2944.     ---------------.  [RUHRCHEMIE, A.-G.]  [Thorium Regeneration.]   FIAT Reel K-20, 1938, frames 24-31; PB 70,211; TOM Reel 287.

        Auergesellschaft A.-G. has developed the following method:  Fe-Th sludge is dissolved in HCl at a temperature of 80.  After cooling, the bulk of the solution is siphoned off, the residue is filtered, and the whole is mixed with H2SO4.  The sulfate precipitates are centrifuged and covered with dilute H2SO4.  The Th sulfate is then stirred with water and converted to Th hydrocarbonate.  The yield of ThO2 by this method is 94%.  The method is compared with the Ruhrchemie method.  The maximum content of SO3 in the Th hydrocarbonate is given as 0.3%.