METHOD FOR PRODUCING COAGULANT BASED ON ALUMINIUM HYDROXOCHLOROSULFATE Russian patent published in 1998 - IPC

FIELD: coagulant for use in water treatment processes, in purification of effluents and process liquors. SUBSTANCE: coagulant is produced by step-wise treatment of aluminium sulfate in aqueous solution with calcium-and chlorine-containing reactants introduced into reaction in such quantities as to ensure production of desired product with basicity 33-66.6 wt.-%. Process is conducted under heating conditions in two steps. In first step, aqueous solution of aluminium sulfate is treated with aqueous suspension of calcium carbonate or hydroxide to obtain aluminium hydroxosulfate. In second step, latter is reacted with aqueous solution of calcium chloride to produce aluminium hydroxochlorosulfate. Calcium sulfate precipitate is subjected to aquo-acidic treatment, followed by separating precipitate by filtering and by washing it on filter with hor water. Filtrate and effluents from washing operation are subsequently used either for synthesis of desired product, or used during operation of aquo-acidic treatment of calcium sulfate precipitate. EFFECT: effective and environmentally safe. 5 cl