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1.
Summary A procedure is proposed for determination of small amounts of silver in copper ores and processed products. The samples are dissolved in a Teflon bomb in a mixture of hydrofluoric and nitric acids, then evaporated in the presence of nitric and boric acids. Silver is extracted from the sample solution with a solution of triphenylphosphine in methyl isobutyl ketone, then determined by atomic-absorption spectrophotometry. The method is precise and accurate. The relative standard deviation for a silver content of 10–4% is about 4%.
Zusammenfassung Ein Verfahren zur Bestimmung kleiner Mengen Silber in Kupfererzen und daraus hergestellten Produkten wurde vorgeschlagen. Die Proben werden in einer Teflonbombe in einem Gemisch aus Flußsäure und Salpetersäure gelöst und dann in Gegenwart von Salpetersäure und Borsäure eingeengt. Das Silber wird mit Triphenylphosphin, gelöst in Isobutylmethylketon, aus der Probelösung extrahiert und dann mit Hilfe der AAS bestimmt. Das Verfahren ist genau, die relative Standardabweichung beträgt bei einem Silbergehalt von 10–4% ungefähr 4%.相似文献
2.
Donaldson EM 《Talanta》1979,26(11):999-1010
Methods for determining trace and moderate amounts of antimony in copper, nickel, molybdenum, lead and zinc concentrates and in ores are described. Following sample decomposition, antimony is oxidized to antimony(V) with aqua regia, then reduced to antimony(III) with sodium metabisulphite in 6M hydrochloric acid medium and separated from most of the matrix elements by co-precipitation with hydrous ferric and lanthanum oxides. Antimony (>/= 100 mug/g) can subsequently be determined by atomic-absorption spectrophotometry, at 217.6 nm after dissolution of the precipitate in 3M hydrochloric acid. Alternatively, for the determination of antimony at levels of 1 mug/g or more, the precipitate is dissolved in 5M hydrochloric acid containing stannous chloride as a reluctant for iron(III) and thiourea as a complexing agent for copper. Then tin is complexed with hydrofluoric acid, and antimony is separated from iron, tin, lead and other co-precipitated elements, including lanthanum, by chloroform extraction of its xanthate. It is then determined spectrophotometrically, at 331 or 425 nm as the iodide. Interference from co-extracted bismuth is eliminated by washing the extract with hydrochloric acid of the same acid concentration as the medium used for extraction. Interference from co-extracted molybdenum, which causes high results at 331 nm, is avoided by measuring the absorbance at 425 nm. The proposed methods are also applicable to high-purity copper metal and copper- and lead-base alloys. In the spectrophotometric iodide method, the importance of the preliminary oxidation of all of the antimony to antimony(V), to avoid the formation of an unreactive species, is shown. 相似文献
3.
Donaldson EM 《Talanta》1979,26(12):1119-1123
Two simple, reliable and moderately rapid atomic-absorption methods for determining trace and minor amounts of bismuth in copper, nickel, molybdenum, lead and zinc concentrates and ores, and in non-ferrous alloys, are described. These methods involve the separation of bismuth from matrix elements either by chloroform extraction of its diethyldithiocarbamate (DDTC) complex, at pH 11.5–12.0, from a sodium hydroxide medium containing citric acid, tartaric acid, EDTA and potassium cyanide as complexing agents, or by co-precipitation with hydrous ferric oxide from an ammoniacal medium. Bismuth is ultimately determined, at 223.1 nm after evaporation of the extract to dryness in the presence of nitric and petchloric acids and dissolution of the salts in 20% v/v hydrochloric acid, or by dissolution of the hydrous oxide precipitate with the same acid solution, respectively. Results obtained by both methods are compared with those obtained spectrophotometrically by the iodide method after the separation of bismuth by DDTC and xanthate extractions. 相似文献
4.
M Donaldson E 《Talanta》1988,35(1):47-53
A method for determining approximately 0.2 mug/g or more of arsenic in ores, concentrates and related materials is described. After sample decomposition arsenic(V) is reduced to arsenic(III) with titanium(III) and separated from iron, lead, zinc, copper, uranium, tin, antimony, bismuth and other elements by cyclohexane extraction of its xanthate complex from approximately 8-10M hydrochloric acid. After washing with 10M hydrochloric acid-2% thiourea solution to remove residual iron and co-extracted copper, followed by water to remove chloride, arsenic is stripped from the extract with 16M nitric acid and ultimately determined in a 2% nitric acid medium by graphite-furnace atomic-absorption spectrometry, at 193.7 nm, in the presence of thiourea (which eliminates interference from sulphate) and palladium as matrix modifiers. Small amounts of gold, platinum and palladium, which are partly co-extracted as xanthates under the proposed conditions, do not interfere. 相似文献
5.
Donaldson EM 《Talanta》1989,36(5):543-548
A method for determining approximately 0.5, mug/g or more of cobalt, nickel and lead and approximately 3 mug/g or more of bismuth and indium in ores, soils and related materials is described. After sample decomposition and dissolution of the salts in dilute hydrochloric-tartaric acid solution, iron(III) is reduced with ascorbic acid and the resultant iron(II) is complexed with ammonium fluoride. Cobalt, nickel, lead, bismuth and indium are subsequently separated from iron, aluminium, zinc and other matrix elements by a triple chloroform extraction of their xanthate complexes at pH 2.00 +/- 0.05. After the removal of chloroform by evaporation and the destruction of the xanthates with nitric and perchloric acids, the solution is evaporated to dryness and the individual elements are ultimately determined in a 20% v/v hydrochloric acid medium containing 1000 mug/ml potassium by atomic-absorption spectrometry with an air-acetylene flame. Co-extraction of arsenic and antimony is avoided by volatilizing them as the bromides during the decomposition step. Small amounts of co-extracted molybdenum, iron and copper do not interfere. 相似文献
6.
Donaldson EM 《Talanta》1990,37(10):955-964
A continuous hydride-generation atomic-absorption spectrometric method for determining approximately 0.02 mug/g or more of antimony in ores, concentrates, rocks, soils and sediments is described. The method involves the reduction of antimony(V) to antimony(III) by heating with hypophosphorous acid in a 4.5M hydrochloric acid-tartaric acid medium and its separation by filtration, if necessary, from any elemental arsenic, selenium and tellurium produced during the reduction step. Antimony is subsequently separated from iron, lead, zinc, tin and various other elements by a single cyclohexane extraction of its xanthate complex from approximately 4.5M hydrochloric acid/0.2M sulphuric acid in the presence of ascorbic acid as a reluctant for iron(III). After the extract is washed, if necessary, with 10% hydrochloric acid-2% thiourea solution to remove co-extracted copper, followed by 4.5M hydrochloric acid to remove residual iron and other elements, antimony(III) in the extract is oxidized to antimony(V) with bromine solution in carbon tetrachloride and stripped into dilute sulphuric acid containing tartaric acid. Following the removal of bromine by evaporation of the solution, antimony(V) is reduced to antimony(III) with potassium iodide in approximately 3M hydrochloric acid and finally determined by hydride-generation atomic-absorption spectrometry at 217.8 nm with sodium borohydride as reluctant. Interference from platinum and palladium, which are partly co-extracted as xanthates under the proposed conditions, is eliminated by complexing them with thiosemicarbazide during the iodide reduction step. Interference from gold is avoided by using a 3M hydrochloric acid medium for the hydride-generation step. Under these conditions gold forms a stable iodide complex. 相似文献
7.
A recent graphite-furnace atomic-absorption method for determining approximately 0.2 mug/g or more of arsenic in ores, concentrates, rocks, soils and sediments, after separation from matrix elements by cyclohexane extraction of arsenic(III) xanthate from approximately 8-10M hydrochloric acid, has been modified to include an alternative hydride-generation atomic-absorption finish. After the extract has been washed with 10M hydrochloric acid-2% thiourea solution to remove co-extracted copper and residual iron, arsenic(III) in the extract is oxidized to arsenic(V) with bromine solution in carbon tetrachloride and stripped into water. Following the removal of bromine by evaporation of the solution, arsenic is reduced to arsenic(III) with potassium iodide in approximately 4M hydrochloric acid and ultimately determined to hydride-generation atomic-absorption spectrometry at 193.7 nm, with sodium borohydride as reductant. Interference from gold, platinum and palladium, which are partly co-extracted as xanthates under the proposed conditions, is eliminated by complexing them with thiosemicarbazide before the iodide reduction step. The detection limits for ores and related materials is approximately 0.1 mug of arsenic per g. Results obtained by this method are compared with those obtained previously by the graphite-furnace method. 相似文献
8.
9.
Donaldson EM 《Talanta》1982,29(12):1069-1075
A method for determining 0.1 μg/g or more of silver in ores and concentrates and 0.001 μg/ml or more of silver in zinc process solutions is described. Silver is separated from the matrix elements by chloroform extraction of the tribenzylamine—silver bromide ion-association complex from 0.08M potassium bromide—2M sulphuric acid and stripped with 9M hydrobromic acid. This solution is evaporated to dryness and organic material is destroyed with nitric and perchloric acids. Silver is determined by atomic-absorption spectrophotometry in an air—acetylene flame, at 328.1 nm, in a 10% v/v hydrochloric acid—1% v/v diethylenetriamine medium. Cadmium, bismuth and molybdenum are partly co-extracted but do not interfere. The method is also applicable to copper metal and copper-base alloys. Results obtained by this method are compared with those obtained by a fire-assay/atomic-absorption method. 相似文献
10.
A method for determining approximately 0.01 mug/g or more of tellurium in ores, concentrates, rocks, soils and sediments is described. After sample decomposition and evaporation of the solution to incipient dryness, tellurium is separated from > 300 mug of copper by co-precipitation with hydrous ferric oxide from an ammoniacal medium and the precipitate is dissolved in 10M hydrochloric acid. Alternatively, for samples containing 300 mug of copper, the salts are dissolved in 10M hydrochloric acid. Tellurium in the resultant solutions is reduced to the quadrivalent state by heating and separated from iron, lead and various other elements by a single cyclohexane extraction of its xanthate complex from approximately 9.5M hydrochloric acid in the presence of thiosemicarbazide as a complexing agent for copper. After washing with 10M hydrochloric acid followed by water to remove residual iron, chloride and soluble salts, tellurium is stripped from the extract with 16M nitric acid and finally determined, in a 2% v/v nitric acid medium, by graphite-furnace atomic-absorption spectrometry at 214.3 nm in the presence of nickel as matrix modifier. Small amounts of gold and palladium, which are partly co-extracted as xanthates if the iron-collection step is omitted, do not interfere. Co-extraction of arsenic is avoided by volatilizing it as the bromide during the decomposition step. The method is directly applicable, without the co-precipitation step, to most rocks, soils and sediments. 相似文献
11.
Donaldson EM 《Talanta》1988,35(8):633-639
A method for determining approximately 0.01 mug/g or more of selenium in ores, concentrates, rocks, soils, sediments and related materials is described. After sample decomposition selenium is reduced to selenium(IV) by heating in 4M hydrochloric acid and separated from the matrix elements by toluene extraction of its 5-nitropiazselenol complex from approximately 4.2M hydrochloric acid. After the extract has been washed with 2% nitric acid to remove residual iron, copper and chloride, the selenium in the extract is oxidized to selenium(VI) with 20% bromine solution in cyclohexane and stripped into water. This solution is evaporated to dryness in the presence of nickel, and selenium is ultimately determined in a 2% v/v nitric acid medium by graphite-furnace atomic-absorption spectrometry at 196.0 nm with the nickel functioning as matrix modifier. Common ions, including large amounts of iron, copper and lead, do not interfere. More than 1 mg of vanadium(V) and 0.25 mg each of platinum(IV), palladium(II), and gold(III) causes high results for selenium, and more than 1 mg of tungsten(VI) and 2 mg of molybdenum(VI) causes low results. Interference from chromium(VI) is eliminated by reducing it to chromium(III) with hydroxylamine hydrochloride before the formation of the selenium complex. 相似文献
12.
Donaldson EM 《Talanta》1980,27(10):779-786
A method for determining trace and moderate amounts of chromium in ores, concentrates, rocks, soils and clays is described. After fusion of the sample with sodium peroxide, the melt is dissolved in dilute sulphuric acid. The chromium(III) produced by the hydrogen peroxide formed is co-precipitated with hydrous ferric oxide. The precipitate is dissolved in 0.7M sulphuric acid and chromium oxidized to chromium(VI) with ceric ammonium sulphate. The chromium(VI) is extracted as an ion-association complex into chloroform containing tribenzylamine and stripped with ammoniacal hydrogen peroxide. This solution is acidified with perchloric acid and chromium determined by atomic-absorption spectrophotometry in an air-acetylene flame, at 357.9 nm. Barium and strontium do not interfere. The procedure is also applicable to iron and steel, and nickel-copper, aluminium and zirconium alloys. Up to 5 mg of manganese and 10 mg each of molybdenum and vanadium will not interfere. In the absence of vanadium, up to 10 mg of tungsten will not interfere. In the presence of 1 mg of vanadium, up to 1 mg of tungsten will not interfere. 相似文献
13.
Summary Germanium extracted by methyl isobutyl ketone from 7.5N hydrochloric acid solutions is made to react directly in the organic phase with phenylfluorone. Very stable colored solutions are obtained. The reaction is instantaneous and twice as sensitive as when carried out in aqueous medium with the same reagent. Optimum range of concentration for absorptiometric measurements was found to be 0.08 to 0.30g Ge/ml. Most of the interfering ions are separated by preliminary extraction of the cupferrates with the same ketone. W(VI) and Nb(V) are removed by previous extraction with excess thiocyanate in reducing medium making use of the same solvent. The procedure is applicable to the determination of germanium in coals.
Zusammenfassung Germanium wird aus 7,5-n Salzsäure mit Methylisobutylketon extrahiert und unmittelbar in der organischen Phase mit Phenylfluoron umgesetzt. Die Reaktion erfolgt sofort, ist doppelt so empfindlich als in wäßriger Phase und führt zu sehr stabil gefärbten Lösungen. Die für Absorptionsmessungen am besten geeignete Konzentration liegt zwischen 0,08 und 0,30g Ge/ml. Die meisten störenden Ionen werden durch vorhergehende Extraktion ihrer Cupferonate mit demselben Keton entfernt. Wolfram(VI) und Niob(V) werden mit demselben Lösungsmittel in Gegenwart überschüssigen Rhodanids in reduzierendem Milieu abgetrennt. Das Verfahren eignet sich für die Bestimmung von Germanium in Kohle.
Résumé On fait réagir directement le germanium avec la phénylfluorone, dans la phase organique, après son extraction par la méthylisobutylcétone de sa solution 7,5N chlorhydrique. On obtient ainsi des solutions colorées très stables. La réaction est instantanée et deux fois plus sensible que lorsqu'elle est effectuée en milieu aqueux avec le même réactif. Le domaine de concentration optimum pour les mesures absorptiométriques est situé entre 0,08 et 0,30g Ge/ml. La plupart des ions gênants sont séparés par une extraction préalable des cupferrates par la cétone. W(VI) et Nb(V) sont éliminés au cours d'une extraction préalable en présence d'un excès de thiocyanate en milieu réducteur et dans le même solvant. La technique est applicable à la détermination du germanium dans les charbons.相似文献
14.
An extractive atomic-absorption spectrophotometric (AAS) procedure is developed for fast and accurate determination of up to 20 mug/g antimony in lead and zinc concentrates and other smelter products. The procedure involves digestion of the sample with potassium bisulphate and sulphuric acid, addition of hydrazine to reduce all antimony to Sb(III), reoxidation to Sb(V), extraction of the chloro-complex of antimony(V) with n-butyl acetate, and AAS analysis of the organic phase for antimony. 相似文献
15.
A simple atomic-absorption spectrophotometry method is described for the determination of silver, bismuth, cadmium, copper, iron, nickel and zinc in lead- and tin-base solders and white-metal bearing alloys, with use of a single sample solution. The sample is dissolved in a mixture of hydrobromic acid and bromine, then fumed with sulphuric acid. The lead sulphate is dissolved in concentrated hydrochloric acid. The method is particularly suitable for the determination of silver and bismuth, which are co-precipitated with lead sulphate. The other elements can also be determined after removal of the lead sulphate by filtration. 相似文献
16.
A new method is described for the determination of silver in ores and metallurgical concentrates. The procedure is based on collection of silver in a tin button during a fire assay fusion, and the subsequent determination by atomic-absorption spectrophotometry. The proposed method is rapid and free from inter-element interferences, and results obtained agree favourably with those obtained by alternative methods. 相似文献
17.
A rapid atomic absorption spectrometric method for the determination of tin, antimony, bismuth, indium, gallium and arsenic in geological materials, steels and alloys is described. The samples are fused with sodium peroxide (for geological samples such as cassiterite and sulphides) or decomposed with sulphuric/hydrochloric acid mixture or by alkaline fusion (for silicates or bauxites) or by acid treatment (for steels, alloys and certain geological samples). The elements of interest are extracted as their iodides into methyl isobutyl ketone, stripped into aqueous solution by treatment with benzene, concentrated nitric acid and water, and determined by flame atomic-absorption spectrometry. Detailed study is made on stripping of the metals from organic phase as there no simple and rapid stripping procedures available. The method allows the determination of Sn, Sb, Bi and In down to 2 ppm and Ga down to 5 ppm. The relative standard deviations range up to 10% with an average of 2.5%. Apparent recoveries of these metals range from 90 to 110 with an average of 95% for Sb and 99% for others. 相似文献
18.
Donaldson EM 《Talanta》1980,27(6):499-505
A simple and moderately rapid method for determining 0.001% or more of tin in ores, concentrates and tailings, iron, steel and copper-, zinc-, aluminium-, titanium- and zirconium-base alloys is described. After sample decomposition, tin is separated from the matrix elements, except arsenic, by toluene extraction of its iodide from a 3M sulphuric acid-1.5M potassium iodide medium containing tartaric and ascorbic acids. It is finally back-extracted into a nitric-sulphuric acid solution containing hydrochloric acid to prevent the formation of an insoluble tin-arsenic compound and the resultant solution is evaporated to dryness. Tin is subsequently determined by atomic-absorption spectrophotometry in a nitrous oxide-acetylene flame, at 235.4 nm in a 10% hydrochloric-0.5% tartaric acid medium containing 250 mug of potassium per ml. Co-extracted arsenic does not interfere. Results obtained by this method are compared with those obtained spectrophotometrically with gallein after the separation of tin by iodide extraction. 相似文献
19.
Donaldson EM 《Talanta》1980,27(2):79-84
A simple and moderately rapid method for determining 0.001% or more of molybdenum in ores, iron and steel is described. After sample decomposition, molybdenum is separated from the matrix elements, except tungsten, by chloroform extraction of its alpha-benzoinoxime complex from a 1.75 M hydrochloric-0.13 M tartaric acid medium. Depending on the amount of tungsten present, molybdenum, if necessary, is back-extracted into concentrated ammonia solution and subsequently separated from coextracted tungsten by chloroform extraction of its xanthate complex from a 1.5M hydrochloric-0.13M tartaric acid medium. It is ultimately determined by atomic-absorption spectrophotometry, at 313.3 nm, in a 15% v/v hydrochloric acid medium containing 1,000 microg/ml of aluminium as the chloride, after evaporation of either extract to dryness with nitric, perchloric and sulphuric acids and dissolution of the salts in dilute ammonia solution. 相似文献
20.
Extraction with sodium diethyldithiocarbamate, followed by mineralization and atomic-absorption spectroscopy is used to determine down to 10(-7)% Cu in 40% ammonium fluoride solution used in the manufacture of semiconductors. 相似文献