Process for recovering sulfuric acid from metallic sulfate-containing exhaust sulfuric acid
AssigneeNittetsu Mining Co., Ltd.
InventorsYasuie Mikami, Nobuyoshi Iyatomi
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Abstract
In order to efficiently and easily recover a spent sulfuric acid exhasuted, for example, in an acid washing liquid or in producing titanium dioxide by a sulfate method in a large amount, as highly concentrated sulfuric acid, bivalent iron ions in the spent sulfuric acid containing metal sulfate are first oxidized into trivalent iron ions, hydrochloric acid is added to such a liquid and then solvent extraction is carried out.
Claims6
A process for regenerating a spent sulfuric acid containing metal sulfates comprising:
- oxidizing bivalent iron ions in a spent sulfuric acid into trivalent iron ions;
- adding hydrochloric acid to said spent sulfuric acid to adjust the molar fraction of chloride ions in said spent sulfuric acid to at least 4 times that of iron ions;
- subjecting said spent sulfuric acid to solvent extraction to remove iron ions;
- concentrating said spent sulfuric acid, after solvent extraction, to a concentration of 60-75% by weight of sulfuric acid while separating hydrochloric acid;
- separating deposited metal sulfates;
- and
- concentrating the separated solution of said spent sulfuric acid again to a concentration of not less than 80% by weight of sulfuric acid.
A process for regenerating a spent sulfuric acid containing metal sulfates comprising oxidizing bivalent iron ions, present in said spent sulfuric acid to trivalent in an amount sufficient to convert the iron values into an iron chloride complex and then solvent extracting said iron chloride complex.
Dependencies are inferred from the claim text.