| 摘要 |
PURPOSE:To recover high-purity ferric sulfate in high efficiency from the waste sulfuric acid discharged from the pickling process of an iron material, by separating the waste sulfuric acid into solid and luquid, and drying and crystallizing the obtained wet ferric sulfate. CONSTITUTION:The surface of an iron material (e.g. steel plate) is washed and cleaned by passing the iron material through the defatting tank 2, the bleacher 5 and the first rinsing tank. The cleaned material is immersed in a sulfuric acid solution 8 (concentration; about 30%, temperature; about 50 deg.C) in the sulfuric acid tank 7 to effect the picking, and transferred successively to the second and third rinsing tanks 10, 11 in suspended state. In the tranafer of the iron material from the sulfuric acid tank 7 to the second rinsing tank 10, the pickling waste sulfuric acid dripping from the iron material is collected with the plate 13 inclined downward to the sulfuric acid tank 7. In the course of flowing through the plate 13, the waste sulfuric acid is separated into wet ferric sulfate 12 and the solution of sulfuric acid 8. The sulfuric acid solution 8 is recyled to the sulfuric acid tank 7, and the wet ferric sulfate 12' left on the inclined plate 13 is dried to obtain ferric sulfate 12.
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