GB869958A - Process for the separation of thorium from lanthanons - Google Patents

Abstract

In a process for separating thorium from rare earth metals a solution containing thorium, rare earth metals and sulphate ions is extracted with a solution in an organic solvent of an amine having an aliphatic chain containing 10 to 30 carbon atoms which will form a complex with the thorium and sulphate ions, the organic solvent extract is washed with an aqueous solution containing chloride and sulphate ions, and the thorium is then removed from the washed organic solvent extract by extraction with an aqueous solution containing ions which displace the thorium from the amine complex. In an example monazite is heated with sulphuric acid, diluted with water, filtered, and the solution extracted with a branched chain amine of formula C20H41NH2 dissolved in xylene, the extract being washed with an aqueous solution of hydrochloric and sulphuric acids and then extracted with an aqueous solution of ammonium nitrate and nitric acid to obtain an aqueous solution of thorium sulphate. Other amines containing 16 to 24 carbon atoms may be used, and the solvent may be kerosene, toluene or benzene. The chloride and sulphate ions in the liquid used to wash the extract may be provided by dissolved salts, e.g. sodium chloride and sodium sulphate. The thorium also may be displaced from the amine complex by using an aqueous solution of ammonium carbonate to obtain an aqueous solution of a complex thorium carbonate.