To provide a method for effectively using a used iron-containing desulfurizing agent used for treating a molding itself or the crushed desulfurizing agent, does not need instrumentation, in view of a control mechanism, a high control technology or an expensive heat source, and can treat the used desulfurizing agent simply by dissolving it with a simple apparatus.
The used desulfurizing agent is dissolved as an iron source in a sulfuric acid waste liquid containing f-H2SO4, an iron sulfate solution, or sulfuric acid, the pH of the solution is adjusted at 2-5, generated hydroxides are removed as impurities, and the iron components in the dissolved used desulfurizing agent are deposited as iron sulfate crystals by a cooling crystallization method to obtain iron sulfate.
IKEDA TSUNEO
YAMAZAKI YOSHINORI
CHIBA MICHIO
