- Email: [email protected]
Chemical phase-analysis of ores and rocks
Tc&wI~~,Vol. 23, pp. Xl-87
Pergamon Press. 1976. Prmted m Great Britm
TALANTA CHEMICAL
MINI-REVIEW*
PHASE-ANALYSIS
OF ORES AND ROCKS
A REVIEW OF METHODS H. F. STEGER
Mineral Sciences Laboratories, Canada Centre for Mineral and Energy Technology, Department of Energy, Mines and Resources, Ottawa, Canada (Received 25 March 1975. Accepted 27 March
1975)
Summary-The methods employed in the chemical phase-analysis of rocks, ores and their treatment products are reviewed. An attempt has been made to be. critical, selective and thorough in the choice of methods available in the literature, in order to provide a convenient manual for workers interested in this aspect of analytical chemistry.
within the past 25 yr. Most older methods have since been modified (and are included in the modified form) or appear in standard analytical texts such as Low,~ Hillebrand and Lundell,g and Maxwell. lo References to Soviet journals which are not readily available to Western readers are omitted wherever subsequent publication of the method has occurred in a more widely circulated journal. References in this review are made to the English edition of Soviet journals wherever possible. Recourse to the Russian edition was necessary where the English edition either does not exist for the complete series of a journal or was not reasonably accessible to the reviewer. Finally it must be mentioned that information on procedures of chemical phase-analysis may be hidden away in the body of papers and is, therefore, effectively inaccessible because titles and references do not convey its existence. It is suggested, therefore, that future authors should strive to prevent the recurrence of this problem by deliberate mention of chemical phase-analysis either in the abstract or, preferably, in the title of their publication.
Chemical phase-analysis (also called rational or practical analysis) is the determination, by a chemical dissolution technique, of the distribution of an element in an ore or rock on the basis of minerals or oxidation states. The goal of the analysis is the selective dissolution of one or more minerals present in the ore, but because no solvent is completely selective in its action, a quantitative separation is seldom achieved and it is necessary to correct the result to allow for the partial dissolution of other minerals. Because the reactivity of a mineral with a particular solvent varies from specimen to specimen, a truly constant correction is not possible and an error of l-100/, is considered to be acceptable. The importance of chemical phase-analysis to the mining industry, e.g., in process control, and to hydrometallurgists has ensured its being a valuable aspect of analytical chemistry. Chemical phase-analysis has enjoyed an appreciable increase in interest since 1960. Reviews, both comprehensive and partial, have appeared at irregular intervals in the literature of the Soviet Unionlp6 but unfortunately English translations are not available and access to the original is often difficult. The need for a review in English was apparent. During the preparation of this manuscript, a book entitled “Chemical Phase Analysis” appeared in print.’ Although there must of necessity be some duplication, the aim and contents of the present review and of the book are significantly different. This review considers only the phase-analysis of ores and rocks and is intended for publication in the open literature as a guide for analysts to the methods employed. The references given herein were selected on the following basis. Emphasis was placed on methods developed
SUMMARYOF METHODS Aluminium
The bauxite minerals, gibbsite Al(OH)3, boehmite, AlO( and diaspore, AlO( can be determined on the basis of different rates of dissolution in potassium hydroxide solution or sulphuric acid under controlled conditions.’ ‘J’ Sodium hydroxide solution and hydrochloric acid can be used if only the gibbsite component is determined.‘3,14 Gibbsite, boehmite and diaspore can be separated by successive chlorinations with carbon tetrachloride vapour at 400, 500 and 600” respectively.” The AlC& formed at each temperature is distilled and collected in ammonia
Crown Copyrights reserved. * For reprints of this Review see Publisher’s announcement near end of this issue. TALMR2. 81
82
H. F. STEGER
solution. The accuracy of the method is improved if the result for a mineral is corrected for the partial conversion of other minerals at a particular temperature. ’ ’ Aluminium phosphate minerals such as crandallite, millesite, etc., are easily separated from kaolinite by dissolution in boiling hydrochloric acid (1 + l).” Approximately 1% of the aluminium in kaolinite also dissolves.
tube containing anhydrous magnesium perchlorate. The residue may be treated with chromium trioxide in phosphoric acid to oxidize the carbonaceous carbon to carbon dioxide,27 or the carbonaceous carbon may be assumed to be the difference between the total and carbonate carbon. The latter method becomes unsatisfactory when the sample contains much carbonate carbon and little carbonaceous material.28
Antimony
Copper
Antimony oxides and sulphides in ores can be separated by treatment with tartaric acid.” The sulphides are not attacked. A method for selectively determining Sb, Sb,03, Sb,S, and Sbz04 + Sb?O, in pyrometallurgical samples has been developed.” The method is subject to an error of 2-3x.
Native copper, cuprite and tenorite. Cuprite, Cu,O, can be selectively extracted from ores which contain native copper and tenorite, CuO. by dilute hydrochloric acid in ethanol plus stannous chloride,” or by a hot saturated potassium iodide solution.30 The native copper is then dissolved with a solution of ferric chloride in 3M hydrochloric acid. Tenorite is given by the difference between the total copper and cuprite + native copper. Cuprite can also be extracted with a 1% aqueous solution of unithiol, sodium 2,3-dimercaptopropanel-sulphonate.31 The residue is treated with a 1% solution of unithiol in 5% ammonium chloride to extract tenorite. The native copper is dissolved in nitric acid. The cuprite result must be corrected to take into account the solubility of tenorite and native copper, 5 and 9% respectively, in the 1% unithiol solution. Copper sulphides and oxidation products. Oxidized copper minerals can be extracted from sulphide ores with a reagent consisting of 2g of sodium sulphite and 1 g of phenylacetic acid in 20ml of acetone and 100 ml 3% H2S04.32 Native copper in the residue is dissolved in 15% ammonium carbonate or bicarbonate solution. The copper sulphides may be dissolved in acid or analysed for mineral phases as in the next section. Treatment of copper ores with a 1% unithiol solution dissolves azurite, CU~(CO~),(OH)~, malachite, Cu2(C03)(0H),. and cuprite. Chrysocolla, Cu2H2Si,O,(OH),, can be extracted from the residue with a 2% sodium sulphite solution in 3% sulphuric acid or extracted together with tenorite with a 1% solution of unithiol in 5% hydrochloric acid. Copper sulphides are unattacked. An error of 3-Q& depending on the copper content of the ore, is expected. Malachite can be extracted from copper ores with a 10% sodium potassium tartrate solution in 10% sodium hydroxide solution in a nitrogen atmosphere.34 The residue is treated with this reagent in an oxygen atmosphere to dissolve cuprite. The residue contains the copper sulphides. Copper sulphides. The following methods apply to copper sulphide ores from which oxidized forms of the copper sulphides are either absent or have been previously extracted (vide supra). Successive treatment of the ore with 2% ferric sulphate in 5% sulphuric acid and a saturated silver sulphate solution in 5% acetic acid will dissolve bornite, Cu,FeS,, and chalcocite, CU,S.~~ The residue is treated with a 1: 1 hyd-
A method of determining certain beryllium minerals in beryllium ores and concentrates has been described.20 Helvine, 3(Mn,Fe)O. 3BeO. Si02. MnS, and danalite, 3(Fe,Zn,Mn)O. 3BeO. 3Si02 (Fe,Zn)S, are dissolved in 3% hydrochloric acid. However, 5 15% of the beryllium vesuvianite, 2(Mg,Mn,Zn)O. 6CaO. 4BeO. Al,O, .6SiO,, also dissolves. The residue is roasted at 7W800” and the remainder of the vesuvianite becomes soluble in hydrochloric acid (1 + I). Beryl, 3BeO.A1,0, .6SiO,, and chrysoberyl, Be0 Al,O,, are determined in the final residue after fusion. Bismuth
Bismuth oxide minerals can be extracted from ores by treatment with a 5% thiourea solution in 0.5N sulphuric acid2’ or a 3% phenylacetic acid solution in 04M hydrochloric acid.22 Native bismuth in the residue is dissolved with @lM silver nitrate in O+ l.OM nitric acid. Bismuth sulphides are then decomposed with nitric acid or hydrofluoric acid-nitric acid mixture. An error of approximately 20”/, is obtained for individual bismuth components. Calcium
Free CaO is extractable from Ca,(PO,),, CaF,, CaCO,, CaSO, or calcium silicate ores with an aqueous sucrose solution. 23,24 Calcite, CaCO,, can be selectively dissolved in the presence of fluorite, CaF,, by 510% acetic acid.25,26 Approximately 0.3% of the fluorite also dissolves and, therefore, the appropriate correction should be made to the calcite result. This method is applicable to both fluorspars and complex sulphide ores. Carbon
Carbonate and carbonaceous carbon in rocks and ores is readily determined. Carbonates are decomposed by heating with hydrochloric or phosphoric acid and the liberated carbon dioxide is absorbed in dilute barium hydroxide solution” or in a preweighed
Chemical phase-analysis of ores rochloric acid-nitric acid mixture to dissolve chalcopyrite, CuFe!$. Bornite, chalcocite and covellite, CuS, can also be extracted from ores with a 2-3% potassium cyanide of solution35,36 or with an acidic solution thiourea.37,38 Only 0.07% of the chalcopyrite dissolves. The analytical results are corrected to take into account either the incomplete dissolution of the mineral(s) being determined or partial dissolution of other minerals. The phase-analysis for malachite, chalcocite, covellite and chalcopyrite by the successive use of sulphuric acid, ferric sulphate in sulphuric acid and potassium cyanide has been critically assessed and errors arising from the partial selectivity of the solvents have been estimated.39 Chalcocite can be separated from bornite, covellite and chalcopyrite by a 5% solution of unithiol in 5% ammonia solution.40 A correction for the slight solubility of the last three minerals must be made. An error of &So/& depending on mineralogical composition, is expected. Chalcocite can be determined in mixtures with bornite by dissolution in neutral silver nitrate solution.41 This method, however, is only semiquantitative. A scheme has been devised whereby a copper ore may be analysed for chalcocite, covellite, bornite, chalcopyrite, stannite [Cu,FeSnS,], bournonite [PbCuSbS,] and the tetrahedrite-tennantite group C(Cu,Fe), ,(As,Sb),S, ~1.~’ Germanium
The germanium compounds that are present in coal-ash may be determined43 if the sample is treated successively with O.lM ammonia to dissolve GeO, (including that in solid solution with SiO& 0.3M EDTA to dissolve CaGeO, and MgGeO,, 3M sodium hydroxide to dissolve aluminium germanates, and IM oxalic acid to dissolve Fe,Ge,O,,. The final residue, which consists of silica and mullite, 3A1,03 . GeO,. SiOz, is dissolved in nitric acid, hydrofluoric acid and phosphoric acid. The result for a particular germanium compound must be corrected to take into account the partial solubility of other germanium compounds in the solvent. Indium
Indium compounds in metallurgical dusts can be determined as follows.44 The dust is treated succcssively with water to extract In,(S04)3, a 3% bromine solution in methanol to dissolve In,S, and 3M hydrochloric acid to dissolve In,O,. The components are determined with an error of approximately 3%. Iron Fe, FeO, Fe,03 and Fe304 in reduced ores. Metallic iron can be selectively extracted from reduced iron ores with a solution of mercuric chloride in water45 or alcohol, 46p48 by aqueous copper sulphate solution 49p52 ammonium dithiocyanatoargentates3 or lead chloride54 or by bromine in alcohol.55-58 The use of bromine in alcohol is superior to that of mer-
83
curie chloride or silver thiocyanate.59 Further, the use of bromine in methanol is preferable to that in ethano16’ Metallic iron can also be determined indirectly (a) by conversion into FeS and subsequent determination of H2S on acid treatment6’ and (b) measurement of the hydrogen evolved by the dissolution of metallic iron in an acid.62 The latter technique gives a metallic iron content with an error less than 3%. To determine Fe0 and Fe203 in reduced iron ores, a sample from which metallic iron has been removed is dissolved in hydrochloric acid in an inert atmosphere. 46,56,57 The iron(B) in solution is determined either by titration with dichromate46 or vanadate,57 or spectrophotometrically.56 The same solution is analysed for total iron, and iron(II1) is obtained by difference. The error in determining each oxidation state is l-2%. Free Fe0 can be distinguished from Fe(I1) in magnetite, Fe30e4* Metallic and total Fe0 are extracted from the sample with a 6% ferric chloride solution. The metallic iron is readily determined (uide supra) to give total FeO. Another sample is treated successively with ethanolic stannous chloride and a 4% ferric chloride solution to dissolve Fe,O, and metallic iron. The magnetite in the residue is collected magnetically and dissolved in hydrochloric acid in an inert atmosphere. The Fe(B) in the magnetite is determined as stated above. The error in these determinations is l5%. Magnetite is selectively extracted from mixtures with hematite, Fe,O,, by 1% hydrochloric acid in phosphoric acid and an oxidant such as hydrogen peroxide or permanganate. 63,64 Approximately 1% of the hematite iron is also dissolved. Ferrous and ferric iron in rocks and ores. For the determination of ferrous iron, the sample is decomposed with sulphuric-hydrofluoric acid mixture either with the exclusion of air and direct determination of ferrous iron65p68 or in the presence of a known excess of ammonium vanadate,69,70 potassium permanganate,’ ’ -72potassium dichromate73 or silver perchlorate74 and indirect determination of ferrous iron by back-titration of the oxidant. The sample decomposition in the presence of excess of ammonium vanadate was found to be very reliable.75 For samples that dissolve in the acid mixture with great difficulty, fusion with sodium fluoroborate is recommended.76~77 The use of platinum crucibles, however, yields low results for ferrous iron.‘* It should be noted that the determination of ferrous iron is subject to error in the presence of Ti(III), V(III), Mn(IV), sulphides and organic matter. Ferric iron in rocks and ores is, in general, assumed to be the difference between the total and ferrous iron. Ferric iron in acid-soluble samples can, however, be determined directly.79,80 After dissolution of the sample in hydrochloric acid (1 + 1) in an inert atmosphere, ferric iron is titrated with EDTA at pH 1.2-2.0. The error is 0.63% depending on the iron content
84
H. F.
and nature of the sample. The presence of Bi, Tl and large amounts of Cu interferes in the titration. Sulphides and higher oxides of Mn and V interfere during decomposition. Iron oxides in iron sulphide ores. Hydrogen will easily reduce iron in iron oxides, silicates and other oxygen-bearing minerals to metallic iron but it will only slightly attack pyrite.” The metallic iron may then be removed by aqueous copper sulphate solution. Magnetite is easily separated from chalcopyrite with phosphoric acid. *’ Pyrrhotite can be extracted from mixtures with Fe0 and Fe,O, by bromine in alcoho1.83 Iron sulphide ores. Pyrrhotite can be determined in the presence of pyrite by dissolution in 4% stannous chloride solution in 6M hydrochloric acid.84 The inertness of pyrite to this reagent is variable, however, and appreciable errors can arise.*’ Pyrrhotite, chalcopyrite and bornite can be extracted from ores with bromine in methanol.86 Pyrite in the residue is dissolved by hydrogen peroxide in methanol. An error of approximately 2% is obtained. Lead
A method for the determination of lead minerals in ores has been developed.s7@ The sample is treated with 25% sodium chloride solution to dissolve anglesite, PbS04, and then with 15% ammonium acetate solution in 3% acetic acid to dissolve cerussite, PbC03. Successive treatment of the residue with 2% sodium hydroxide solution and ammonium acetate solution extracts the combined lead of crocoite, PbCrO,, and wulfenite, PbMoO& Mimetite, Pb,(AsO,),Cl,pyromorphite,Pb,(PO,),Cl,andvanadinite, Pb,(VO,),Cl, are then extracted with a 25% solution of sodium chloride in 0.5% hydrochloric acid [containing approximately 5 mg of mercury(I1) per litre to inhibit the dissolution of galena].88 The galena, PbS, in the residue may be dissolved either with a 25% solution of sodium chloride in 6% ferric chloride solution or with hydrogen peroxide.s8 The final residue contains beaverite, Pb(Cu,Fe,A1),(S04)2(OH)6, beudantite, PbFe,(AsO,)(SO,)(OH),, and plumbojarosite, PbFe6(S04)4(0H),, and is dissolved in hydrochloric acid (1 + 3). The determination of cerussite by 15% ammonium acetate in 3% acetic acid gives high results for ores containing galena, pyrite and organic matter.” The addition of ascorbic acid will suppress the oxidation and dissolution of galena. Galena may be determined in mixtures with betekhinite, Cu,e(Fe,Pb)S,, by dissolution with 4% hydrogen peroxide in 4M ammonium acetate in 5% acetic acid.“’ Because of the slight dissolution of betekhinite in this reagent, the determination is subject to an error of 14%. Manganese
Manganese carbonate minerals can be selectively dissolved in the presence of manganite, MnO,, by
STEGER
6N ammonium sulphate acidified with sulphuric acid to pH 2.” Manganite in the residue is dissolved with a 2% solution of sulphosalicylic acid in O.l-l.ON sulphuric acid. The treatment of carbonate-oxide ores with 1% acetic acid completely dissolves manganocalcite, (Mn,Ca)C03, and 78% of rhodochrosite, MnCO,, and oligonite, (Fe,Mn)C03.” The complete dissolution of rhodochrosite and oligonite is accomplished with 8% sulphuric acid. Manganese oxides are separated from manganese silicates in the residue, with 15% hydrochloric acid. The results for manganocalcite, rhodochrosite and oligonite must be adjusted to take into account the 78% solubility of the last two in 1% acetic acid. Mercury
Mercury compounds in pyro- and hydrometallurgical products may be determined semiquantitatively. Leaching of the sample with 5% nitric acid selectively dissolves HgO. Metallic mercury in the residue is extracted with nitric acid (2 + 1). HgS in the residue is then dissolved in a 5% sodium hydroxide-5% sodium sulphide solution. The compounds may be determined with an error of less than 20%. Molybdenum
Molybdenum oxide, MOO,, can be extracted from roasted molybdenite ore with 2(rSOo/, ammonia solution.g4,95 The molybdenite, MoS,, in the residue is then roasted to Moo3 and determined as above or is assumed to be given by the difference between total MO and the MoO,.‘~ The partial roasting of MoSz at 45&550” gives a product which contains Mo(IV) and Mo(V1) as well as sulphide and sulphate.g6 MO(W) compounds, MOO, and MoO$O&, are dissolved in boiling 20% sodium hydroxide solution. Mo(IV) can be determined in the residue. Sulphate is extracted from the roasted MO& on heating with 15% hydrochloric acid. Sulphide in the residue is determined by oxidation to sulphate. Nickel, cobalt
Chondritic meteorites (and lateritic nickel ores) can be analysed for the metallic, sulphide and silicate phases of nickel and cobaltg7 Metallic nickel and cobalt are dissolved in a 12% solution of mercuric chloride in 6% ammonium chloride solution, in an inert atmosphere. The sulphides are extracted from the residue with 2% bromine in methanol. The silicates are decomposed with hydrofluoric acid. The error in the determination is approximately 1%. Ascorbic acid-hydrogen peroxide selectively dissolves Ni, Co and Cu sulphide minerals in rocks.98 A total and sulphide-phase metal determination permits the calculation of the distribution of metal(s) over the mineral phases in the rock.
Chemical phase-analysis of Silicon
(quartz
in silicates)
Quartz in silicates may be determined as follows.“’ The sample is roasted at 60@650” and treated with a 1:3 mixture of nitric and hydrochloric acids to dissolve oxide minerals. The residue is heated to 25@ 275” with freshly prepared pyrophosphoric acid to dissolve the silicates. The quartz is then dissolved with hydrofluoric-sulphuric acid mixture. An error of 0.5% is claimed. Quartz may also be determined in rocks by pyrosulphate fusion followed by fluorosilicic acid treatment.“’ The latter must be repeated if much feldspar is present in the sample. A decrease in the recovery of quartz with each dissolution stage must be taken into account in calculating the result for quartz. Both pyrophyllite, A12Si,0,,(OH), and zircon. ZrSiO,, offer significant resistance to this procedure. Sulphur Elemental
sulphur
in
OWS
and
mirzerals.
Karchmer”’ has reviewed several methods for the determination of elemental sulphur. In addition, specand chromatographic104~‘0s trophotometric102~103 methods are available. In the spectrophotometric method, the elemental sulphur is extracted from the sample with a solvent such as carbon disulphide or acetone and the absorbance due to sulphur is measured at the appropriate wavelength. The presence of other sulphur compounds may interfere. Also sulphur, if present in the amorphous form, may be incompletely dissolved. lo1 After extraction from the sample with acetone, elemental sulphur is determined by thin-layer chromatdisulphide extract of the ography. lo5 A carbon sample may be analysed for both elemental and xanthate sulphur.lo4 Total sulphur in the extract (in a fixed volume of carbon disulphide) is determined by oxidation of all sulphur compounds to sulphur dioxide. Xanthate sulphur is determined in a second portion of extract by thermal decomposition of all combined-sulphur compounds. All measurements are by gas chromatography. Elemental sulphur is the difference between total and xanthate sulphur. Sulphide. Sulphide in the presence of sulphate is usually determined by evolution of hydrogen sulphide on treatment of the sample with acid.82,‘06 Sulphate may then be determined directly as barium sulphate or as the difference between total and sulphide sulphur. Sulphide may also be determined by pyrolysis of the sample, mixed with reduced copper, at 700 in a stream of nitrogen.“’ Oxidized forms of sulphur are converted into sulphur dioxide, which is collected. Sulphide forms CuS which, of course. gives hydrogen sulphide on addition of acid. Pyrrhotite sulphur can be determined in the presence of pyrite sulphur by its evolution as hydrogen sulphide by a 4”/, stannous chloride solution in hydrochloric acid (1 + 1).84 This reagent may, however, also partially decompose pyrite and it is recom-
85
ores
mended that a solution acid be used instead.85
of hydrazine
in 4N sulphuric
A mixture of hydrofluoric and hydrochloric acids, used at slightly elevated pressure, decomposes pyrochlore, (Na,Ca),(Ta,Nb),O,(OH.F), and microlite, (Na,Ca)2(Ta,Nb)20,(0,0H,F), but only slightly attacks simpsonite, A14(Ta,Nb)3(0,0H,F),+108 Hydrofluoric acid (4M) dissolves 98”/, of microlite but only 7715”~ of columbiteetantahte.iO” Correction for the degree of dissolution of these minerals in this reagent permits the determination of the distribution of TazO, and Nb,O, in microlite and columbite-tantalite, (Fe,Mn)(Ta.Nb),O,. with an error of 226%. Tin
A method has been developed for differentiating and determining free cassiterite, SnO,, cassiterite occluded in the silicate lattice and silicate-bound tin in rocks.“’ The sample is decomposed with a 2:1 hydrofluoric-hydrochloric acid mixture and subsequently heated with ammonium iodide to give total tin. Lattice-bound tin is determined by decomposition with the same acid mixture and subsequent heating with hydriodic acid to dissolve the freshly formed tin oxide. The rock is heated with ammonium iodide to determine the free cassiterite. The difference between total and free cassiterite and lattice-bound tin is the occluded cassiterite. An error of 5-20”/,, depending on tin content, is obtained. Stannite. Cu,FeSnS,, may be selectively decomposed in the presence of cassiterite with concentrated nitric acid.“’ bromine in ethanol or carbon tetrachloride’ ” or sodium nitrate in glacial acetic acid.’ I3 The cassiterite may be determined directly in the residue or by difference between total and stannite tin. The error in the determination is l-2”,
Ilmenite, FeTiO,, titanomagnetite, (Fe,Ti),O, and sphene CaTiSO,. may be extracted from mixtures with rutile. TiO,, with a 2% solution of sodium fluoride in 8 M hydrochloric acid.’ l4 Because l-2’% of the rutile also dissolves, the results for these minerals must be corrected accordingly. Sphene can be determined in the presence of ilmenite and titanomagnetite. The sample is reduced in a stream of hydrogen at 880 and then treated with 1M hydrochloric acid to dissolve iron oxides. Subsequent treatment with a 1.50/, solution of sodium fluoride in 8M hydrochloric acid dissolves sphene, leaving ilmenite and titanomagnetite in the residue. Rutile, if present, also remains in the residue but may be determined as above. The error in these determinations is l-100/ depending on the mineral and its content in the ore.
Members of the wolframite FeWO,, and huebnerite, MnWO,,
group, ferberite, can be determined
H. F.
86
STEGER
in scheelite. ’ ’ ’ The sample is first roasted at 400” to oxidize all ferrous minerals soluble in hydrochloric acid, other than wolframite, to their ferric counterparts, and is then completely dissolved in concentrated hydrochloric acid, in an inert atmosphere. Ferrous iron in the solution represents ferberite. Also, experimental studies 1’ 5 indicate that huebnerite is the only manganese mineral of appreciable amount in scheelite and, therefore, the determination of manganese will yield the huebnerite content of the scheelite. Uranium The ratio of U(IV) to U(W) in rocks and ores can be evaluated.’ 16,117 The sample is decomposed with a non-oxidizing acid in an inert atmosphere. U(N) is precipitated with cupferron, Ti(IV) being used as carrier, and is determined by fluorimetry.“’ Otherwise, U(W) is separated from U(IV) by extraction as an anionic phosphate complex with a So/, solution of tri-n-octylamine in benzene’ I6 or xylene.’ I7 A total uranium determination gives by difference the amount of the oxidation state of uranium not determined directly. The error in the determination is 23%. Zinc
Oxidized zinc minerals such as smithsonite, willemite, Zn,SiO, and hemimorphite, ZnCO,, Zn,Si,O,(OH), H20, are easily separated from sphalerite, ZnS, by dissolution in boiling 5% acetic acid.’ I9 The result must be corrected for the 510% of ZnS which also dissolves. The error in this determination is 1l&l 5% for the oxidized minerals and Z5% for ZnS. ZnS is easily determined in the presence of zinc spine1 by dissolution in acidic hydrogen peroxide.’ 2o The error in the determination is approximately 3’j/,.
REFERENCES
1. V. G. Ageenkov, Tr. Vses. Konf Anal. Khim., 1943, 2, 15. 2. V. V. Dolivo-Dobrovol’skii and Yu. V. Klimenko, Pructical Analysis of Ores, Metallurgiya, 1947. 3. V. V. Dolivo-Dobrovol’skii, Ed., Phase Chemical Analysis of Ores and Minerals, Leningrad Univ., 1962. 4. N. A. Filippova, Phase Analysis of Ores, Metallurgizdat, Moscow 1963. Ibid., 1964. Ihid., 1966. 5. S. A. Yushko, Ed., Phase Microchemical Analysis
Nedra, Moscow, 1969. 6. M. N. Fedorova, K. S. Krivodubskaya and G. N. Osokina, Phase Chemical Analysis of Ferrous Metal Ores and Their Treatment Products, Nedra, MOSCOW, 1912. 7. R. S. Young,
Chemical Phase Analysis, HalsteadWiley, New York, 1974. 8. A. H. Low, Technical Methods of Ore Analysis for Chemists and Colleges, 9th Ed., Wiley, New York, 1922. 9. W. F. Hillebrand, G. E. F. Lundell, H. A. Bright and J. 1. Hoffman, Applied Inorganic Analysis, 2nd Ed., Wiley, New York, 1959. 10. J. A. Maxwell, Rock und Mineral Analysis, Interscience, New York, 1968.
Il. I. N. Maslenitskii, Zavodsk. Lah., 1939, 8. 933. 12. G. G. Mathad and V. A. Altekar. Sci. Cult. India. 1960, 25, 695. 13. E. V. Kopchenova and V. N. Karyukina, Zavodsk. Lab., 1945, 11. 360. 14. I. V. Shmanenkov, ihid., 1945, 11, 459. 15. K. V. Podoinikova and A. T. Chernyi, J. Appl. Chem. USSR, 1963, 36, 2681.
16. Idem. ibid., 1966, 39, 1578. 17. 1. May and R. Smith, J. Assoc. OjY Surv., 1956, 39. 766. 18. S. Lebedev and K. Mikic-Indin, Zh. Radova Srpsku Akad. Nauk, 1952. 22, 169. 19. G. V. Afanas’eva and L. P. Bogatyerva, Ind. Lab., 1973, 39, 721. 20. Cl. N. Samorokova, ibid., 1967, 33, 320. 21. F. E. Merlina and V. N. Budnikova, ihid.. 1969, 35, 1413. 22. L. P. Bogatyreva and G. V. Afanas’eva. ihid., 1970, 36, 1155. 23. M. R. Verma, V. M. Bhuchar, K. J. Theraitil and S. S. Sharma, J. Sci. Ind. Res. B, India, 1955, 14, 192. 24. R. S. Young, Tulantu, 1973. 20, X91. 25. M. A. Popov and S. Boldina, Ilch. Zap. Tsentr. Nauch.-Issled. Inst. Olovyan. Prom.. 1967, 68. 26. G. A. Tiunova, G. D. Sizikhina and A. F. Shal’nova, Nauch. Tr. Sib. Nuuch-Issled. Proekr. In~t. Tsvet. Met., 1971, 63. 27. J. Hoefs, Geochim. Cosmochim. Acfu, 1965, 29, 399.
28. Reference 9, pp. 22632. 29. I. Baker and R. Stevens, Ind. Eng. C’hem.. Anul. Ed.. 1946, 18, 124. 30. S. M. Mehta and R. N. Bharucha. Proc. Indim Acad. Sri.. 1953, 3lA, 29.
31. Kh. K. Ospanov and 0. A. Songina, Ind. Luh.. 1968, 34, 189. 32. K. D. Leont’eva and R. V. Shelankova, Sh. Nuuch. Tr. Gas. Nuuch.-Issled. Inst. Tsvet. Mrtul., 1967. 27, 95. 33. 0. N. Pashevkina and T. V. Gurkina, Ind. Lah., 1971.
37, 1135. 34. Jen-Yin Yen and Yii-Shan Liu, Actu Ckim. Sinicu, 1959, 25, 346. Tr. Altaisk Gorno-Me&d. Nauch.Issled. Akad, Nauk Kaz. SSR, 1961. 11, 153.
35. B. S. Khristoforov,
36. Reference 3, pp. 3349. 37. B. S. Khristoforov and M. I. Timerbulatova. Khim. Analit. Tsvet. Redk. Metal., 1964, 93, 116. 38. L. D. Dolaberidze and Yu. V. Politova, Ind. Lab.. 1966, 32, 953. 39. B. S. Khristoforov and A. G. Merkulov. Kkim. Anulit. Tsvet. Redk. Metal., 1964, 93, 106. 40. 0. A. Songina, Kh. K. Ospanov and 2. B. Rozhdestvenskaya, lnd. Lab., 1966, 32, 956. 41. N. I. Solntsev and L. V. Usova. Sh. Tr. Gos. N~mch.Issled. Inst. Tsvet. Met., 1962, 756. 42. F. E. Merlina, Ind. Lab., 1974, 40, 314. 43. A. V. Zagorodnyuk, R. L. Magunov and I. V. Stasenko, ihid.. 1973. 39, 1388. 44. L. N. Terzeman, ibid., 1972, 38, 1824. 45. S. P. Leiba and Yu. 1. Dolgina. Zavodsk. Lah., 1935, 4, 743.
46. N. S. Tkachenko, P. I. Davidenko and A. V. Dobrzkanskii, Ind. Lab., 1963, 29, 557. 47. J. Aubry and P. Perrot, Chim. Antd. (Paris). 1965, 47, 177. 4x. T. A. Frantsuzova and 0. P. Lebedev. Ind. Luh.. 1968, 34, 1578. 49. N. 1. Stoenii and A. G. Kirilenko, Zavodsk. Lab., 1955, 21,594. 50. M. G. Habashv. Anal. Chem.. 1961. 33, 586 51. J. Vorlicek and’s, Lang, Tech. Zpruvodtzi VUZDH, 1963, 2, 19.
Chemical
phase-analysis
52. T. P. Prasad, Talanta, 1969, 16, 1484. 53. F. Marion and J. Aubry, Chim. Anal. (Paris), 1959, 41, 401. 54. L. Balabanoff, E. Schmidt and B. Seegar, Z. Anal. Chem., 1964, 204, 107. 55. G. Kraft and J. Fischer, ibid., 1963, 197, 217. 56. A. M. Leblond. R. Wendling and J. M. Bourdieu, Chim. Anal. (Paris), 1968, 50,431. 57. B. R. Sant and T. P. Prasad. Talanta. 1968. 15. 1483. 58. K. Kinson, J. E. Dickeson &d C. B. Beldher: Anal. Chim. Acta, 1968, 41. 107. 59. S. C. Blum and T. D. Searl. Anal. Chem.. 1971.,, 43. 150. 60. N. A. Filippova, L. A. Martynova and N. Yu. Gusel’nikova, Ind. Lub.,‘1971, 37, 999. 61. A. T. Chernyi and K. V. Podoinikova, Zavodsk. Lab., 1950, 16, 1308. 62. A. Piksarv, H. Arro and V. Vares, Tr. Tallin. Politeckh. Inst. Ser. A, 1964, 215, 137. 63. Yu. V. Morachevskii and N. Kh. Pinchuk, Vestn. Leningrad. Univ., 1956, 60. 64. N. Kh. Pinchuk and Yu. V. Morachevskii, ibid., 1958, 126. 65. J. P. Riley and H. P. Williams, Mikrochim. Acta, 1959, 4. 66. C. V. Clemency and A. F. Hagner, Anal. Chem., 1961, 33, 888. 67. M. Yu. Budilovskii and Yu. I. Usatenko, Ind. Lab., 1970, 36, 994. 68. Lo-Sun Jen, Anal. Chim. Acta, 1973, 66, 315. 69. A. D. Wilson, Bull. Geol. Suru. G.B., 1955, 9, 56. 70. A. Peters, Neues Jahrb. Mineral. Monatsh., 1968, 119. 71. C. 0. Ingamells, Talanta, 1960, 4, 268. 72. K. Pamnani and S. K. Agnihotri, Lab. Pratt., 1966, 15, 867. 73. R. Meyrowitz, Am. Min., 1963, 48, 340. 74. H. Ungethiim, Z. Angew. Geol., 1965, 11, 500. 75. E. R. Whipple, Chem. Geol., 1974, 14, 223. 76. Z. M. Mil&ailova, A. A. Yarushka, R. V. Mirskii and E. A. Shil’dkrot. Tr. Gos. Nauch.-lssled. Inst. Neft. Prom., 1963, 124. Zh. Analit. Khim., 1968, 23, 1057. 77. Yu. N. Novikova, Anal. Chem., 1969. 41. 501. 78. E. M. Donaldson. 79. J. VorliEek and F. Vydra, Hutn. Listy, 1963, 18, 733. 80. F. Vydra and J. VorliEek, Chem. Anal. (Warsaw), 1964, 53, 103. 81. Yu. V. Klimenko and M. N. Fedorova, Zavodsk. Lab., 1955, 21, 294. 82. Yu. V. Morachevskii and N. Kh. Pinchuk, Vestn. Leningrad. Univ., 1956, 170. 83. Y. Okura. Bunseki Kagku, 1960, 9. 845-849. 84. S. Yu. Fainberg, Analysis of the Ores of Non-Ferrous Metals, Metallurgizdat, Moscow, 1953. 85. Z. Valcha and J. Pelikan, Vestn. Ustred. Ustauu Geol., 1958. 33, 244. 86. N. A. Filippova and L. A. Martynova, Ind. Lab., 1964, 33. 1253. 87. N. I. Solntsev and R. I. Chudina, Sb. Nauch. Tr. Gos. Nauch.-lssled. Inst. Tsvet. Metal., 1958, 80. 88. N. A. Filippova, V. A. Korosteleva and Yueh-Ying Chu, Ind. Lab., 1961, 27. 1351. 89. A. G. Kudenko and 0. N. Pashevkina, ibid., 1970, 36, 187.
of ores
87
Obogashch. Rud., 90. F. E. Merlina and N. V. Budhikova, 1964, 9, 36. 91. L. P. Buadze, Ezhegodnik Kavkazsk. Inst. Mineral’n. Syr’yaza 1957, p. 50. Nauchn. Tekhn. Izdat, Moscow, 1959. and G. N. Samorokova, Byull. 92. M. N. Fedorova Nauch.-Tekh. Inform. Min. Geol. Okhrany, Nedr., USSR, 1962, %, 102. and G. V. Afanas’eva, Ind. Lab., 93. L. P. Bogatyreva 1970, 36,83;. 94. V. G. Shcherbakov and I. S. Sakhiev. Zauodsk. Lab.. 1937, 6, 684. 95. N. C. Angelotti and E. G. Gooch, Anal. Chim. Acta, 1972, 58, 445. and L. I. Lebedev, J. Appl. Chem. 96. I. K. Gromozova USSR, 1971, 44, 1488. Z. Anal. 97. N. R. Sen Gupta and A. N. Chowdbury, Chem., 1974, 268, 32. 98. J. J. Lynch in Geochemical Exploration, R. W. Boyle, Ed., pp. 313-14. Can. Inst. Mining Met., Montreal, 1971. and A. A. Zubritskaya, lnd. Lab., 99. E. G. Romanenko 1964, 30, 212. J. K. Syers and M. L. Jackson, Soil 100. S. L. Chapman, Sci., 1969, 107, 348. Ed., The Analytical Chemistry of Sul101. J. H. Karchmer, fur and its Compounds, Part I, pp. 6684. Wiley-Interscience, New York, 1970. 102. T. Ozawa, Nippon Kagaku Zasshi, 1966, 87. 578. 103. J. G. Koren, Appl. Spectry. 1969, 23. 275. 104. S. A. Allison, Rept. Natn. Inst. Metall. (S. Afr.), 1972, No. 1495. and M. Sliwiok, Chem. Anal. (War105. S. Banaszkiewicz saw), 1973, 18, 1013. M. Yoshida and T. Ozawa, Bull. Chem. 106. S. Nagashima, Sot. Japan, 1972, 45, 3446. 107. M. A. Volodina, M. Abdukarimova and L. V. Kozlovskaya, Vestn. Mosk. Univ., Khim., 1968, 23, 116. 108. S. Kallmann, H. Oberthin and R. Liu, Anal. Chem., 1962, 34, 609. and S. M. Chernikova, Ind. Lab., 109. A. B. Kroshkina 1967, 33, 1568. 110. J. Agterdenbos and J. Vlogtman, Talanta, 1972, 19, 1295. 111. B. Hirsch, Chem.-Ztg. 1932, 56, 127. 112. L. V. Zverev and N. V. Petrova, Zavodsk. Lab., 1957, 23, 1403. 113. H. F. Steger, Talanta, 1975, 22, 543. Ind. Lab., 114. M. N. Fedorova and K. S. Krivodubskaya, 1964, 30, 643. 115. S. Kallmann, Anal. Chem., 1955, 27, 1433. and T. T. Bykhovtseva, J. Anal. 116. I. A. Tserkovnitskaya Chem. USSR, 1967, 22, 79. 117. I. Hodara and I. Balouka, Anal. Chem., 1971, 43. 1213. 118. R. S. Clarke, Jr. and Z. S. Altschuler, Geochim. Cosmochim. Acta, 1968, 13, 127. 119. L. G. Samokhvalova and N. A. Filippova, Ind. Lab., 1971, 37, 368. 120. N. I. Resketnikov, ibid., 1973, 40, 169.
Pergamon Press. 1976. Prmted m Great Britm
TALANTA CHEMICAL
MINI-REVIEW*
PHASE-ANALYSIS
OF ORES AND ROCKS
A REVIEW OF METHODS H. F. STEGER
Mineral Sciences Laboratories, Canada Centre for Mineral and Energy Technology, Department of Energy, Mines and Resources, Ottawa, Canada (Received 25 March 1975. Accepted 27 March
1975)
Summary-The methods employed in the chemical phase-analysis of rocks, ores and their treatment products are reviewed. An attempt has been made to be. critical, selective and thorough in the choice of methods available in the literature, in order to provide a convenient manual for workers interested in this aspect of analytical chemistry.
within the past 25 yr. Most older methods have since been modified (and are included in the modified form) or appear in standard analytical texts such as Low,~ Hillebrand and Lundell,g and Maxwell. lo References to Soviet journals which are not readily available to Western readers are omitted wherever subsequent publication of the method has occurred in a more widely circulated journal. References in this review are made to the English edition of Soviet journals wherever possible. Recourse to the Russian edition was necessary where the English edition either does not exist for the complete series of a journal or was not reasonably accessible to the reviewer. Finally it must be mentioned that information on procedures of chemical phase-analysis may be hidden away in the body of papers and is, therefore, effectively inaccessible because titles and references do not convey its existence. It is suggested, therefore, that future authors should strive to prevent the recurrence of this problem by deliberate mention of chemical phase-analysis either in the abstract or, preferably, in the title of their publication.
Chemical phase-analysis (also called rational or practical analysis) is the determination, by a chemical dissolution technique, of the distribution of an element in an ore or rock on the basis of minerals or oxidation states. The goal of the analysis is the selective dissolution of one or more minerals present in the ore, but because no solvent is completely selective in its action, a quantitative separation is seldom achieved and it is necessary to correct the result to allow for the partial dissolution of other minerals. Because the reactivity of a mineral with a particular solvent varies from specimen to specimen, a truly constant correction is not possible and an error of l-100/, is considered to be acceptable. The importance of chemical phase-analysis to the mining industry, e.g., in process control, and to hydrometallurgists has ensured its being a valuable aspect of analytical chemistry. Chemical phase-analysis has enjoyed an appreciable increase in interest since 1960. Reviews, both comprehensive and partial, have appeared at irregular intervals in the literature of the Soviet Unionlp6 but unfortunately English translations are not available and access to the original is often difficult. The need for a review in English was apparent. During the preparation of this manuscript, a book entitled “Chemical Phase Analysis” appeared in print.’ Although there must of necessity be some duplication, the aim and contents of the present review and of the book are significantly different. This review considers only the phase-analysis of ores and rocks and is intended for publication in the open literature as a guide for analysts to the methods employed. The references given herein were selected on the following basis. Emphasis was placed on methods developed
SUMMARYOF METHODS Aluminium
The bauxite minerals, gibbsite Al(OH)3, boehmite, AlO( and diaspore, AlO( can be determined on the basis of different rates of dissolution in potassium hydroxide solution or sulphuric acid under controlled conditions.’ ‘J’ Sodium hydroxide solution and hydrochloric acid can be used if only the gibbsite component is determined.‘3,14 Gibbsite, boehmite and diaspore can be separated by successive chlorinations with carbon tetrachloride vapour at 400, 500 and 600” respectively.” The AlC& formed at each temperature is distilled and collected in ammonia
Crown Copyrights reserved. * For reprints of this Review see Publisher’s announcement near end of this issue. TALMR2. 81
82
H. F. STEGER
solution. The accuracy of the method is improved if the result for a mineral is corrected for the partial conversion of other minerals at a particular temperature. ’ ’ Aluminium phosphate minerals such as crandallite, millesite, etc., are easily separated from kaolinite by dissolution in boiling hydrochloric acid (1 + l).” Approximately 1% of the aluminium in kaolinite also dissolves.
tube containing anhydrous magnesium perchlorate. The residue may be treated with chromium trioxide in phosphoric acid to oxidize the carbonaceous carbon to carbon dioxide,27 or the carbonaceous carbon may be assumed to be the difference between the total and carbonate carbon. The latter method becomes unsatisfactory when the sample contains much carbonate carbon and little carbonaceous material.28
Antimony
Copper
Antimony oxides and sulphides in ores can be separated by treatment with tartaric acid.” The sulphides are not attacked. A method for selectively determining Sb, Sb,03, Sb,S, and Sbz04 + Sb?O, in pyrometallurgical samples has been developed.” The method is subject to an error of 2-3x.
Native copper, cuprite and tenorite. Cuprite, Cu,O, can be selectively extracted from ores which contain native copper and tenorite, CuO. by dilute hydrochloric acid in ethanol plus stannous chloride,” or by a hot saturated potassium iodide solution.30 The native copper is then dissolved with a solution of ferric chloride in 3M hydrochloric acid. Tenorite is given by the difference between the total copper and cuprite + native copper. Cuprite can also be extracted with a 1% aqueous solution of unithiol, sodium 2,3-dimercaptopropanel-sulphonate.31 The residue is treated with a 1% solution of unithiol in 5% ammonium chloride to extract tenorite. The native copper is dissolved in nitric acid. The cuprite result must be corrected to take into account the solubility of tenorite and native copper, 5 and 9% respectively, in the 1% unithiol solution. Copper sulphides and oxidation products. Oxidized copper minerals can be extracted from sulphide ores with a reagent consisting of 2g of sodium sulphite and 1 g of phenylacetic acid in 20ml of acetone and 100 ml 3% H2S04.32 Native copper in the residue is dissolved in 15% ammonium carbonate or bicarbonate solution. The copper sulphides may be dissolved in acid or analysed for mineral phases as in the next section. Treatment of copper ores with a 1% unithiol solution dissolves azurite, CU~(CO~),(OH)~, malachite, Cu2(C03)(0H),. and cuprite. Chrysocolla, Cu2H2Si,O,(OH),, can be extracted from the residue with a 2% sodium sulphite solution in 3% sulphuric acid or extracted together with tenorite with a 1% solution of unithiol in 5% hydrochloric acid. Copper sulphides are unattacked. An error of 3-Q& depending on the copper content of the ore, is expected. Malachite can be extracted from copper ores with a 10% sodium potassium tartrate solution in 10% sodium hydroxide solution in a nitrogen atmosphere.34 The residue is treated with this reagent in an oxygen atmosphere to dissolve cuprite. The residue contains the copper sulphides. Copper sulphides. The following methods apply to copper sulphide ores from which oxidized forms of the copper sulphides are either absent or have been previously extracted (vide supra). Successive treatment of the ore with 2% ferric sulphate in 5% sulphuric acid and a saturated silver sulphate solution in 5% acetic acid will dissolve bornite, Cu,FeS,, and chalcocite, CU,S.~~ The residue is treated with a 1: 1 hyd-
A method of determining certain beryllium minerals in beryllium ores and concentrates has been described.20 Helvine, 3(Mn,Fe)O. 3BeO. Si02. MnS, and danalite, 3(Fe,Zn,Mn)O. 3BeO. 3Si02 (Fe,Zn)S, are dissolved in 3% hydrochloric acid. However, 5 15% of the beryllium vesuvianite, 2(Mg,Mn,Zn)O. 6CaO. 4BeO. Al,O, .6SiO,, also dissolves. The residue is roasted at 7W800” and the remainder of the vesuvianite becomes soluble in hydrochloric acid (1 + I). Beryl, 3BeO.A1,0, .6SiO,, and chrysoberyl, Be0 Al,O,, are determined in the final residue after fusion. Bismuth
Bismuth oxide minerals can be extracted from ores by treatment with a 5% thiourea solution in 0.5N sulphuric acid2’ or a 3% phenylacetic acid solution in 04M hydrochloric acid.22 Native bismuth in the residue is dissolved with @lM silver nitrate in O+ l.OM nitric acid. Bismuth sulphides are then decomposed with nitric acid or hydrofluoric acid-nitric acid mixture. An error of approximately 20”/, is obtained for individual bismuth components. Calcium
Free CaO is extractable from Ca,(PO,),, CaF,, CaCO,, CaSO, or calcium silicate ores with an aqueous sucrose solution. 23,24 Calcite, CaCO,, can be selectively dissolved in the presence of fluorite, CaF,, by 510% acetic acid.25,26 Approximately 0.3% of the fluorite also dissolves and, therefore, the appropriate correction should be made to the calcite result. This method is applicable to both fluorspars and complex sulphide ores. Carbon
Carbonate and carbonaceous carbon in rocks and ores is readily determined. Carbonates are decomposed by heating with hydrochloric or phosphoric acid and the liberated carbon dioxide is absorbed in dilute barium hydroxide solution” or in a preweighed
Chemical phase-analysis of ores rochloric acid-nitric acid mixture to dissolve chalcopyrite, CuFe!$. Bornite, chalcocite and covellite, CuS, can also be extracted from ores with a 2-3% potassium cyanide of solution35,36 or with an acidic solution thiourea.37,38 Only 0.07% of the chalcopyrite dissolves. The analytical results are corrected to take into account either the incomplete dissolution of the mineral(s) being determined or partial dissolution of other minerals. The phase-analysis for malachite, chalcocite, covellite and chalcopyrite by the successive use of sulphuric acid, ferric sulphate in sulphuric acid and potassium cyanide has been critically assessed and errors arising from the partial selectivity of the solvents have been estimated.39 Chalcocite can be separated from bornite, covellite and chalcopyrite by a 5% solution of unithiol in 5% ammonia solution.40 A correction for the slight solubility of the last three minerals must be made. An error of &So/& depending on mineralogical composition, is expected. Chalcocite can be determined in mixtures with bornite by dissolution in neutral silver nitrate solution.41 This method, however, is only semiquantitative. A scheme has been devised whereby a copper ore may be analysed for chalcocite, covellite, bornite, chalcopyrite, stannite [Cu,FeSnS,], bournonite [PbCuSbS,] and the tetrahedrite-tennantite group C(Cu,Fe), ,(As,Sb),S, ~1.~’ Germanium
The germanium compounds that are present in coal-ash may be determined43 if the sample is treated successively with O.lM ammonia to dissolve GeO, (including that in solid solution with SiO& 0.3M EDTA to dissolve CaGeO, and MgGeO,, 3M sodium hydroxide to dissolve aluminium germanates, and IM oxalic acid to dissolve Fe,Ge,O,,. The final residue, which consists of silica and mullite, 3A1,03 . GeO,. SiOz, is dissolved in nitric acid, hydrofluoric acid and phosphoric acid. The result for a particular germanium compound must be corrected to take into account the partial solubility of other germanium compounds in the solvent. Indium
Indium compounds in metallurgical dusts can be determined as follows.44 The dust is treated succcssively with water to extract In,(S04)3, a 3% bromine solution in methanol to dissolve In,S, and 3M hydrochloric acid to dissolve In,O,. The components are determined with an error of approximately 3%. Iron Fe, FeO, Fe,03 and Fe304 in reduced ores. Metallic iron can be selectively extracted from reduced iron ores with a solution of mercuric chloride in water45 or alcohol, 46p48 by aqueous copper sulphate solution 49p52 ammonium dithiocyanatoargentates3 or lead chloride54 or by bromine in alcohol.55-58 The use of bromine in alcohol is superior to that of mer-
83
curie chloride or silver thiocyanate.59 Further, the use of bromine in methanol is preferable to that in ethano16’ Metallic iron can also be determined indirectly (a) by conversion into FeS and subsequent determination of H2S on acid treatment6’ and (b) measurement of the hydrogen evolved by the dissolution of metallic iron in an acid.62 The latter technique gives a metallic iron content with an error less than 3%. To determine Fe0 and Fe203 in reduced iron ores, a sample from which metallic iron has been removed is dissolved in hydrochloric acid in an inert atmosphere. 46,56,57 The iron(B) in solution is determined either by titration with dichromate46 or vanadate,57 or spectrophotometrically.56 The same solution is analysed for total iron, and iron(II1) is obtained by difference. The error in determining each oxidation state is l-2%. Free Fe0 can be distinguished from Fe(I1) in magnetite, Fe30e4* Metallic and total Fe0 are extracted from the sample with a 6% ferric chloride solution. The metallic iron is readily determined (uide supra) to give total FeO. Another sample is treated successively with ethanolic stannous chloride and a 4% ferric chloride solution to dissolve Fe,O, and metallic iron. The magnetite in the residue is collected magnetically and dissolved in hydrochloric acid in an inert atmosphere. The Fe(B) in the magnetite is determined as stated above. The error in these determinations is l5%. Magnetite is selectively extracted from mixtures with hematite, Fe,O,, by 1% hydrochloric acid in phosphoric acid and an oxidant such as hydrogen peroxide or permanganate. 63,64 Approximately 1% of the hematite iron is also dissolved. Ferrous and ferric iron in rocks and ores. For the determination of ferrous iron, the sample is decomposed with sulphuric-hydrofluoric acid mixture either with the exclusion of air and direct determination of ferrous iron65p68 or in the presence of a known excess of ammonium vanadate,69,70 potassium permanganate,’ ’ -72potassium dichromate73 or silver perchlorate74 and indirect determination of ferrous iron by back-titration of the oxidant. The sample decomposition in the presence of excess of ammonium vanadate was found to be very reliable.75 For samples that dissolve in the acid mixture with great difficulty, fusion with sodium fluoroborate is recommended.76~77 The use of platinum crucibles, however, yields low results for ferrous iron.‘* It should be noted that the determination of ferrous iron is subject to error in the presence of Ti(III), V(III), Mn(IV), sulphides and organic matter. Ferric iron in rocks and ores is, in general, assumed to be the difference between the total and ferrous iron. Ferric iron in acid-soluble samples can, however, be determined directly.79,80 After dissolution of the sample in hydrochloric acid (1 + 1) in an inert atmosphere, ferric iron is titrated with EDTA at pH 1.2-2.0. The error is 0.63% depending on the iron content
84
H. F.
and nature of the sample. The presence of Bi, Tl and large amounts of Cu interferes in the titration. Sulphides and higher oxides of Mn and V interfere during decomposition. Iron oxides in iron sulphide ores. Hydrogen will easily reduce iron in iron oxides, silicates and other oxygen-bearing minerals to metallic iron but it will only slightly attack pyrite.” The metallic iron may then be removed by aqueous copper sulphate solution. Magnetite is easily separated from chalcopyrite with phosphoric acid. *’ Pyrrhotite can be extracted from mixtures with Fe0 and Fe,O, by bromine in alcoho1.83 Iron sulphide ores. Pyrrhotite can be determined in the presence of pyrite by dissolution in 4% stannous chloride solution in 6M hydrochloric acid.84 The inertness of pyrite to this reagent is variable, however, and appreciable errors can arise.*’ Pyrrhotite, chalcopyrite and bornite can be extracted from ores with bromine in methanol.86 Pyrite in the residue is dissolved by hydrogen peroxide in methanol. An error of approximately 2% is obtained. Lead
A method for the determination of lead minerals in ores has been developed.s7@ The sample is treated with 25% sodium chloride solution to dissolve anglesite, PbS04, and then with 15% ammonium acetate solution in 3% acetic acid to dissolve cerussite, PbC03. Successive treatment of the residue with 2% sodium hydroxide solution and ammonium acetate solution extracts the combined lead of crocoite, PbCrO,, and wulfenite, PbMoO& Mimetite, Pb,(AsO,),Cl,pyromorphite,Pb,(PO,),Cl,andvanadinite, Pb,(VO,),Cl, are then extracted with a 25% solution of sodium chloride in 0.5% hydrochloric acid [containing approximately 5 mg of mercury(I1) per litre to inhibit the dissolution of galena].88 The galena, PbS, in the residue may be dissolved either with a 25% solution of sodium chloride in 6% ferric chloride solution or with hydrogen peroxide.s8 The final residue contains beaverite, Pb(Cu,Fe,A1),(S04)2(OH)6, beudantite, PbFe,(AsO,)(SO,)(OH),, and plumbojarosite, PbFe6(S04)4(0H),, and is dissolved in hydrochloric acid (1 + 3). The determination of cerussite by 15% ammonium acetate in 3% acetic acid gives high results for ores containing galena, pyrite and organic matter.” The addition of ascorbic acid will suppress the oxidation and dissolution of galena. Galena may be determined in mixtures with betekhinite, Cu,e(Fe,Pb)S,, by dissolution with 4% hydrogen peroxide in 4M ammonium acetate in 5% acetic acid.“’ Because of the slight dissolution of betekhinite in this reagent, the determination is subject to an error of 14%. Manganese
Manganese carbonate minerals can be selectively dissolved in the presence of manganite, MnO,, by
STEGER
6N ammonium sulphate acidified with sulphuric acid to pH 2.” Manganite in the residue is dissolved with a 2% solution of sulphosalicylic acid in O.l-l.ON sulphuric acid. The treatment of carbonate-oxide ores with 1% acetic acid completely dissolves manganocalcite, (Mn,Ca)C03, and 78% of rhodochrosite, MnCO,, and oligonite, (Fe,Mn)C03.” The complete dissolution of rhodochrosite and oligonite is accomplished with 8% sulphuric acid. Manganese oxides are separated from manganese silicates in the residue, with 15% hydrochloric acid. The results for manganocalcite, rhodochrosite and oligonite must be adjusted to take into account the 78% solubility of the last two in 1% acetic acid. Mercury
Mercury compounds in pyro- and hydrometallurgical products may be determined semiquantitatively. Leaching of the sample with 5% nitric acid selectively dissolves HgO. Metallic mercury in the residue is extracted with nitric acid (2 + 1). HgS in the residue is then dissolved in a 5% sodium hydroxide-5% sodium sulphide solution. The compounds may be determined with an error of less than 20%. Molybdenum
Molybdenum oxide, MOO,, can be extracted from roasted molybdenite ore with 2(rSOo/, ammonia solution.g4,95 The molybdenite, MoS,, in the residue is then roasted to Moo3 and determined as above or is assumed to be given by the difference between total MO and the MoO,.‘~ The partial roasting of MoSz at 45&550” gives a product which contains Mo(IV) and Mo(V1) as well as sulphide and sulphate.g6 MO(W) compounds, MOO, and MoO$O&, are dissolved in boiling 20% sodium hydroxide solution. Mo(IV) can be determined in the residue. Sulphate is extracted from the roasted MO& on heating with 15% hydrochloric acid. Sulphide in the residue is determined by oxidation to sulphate. Nickel, cobalt
Chondritic meteorites (and lateritic nickel ores) can be analysed for the metallic, sulphide and silicate phases of nickel and cobaltg7 Metallic nickel and cobalt are dissolved in a 12% solution of mercuric chloride in 6% ammonium chloride solution, in an inert atmosphere. The sulphides are extracted from the residue with 2% bromine in methanol. The silicates are decomposed with hydrofluoric acid. The error in the determination is approximately 1%. Ascorbic acid-hydrogen peroxide selectively dissolves Ni, Co and Cu sulphide minerals in rocks.98 A total and sulphide-phase metal determination permits the calculation of the distribution of metal(s) over the mineral phases in the rock.
Chemical phase-analysis of Silicon
(quartz
in silicates)
Quartz in silicates may be determined as follows.“’ The sample is roasted at 60@650” and treated with a 1:3 mixture of nitric and hydrochloric acids to dissolve oxide minerals. The residue is heated to 25@ 275” with freshly prepared pyrophosphoric acid to dissolve the silicates. The quartz is then dissolved with hydrofluoric-sulphuric acid mixture. An error of 0.5% is claimed. Quartz may also be determined in rocks by pyrosulphate fusion followed by fluorosilicic acid treatment.“’ The latter must be repeated if much feldspar is present in the sample. A decrease in the recovery of quartz with each dissolution stage must be taken into account in calculating the result for quartz. Both pyrophyllite, A12Si,0,,(OH), and zircon. ZrSiO,, offer significant resistance to this procedure. Sulphur Elemental
sulphur
in
OWS
and
mirzerals.
Karchmer”’ has reviewed several methods for the determination of elemental sulphur. In addition, specand chromatographic104~‘0s trophotometric102~103 methods are available. In the spectrophotometric method, the elemental sulphur is extracted from the sample with a solvent such as carbon disulphide or acetone and the absorbance due to sulphur is measured at the appropriate wavelength. The presence of other sulphur compounds may interfere. Also sulphur, if present in the amorphous form, may be incompletely dissolved. lo1 After extraction from the sample with acetone, elemental sulphur is determined by thin-layer chromatdisulphide extract of the ography. lo5 A carbon sample may be analysed for both elemental and xanthate sulphur.lo4 Total sulphur in the extract (in a fixed volume of carbon disulphide) is determined by oxidation of all sulphur compounds to sulphur dioxide. Xanthate sulphur is determined in a second portion of extract by thermal decomposition of all combined-sulphur compounds. All measurements are by gas chromatography. Elemental sulphur is the difference between total and xanthate sulphur. Sulphide. Sulphide in the presence of sulphate is usually determined by evolution of hydrogen sulphide on treatment of the sample with acid.82,‘06 Sulphate may then be determined directly as barium sulphate or as the difference between total and sulphide sulphur. Sulphide may also be determined by pyrolysis of the sample, mixed with reduced copper, at 700 in a stream of nitrogen.“’ Oxidized forms of sulphur are converted into sulphur dioxide, which is collected. Sulphide forms CuS which, of course. gives hydrogen sulphide on addition of acid. Pyrrhotite sulphur can be determined in the presence of pyrite sulphur by its evolution as hydrogen sulphide by a 4”/, stannous chloride solution in hydrochloric acid (1 + 1).84 This reagent may, however, also partially decompose pyrite and it is recom-
85
ores
mended that a solution acid be used instead.85
of hydrazine
in 4N sulphuric
A mixture of hydrofluoric and hydrochloric acids, used at slightly elevated pressure, decomposes pyrochlore, (Na,Ca),(Ta,Nb),O,(OH.F), and microlite, (Na,Ca)2(Ta,Nb)20,(0,0H,F), but only slightly attacks simpsonite, A14(Ta,Nb)3(0,0H,F),+108 Hydrofluoric acid (4M) dissolves 98”/, of microlite but only 7715”~ of columbiteetantahte.iO” Correction for the degree of dissolution of these minerals in this reagent permits the determination of the distribution of TazO, and Nb,O, in microlite and columbite-tantalite, (Fe,Mn)(Ta.Nb),O,. with an error of 226%. Tin
A method has been developed for differentiating and determining free cassiterite, SnO,, cassiterite occluded in the silicate lattice and silicate-bound tin in rocks.“’ The sample is decomposed with a 2:1 hydrofluoric-hydrochloric acid mixture and subsequently heated with ammonium iodide to give total tin. Lattice-bound tin is determined by decomposition with the same acid mixture and subsequent heating with hydriodic acid to dissolve the freshly formed tin oxide. The rock is heated with ammonium iodide to determine the free cassiterite. The difference between total and free cassiterite and lattice-bound tin is the occluded cassiterite. An error of 5-20”/,, depending on tin content, is obtained. Stannite. Cu,FeSnS,, may be selectively decomposed in the presence of cassiterite with concentrated nitric acid.“’ bromine in ethanol or carbon tetrachloride’ ” or sodium nitrate in glacial acetic acid.’ I3 The cassiterite may be determined directly in the residue or by difference between total and stannite tin. The error in the determination is l-2”,
Ilmenite, FeTiO,, titanomagnetite, (Fe,Ti),O, and sphene CaTiSO,. may be extracted from mixtures with rutile. TiO,, with a 2% solution of sodium fluoride in 8 M hydrochloric acid.’ l4 Because l-2’% of the rutile also dissolves, the results for these minerals must be corrected accordingly. Sphene can be determined in the presence of ilmenite and titanomagnetite. The sample is reduced in a stream of hydrogen at 880 and then treated with 1M hydrochloric acid to dissolve iron oxides. Subsequent treatment with a 1.50/, solution of sodium fluoride in 8M hydrochloric acid dissolves sphene, leaving ilmenite and titanomagnetite in the residue. Rutile, if present, also remains in the residue but may be determined as above. The error in these determinations is l-100/ depending on the mineral and its content in the ore.
Members of the wolframite FeWO,, and huebnerite, MnWO,,
group, ferberite, can be determined
H. F.
86
STEGER
in scheelite. ’ ’ ’ The sample is first roasted at 400” to oxidize all ferrous minerals soluble in hydrochloric acid, other than wolframite, to their ferric counterparts, and is then completely dissolved in concentrated hydrochloric acid, in an inert atmosphere. Ferrous iron in the solution represents ferberite. Also, experimental studies 1’ 5 indicate that huebnerite is the only manganese mineral of appreciable amount in scheelite and, therefore, the determination of manganese will yield the huebnerite content of the scheelite. Uranium The ratio of U(IV) to U(W) in rocks and ores can be evaluated.’ 16,117 The sample is decomposed with a non-oxidizing acid in an inert atmosphere. U(N) is precipitated with cupferron, Ti(IV) being used as carrier, and is determined by fluorimetry.“’ Otherwise, U(W) is separated from U(IV) by extraction as an anionic phosphate complex with a So/, solution of tri-n-octylamine in benzene’ I6 or xylene.’ I7 A total uranium determination gives by difference the amount of the oxidation state of uranium not determined directly. The error in the determination is 23%. Zinc
Oxidized zinc minerals such as smithsonite, willemite, Zn,SiO, and hemimorphite, ZnCO,, Zn,Si,O,(OH), H20, are easily separated from sphalerite, ZnS, by dissolution in boiling 5% acetic acid.’ I9 The result must be corrected for the 510% of ZnS which also dissolves. The error in this determination is 1l&l 5% for the oxidized minerals and Z5% for ZnS. ZnS is easily determined in the presence of zinc spine1 by dissolution in acidic hydrogen peroxide.’ 2o The error in the determination is approximately 3’j/,.
REFERENCES
1. V. G. Ageenkov, Tr. Vses. Konf Anal. Khim., 1943, 2, 15. 2. V. V. Dolivo-Dobrovol’skii and Yu. V. Klimenko, Pructical Analysis of Ores, Metallurgiya, 1947. 3. V. V. Dolivo-Dobrovol’skii, Ed., Phase Chemical Analysis of Ores and Minerals, Leningrad Univ., 1962. 4. N. A. Filippova, Phase Analysis of Ores, Metallurgizdat, Moscow 1963. Ibid., 1964. Ihid., 1966. 5. S. A. Yushko, Ed., Phase Microchemical Analysis
Nedra, Moscow, 1969. 6. M. N. Fedorova, K. S. Krivodubskaya and G. N. Osokina, Phase Chemical Analysis of Ferrous Metal Ores and Their Treatment Products, Nedra, MOSCOW, 1912. 7. R. S. Young,
Chemical Phase Analysis, HalsteadWiley, New York, 1974. 8. A. H. Low, Technical Methods of Ore Analysis for Chemists and Colleges, 9th Ed., Wiley, New York, 1922. 9. W. F. Hillebrand, G. E. F. Lundell, H. A. Bright and J. 1. Hoffman, Applied Inorganic Analysis, 2nd Ed., Wiley, New York, 1959. 10. J. A. Maxwell, Rock und Mineral Analysis, Interscience, New York, 1968.
Il. I. N. Maslenitskii, Zavodsk. Lah., 1939, 8. 933. 12. G. G. Mathad and V. A. Altekar. Sci. Cult. India. 1960, 25, 695. 13. E. V. Kopchenova and V. N. Karyukina, Zavodsk. Lab., 1945, 11. 360. 14. I. V. Shmanenkov, ihid., 1945, 11, 459. 15. K. V. Podoinikova and A. T. Chernyi, J. Appl. Chem. USSR, 1963, 36, 2681.
16. Idem. ibid., 1966, 39, 1578. 17. 1. May and R. Smith, J. Assoc. OjY Surv., 1956, 39. 766. 18. S. Lebedev and K. Mikic-Indin, Zh. Radova Srpsku Akad. Nauk, 1952. 22, 169. 19. G. V. Afanas’eva and L. P. Bogatyerva, Ind. Lab., 1973, 39, 721. 20. Cl. N. Samorokova, ibid., 1967, 33, 320. 21. F. E. Merlina and V. N. Budnikova, ihid.. 1969, 35, 1413. 22. L. P. Bogatyreva and G. V. Afanas’eva. ihid., 1970, 36, 1155. 23. M. R. Verma, V. M. Bhuchar, K. J. Theraitil and S. S. Sharma, J. Sci. Ind. Res. B, India, 1955, 14, 192. 24. R. S. Young, Tulantu, 1973. 20, X91. 25. M. A. Popov and S. Boldina, Ilch. Zap. Tsentr. Nauch.-Issled. Inst. Olovyan. Prom.. 1967, 68. 26. G. A. Tiunova, G. D. Sizikhina and A. F. Shal’nova, Nauch. Tr. Sib. Nuuch-Issled. Proekr. In~t. Tsvet. Met., 1971, 63. 27. J. Hoefs, Geochim. Cosmochim. Acfu, 1965, 29, 399.
28. Reference 9, pp. 22632. 29. I. Baker and R. Stevens, Ind. Eng. C’hem.. Anul. Ed.. 1946, 18, 124. 30. S. M. Mehta and R. N. Bharucha. Proc. Indim Acad. Sri.. 1953, 3lA, 29.
31. Kh. K. Ospanov and 0. A. Songina, Ind. Luh.. 1968, 34, 189. 32. K. D. Leont’eva and R. V. Shelankova, Sh. Nuuch. Tr. Gas. Nuuch.-Issled. Inst. Tsvet. Mrtul., 1967. 27, 95. 33. 0. N. Pashevkina and T. V. Gurkina, Ind. Lah., 1971.
37, 1135. 34. Jen-Yin Yen and Yii-Shan Liu, Actu Ckim. Sinicu, 1959, 25, 346. Tr. Altaisk Gorno-Me&d. Nauch.Issled. Akad, Nauk Kaz. SSR, 1961. 11, 153.
35. B. S. Khristoforov,
36. Reference 3, pp. 3349. 37. B. S. Khristoforov and M. I. Timerbulatova. Khim. Analit. Tsvet. Redk. Metal., 1964, 93, 116. 38. L. D. Dolaberidze and Yu. V. Politova, Ind. Lab.. 1966, 32, 953. 39. B. S. Khristoforov and A. G. Merkulov. Kkim. Anulit. Tsvet. Redk. Metal., 1964, 93, 106. 40. 0. A. Songina, Kh. K. Ospanov and 2. B. Rozhdestvenskaya, lnd. Lab., 1966, 32, 956. 41. N. I. Solntsev and L. V. Usova. Sh. Tr. Gos. N~mch.Issled. Inst. Tsvet. Met., 1962, 756. 42. F. E. Merlina, Ind. Lab., 1974, 40, 314. 43. A. V. Zagorodnyuk, R. L. Magunov and I. V. Stasenko, ihid.. 1973. 39, 1388. 44. L. N. Terzeman, ibid., 1972, 38, 1824. 45. S. P. Leiba and Yu. 1. Dolgina. Zavodsk. Lah., 1935, 4, 743.
46. N. S. Tkachenko, P. I. Davidenko and A. V. Dobrzkanskii, Ind. Lab., 1963, 29, 557. 47. J. Aubry and P. Perrot, Chim. Antd. (Paris). 1965, 47, 177. 4x. T. A. Frantsuzova and 0. P. Lebedev. Ind. Luh.. 1968, 34, 1578. 49. N. 1. Stoenii and A. G. Kirilenko, Zavodsk. Lab., 1955, 21,594. 50. M. G. Habashv. Anal. Chem.. 1961. 33, 586 51. J. Vorlicek and’s, Lang, Tech. Zpruvodtzi VUZDH, 1963, 2, 19.
Chemical
phase-analysis
52. T. P. Prasad, Talanta, 1969, 16, 1484. 53. F. Marion and J. Aubry, Chim. Anal. (Paris), 1959, 41, 401. 54. L. Balabanoff, E. Schmidt and B. Seegar, Z. Anal. Chem., 1964, 204, 107. 55. G. Kraft and J. Fischer, ibid., 1963, 197, 217. 56. A. M. Leblond. R. Wendling and J. M. Bourdieu, Chim. Anal. (Paris), 1968, 50,431. 57. B. R. Sant and T. P. Prasad. Talanta. 1968. 15. 1483. 58. K. Kinson, J. E. Dickeson &d C. B. Beldher: Anal. Chim. Acta, 1968, 41. 107. 59. S. C. Blum and T. D. Searl. Anal. Chem.. 1971.,, 43. 150. 60. N. A. Filippova, L. A. Martynova and N. Yu. Gusel’nikova, Ind. Lub.,‘1971, 37, 999. 61. A. T. Chernyi and K. V. Podoinikova, Zavodsk. Lab., 1950, 16, 1308. 62. A. Piksarv, H. Arro and V. Vares, Tr. Tallin. Politeckh. Inst. Ser. A, 1964, 215, 137. 63. Yu. V. Morachevskii and N. Kh. Pinchuk, Vestn. Leningrad. Univ., 1956, 60. 64. N. Kh. Pinchuk and Yu. V. Morachevskii, ibid., 1958, 126. 65. J. P. Riley and H. P. Williams, Mikrochim. Acta, 1959, 4. 66. C. V. Clemency and A. F. Hagner, Anal. Chem., 1961, 33, 888. 67. M. Yu. Budilovskii and Yu. I. Usatenko, Ind. Lab., 1970, 36, 994. 68. Lo-Sun Jen, Anal. Chim. Acta, 1973, 66, 315. 69. A. D. Wilson, Bull. Geol. Suru. G.B., 1955, 9, 56. 70. A. Peters, Neues Jahrb. Mineral. Monatsh., 1968, 119. 71. C. 0. Ingamells, Talanta, 1960, 4, 268. 72. K. Pamnani and S. K. Agnihotri, Lab. Pratt., 1966, 15, 867. 73. R. Meyrowitz, Am. Min., 1963, 48, 340. 74. H. Ungethiim, Z. Angew. Geol., 1965, 11, 500. 75. E. R. Whipple, Chem. Geol., 1974, 14, 223. 76. Z. M. Mil&ailova, A. A. Yarushka, R. V. Mirskii and E. A. Shil’dkrot. Tr. Gos. Nauch.-lssled. Inst. Neft. Prom., 1963, 124. Zh. Analit. Khim., 1968, 23, 1057. 77. Yu. N. Novikova, Anal. Chem., 1969. 41. 501. 78. E. M. Donaldson. 79. J. VorliEek and F. Vydra, Hutn. Listy, 1963, 18, 733. 80. F. Vydra and J. VorliEek, Chem. Anal. (Warsaw), 1964, 53, 103. 81. Yu. V. Klimenko and M. N. Fedorova, Zavodsk. Lab., 1955, 21, 294. 82. Yu. V. Morachevskii and N. Kh. Pinchuk, Vestn. Leningrad. Univ., 1956, 170. 83. Y. Okura. Bunseki Kagku, 1960, 9. 845-849. 84. S. Yu. Fainberg, Analysis of the Ores of Non-Ferrous Metals, Metallurgizdat, Moscow, 1953. 85. Z. Valcha and J. Pelikan, Vestn. Ustred. Ustauu Geol., 1958. 33, 244. 86. N. A. Filippova and L. A. Martynova, Ind. Lab., 1964, 33. 1253. 87. N. I. Solntsev and R. I. Chudina, Sb. Nauch. Tr. Gos. Nauch.-lssled. Inst. Tsvet. Metal., 1958, 80. 88. N. A. Filippova, V. A. Korosteleva and Yueh-Ying Chu, Ind. Lab., 1961, 27. 1351. 89. A. G. Kudenko and 0. N. Pashevkina, ibid., 1970, 36, 187.
of ores
87
Obogashch. Rud., 90. F. E. Merlina and N. V. Budhikova, 1964, 9, 36. 91. L. P. Buadze, Ezhegodnik Kavkazsk. Inst. Mineral’n. Syr’yaza 1957, p. 50. Nauchn. Tekhn. Izdat, Moscow, 1959. and G. N. Samorokova, Byull. 92. M. N. Fedorova Nauch.-Tekh. Inform. Min. Geol. Okhrany, Nedr., USSR, 1962, %, 102. and G. V. Afanas’eva, Ind. Lab., 93. L. P. Bogatyreva 1970, 36,83;. 94. V. G. Shcherbakov and I. S. Sakhiev. Zauodsk. Lab.. 1937, 6, 684. 95. N. C. Angelotti and E. G. Gooch, Anal. Chim. Acta, 1972, 58, 445. and L. I. Lebedev, J. Appl. Chem. 96. I. K. Gromozova USSR, 1971, 44, 1488. Z. Anal. 97. N. R. Sen Gupta and A. N. Chowdbury, Chem., 1974, 268, 32. 98. J. J. Lynch in Geochemical Exploration, R. W. Boyle, Ed., pp. 313-14. Can. Inst. Mining Met., Montreal, 1971. and A. A. Zubritskaya, lnd. Lab., 99. E. G. Romanenko 1964, 30, 212. J. K. Syers and M. L. Jackson, Soil 100. S. L. Chapman, Sci., 1969, 107, 348. Ed., The Analytical Chemistry of Sul101. J. H. Karchmer, fur and its Compounds, Part I, pp. 6684. Wiley-Interscience, New York, 1970. 102. T. Ozawa, Nippon Kagaku Zasshi, 1966, 87. 578. 103. J. G. Koren, Appl. Spectry. 1969, 23. 275. 104. S. A. Allison, Rept. Natn. Inst. Metall. (S. Afr.), 1972, No. 1495. and M. Sliwiok, Chem. Anal. (War105. S. Banaszkiewicz saw), 1973, 18, 1013. M. Yoshida and T. Ozawa, Bull. Chem. 106. S. Nagashima, Sot. Japan, 1972, 45, 3446. 107. M. A. Volodina, M. Abdukarimova and L. V. Kozlovskaya, Vestn. Mosk. Univ., Khim., 1968, 23, 116. 108. S. Kallmann, H. Oberthin and R. Liu, Anal. Chem., 1962, 34, 609. and S. M. Chernikova, Ind. Lab., 109. A. B. Kroshkina 1967, 33, 1568. 110. J. Agterdenbos and J. Vlogtman, Talanta, 1972, 19, 1295. 111. B. Hirsch, Chem.-Ztg. 1932, 56, 127. 112. L. V. Zverev and N. V. Petrova, Zavodsk. Lab., 1957, 23, 1403. 113. H. F. Steger, Talanta, 1975, 22, 543. Ind. Lab., 114. M. N. Fedorova and K. S. Krivodubskaya, 1964, 30, 643. 115. S. Kallmann, Anal. Chem., 1955, 27, 1433. and T. T. Bykhovtseva, J. Anal. 116. I. A. Tserkovnitskaya Chem. USSR, 1967, 22, 79. 117. I. Hodara and I. Balouka, Anal. Chem., 1971, 43. 1213. 118. R. S. Clarke, Jr. and Z. S. Altschuler, Geochim. Cosmochim. Acta, 1968, 13, 127. 119. L. G. Samokhvalova and N. A. Filippova, Ind. Lab., 1971, 37, 368. 120. N. I. Resketnikov, ibid., 1973, 40, 169.