The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 15, 2019
Filed:
Sep. 15, 2015
Sumitomo Metal Mining Co., Ltd., Tokyo, JP;
Hiroyuki Mitsui, Tokyo, JP;
Osamu Nakai, Tokyo, JP;
Keisuke Shibayama, Tokyo, JP;
Sho Shirai, Tokyo, JP;
SUMITOMO METAL MINING CO., LTD., Tokyo, JP;
Abstract
The present invention provides a chromium-containing water treatment method that allows treatment of water that contains chromium (chromium-containing water) at low cost. A chromium-containing water treatment method according to the present invention comprises: a reduction step in which chromium-containing waterand a liquidcontaining 5-50 ppm of hydrogen sulfide are mixed, and the mixture is adjusted to pH 3.5 or lower and ORP 200-400 mV by adding an acidthereto, so as to reduce chromium contained in the water; and a precipitation separation step in which a neutralizing agent is added to a solutionobtained via the reduction step so as to adjust the solutionto pH 8-9, thereby precipitating and separating, as a hydroxide, the reduced chromium contained in the solution.