National Repository of Grey Literature 2 records found  Search took 0.02 seconds. 
Perpectives of cyech lithium sources exploitation
Brožek, Vlastimil ; Dufek, V.
In the mineral reserve balance of Czech republic there is filed more than 53 Mt of Sn-W ores with 0,208 - 0,286 % Li content, but unfortunately this low content did not lately allow to take advantage of their exploitation in competition with cheap processing e.g. of German company CHEMETALL. In sixtieth years after promising start of lithium carbonate production from zinnwaldite in Lachema Kaznějov the researchers of Institute of Chemical Technology Prague prepared metallic lithium by classical electrolytic process from chloride melt. The metal was destined first for lithium hydride an lithium aluminium hydride production. The establishing of such production failed from different reasons. The predominant part of domestic lithium sources is constituted as ferrous micas. Therefore the possibility to obtain concentrates, which would be acceptable from economic point of view reveals in magnetic separation, especially by the use of highly intensive superconducting magnets. They can deliver concentrates with about five time higher lithium content.
Behaviour of tungsten carbide during plasma deposition
Brožek, Vlastimil ; Flemr, V. ; Matějíček, Jiří ; Neufuss, Karel
Analysis of the spheroidized tungsten carbide powder prepared by plasma spraying showed marked changes in chemical and phase composition, especially in dependence on particle size. In sub-micrometric or nanometric particles, the bonded carbon content is reduced to nearly zero and increases with particle diameter. Nanometric particles consist of almost pure tungsten. this permits to draw some conclusions about the tungsten carbide decomposition and carbon transport in molten carbide under extreme conditions of plasma melting and deposition onto solid substrates.

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