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:
Mar. 30, 1999
Filed:
Apr. 28, 1998
Susumu Makino, Niihama, JP;
Naoyuki Tsuchida, Niihama, JP;
Masaki Imamura, Niihama, JP;
Kazuyuki Takaishi, Uma-gun, JP;
Yoshitomo Ozaki, Niihama, JP;
Sumitomo Metal Mining Co., Ltd., Tokyo, JP;
Abstract
A method of solvent extraction of a nickel sulfate solution uses a multi-stage, counter-current, organic solvent extraction system composed of at least two extractors connected in series, and includes a first extraction step of feeding a crude nickel sulfate solution that contains sodium and ammonium impurities into a second-stage extractor, wherein it is treated in countercurrent flow and at a pH of 6.5 to 7.0 with an organic extractant fed into the second-stage extractor from the first-stage extractor, to thereby extract some of nickel in the crude nickel sulfate solution into the organic extractant; and a second extraction step of transferring the nickel-containing, organic phase to an organic phase-scrubbing step to remove sodium and ammonium, while transferring the nickel sulfate solution, from the first extraction step and from which some of nickel has been removed, to the first-stage extractor, wherein it is treated in countercurrent flow and at a pH of 5.5 to 6.5 with a fresh organic extractant, to thereby extend the remaining nickel in the nickel sulfate solution into the organic extractant. The nickel-containing organic phase from the second extraction step is divided into two portions, one portion being fed into the second-stage extractor while the other portion is transferred to a by-pass, organic phase-scrubbing step it to remove sodium and ammonium.