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US 4,241,039 AGranted
Method of removal of arsenic from a sulfuric acid solution
AssigneeDowa Mining Co., Ltd.
InventorsShiro Koh, Tomomichi Kudo, Michihiro Maeshima, Tamotsu Kibayashi
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Abstract
A method of removal of arsenic from an acidic solution, in which ferrous ions contained in the solution are oxidized in the presence of high pressured oxygen and sulfuric acid to ferric ions, the solution with said ferric ions being mixed with the solution which has not subjected to oxidation, and the mixture of said solutions being controlled of its pH whereby ferric hydroxide is precipitated, which coprecipitates and adsorbs arsenic thereto.
Claims2
A method of removal of As.sup.3+ from a sulfuric acid solution containing arsenic and ferrous ions which comprises:
- (a) subjecting a part of said solution to oxygen under pressure so as to oxidize said ferrous ions to ferric ions;
- (b) mixing the oxidized solution with the remainder of the solution under agitation in amounts such that the weight ratio of Fe.sup.3+ /As.sup.3+ in the mixture is between about 2 and 40;
- (c) adjusting the pH of the mixture from step (b) to 3.5 to 4.6 to produce a precipitate which coprecipitates or adsorbs arsenic;
- and
- (d) separating and removing the precipitates from the mixture.
2 more elements
Dependencies are inferred from the claim text.