PROCESS FOR PRODUCING ALUMINUM HYDROXIDE FROM ALUMINA-CONTAINING ORE.

摘要

A process for producing aluminum hydroxide from an alumina-containing ore by extracting alumina with an aqueous alkali solution from the ore, which process comprises feeding a high-concentration alumina-containing ore slurry which has been prepared by using a small amount of an aqueous alkali solution and an aqueous alkali solution which has been preheated in such a manner that the temperature of the slurry after being mixed with the alkali solution exceeds the temperature for extracting alumina to an extractor composed of tubular reactors at the same time or after the slurry is mixed with the alkali solution, extracting alumina from the ore under the extracting conditions of 120 to 160 DEG C and ten minutes or less, removing immediately thereafter a dissolution residue from a liquid extract, desilicating the extract, and adding seed aluminum hydroxide to the desilicated extract to thereby deposit aluminum hydroxide. The process enables aluminum hydroxide reduced in the possibility of pollution caused by silica to be economically produced even from an alumina-containing ore with a high reactive silica content.