AQUEOUS/ORGANIC PROCESSING OF RARE-EARTH CARBONATE POWDERS FROM RARE-EARTH LOADED CARBOXYLATE SOLUTIONS USING CO_2 GAS

摘要

This paper describes a new processing of rare-earth oxide precursor, in which rare-earth carbonate powders are precipitated directly from emulsions of rare-earth loaded carboxylate solutions, using CO_2 gas and water. This synthetic route of rare earth carbonate is a combined process of the stripping and precipitation stages in a conventional solvent extraction. Using this technique, lanthanum carbonate and yttrium carbonate were prepared at temperatures of 10 to 80℃ and CO_2 pressures of 0.1 to 3.0 MPa for 120 min. The rates of carbonate precipitation in a batch autoclave were sensitive to processing parameters such as CO_2 pressure, temperature, and organic-phase composition. The particle size distributions of the carbonate powders were markedly dependent on temperature and CO_2 pressure.