Abstract: Process for the removal of heavy metal, metalloid and fluoride species present in trace mounts from aqueous brine of use in the production of chlorine and sodium hydroxide by electrolysis in membrane cells or in chlorate production; particularly to said removal by adsorption on hydroxyapatite; and more particularly to adsorption on bone charcoal.

Abstract: A method for removing sulphate ions from an aqueous solution of an alkali metal halide containing sulphate ions, which method comprises contacting said solution with a particulate, composite ion-exchange material comprising a hydrous oxide of a metal selected from the group consisting of titanium, zirconium and cerium, dispersed on a support comprising a brine solution compatible material. Preferably the compatible material is selected from hydrous oxides of titanium, cerium and zirconium. An improved cost-effective practical method of sulphate removal is provided.