Manganese removal from aqueous industrial waste effluents

摘要

A chemical treatment for the removal for manganese or manganese and fluoride from an aqueous waste effluent obtained from the acid-fluoride washing or alkali (non-fluoride) washing in a step in the manufacture of aluminum cans. The treatment consists of adding in an acid medium sufficient phosphate ion to react with the manganese and/or fluoride and thereafter adding in an alkali medium sufficient calcium ion to react with the manganese, phosphate and/or fluoride. The ratio of phosphate to calcium ion added is 3:1 to 1:2.5.