SOLVENT EXTRACTION OF SOLUTIONS CONTAINING RARE EARTHS. PREPARATION OF THORIUM COMPOUNDS FROM MONAZITE BY SULFURIC ACID DECOMPOSITION AND SOLVENT EXTRACTION

An investigation was made of the feasibility of producing pure Th compounds from monazite sand by a process involving the digestion of the sand with H/sub 2/SO/sub 4/ and separation of Th from the rare earths by solvent extraction. Direct extraction was not practicable. Precipitation of the sulfate from the system with lime and HNO/sub 3/ was tried and found to be partially successful but impracticable because of the large losses of Th by occlusion in the precipitate. A successful method for producing tributylphosphate-extractable solution was found, consisting of neutralizing the original solution to precipitate the heavy metals as phosphates, and, after filtering and washing, dissolving this precipitate in HNO/sub 3/. (auth