Separations involving sulphides: Separation of zinc from some elements that form thiosalts

It has been shown that 2 N sodium sulphide reagent can be used for separating arsenic, antimony, tellurium, selenium, molybdenum, mercury, gold, platinum or rhenium from zinc.     

Separations involving sulphides : Separation of thorium or titanium from some elements that form thiosalts

Sodium sulphide can be used to separate arsenic, antimony, tellurium, selenium, molybdenum, mercury, gold, platinum or rhenium from thorium and antimony, tellurium, selenium or mercury from titanium     

Separations involving sulphides: Separations of alkaline earth metals from some elements that form thiosalts

It has been shown that 2N sodium sulphide reagent can be used for separating strontium, calcium or magnesium from arsenic, antimony, tellurium, selenium or molybdenum.     

Separations involving sulphides : Separation of (a) bismuth,lead and cadmium from mercury,and (b) bismuth and mercury from indium

It has been shown that 2N sodium sulphide reagent can be successfully used in the seperation and estimation of: (a) bismuth, lead and cadmium from mercury, and (b) bismuth and mercury from indium     

Separations involving sulphides: Separation of ruthenium and indium from alkaline earth metals

It has been shown that 2N sodium sulphide reagent can be efficiently used for separating ruthenium or indium from alkaline earth metals.     

Seperations involving sulphides : Separation of alkaline earth metals from some elements that form sulphides

It has been shown that 2N sodium sulphide reagent can be used efficiently for separating. 1.Barium from rhenium, platinum, gold, bismuth, palladium, lead or cadmium. 2.Strontium, calcium and magnesium from rhenium, platium, gold, mercury, bismuth, palladium, lead or cadmium     

Separations involving sulphides : Separation of rhenium and antimony from mercury

It has been shown that it is possible to estimate rhenium or antimony in the presence of mercury by decomposing their thiosalts but not platinum, gold. selenium and tin.     

Separations involving palladium: Separation of lead,bismuth, cadmium,thallium, copper,cobalt and nickel from palladium

It has been shown that 1% dimethylglyoxime solution in alcohol can be efficiently used to separate quantitatively palladium from other metals of the copper group, as indicated in the new and more comprehensive scheme of qualitative analysis.     

Estimation of metals as sulphides : Estimation of bismuth,cadmium, lead,and indium

1. It has been shown, that under proper conditions bismuth, cadmium, lead and indium can be precipitated quantitatively as pure sulphides by alkali sulphides and the precipitate weighed directly for the estimation of the motal. 2. In the case of bismuth ammonium sulphide gives a pure precipitate of Bi₂0₃ which is washed with hot water and weighed directly. 3. In the case of cadmium sodium sulphide gives a pure orange coloured precipitate of the Bulphide which is washed with water and without any further treatment, weighed as CdS. 4. In the case of lead the solution is treated with alkali sulphide, the mixture is then acidified with. acetic acid and the pure precipitate of PbS after washing with water weighed directly without heating. 5. In the case of indium treatment with ammonium sulphide gives a pure precipitate of In₂S₃ which after washing and heating can be weighed directly for the estimation of the metal. Equally good results are obtained if the mixture is acidified with acetic acid after treatment with ammonium sulphide. 6. The given procedures provide for a convenient, quick and accurate estimation of the metals.     

Separations involving sulphides : Separation of platinum,gold, selenium,arsenic, rhenium and molybdenum from lead

It has been shown that it is possible to determine platinum, gold, selenium, arsenic, rhenium or molybdenum in the presence of lead with 2N sodium sulphide reagent but not tellurium, antimony and tin.     

Separations involving sulphides : separation of arsenic,molybdenum and tellurium from mercury

It has been shown that it is possible to determine arsenic, molybdenum m tellurium in tlic presence of mercury by decomposing in one portion the thiosalt of mercury alone with ammonium acetate and in another portion the thioaalts of both the metals with hydrochloric acid.     

Separation of bismuth from lead, copper and other elements by means of anion exchange

The anion-exchange behaviour of bismuth and various other elements has been investigated in media consisting of methyl glycol and nitric acid. Through the determination of the distribution coefficients in such mixtures, a method for the anion-exchange separation of bismuth from many metal ions has been developed. A mixture of 90% methyl glycol and 10% 5M nitric acid is a suitable medium for this separation on the strongly-basic anion exchanger Dowex 1, X8. Only bismuth, thorium and lanthanum are strongly retained on the resin in these conditions. All other elements investigated, such as lead, copper, iron, etc., are either only weakly adsorbed or are not absorbed. By means of this ion-exchange procedure, a series of analyses of copper-base alloys for bismuth has been carried out. The results show that this method can be used successfully for the quantitative isolation of bismuth from such materials. The final determination of bismuth in the eluates is performed by complexometric titration.     

Quantitative separation of gold from cadmium, indium, zinc and other elements by cation-exchange chromatography in hydrochloric acid-acetone medium

Gold(III) can be separated from Cd, In. Zn, Ni, Cu(II), Mn(II), Co(II), Mg, Ca, Al, Fe(III), Ga and U(VI) by adsorbing these elements on a column of AG50W-X8 sulphonated polystyrene cation-exchange resin from 0.1M HCl containing 60% v v acetone, while Au(III) passes through and can be eluted with the same reagent. Separations are sharp and quantitative. The amounts of gold retained by the resin are between 1 and 2 orders of magnitude lower than encountered during adsorption from aqueous 0.1M HCl. Recoveries for mg amounts of gold are 99.9% or better and for ng amounts are still better than 99%, as shown by radioactive tracer methods. Hg(II), Bi, Sn(IV), the platinum metals and some elements which tend to form oxy-anions in dilute acid accompany gold. All other elements, though not investigated in detail, should be retained, according to their known distribution coefficients. Relevant elution curves, results of quantitative separations of binary mixtures and of recovery tests are presented.     

Improved separation of cadmium from indium,zinc, gallium and other elements by anion-exchange chromatography in hydrobromic nitric acid mixtures

The separation of cadmium from indium, zinc and many other elements is considerably improved by eluting these elements with 0.1 M hydrobromic–0.5 M nitric acid solution from a column of AG1-X8 resin. Cadmium is retained very strongly and can be eluted with 2 M nitric acid or 1 M ammonia–0.2 M ammonium nitrate solution. Separations are sharp and quantitative and from microgram amounts up to 2 g of indium and zinc are separated from amounts of cadmium ranging from micrograms up to 100 mg on a 2-g (4.6 ml) resin column. Ga(II), Fe(III). Mn(II), Co(II), U(VI) and Ni(II) can be separated quantitatively from cadmium in the same way. The behaviour of numerous elements is discussed, with special attention to lead, and relevant elution curves and results from the analysis of synthetic mixtures are presented.     

Separation of silver from zinc, cadmium, copper, nickel and other elements in nitric acid with a macroporous resin

Traces of silver and amounts up to 50 mg can be separated from up to gram amounts of Zn, Cu(II), Ni, Co(II), Mg, Be, Ti(IV), V(IV), Li and Na by eluting these with 2.0M nitric acid from a column containing 54 ml (20 g) of macroporous AG MP-50 cation-exchange resin of 100-200 mesh particle size, in the H(+)-form. Silver is retained and can be eluted with 0.5M hydrobromic acid in 9:1 v v acetone-water. Separations are sharp and quantitative and only a few microg of the other elements are found in the silver fraction. Cadmium and manganese (II) can also be separated quantitatively but show tailing and require larger elution volumes. Some typical elution curves and results of analyses of synthetic mixtures are presented.     

Anion-exchange separation of gallium from indium,thallium, aluminium and other elements in malonic acid

Summary Systematic studies of gallium on Dowex-21K in malonate media are reported. On the basis of the value of the elution constant (E) it was separated from large number of metal ions. By selective sorption it was separated from the alkalis, alkaline earths, bismuth, thallium (I), mercury (II), iron (II) and germanium (IV). With water as eluant it was separated from cobalt, nickel, zinc, manganese and palladium, with ammonium chloride it was possible to separate it from copper, iron and vanadium, and with a specific eluant it was separated from lead and zirconium. Finally the sequential separation of gallium from thallium, aluminium and indium was accomplished.     

Separation of traces and minor amounts of lead from large amounts of zinc,indium, gallium and other elements on a low cross-linked anion-exchange resin

Lead is separated from gram amounts of Zn, In, Ga, Fe(III), Cu(II), Co(II), Mn(II), U(VI), Ca and Ba on a short column of AG1-X4 anion-exchange resin in the bromide form. Lead is retained from 0.2 M hydrobromic acid while the other elements are eluted completely with this reagent. Lead is then eluted with 2 M nitric acid. Separations are sharp and quantitative and, especially for gram amounts of zinc, much better than those obtained with an 8% cross-linked resin; up to 10 mg of lead can be separated from 2 g of zinc. Results are given for synthetic mixtures and lead is determined in several analytical grade chemicals.     

Separation of titanium and uranium from other elements by tannin

Summary Titanium and uranium have been precipitated by tannin in the presence of various other ions, e.g., Fe³⁺, Al³⁺, Cr³⁺, Th⁴⁺, Zr⁴⁺, Bi³⁺, Pb²⁺, (VO)²⁺ and rare earths, which are kept in solution by EDTA. The precipitation was carried out by raising the p_H of the acidic solution containing EDTA and tannin by dilute ammonium hydroxide or hexamine. The p_H of complete precipitation of titanium is 4.0 and above and that of uranium is 6.0 and above.

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Zusammenfassung Titan und Uran werden mit Tannin in Gegenwart verschiedener Fremdionen, die durch ÄDTA in Lösung gehalten werden, gefällt (z.B. in Gegenwart von Fe³⁺, Al³⁺, Cr³⁺, Th⁴⁺, Zr⁴⁺, Bi³⁺, Pb²⁺, (VO)²⁺, Seltenen Erden). Die Fällung wird durchgeführt, indem man die saure Lösung, die ÄDTA und Tannin enthält, mit Ammoniak oder Hexamethylentetramin neutralisiert. Titan wird bei p_H-Werten über 4,0 und Uran bei solchen über 6,0 vollständig ausgefällt.

     

Separation and spectrophotometric determination of trace elements in high-purity cadmium

Zusammenfassung Die Spurenanalyse zur Bestimmung von Ag, Al, Bi, Co, Cu, Ga, Hg, In, Mn, Ni, Pb, Tl und Zn in reinstem Cadmium wurde ausgearbeitet. Nach dem vorgeschlagenen Schema werden einzelne Gruppen von Spurenelementen durch Extraktion bzw. Mitfällung getrennt und spektrophotometrisch mit Hilfe der folgenden organischen Reagenzien bestimmt: Dithizon, PAN, PAR, Rhodamin B, Brillantgrün, Chromazurol S, 1-Nitroso-2-naphthol und-Furildioxim. Durch die Analyse einer Cadmiumprobe mit dem Zusatz bekannter Mengen der zu bestimmenden Elemente wurden Genauigkeit und Präzision der vorgeschlagenen Methode erwiesen.