GB189698A - Method for the treatment of monazite and other phosphate ores - Google Patents

Abstract

Phosphoric acid mixed with excess of sulphuric acid, is obtained by treating with sulphuric acid phosphate ores of thorium and rare earths, such as monazite. The sulphates separate and are removed mechanically. Alternatively the reaction mixture may be poured into dilute sulphuric acid and a part of the thorium separates as sulphate with the rare earths. The precipitate is separated, the thorium separated from the rare earths in known manner, and added to the solution, which is then concentrated until the thorium sulphate separates.ALSO:Phosphate ores of thorium and rare earths such as monazite are decomposed by strong sulphuric acid, and the insoluble sulphates are separated mechanically from the liberated phosphoric acid, the sulphates being freed from remaining phosphoric acid by washing with strong sulphuric acid, after which the washings are used for treating a fresh batch of ore. The thorium is separated from the mixed sulphates in known ways. Alternatively, the reaction mass may be diluted with dilute sulphuric acid which causes most of the thorium to dissolve, while a part of the thorium and the rare earth sulphates remain insoluble in a crystalline condition. The thorium, separated from the rare earths in known manner, is added to the acid solution, and thorium sulphate is subsequently recovered by concentrating the solution when it again becomes insoluble.