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. 06, 1984
Filed:
Sep. 29, 1981
Dysart E Holcomb, Shreveport, LA (US);
Erhart K Drechsel, Montgomery, TX (US);
John B Sardisco, Shreveport, LA (US);
Pennzoil Company, Houston, TX (US);
Abstract
Monocalcium phosphate, phosphoric acid and/or potassium phosphate, calcium fluoride and gypsum are produced in a process involving acidulation of phosphate rock with phosphoric acid, and wherein monocalcium phosphate dissolved in phosphoric acid is formed during acidulation. In important features, insolubles and impurities are removed and a portion of the monocalcium phosphate may be separated and recovered. Alkali metal ion is added to the solution to form alkali metal fluosilicate, such as K.sub.2 SiF.sub.6, is separated and hydrolyzed with calcium ion to form CaF.sub.2 and the solution is recycled as RH.sub.2 PO.sub.4 /H.sub.3 PO.sub.4 for further reaction with fluorides, where R is alkali metal. A portion of the MCP/H.sub.3 PO.sub.4 solution and/or crystallized monocalcium phosphate can then be reacted with potassium sulfate, potassium bisulfate, or mixtures thereof, to form KH.sub.2 PO.sub.4 or KH.sub.2 PO.sub.4 /H.sub.3 PO.sub.4 solutions, and gypsum or with H.sub.2 SO.sub.4 to produce phosphoric acid. The remaining monocalcium phosphate/phosphoric acid solution can be reacted with sulfuric acid to produce phosphoric acid product and the recycle phosphoric acid required in the phosphate rock acidulation step.