PROCESS FOR PRODUCING ALUMINA

摘要

A process for producing alumina from bauxite is described in which bauxite is treated with an alkali to form a mixture comprising a solution of aluminium-containing ions and alumina trihydrate is precipitated from the solution. The process comprises treatment of the solution before or after the precipitation step with a layered double hydroxide in order to remove impurities from the solution by intercalation into the layers in the double hydroxide. The double hydroxide may contain layers of the formula: [LiAl2(OH)6]<+>.