure is being developed as a nodal procedure for indigenously development of alloy for secondary standards purpose. A Relative Standard Deviation of less than ± 5% has been achieved for all the elements.

Keywords: Estimation; Gold, Mercury, Indium and Palladium; CM-247 supercast alloy; ICP-AES

DETERMINATION OF ARSENIC BY ICP-OES WITH CONCOMITANT METALS ANALYSER (CMA) – AN ASSESSMENT.

Alok Pandey, G. S. Chowdary and Adarsh Kumar

Chemistry Laboratory,
Atomic Minerals Directorate for Exploration and Research,
Department of Atomic Energy
Northern Region, New Delhi-110 066

Abstract

Arsenic was determined by ICP-OES model JY2000(2) in combination with Concomitant Metal Analyser (CMA) in order to assess its performance and its actual utility. Water samples as well as rock samples were analysed. CMA gives improvement in the signal (10-15 times), but it depends on the oxidation state of arsenic . The efficiency of hydride generation is not the same for Arsenic (III) and Arsenic (V) both in acidic and in alkaline conditions. In acidic conditions the difference is less. So presenting As in single form in samples similar to that of the solution used for calibration is important for accurate analysis. In the continuous generation of hydrides only a small portion of sample enters the spray chamber. No pre-concentration of analyte from whole of the sample is possible as in discrete hydride generators used with atomic absorption spectrometers. For rock samples hydrochloric acid concentration of hydride generator has to be increased to prevent precipitation of hydroxides of concomitant elements in spray chamber.

Keywords: Arsenic; Hydride generation; Sodium borohydride; Pre-concentration; water and rock samples

DETERMINATION OF NEPTUNIUM IN DISSOLVER SOLUTION OF
SPENT PHWR FUEL BY INDUCTIVELY COUPLED
PLASMA ATOMIC EMISSION SPECTROMETRY

D.K.Pant¹, G.A.Chaugule¹, K.K.Gupta¹, P.G.Kulkarni¹, P.B.Gurba¹, P.Janardan¹, R.D.Changrani¹, P.K.Dey¹, D.R. Prabhu², P.N. Pathak² and V.K.Manchanda²

¹PREFRE Plant, Nuclear Recycle Group, Bhabha Atomic Research Centre,Tarapur-401502
²Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai-400085

Abstract

A method has been standardized for the determination of Np in the dissolver solution of the spent PHWR fuel. The method involves the quantitative separation of Np from the dissolver solution by solvent extraction with 0.5 M thenoyltrifluoroacetone - xylene (TTA) and its determination by ICP-AES after stripping Np from the organic phase into the aqueous medium with 8M HNO₃. The reliability of the method is checked by standard addition technique. The method is precise and accurate yielding Np analytical recovery of 99.8 ±1%. The Np concentration of dissolver solution of the spent PHWR fuel is found to be in the range of 8- 10 mg/L.

Keywords: Determination; Neptunium; ICP-AES; Spent PHWR fuel

DETERMINATION OF YTTRIUM, RARE EARTH ELEMENTS, ZIRCONIUM AND THORIUM IN COMPLEX GEOLOGICAL SAMPLES BY ICP-OES

Beena Sunilkumar, G. S. Chowdary and Adarsh Kumar

Chemistry Laboratory, Atomic Minerals Directorate for Exploration and Research,
Department of Atomic Energy
Northern Region, New Delhi-110 066

Abstract

Three methods of sample solution preparation for the determination of yttrium, rare earth elements and thorium in complex geological samples by ICP-OES using JY2000(2), were compared and assessed for their environmental friendliness , ease of handling time required for the analysis.

Keywords: Yttrium; Rare earth elements; Charcoal; Sodium peroxide

DEVELOPMENT, DESIGN AND FABRICATION OF HIGH SENSITIVITY BOREHOLE LOGGING PROBE FOR LOGGING
AT BELOW 10PPM eU₃O₈ LEVEL

N.K.Johri, B.R.Singh, S.S.Raghuwanshi, B.K.Bhaumik, C.L.Bhairam

Atomic Minerals Directorate for Exploration and Research
Department of Atomic Energy, Northern Region, New Delhi

Abstract

Gamma ray logging of boreholes is a method of measuring naturally occuring gamma radiation to characterize the rock or sediment in a borehole. It is most commonly used for finding the grade and depthwise extension of uranium anomaly located on the surface . Gamma-ray measurements detect variations in the natural radioactivity originating from changes in concentrations of the trace elements uranium (U) and thorium (Th) as well as changes in concentration of the major rock forming element potassium (K). Since the concentrations of these naturally occurring radioelements vary between different rock types, natural gamma-ray logging provides an important tool for lithologic mapping and stratigraphic correlation, for detecting alteration zones. For example, in sedimentary rocks, sandstones can be easily distinguished from shales due to the low potassium content of the sandstones compared to the shales.

In AMD, point-by-point logging method is used to determine eU₃O₈ concentration up to 20 ppm level using scintillation dtecetor ( NaI(Tl) : 1/2” X 2” size). However as the surface manifestations of uraniums deposits are becoming sparse, a need is being felt that eU₃O₈ data below 20 ppm is required for picking up alteration zones which will help in conceptual geological modelling, enabling discovery of concealed uranium deposits.

The authors have developed, designed and fabricated a new high sensitivity logging probe which provides ppm eU₃O₈ data at 3ppm level with a precision of 10%. The probe houses two NaI(Tl) detectors (1/2” X 2”) connected head-to-head, increasing both the detector and sample volume and thereby enhancing sensitivity and accuracy. The highlight of the probe is its sensitivity of 8 cps / ppm eU₃O₈.The probe also provides better average grade of in-situ sample. The use of two detectors provides the flexibility of variable sample volume which can be further increased by increasing the detector separation. An additional feature is a passive mixer electronic circuit used in connecting two detectors to minimise the counting losses. This probe is well integrated with existing logging equipment.

This paper describes the characteristics of high sensitivity logging probe and the favourable results obtained with its use in some boreholes of Pisnari prospect.

Keywords: Gamma ray logging; Boreholes; eU₃O₈ ; Rock samples

DEVELOPMENT OF AN INDIGENOUS ECHELLE SPECTROMETER WITH PIXEL PROFILING FOR SIMULTANEOUS SPECTRO-CHEMICAL ANALYSIS

D. V. Udupa, B. J. Shetty, N. Omana, P. B. Patil, Sanjiva Kumar and Ajaya Kumar

Spectroscopy Division, Bhabha Atomic Research Centre, Mumbai 400 085

Abstract

An indigenously developed echelle grating spectrometer has been used for simultaneous analysis of eight impurities in aluminium using an ICP source of excitation. An improvement in the signal / background ratio is observed when the analysis is carried out by profiling of the lines, so as to get the pixel with the peak intensity on the CCD every time before starting the analysis as compared to analysis without profiling. The instrument uses a 2-D CCD detector for recording the spectrum in the range of 2100 – 4000 Å with wavelength resolution of 0.2 Å at 3000 Å.

Keywords: Determination; Impurities; Aluminium samples; Echelle grating; CCD detector

ANALYTICAL INSTRUMENTATION FOR IN-SITU RADIOACTIVITY MEASUREMENTS IN MINERAL EXPLORATION

S.Kannan* , C.V.R.Sarma

Atomic Minerals Directorate for Exploration and Research
Department of Atomic Energy, India

Abstract

Radioactivity measurement in boreholes, core and powder samples is essential for exploration of radioactive minerals. With the recent advancements in technology, the design of instrumentation for these measurements resulted in miniaturization, low power consumptions and additional user friendly features.

A Portable micro controller based Digital count rate meter was designed and developed for gamma ray bore-hole logging employing Geiger Muller /Scintillation detectors. The features of in-situ calibration and evaluation of data resulted in quick and rapid logging of boreholes and processing of data.

Instrumentation required for Radioactivity measurement of the borehole core and powder samples were also designed, developed with similar state of art technology employing microcontrollers for in-situ estimation of results. The battery operated and portable Micro controller based Core and radiometric analysis systems with storage memory acquires and stores the data and display the evaluated results on panel mounted alphanumeric Liquid Crystal display(LCD). Further the data may be retrieved and downloaded to a computer for further analysis. In-situ printing of data without the additional requirement of personal Computer would assist the geoscientist in quick evaluation of results for further interpretation.

The above Instrumentation was successfully deployed at several field areas in the country for radioactive mineral exploration program of Atomic Minerals Directorate.

The present paper describes the design and fabrication details, software modules developed for the above Instrumentation.

Keywords: Digital count meter; Core analysis system; Scintillation; Core; Logging
*corresponding author

WAVELENGTH DISPERSIVE X-RAY FLUORESCENCE VIS-À-VIS INDUCTIVELY COUPLED PLASMA- OPTICAL EMISSION SPECTROMETRY OF MAJOR AND TRACE ELEMENTS IN SILICATE ROCKS

Chanchal Sarbajna, Smeer Durani, V.Rajagopalan and D.S.R.Murthy

Atomic Minerals Directorate for Exploration & Research
Department of Atomic Energy
1-10-153, Begumpet, Hyderabad-500629, A.P.

Abstract

A simple, precise, accurate and rapid technique is described for the analysis of major (Na, Mg, Al, Si, K, Ca and Fe, P, Ti and Mn) and selected trace elements (V, Cr, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Nb, Ba, Pb, Ce, U and Th) by WDXRFS and ICP-OES techniques in geo-materials, especially silicate rocks. The state of art MagiX-PRO Wavelength Dispersive X-ray Fluorescence Spectrometer and ULTIMA-2 Inductively Coupled Plasma- Optical Emission Spectrometer have been used in the present study as an indispensable geo-analytical tool for the analysis of major and selected trace elements at ppm to percentage level, with high precision and relatively better accuracy. However, the more thrust is being laid in developing an analytical methodology that gives a user friendly procedure with the availability of integrated software and matrix interference algorithms. The standard reference material (G-2) was analyzed following the method developed by both the techniques and the results obtained are in good agreement with the recommended values. The relative accuracy and precision of both the proposed methods are excellent for most of the elements.

Keywords: Wavelength dispersive X-ray fluorescence; ICP-OES; Major and trace elements; Silicate rocks

WAVELENGTH-DISPERSIVE X-RAY FLUORESCENCE SPECTROMETRIC DETERMINATION OF SOME RARE-EARTH ELEMENTS IN COLUMBITE-TANTALITE USING THEIR K-SPECTRA AND AN LiF 420 ANALYSING CRYSTAL

B.N. Tikoo*, Anjan Chaki+, Yamuna Singh, and S. Viswanathan
Atomic Minerals Directorate for Exploration and Research, Department of AtomicEnergy,
Government of India, 1-10-153-156, Begumpet, Hyderabad-500 016, India
amdhyd@ap.nic.in

Abstract

The paper proposes a simple, accurate, precise, rapid, and non-destructive unconventional wavelength-dispersive x-ray fluorescence spectrometric technique for determining Ce, Nd, Sm, and Gd in rare-earth element (REE) concentrates chemically extracted from columbite-tantalite. The method uses the K x-ray spectra of Ce, Nd, Sm, and Gd and an LiF 420 analysing crystal to overcome the problems inherent in the conventional method which uses their complex L x-ray spectra with troublesome spectral-line coincidences and overlaps.

In the present method the achievable coefficient of variations (n = 4) in an admixture containing the elements at the specified levels respectively. The coefficient of variation obtained in the case of Ce, Nd, Sm and Gd respectively is 6.7, 7.6, 3.2, and 3% in analysing four synthetic samples containing Ce, Nd, Sm and Gd respectively 955, 488, 3929 and 1002 µg/g. The precision is excellent (within 3% for Gd and within 3.2% for Sm) and very good (within 6.7% for Ce and within 7.6% for Nd).

For a single analysis total time taken for determining Ce, Nd, Sm, and Gd in a batch of twentyfour samples, in quadruplicate using a manual spectrometer is twenty hours.

Keywords: X-ray fluorescence spectrometry; WDXRFS; Rare-earth elements; Columbite-tantalite.
*Deceased. +corresponding author

AN X-RAY DIFFRACTION STUDY OF URANINITE FROM
THE KARIMNAGAR GRANULITE BELT, ANDHRA PRADESH, INDIA,
WITH ANOMALOUS UNIT-CELL DIMENSION

R. Viswanathan, Yamuna Singh, M. Sai Baba, Anjan Som, K.
Shiv Kumar, and K. Umamaheswar

Atomic Minerals Directorate for Exploration and Research,
Department of Atomic Energy, Begumpet, Hyderabad-500 016

Abstract

The paper presents the results of an x-ray diffraction (XRD) study of uraninite from the Karimnagar granulite belt (KGB) of Andhra Pradesh, with its compositional characteristics. It is observed that the unit-cell parameter (a₀ = 5.4729Å) of uraninite in the granulite is higher than the value (a₀ = 5.4682Å) given in ICDD Card No. 5-550 for uraninite standard. This unit-cell size of the investigated uraninite in the granulite is even higher than the ideal unit-cell size of 5.4700Å given for uraninite. Therefore, the unit-cell size of the investigated uraninite belongs to the category of anomalous unit-cell size. The anomalous unit-cell dimension (a₀ = 5.4729Å) of the investigated uraninite from the granulite of the KGB, as against the reference value of 5.4682Å, is interpreted to be due to extensive substitution of U by Th. This interpretation is supported by the fact that the uraninites from the granulite of the KGB contain high amounts of thorium (5.99-7.12% ThO₂; av. 6.62% ThO₂). Furthermore, extensive substitution of U by Th has also resulted in low contents of U (53.16-59.62% UO₂, av. 56.23% UO₂) in uraninite. In contrast, the unit-cell parameter (a₀ = 5.4658Å) of uraninite from the gneiss, with its oxygen content in the formula-unit (FU), i.e., UO_2.04, is nearly the same as given in ICDD Card No. 5-550 for uraninite standard (a₀ = 5.4682Å; FU = UO_2.03). The normal unit-cell dimension of uraninite from the gneiss is due to its low thorium (0.10% ThO₂) and REE (0.94%) contents.

Keywords: X-ray diffraction; Uraninite; Unit-cell dimension; Karimnagar Granulite belt; Andhra Pradesh

SPECTROPHOTOMETRIC DETERMINATION OF NITROGEN IN NIOBIUM METAL

A.Narsing Rao, K. Madhava Krishna, Vijaya Ram Mohan and R.B. Yadav

Control Laboratory, Nuclear Fuel Complex,
ECIL Post, Hyderabad 500 062
rby@nfc.gov.in

Abstract

This paper describes the analytical procedure for the spectrophotometric determination of trace quantities of nitrogen in niobium metal that finds extensive application as strategic material in nuclear and space industries.

The method entails boiling a known quantity of sample with concentrated sulphuric acid in the presence of potassium sulphate and copper sulphate. After the mineralisation, the acidic solution is carefully diluted with water and made alkaline with excess of sodium hydroxide during which ammonia is generated. This is steam distilled and collected as the condensate. When Nessler’s reagent is added to the distillate, a brownish yellow complex is formed that has the maximum absorbance at 400 nm thus facilitating its quantification by photometric measurement. The results obtained have been compared with that obtained by nitrogen analyzer (inert gas fusion coupled with thermal conductivity measurement) and the values are found to be in good agreement.

Replicate analysis performed on the sample gave a RSD of ± 10% at 100 ppm level.

Keywords: Determination; Nitrogen; Spectrophotometry; Nessler’s reagent; Niobium metal samples

STANDARDIZATION OF A PARTICLE INDUCED GAMMA RAY EMISSION (PIGE) METHOD FOR FLUORINE DETERMINATION AT FOTIA, BARC AND ITS APPLICATION TO BOROSILICATE GLASS SAMPLES

R. Acharya¹*, R. Tripathi¹, K. Sudarshan¹, A.V.R. Reddy¹, R. G. Thomas², S. Santra², S.K. Gupta², R.K. Choudhury², R.K. Mishra³, V.G. Katarni³, C.P. Kaushik³

¹Radiochemistry Division, ²Nuclear Physics Division, ³Waste Management Division
Bhabha Atomic Research Centre, Trombay, Mumbai 400 085
racharya@barc.gov.in

Abstract

A particle induced gamma ray emission (PIGE) method has been standardized to determine fluorine non-destructively in percentage to trace concentrations using proton beam of 4 MeV at FOTIA, BARC. Samples of NaF mixed with cellulose were palletized and used to obtain calibration plot for F. The method was validated by determining F in synthetic samples and then applied to determine F in barium borosilicate glass samples, which was otherwise difficult by other analytical techniques. Irradiation times were kept in the range of 30 min – 5 h depending on F concentrations. The current was monitored using a thin gold foil. The prompt gamma rays of 110 and 197 keV from 19F(p, p^'gamma)19F reaction, measured by a high resolution gamma ray spectrometer, were used for calculation of F concentrations. The measured F concentrations in four borosilicate glass samples were in the range of 0.6-4 wt%. Detection limit for fluorine in the present experiments was 60 mg kg-1 using 197 keV gamma-ray.

Keywords: PIGE; Determination; Fluorine; Borosilicate glass

DETERMINATION OF TRACE AMOUNTS OF BORON
IN GRAPHITE USING ICP-AES

G.A.Tambe, K. Venkatesh and P.V. Ravindran

Analytical Chemistry Division,
Bhabha Atomic Research Centre, Trombay, Mumbai-85

Abstract

Determination of trace amounts of boron was carried out in graphite powder samples using ICP-AES. The possible loss of boron during the sample dissolution stage was overcome by fixing boron as barium borate. Analytical parameters were optimized for quantitative recovery of boron from the sample matrix. Over triplicate analyses, the co-efficient of variation was found to be ±6%. This method was adopted for the routine analysis of graphite samples for the boron content.

Keywords: ICP-AES; Determination; Boron; Graphite samples

DETERMINATION OF ¹⁰B-ENRICHMENT IN THE CaF₂-BF₃ COMPLEX PREPARED BY HEAVY WATER BOARD, DAE

A.M. Shaikh, S.S. Desai and M. Padalakshmi

Solid State Physics Division,
Bhabha Atomic Research Centre, Mumbai 400 085, India
shaikham@barc.gov.in

Abstract

The paper gives detailed account of generation of BF₃ gas by thermal decomposition of CaF₂-BF₃ complex prepared by Heavy Water Board(HWB) and its purification. The BF₃ gas obtained is used for making neutron detectors and various tests are carried out to check its performance. The 10B-enrichment in the complex is determined by comparing the performance of this neutron detector with that made using gas from imported complex with 10B-enrichment of 93 ± 1 %. The 10B-enrichment in HWB complex is estimated to 89 ± 2 %.

Keywords: Determination ;10B enrichment; CaF₂-BF₃ complex; Neutron detector

APPLICATION OF GAS CHROMATOGRAPHY IN GEOCHEMICAL PROSPECTING OF HYDROCARBONS

T. Madhavi, G. Kalpana, M. Lakshmi and A.M. Dayal
National Geophysical Research Institute
(Council of Scientific and Industrial research)
Uppal Road, Hyderabad-500606
madhavit19@gmail.com

Abstract

Gas Chromatography is employed for adsorbed soil gas analyses of light gaseous hydrocarbons which serve as direct indicators in surface geochemical prospecting of hydrocarbons. Light gaseous hydrocarbons from the subsurface oil and natural gas reservoirs seep to the surface soils through the process of diffusion, effusion & buoyancy and get adsorbed to the soil particles. These hydrocarbons are desorbed from the soil particles by acid extraction and measured by Gas Chromatograph-Flame Ionization Detector (GC-FID). The concentrations of the hydrocarbons are subjected to statistical evaluation which gives information on anomalous hydrocarbon zones, origin of the gases and oil & gas association of the area. This paper presents the results of adsorbed soil gas survey conducted in part of Cuddapah Basin.

Keywords: Gas Chromatography; Geochemical prospecting; Hydrocarbons

APPLICATION OF GC-C-IRMS IN GEOCHEMICAL EXPLORATION OF HYDROCARBONS

Anu Radha .B*., Srinu. D., Patil. D. J. and Dayal.A.M.

National Geophysical Research Institute
(Council of Scientific & Industrial Research),
Hyderabad-500 606.
*annnudin@gmail.com

Abstract

Geochemical exploration for hydrocarbons is a search for chemically identifiable surface or near-surface occurrences of hydrocarbons, which serve as clues to the location of undiscovered oil and gas accumulations. Surface geochemical methods assume that hydrocarbons generated and trapped at depth leak in varying and detectable quantities to the surface. Geochemical exploration techniques can be direct or indirect. In indirect techniques seepage-induced changes in soil, sediment or vegetation are studied. In direct techniques small quantities of hydrocarbons that occur in pore space of soil, is desorbed and injected in to a Gas Chromatograph – Combustion interface coupled with IRMS. This facilitates the analysis of even the minute amount of sample, typically of the order of 1nmole.

Keywords: Geochemical Exploration; Hydrocarbons; GC-C-IRMS

*Corresponding author

ELEMENTAL ORGANIC ANALYSIS

Unnikrishnan E.K.

Analytical Chemistry Division, Bhabha Atomic Research Centre,
Mumbai 400085, India.

Abstract

An effort is made to adopt methods to determine elements like C, H, N, S and O in organics and organometallic samples. Simultaneous analysis of C, H, N and S in solid as well as liquid samples by using milligram size samples has been carried out using established technique. Samples are subjected to high temperature in presence of oxygen and the gases formed after oxidation and reduction processes are separated and determined. Introducing vertical sample loading and coupling of combustion gas chromatography could make determinations faster compared to classical methods. Introduction of micro TCD made the determinations more sensitive. On the other hand Oxygen in samples were determined in a separate run by pyrolysis. Over the last two-years, about 200 samples have been analyzed. Statistical analysis of data showed that the method is reliable. Considering 3sigma of blank, 21µg is detectable. However, due to weighing difficulties, 100µg is taken as the detection limit.

Keywords: Determination; C, H, N, S and O elements; Organic and Organometallic samples; Thermal conductivity

LIQUID-LIQUID EXTRACTION AND SPECTROPHOTOMETRIC DETERMINATION OF SCANDIUM(III) WITH HEXAACETATO
CALIX(6)ARENE

C. M. Swamidoss¹, S. M. Khopkar², D. D. Malkhede³

¹Department of Chemistry, Sant Gadge Baba Amravati University, India,
²Indian Institute of Technology, Mumbai, India,
³Department of Chemistry, University of Pune, India.

Abstract

A method is proposed for the extraction of Scandium(III) using Hexaacetato Calix(6)arene. The optimum extraction conditions are evaluated from a critical study of the effect of pH, concentration of extractant, shaking time, concentration of various mineral acids used as stripping agents, different types of polar and non polar diluents and effect of diverse ions. Solvent extraction of Scandium(III) was carried out using Hexaacetato Calix(6)arene in Toluene. Scandium(III) is quantitatively extracted with 1 x 10^-4 M of the ligand in Toluene at pH 5 when equilibrated for 12 minutes. Scandium in the organic phase was stripped with 1 M Nitric acid and determined spectrophotometrically by the Arsenazo(III) method at 675 nm. The metal loading capacity of the reagents is also studied. The extraction of Sc(III) was carried out in the presence of various ions to ascertain the tolerance limit of individual ions. The method can be extended for the determination of Scandium in real samples.

Keywords: Solvent Extraction; Scandium(III); Hexaacetato Calix(6)Arene.

DETERMINATION OF TITANIUM IN SPECIAL STEELS BY FLAME ATOMIC ABSORPTION SPECTROMETRY

S. Raju, Y. Balaji Rao* and R.B. Yadav
Control Laboratory, Nuclear Fuel Complex,

Dept. of Atomic Energy, Govt. of India, ECIL Post, Hyderabad 500062
ybr@nfc.gov.in

Abstract

The present paper describes a FlameAtomic Absorption Spectrometric method for the determination of Ti in various grades of special stainless steels like SS-321, D-9, Oxide Dispersed strengthened steel (ODS), SS-316 Ti, etc. The samples are dissolved in aquaregia and Hydrofluoric acid. Ti Free SS-304 grade samples solution is prepared for stock solution, from which matching standards are prepared. The samples are analysed by AAS (Model GBC-902). The absorbance is measured at 365.4 nm using reducing Nitrous Oxide-Acetylene flame. The proposed method is compared with the earlier method (H₂O₂) and found to be in excellent agreement. A relative standard deviation of ± 5% has been achieved.

Keywords: Determination; Titanium; Steel samples; FAAS

CHARACTERIZATION OF SELENIUM (IV) AND SELENIUM (VI) IN WATER SAMPLES USING DIAMINOBENZIDINE AND ESTIMATION BY GRAPHITE FURNACE ATOMIC ABSORPTION SPECTROSCOPY

Suvarna Sounderajan, G. Kiran Kumar, A.C.Udas*

Analytical Chemistry Division,
Bhabha Atomic Research Center,
Mumbai - 400 085.

Abstract

Selenium (IV) is known to form stable yellow-colored piazselenol complex by reaction of Se (IV) with 3, 3’-diaminobenzidine hydrochloride (DAB), which is then quantitatively extracted in organic solvent. . In the present work stable yellow-colored piazselenol extracted in toluene is used for quantification of Se (IV). Microwave digestion protocol is optimized for converting selenium (VI) to selenium (IV) by digesting samples with 4 M HCl. Total Se is then estimated. Concentration of Se (VI) in the sample solutions could be calculated by the difference in total selenium and selenium (IV). The characterization of selenium was carried out by GFAAS using Pd as modifier. The EPA permissible level of Se (total) in water is 50 µg/L ^-1 as a consequence the concentration of individual species is much lower. Optimization of the experimental conditions and instrumental parameters was investigated in detail. Recoveries of (90-110%) were obtained in the spiked samples. The detection limit was 1µg L^-1, and an enrichment factor of 20 was obtained. The proposed method was successfully applied for the determination of trace amounts of selenium (IV) and selenium (VI) in process water samples.

Keywords: Speciation; Selenium; Graphite Furnace Atomic Absorption Spectroscopy; 3, 3’- Diamino Benzidine; Pd Modifier.

*Corresponding author: +91-22-25505151, +91-22-25519613

AN IMPROVED METHOD FOR ULTRA-TRACE DETERMINATION OF GOLD IN GEOLOGICAL SAMPLES BY GRAPHITE FURNACE-ATOMIC ABSORPTION SPECTROPHOTOMETRY

S.K.Pradhan and P.K.Tarafder*

Regional Centre for Exploration and Research
Department of Atomic Energy
AMD Complex, Khasmahal
P.O. Tatanagar, Jamshedpur-831002, India

Abstract

A simple, precise, rapid and improved method is developed for the ultra trace determination of gold in geological samples by Graphite Furnace Atomic Absorption Spectrophotometry (GF-AAS). After aqua regia treatment and hydrochloric acid digestion of the sample, gold passes into solution along with other impurities. The metal is extracted into MIBK (Methyl Iso-Butyl Ketone) and then stripped back into aqueous phase with HBr. Gold is then determined by GF-AAS coupled with an auto sampler. The RSD of this method is ± 10% at 10 ppb concentration level. This method has been applied to various geological samples for gold determinations.

Keywords: Determination; Gold; MIBK; GF-AAS; Geological samples

*corresponding author P.K.Tarafdar

SENSING OF SO₂ GAS IN BINARY MIXTURE WITH N₂ GAS USING ULTRASONIC GAS SENSOR AND ITS COMPARISON WITH OTHER STANDARD METHODS

*J.C. Vyas ¹, A.M. Banerjee ², A.K. Tripathi ², K.A. Jadhav ³, V. Nataraju ³,
and S.K. Gupta ¹

¹Technical Physics & Prototype Engineering Division, ²Chemistry Division,
³Vacuum Physics and Instrumentation Division,
Bhabha Atomic Research Centre, Mumbai 400 085, India
vyas@barc.gov.in

Abstract

Quantitative determination of a given gas in mixed form with a background gas has important applications for control and monitoring of chemical processes. SO₂ gas is a highly reactive gas used in several laboratory / industrial processes and in particular it is used at an intermediate step in some chemical methods for conversion of thermal energy into chemical energy in the form of hydrogen. We measured composition of this gas in binary mixtures with nitrogen as background, using ultrasonic gas sensor (UGS). This sensor works non-invasively, and the gas concentration is determined by measurement of time of flight (TOF) of ultra-sound. For calibration and testing of UGS, binary gas mixtures were prepared by using rotameters, and gas compositions were determined by UGS, and for comparison purpose by gas chromatography and an indigenously fabricated mass spectrometer. The SO₂ gas mixtures in nitrogen were prepared in 0 – 10% (by volume) range, and it was found that the TOF has approximately linear dependence with SO₂ gas concentration within the explored range. The SO₂ gas concentrations measured by UGS agreed well with results obtained by gas chromatography. However, the gas concentrations obtained by mass spectrometry differed by a numerical multiplication factor. A tentative explanation for this discrepancy has been provided.
Keywords: Ultrasonic gas sensor; SO₂ gas; Determination; Time of flight(TOF) of ultra-sound

*Corresponding author

A REFRACTIVE INDEX BASED METHOD FOR ESTIMATION OF D₂O CONCENTRATION IN D₂O-H₂O MIXTURES

Shekhar Kumar*, Pranay Kumar Sinha, Rajnish Kumar, D. Sivakumar, M. Balamurugan, M. Samapth and S.B. Koganti

Reprocessing R&D Division,
Indira Gandhi Centre for Atomic Research, Kalpakkam 603102.
*shekhar@igcar.gov.in

Abstract

Refractive index of pure D₂O and aqueous solutions of D₂O was determined experimentally. These experimental values were correlated and an excellent agreement between predicted and experimental values was observed. Based on these results, one simple method (based on refractive index) is proposed for estimating the D₂O content in the D₂O-H₂O mixtures at 298.15 K.

Keywords: Estimation; D₂O concentration; D₂O-H₂O mixtures; refractive index; refractometer.

*Corresponding Author

SEQUENTIAL DETERMINATION OF FREE MAGNESIUM AND FREE ZIRCONIUM IN REDUCTION RESIDUE BY GAS VOLUMETRIC METHOD

M. Koteshwar Rao, Vinay Buche, T. Amar Prakash,
Vijaya Ram Mohan and R.B.Yadav

Control Laboratory, Nuclear Fuel Complex,
ECIL Post, Hyderabad 500062
rby@nfc.gov.in

Abstract

This paper describes a simple and effective method for the sequential determination of free magnesium (Mg) and free zirconium (Zr) in the reduction residue generated in the Zirconium Sponge Plant during the production of reactor grade zirconium sponge by the Kroll’s process. As the residue cannot be recycled and being pyrophoric, the amount of free Mg and free Zr in the sample is very vital for its safe disposal. The proposed method involves the measurement of volume of hydrogen gas generated by dissolution of known quantity of sample in HCl and HF added in succession.

A relative standard deviation of ± 5% is obtained at less than 0.5% concentration of the analytes.

Keywords: Determination; Magnesium; Zirconium; Gas Volumetric method

HIGHLY SENSITIVE, SIMPLE AND COST-EFFECTIVE
ANALYTICAL INSTRUMENTAL METHOD FOR THE DETERMINATION OF SELENIUM IN ENVIRONMENTAL SAMPLES

B.P. Dayananda and T.N. Kiran Kumar

Department of Chemistry (PG), Maharani’s Science College for Women,
JLB Road, Mysore 570 005, Karnataka State

Abstract

Highly sensitive and simple spectrophotmetric determination of selenium is described for the determination of selenium(IV) using a new reagent Safranine-O. The method is based on the reaction of selenium with potassium iodide in an acid medium to liberate iodine. The liberated iodine bleaches the color of safranine-O and cause decrease in absorbance at 532 nm. This decrease in absorbance is directly proportional to selenium concentration obeying Beer’s law in the range 0.5 – 5.0 µg of Se in a final volume of 10 mL. The molar absorption coefficient and Sandell’s sensitivity of the method were found to be 8.21 ' 104 L mol^-1 cm^-1 and 0.001 µg cm^-2, respectively. The proposed analytical procedure has been successfully applied to the determination of selenium in real samples of water, soil, and plant material. The results were compared to those obtained with the reference method. Statistical analysis of the results confirms the precision and accuracy of the proposed method. In addition, the developed method is cost-effective and involves easily accessible instrumentation technique which can be used by ordinary research laboratories.

Keywords: Selenium; Environmental samples; Determination; Spectrophotometry

NEW IMPROVED SYSTEM FOR IN-SITU PRE-CONCENTRATION OF ¹³⁷Cs IN COASTAL MARINE ENVIRONMENT

M. B. Pote^#; P. Lenka, S. Sartandel, S. Gothankar, S. Bara,
S. K. Jha*, V. D. Puranik

Environmental Assessment Division
Bhabha Atomic Research Centre, Mumbai
^#mbpote@barc.gov.in; *skjha@barc.gov.in

Abstract

A new improved system was designed, fabricated and used in evaluating the ¹³⁷Cs fallout activity around the coastal environment of Gujarat. This system allows rapid in-situ pre-concentration from large volume of sea water samples and is based on copper ferrocyanide [Cu₂Fe(CN)₆] coated ion-exchanger resin. The 90-95% recovery was observed, using dual cartridge exchanger, by passing 1000 liters of seawater at the flow rate of 15 liters/min. Considering the constrain experienced in the field experiment, the system was modified to incorporate new features in order to precisely measure ¹³⁷Cs fallout activity in coastal marine environment. Environmental Assessment Division at present engaged in establishing the baseline data on fallout ¹³⁷Cs in coastal marine environment of India. Recently the system was used to measure the activity at three different locations in coastal region of Gujarat and the data presented here.

Keywords: Preconcentration; ¹³⁷Cs; Marine environment; Copper ferrocyanide; Ion exchanger

SIGNIFICANCE OF ANALYTICAL CHEMISTRY AND PRODUCT CHARACTERIZATION TECHNIQUES IN NUCLEAR WASTE MANAGEMENT

S.Rajasekaran¹, A.S.Pente², M.Ramchandran², C.P.Kaushik²* and Kanwar Raj²

¹Waste Immobilization Plant, Nuclear Recycle Group Projects, Kalpakkam
²Waste Immobilization Plant, Waste Management Division, Nuclear Recycle Group
Bhabha Atomic Research Centre, Mumbai
cpk@barc.gov.in

Abstract

Analytical chemistry plays a vital role in day-to-day activities at radioactive waste management plants by way of meeting the requirements pertinent to process realization, troubleshooting and relevant research & development. Successful implementation of scientific activities depends upon the support of a variety of chemistry disciplines like radiochemistry, radiation chemistry, analytical chemistry, materials chemistry, separation chemistry, geochemistry, etc. Present paper highlights the importance of analytical chemistry and product characterization techniques deployed in waste management plants. An attempt has been made to summarize the contribution of compositional characterization of raw materials, nuclear waste, process streams and plant products as well as in process control and troubleshooting areas.

Keywords: Waste management; Characterization of materials; Nuclear waste

*Corresponding Author

Pb-Pb STEPWISE LEACHING TECHNIQUE: A RELIABLE
GEOCHRONOMETER FOR VARIOUS ROCKS AND MINERALS.

Veena Krishna, B.K.Pandey, D.V.L.N. Sastry

Geochronology Laboratory, Atomic Minerals Directorate for Exploration and Research,
Department of Atomic Energy, Govt. of India, Begumpet, Hyderabad-500629.

Abstract

The Lead Stepwise Leaching (PbSL) procedure has been applied successfully to date a variety of rock forming minerals. Stepwise leaching aids in the selective extraction of radiogenic and common lead in successive stages, which make it possible to obtain age information from a single phase of the sample. This paper gives a brief account of its application to different minerals and rock types. It also discusses the application of this procedure to the dating of banded hematite quartzites from the Morar formation, Gwalior

Keywords: Geochronometer; Leaching; Radiogenic; Lead

AN OVERVIEW OF THE THERMAL IONIZATION MASS SPECTROMETRY (TIMS) PRESENT STATUS AND FUTURE PROSPECTS.

B.K.Pandey, Veena Krishna, U.K.Pandey, D.V.L.N. Sastry and Girija Srinivasan

Geochronology Laboratory, AMD/DAE, Hyderabad-500016

Abstract

The TIMS instrument is used for geochronological studies which require a very precise determination of isotopic composition of elements like Sr, Nd and Pb. During seventies work was carried out using indigenously developed instruments and a number of age determinations by Rb-Sr and U-Pb methods were carried out. Later a modern TIMS, VG354, was imported and installed in March 1984. This instrument was capable of accurate isotopic analyses with precision better than 0.003% for Sr and Nd. During the past 25 years the VG354 TIMS has been used extensively for a number of age determination studies. Some typical applications are described briefly. The first ever Sm-Nd age determination in an Indian laboratory was made on the soda granites of Singhbhum which yielded depleted mantle model age of around 2.5 Ga. Looking at the future needs for more precise isotopic measurements of presently established procedures and also to introduce new techniques of dating such as Re-Os and U-series disequilibrium dating, a TIMS instrument with advanced features is under fabrication at the Vacuum and Prototype Instrumentation Division, BARC, Mumbai.

Keywords: Thermal ionization mass spectrometry (TIMS); Geochronological; isotopic; Singhbhum

VOLTAMMETRIC ANALYSIS OF SCORODITE MINERAL

P.K.Tamrakar and A.K.Sarangi

Uranium Corporation of India Limited
Jaduguda-832 102, Distt. East Singhbhum (Jharkhand)
pk_tamrakar@rediffmail.com

Abstract

Electroanalytical method i.e. Differential pulse polarography (DPP) and Differential pulse anodic stripping Voltammetry (DPASV) were developed for the trace determination of osmium and other metals in scorodite mineral samples. The analysis of trace metals was performed in two different supporting electrolytes viz. 0.1M (NH4)₂ tartrate and 0.1M HCl. The results indicated the presence of Tl+, Sb³⁺, Zn²⁺, Os⁸⁺ and As³⁺ in the sample. The method of standard addition was used for quantitative analysis. The accuracy of the methods was verified by comparing the observed results with those obtained using atomic absorption spectrometric(AAS) technique.

Keywords: Voltammetric analysis; Scorodite mineral; Atomic absorption spectrometry

APPLICATION OF SPECTROSCOPIC TECHNIQUES FOR IDENTIFICATION OF MINERALS FROM THE BEACH ROCKS OF TAMILNADU, INDIA

R.Ravisankar

Department of Physics, SSN College of Engineering,
Kalavakkam- 603110,Tamilnadu, India

Abstract

Beach rock is a peculiar type of formation when compared to other types of rock formations. It needs intensive and extensive investigation on its formation. Beach rock samples were collected from a vast area extending from Rameswaram to Kanyakumari of South East Coast of Tamilnadu and were subjected to spectroscopic studies. The qualitative identification of the minerals in beach rock samples were carried out by using FT-IR and XRD techniques. The infrared study on these beach rocks was found to be highly useful in identifying the various minerals in beach rocks. The minerals present in beach rocks were further confirmed by the X-ray diffraction(XRD) technique. Results are discussed and conclusion is drawn.

Keywords: Beach Rock; Mineral Analysis; FT-IR; XRD techniques

METHOD DEVELOPMENT FOR THE CHEMICAL CHARACTERIZATION OF Ni, Mn, Ga, A MAGNETO-CALORIC EFFECT MATERIAL

S. S. Kalyan Kamal*, J. Vimala, P. K. Sahoo, P. Bhasker Rao and L. Durai

Analytical Chemistry Group, Defence Metallurgical Research Laboratory (DMRL), P.O. Kanchanbagh , Hyderabad – 500 058.
Kalyanchem@dmrl.drdo.in

Abstract

In this report a method development procedure for the analysis of a new magnetocaloric effect material (NiMnGa) using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) is discussed. The process of method validation was carried out using various analytical techniques like conventional wet chemical techniques and instrumental techniques such as Atomic Absorption Spectrometry (AAS), and Electron Probe Micro Analyzer (EPMA). All the techniques show a close agreement in values, thus this method could be applied for regular analysis of NiMnGa alloys.

Keywords: Chemical characterization; ICP-OES; NiMnGa alloys.

*corresponding author

INAA FOR TRANSPORT OF METAL IONS FROM SIMULATED HIGH LEVEL WASTE ACROSS HOLLOW FIBER SUPPORTED LIQUID MEMBRANE

D.R. Raut, R. Acharya, P.K. Mohapatra and V.K. Manchanda*

Radiochemistry Division, Bhabha Atomic Research Centre,
Trombay, Mumbai-400085
*vkm@barc.gov.in

Abstract

Transport behaviour of metal ions (including lanthanides) from Simulated High Level Waste (SHLW) of PHWR (Pressurized Heavy Water Reactor) was investigated using hollow fiber supported liquid membrane (HFSLM) containing 0.1M TODGA + 0.5M DHOA in NPH as the carrier. Elemental concentrations were determined by Instrumental Neutron Activation Analysis (INAA) which involves irradiation of samples using nuclear reactors and radioactive assay using high resolution gamma spectrometry. The % transport for both unirradiated and irradiated TODGA samples was obtained. The % transport of elements viz. La, Ce, Sm, Cr, Ba, Mo and Cs were determined by INAA and compared with that obtained earlier by ICP-AES technique.

Keywords: Simulated high level waste; Hollow fibre supported liquid membrane; INAA

QUANTITATIVE ELECTRON PROBE MICRO ANALYSIS OF URANIUM MINERALS IN PROTEROZOIC QUARTZITES AND BASAL GRANITOIDS OF DAMARCHERLA AREA, PALNADU SUB-BASIN OF CUDDAPAH BASIN, NALGONDA DISTRICT, ANDHRA PRADESH, INDIA

V.Rajagopalan, A.K.Paul, S.V.S.Reddy and H.K.Sabot

Atomic Minerals Directorate for Exploration & Research
Department of Atomic Energy, Government of India
1-10-153, Begumpet, Hyderabad-500629, A.P.India

Abstract

The representative borehole core and grab samples comprising quartzites of the Proterozoic Palnad basin (PPB) and basement granitoids from Damarcherla and adjoining areas of Andhra Pradesh in southern Peninsular India are investigated for knowing the nature of uranium mineralisation. The quartzites over the unconformity and dominantly the basal granitoids, with few variants, form the mineralized horizon in the area. the mineralized host lithounits essentially contain a number of primary and secondary uranium minerals besides other associated phases like monazite, zircon and pyrite. The radioactive phases, mainly different uranium phases, after identification under back scattered electron imaging and supplemented by the optical microscopy, were spectrally scanned and qualitatively investigated for a number of major and minor elements. Selected probe compatible grains were quantitatively analyzed by electron micro probe, using a number of EPMA standards, for U, Th, Pb, Ca, Ti, Mn, Fe, Al, Si, P, Y, La, Ce, Pr, Nd, Sm, Gd, Tb, dy, Ho, Er, Tm, Yb, Lu and Lu and computed as respective oxides. Thus, the radioactive phases, essentially as discrete grains of varying shape and size, were analyzed.

The accrued multi-elemental analytical data has been mineralo-chemically sifted, synthesized and finally characterized as uraninite, pitchblende, coffinite, kasolite, autunite and U-Si (tending towards coffinite), U-Si-Ti, U-Pb-Si complexes. Most of the identified uranium phases, excluding uraninite and kasolite are occurring as veins, cavity/fracture/grain boundary fillings. The secondary phases invariably occur as smear on phenocrysts of the granitoid. The varying mineral chemistry of radioactive phases represent multi-phase and the physical occurrence of discrete U-phases with associated petro-mineralogical and geochemical characters throw light on multi-episodic radioactive mineralization in the host rock domain. Detailed study on spatially distributed radioactive and non-radioactive core samples shall reveal the mineralogical and geochemical guides for uranium exploration in this part of the country.

Key words: Uranium, electron probe micro analysis, Quartzites, Granitoids

LARGE SAMPLE ANALYSIS OF COAL AND URANIUM ORE USING K₀-BASED INTERNAL MONO STANDARD NAA METHOD

R. Acharya¹, K. K. Swain², T. N. Newton¹, R. Tripathi¹, K. Sudarshan¹,
P. K. Pujari¹, A. V. R. Reddy²*

Radiochemistry Division, *Analytical Chemistry Division,
Bhabha Atomic Research Centre, Trombay, Mumbai 400 085
*avreddy@barc.gov.in

Abstract

The k₀-based internal mono standard neutron activation analysis (IM-NAA) method was used to analyze larger size (20-32 g) samples of coal and uranium ore. Samples were irradiated in the thermal column position of the Apsara reactor. In order to arrive at representative sample size, six small size samples (50-1000 mg) of coal were also irradiated using core position of Apsara reactor. Using in-situ relative efficiency elemental concentrations were determined by IM-NAA. The element Na was used as the mono standard and IAEA RM SL-1 was used as the reference standard.

Keywords: Determination; IM-NAA; Coal; Uranium ore

NATURAL RADIOACTIVITY MEASUREMENT IN SEDIMENT SAMPLES IN AND AROUND THARANGAMBADI, TAMILNADU

R.Ravisankar¹, A.Rajalakshmi¹, M.Suresh¹, A. Chandrasekaran¹, A.Senthilkumar² V.Gajendiran³and V.Meenakshisundaram³

¹Department of Physics, SSN College of Engineering,
SSN Nagar, Kalavakkam - 603110, Tamilnadu, India
²Department of physics, Thangavelu Engineering College,
Karapakkam, Chennai Tamilnadu
³Radiological Safety Division, Safety Group,
Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam – 603102,
ravisankarr@ssn.edu.in

Abstract

Thorium (²³²Th), Uranium (²³⁸U) and Potassium (⁴⁰K) concentration in sediment samples of Tharagambadi, Tamilnadu is measured using NaI(Tl) detector based gamma ray spectrometer. The specific activity for ²³²Th, ²³⁸U and ⁴⁰K are in the range 119.92 to 860.64 Bq/kg 23.11 to 205.38 Bq/kg and 186.44 to 644.52 Bq/kg respectively. The measured activity concentrations for these radionuclides were compared to world average activity of soil. The average activity concentration of ²³²Th and ²³⁸U in the present study is 27.12 and 2.01 times higher than world median value while the activity of ⁴⁰K is found to be lower. This increased activity level of U & Th might be due to the coastal processes involving onshore and offshore movements and the long shore currents for the transportation of heavies in these places.

Keywords: Natural Radioactivity; Gamma ray Spectrometer; Sediment samples.

GEO-MICROBIAL PROSPECTING STUDIES OF SURFACE SEDIMENT FROM PETROLIFEROUS REGION OF THE MEHSANA BLOCK,
NORTH CAMBAY BASIN, INDIA

Rasheed, M.A*. Veena Prasanna, M. Kalpana, G. Patil, D.J. and Dayal A.M.

Microbiology Laboratory, Surface Geochemical Prospecting of Hydrocarbons Division,
National Geophysical Research Institute
(Council of Scientific & Industrial Research), Hyderabad- 500 606
*rasheedmicro@rediffmail.com

Abstract

Geo-microbial prospecting studies has been carried out to test its efficacy as surface geochemical methods as regional evaluation tools in petroliferous region of the Mehsana block, North Cambay Basin and to investigate whether the geo-microbial anomalies that can establish an upward migration of hydrocarbons from the deep subsurface source on correlation with adsorbed soil gas method. A set of 135 sub-soil samples collected, were analyzed for indicator hydrocarbon oxidizing bacteria and adsorbed light gaseous hydrocarbons. The microbial prospecting studies showed the presence of high population of propane oxidizing bacteria in soil samples. The microbial prospecting studies carried out in existing Oil and Gas fields of Mehasana, Cambay basin, Gujarat showed high concentrations of propane oxidizing bacteria in the soils. This paper reports the results of microbial prospecting studies, adsorbed light gaseous hydrocarbon analysis of samples collected over petroliferous region of the Mahesana block, north Cambay basin. The aim of the present work is to define the geo-microbial signatures, and to investigate whether the geo-microbial anomalies that can establish an upward migration of hydrocarbons from the deep subsurface source on correlation with adsorbed soil gas method over oil and gas proven areas.

Key words: Geo-microbial; Petroliferous; Mehsana block; Hydrocarbons

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