PROCESS FOR RECOVERING ALUMINA IN MINERALS OR ROCKS OR INDUSTRIAL WASTE PRODUCTS DERIVED FROM SUCH MINERALS OR ROCK

摘要

1499144 Recovery of alumina; Ca aluminate CHEMOKOMPLEX VEGYIPARI GEP-ES BERENDEZES EXPORT-IMPORT VALLALAT and TATABANYAI SZENBANYAK 26 March 1975 [4 April 1974] 12632/75 Heading C1A A process for recovering alumina contained in minerals or rocks or industrial waste products derived from such minerals or rocks comprises kneading the starting material with 1-3 moles of lime (CaO or Ca(OH) 2 ) per mole of alumina present and water to form a homogeneous plastic mass, forming the mass into a multiplicity of shaped bodies, maintaining the bodies at ambient to 200‹ C. in a closed reactor where temperatures over 100‹ C. are used, until the alumina is solubilized by reaction with the lime and the bodies are hardened by reaction with the water, comminuting the bodies, and recovering alumina in solution by leaching the comminuted material. One mole of lime may additionally be added to the starting material for each mole of silica present. Alumina may be recovered from the final solution by addition of ammonia to form an alumina precipitate and ammonium nitrate when the leaching step is performed in nitric acid.