The components of the dust, which contain zinc, ammonium or chloride, are dissolved by suspending them in water or spent acid or flux bath, if necessary by addition of further acid or ammonia and/or ammonium compounds. If the dust has a low iron content, it can be processed directly to a flux bath in this way. As a rule, however, the iron is separated off after oxidation to iron(III) compounds. This can be effected, for example, by oxidation with hydrogen peroxide or atmospheric oxygen, or else by anodic oxidation. The remaining solution is used as a flux or further processed to give fluxes, or marketable chemicals are recovered from the solution in a known manner.
展开▼
