PROCESS FOR PRODUCTION OF ALUMINIUM HYDROXIDE FROM ORE CONTAINING ALUMINA

摘要

In a process for the production of aluminum hydroxide involving extraction of alumina from an alumina-containing ore by an aqueous alkaline solution, supplying a slurry containing the alumina-containing ore with a high solid content, which has been prepared from a small amount of an alkaline solution together with an aqueous alkaline solution which is preheated to a temperature that is high enough to have a temperature after the mixing with the slurry that is higher than the extraction temperature of alumina. Simultaneously or after the mixing feedings the mixture to an extraction apparatus comprising a tube reactor, extracting alumina from the alumina-containing ore under conditions of a temperature of 120-160.degree.C and an extraction time within 10 minutes, separating residue from an extract solution immediately after the extraction, desilicating the extract solution, and adding seeds of aluminum hydroxide to the extract solution which is desilicated to precipitate aluminum hydroxide. By this production process, it is possible to economically produce aluminum hydroxide with little contamination by silica from an alumina-containing ore with a high content of reactive silica.