Germanium extraction

Figure 32 Comparison of germanium extraction with Kelex 100 in liquid-liquid and solid-liquid extraction systems. (From Ref. 30.)...

Billions of years were required for the formation of the earth s crust with its minerals and ores—a process bearing witness to many whims of nature which, to be more exact, reflect the laws of geochemistry. Some elements were less fortunate they did not succeed in forming their own minerals, that is, those in which they would be the principal or, at least, a noticeable component. They exist only as admixtures to all sorts of minerals consisting of other elements. They seem to be widely dispersed in the earth s crust and are called trace elements. Only in the rarest cases do they form their own minerals and if the scientists were lucky to come across them, the new element immediately became the target of chemical analysis. As we shall see later, this was the case of germanium extracted from argyrodite, a uniquely rare mineral. 

Chen, S. Li, X. Huang, H. Winning germanium from zinc sulfate solution by solvent extraction. Hydrometallurgy, Proceedings of the International Conference, 3rd, Kunming, China, Nov. 3-5, 1998, 509-512. 

Harbuck, D. D. Judd, J. C. Behunin, D. V. Germanium solvent extraction from sulfuric acid solutions (and co-extraction of germanium and gallium). Solvent Extr. Ion Exch. 1991, 9, 383-401. 

Elemental compositions Ge 33.86%, Cl 66.14%. The compound may be digested with nitric acid, diluted with water, and the diluted acid extract may be analyzed for germanium by AA and ICP spectrophotometry (See Germanium). The compound may be dissolved in a suitable organic solvent and analyzed by GC/MS. It may be identified from its molecular ions 212 and 220. 

Germanium dioxide may he characterized hy x-ray methods. Germanium metal may he analyzed in the acidified aqueous extract of the compound by AA, ICP, and other instrumental techniques (See Germanium). 

Paik, N. H., M. K. Park, S. H. Choi, D. C. Moon, and T. L. Kang. Studies of germanium in herbal drugs. II. Extracting effect of germanium of different solvents in Zingiberis rhizoma. Seoul Taehakkyo YakhakNonmunjip 1980 5 75-79. 

Dennis L. M. and J. Papish, Germanium. I. Extraction from germanium-... 

Concentrated hydrochloric acid also dissolves the trichloride, about 100 g. of the latter dissolving in 1 litre of acid at 100° C.7 Dissolution in hydriodic acid is accompanied by evolution of heat and the triiodide is formed.8 Ethyl iodide reacts similarly.9 Double decomposition reactions occur w hen arsenic trichloride is heated with phosphorus triiodide, stannic iodide or germanium iodide, the reactions being complete.10 Similarly, potassium iodide heated with arsenic trichloride in a sealed tube at 210° C., and potassium bromide at 180° to 200° C., form respectively arsenic triiodide and tribromide.11 Stannous chloride, added to the solution in hydrochloric acid, causes reduction to arsenic (see p. 29). Arsenic trichloride may be completely separated from germanium chloride by extraction with concentrated hydrochloric acid.12 Ammonium, sodium and cobaltic chlorides react with arsenic trichloride to form additive compounds with magnesium, zinc and chromic chlorides there is no reaction.13... 

Germanium, tin, and lead have relatively low abundances in the earth s crust (Table 19.4, page 823), but tin and lead are concentrated in workable deposits and are readily extracted from their ores. Tin is obtained from the mineral cassiterite (Sn02) by reducing the purified oxide with carbon ... 

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