Decontamination of zinc-containing metallurgical residues by continuous electro-hydrometallurgical treatment in alkaline environment

摘要

A process is claimed for the cleansing, by electro-metallurgy in a basic medium, of metallurgical residues (1), such as electric steel-making dusts, consisting of leaching the residues in a soda solution and according to which the leachant (D), after cementation (4) by the zinc of the heavy metals (F) that it contains, is subjected to an electrolysis phase (6) for recovery of the zinc metal by cathodic deposition. The soda solution is then recycled to the head of the treatment. The leaching operation (2') is effected under a ventilated atmosphere in a heated leaching tank with the residues (A) in a humid state from a prior operation of washing with water (11) in order to eliminate chloride and sulphate salts by dissolving them. An acid neutralisation operation (13) is effected on the water from the washing (P) to precipitate and extract the metal hydroxides (K), such as lead hydroxide, and it is then leached with the humid residues (A) to be treated.