Sepn. of iron@ and zinc@ impurities from hot galvanising pre- and post-treatment baths - by concentrating liq. by evaporation and separating iron-contg. crystals from the residue to be cleaned for further use

摘要

To separate impurities from water and/or acid content baths, especially for ferrous and zinc from the pre- and post-treatment baths in a hot galvanising process for iron and steel components, the fluid is concentrated by evaporation. The evaporation rate is set so that the remaining material has a consistency with at least a high proportion of ferrous crystals which precipitate after removal from the evaporation stage and any cooling. They are separated and further cleaned for use as the purest possible recycled iron. The precipitated iron is separated mechanically from the remainder of the unevaporated residue, where the crystals are cleaned in water with an ion exchanger. A centrifuge is used to separate the ferrous crystals mechanically. Any viscous impurities clinging to the separated crystals are cleaned off by a solvent. ADVANTAGE - The method gives an increased volume of recovered material, with simple equipment and low energy consumption.