PURIFICATION OF THALLIUM BY CRYSTALLIZATION METHODS (in Russian)
In connection with the current interest in Tl and its compounds for novel applications in atomic technology and instrumentation, there is an increased demand for a very high purity material; in particular the semiconductor- grade Tl must contain less than about 10/sup -6/% of each of Fe, In, Cd, Ca, Si, Cu, Sn, Hg, Pb, S and Zn. Therefore a systematic study was undertaken to remove tbe impurities by crystallization methods, making use of the currently available 29 partial phase diagrams of binary Tl systems. On the basis of the pertinent Tl- impurity diagram, the efficiency of the puriflcation method could be estimated. Deviation from the anticipated behavior usually indicated secondary processes which in general enhanced the purification process; Cd, Hg and S could be removed by sublimation while oxidation reactions were found helpful to eliminate Sn and Cu. Stirring of zone melts in the recrystallization zone improved the purity of the end product. As Fe is insoluble in Tl, it must be eliminated by filtration. There are no very gocd methods available for removing Pb. Alkallne and electrochemical refining techniques show good promise. (TTT)
- Research Organization:
- Kalinin Inst. of Nonferrous Metallurgy, Moscow
- NSA Number:
- NSA-15-029633
- OSTI ID:
- 4837232
- Journal Information:
- Izvest. Akad. Nauk S.S.S.R., Otdel. Tekh. Nauk, Met. i Toplivo, Journal Name: Izvest. Akad. Nauk S.S.S.R., Otdel. Tekh. Nauk, Met. i Toplivo Vol. Vol: No. 3
- Country of Publication:
- Country unknown/Code not available
- Language:
- Russian
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