METHOD FOR TREATING AND UPGRADING EFFLUENTS CONTAINING METALLIC SULPHATES USING AN AMMONIA ADDITION STEP

摘要

The invention concerns a method for treating and upgrading effluents containing at least a metallic sulphate, characterised in that it comprises steps which consist in: adding at least a base to the effluent to precipitat e the metallic ions in the form of metallic hydroxides Mea(OH)e; separating th e precipitated hydroxide during a step of alkalinization of the rest of the effluent; adding to said effluent calcium hydroxide Ca(OH)2 so as to precipitate hydrated calcium sulphate CaSO4; and separating the calcium sulphate CaSO4 precipitated during the preceding step. Said method enables t o obtain calcium sulphate (white gypsum) substantially free of metals and therefore capable of being upgraded and metallic oxy-hydroxides likewise capable of being upgraded.