Abstract: A process for the extraction of alumina from aluminum-containing silicates is disclosed. The process comprises acid leaching of the raw material, iron extraction, precipitation of the aluminum fraction as the aluminum chloride hexahydrate, removal of sodium chloride and calcination to alumina. The process can be made continuous with substantial regeneration and recycling of process components.

Abstract: An improved liquid-liquid extraction process for the separation of the elements of the lanthanide series is disclosed. The process involves dissolving the lanthanides in a sulfuric acid solution to form rare earth sulfates whereafter the solution is contacted with an organic solvent immiscible with water and containing di (2-ethylhexyl) phosphoric acid whereby the lanthanides are separated from impurities and at least some of the lanthanides are extracted into the organic phase. Thereafter, the organic and aqueous phases are separated and the organic phase containing the impurities-separated lanthanides is subjected to a back extraction with an aqueous phase comprising an aqueous solution with sulfuric acid. The contact time between the aqueous and organic phases in the back extraction is regulated so that a desired or desired elements of the lanthanides are back extracted into the aqueous phase. The contact time is controlled and is less than the total extraction equilibrium time between the phases.