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:
Jan. 04, 1983
Filed:
Mar. 02, 1981
Gary L Long, Pocatello, ID (US);
Roger B Humberger, Pocatello, ID (US);
J. R. Simplot Company, Boise, ID (US);
Abstract
Methods for control of excessive corrosion in wet process phosphoric circuits are effected by oxidation of reduced ion species in the acid with maintenance of EMF value of the acid above about 190 millivolts (S.C.E. reference) through the digestion circuit. Supplementary monitoring is by a ceric red-ox titration procedure. In one embodied form, the present invention is utilized to control corrosion in a phosphoric acid plant digestion system (and subsequent processing equipment) operating by a dihydrate (gypsum) process even when such a process employs a calcined western U.S. phosphate ore feed from a relatively highly carbonaceous ore. The invention is also applicable for treating wet process phosphoric acid in phosphoric acid plants having a digester system operating by a hemihydrate process. In a presently preferred embodiment, additions of manganese dioxide to a primary digester in a sufficient amount effective to achieve an EMF value over about 190 millivolts will significantly control the occurrence of excessive corrosion in phosphoric acid circuits. In yet another preferred embodiment, an oxygen autoclave oxidation is used to oxidize the reduced ion species present in the acid to inhibit corrosion.