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:
Nov. 10, 1981
Filed:
Dec. 17, 1979
Applicant:
Inventors:
Assignee:
Hoechst Aktiengesellschaft, , DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C01B / ;
U.S. Cl.
CPC ...
423308 ; 423309 ; 423312 ; 423313 ;
Abstract
The invention relates to the production of alkali metal phosphate solutions free of zinc, from phosphoric acid solutions contaminated with zinc. To this end, feed solution is admixed with alkali metal hydroxide or carbonate so as to establish in the resulting suspension a pH-value within the range 8 to 14. Next, resulting suspension is reacted under pressure and with thorough agitation with H.sub.2 S or an alkali metal sulfide solution; and decontaminated alkali metal phosphate solution is separated from solid matter, the pressure being maintained.