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. 17, 1981
Filed:
Mar. 01, 1979
Subhas K Sikdar, San Juan Capistrano, CA (US);
Occidental Research Corporation, Irvine, CA (US);
Abstract
In a process for purifying an aqueous phosphoric acid containing up to about 55% P.sub.2 O.sub.5 by weight and dissolved magnesium, iron and aluminum ions, wherein (a) said phosphoric acid is contacted with an organic extractant containing a water immiscible organic sulfonic acid to form: an organic extractant phase containing the organic sulfonic acid, extracted ionic metallic impurities and extracted P.sub.2 O.sub.5 values, and a purified aqueous phosphoric acid; and (b) the purified aqueous phosphoric acid phase is separated from the organic extractant phase; the improvement comprising (i) contacting said separated organic extractant phase with a solution phase containing calcium ions (e.g., calcium nitrate), under conditions whereby at least some of said extracted ionic metallic impurities (e.g., Mg.sup.+2, Al.sup.+3, Fe.sup.+3) are replaced by calcium and are transferred to said solutions phase; and (ii) separating said solution phase from the contacted extractant phase. The separated extractant phase can be acidified to convert at least some of the metal form of the extractant to the hydrogen or acid form. The separated solution phase from step (ii) can be neutralized to cause a solid precipitate to form, comprising at least some of the metallic impurities and/or P.sub.2 O.sub.5 values from phosphoric acid which was entrained in the organic extractant.