3133. ----- [RUHRCHEMIE, A.G.] [Process for Recovering Thorium.] German Patent 745,557, Nov. 30, 1944; appl. R 103,507, R 408, filed Oct. 7, 1938 (Cl. IV b-12 m). TOM Reel 37, bag 3,451, item 35, 3pp.; Meyer Transl. PC-S-II, Fischer-Tropsch, vol. 4, chap.

PATENT

3133. ----- [RUHRCHEMIE, A.G.] [Process for Recovering Thorium.] German Patent 745,557, Nov. 30, 1944; appl. R 103,507, R 408, filed Oct. 7, 1938 (Cl. IV b-12 m). TOM Reel 37, bag 3,451, item 35, 3pp.; Meyer Transl. PC-S-II, Fischer-Tropsch, vol. 4, chap. 135, 1949, p.22.

This application is a further development of the process, German Patent 729,059 (abs. 274), for recovering Th from Fe-Th sludges resulting from precipitation. These sludges are dissolved in H₂SO₄, and the Th is precipitated from the resulting solution as K₂Th(SO₄)₃ by addition of K₂SO₄. It has now been found that in the decomposition of the K₂Th(SO₄)₃ double salt to Th bicarbonate by heating with alkali carbonate solution, a K₂SO₄:Na₂SO₄ ratio of 1:1 must not be exceeded in the reaction mixture. A part of the soda solution used for precipitating the Th may be replaced by potash. By maintaining the above ratio, a virtually Fe-free Th precipitates.