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:
Dec. 09, 1980
Filed:
Jun. 18, 1979
John F Phillips, Jr, Florence, AL (US);
Guerry H McClellan, Killen, AL (US);
John F McCullough, Florence, AL (US);
Tennessee Valley Authority, Muscle Shoals, AL (US);
Abstract
A method of selectively extracting calcite and dolomite away from apatite in phosphate rock or phosphatic limestone wherein the phosphate rock or phosphatic limestone is treated with a mixture of sulfur dioxide, water, and a carbonyl compound. Solids are separated from the liquid phase. The solids consist principally of apatite admixed with clay, quartz, and other accessory minerals originally in the rock. The solids are heated to drive off adhering sulfur dioxide, water, and carbonyl. The liquid phase consists of carbonyl, water, sulfur dioxide, and magnesium and calcium ions. Heating this liquid preferentially precipitates CaSO.sub.3.1/2H.sub.2 O. This solid is filtered off and the filtrate further heated to precipitate MgSO.sub.3.3H.sub.2 O largely free of CaSO.sub.3.1/2H.sub.2 O. All off gas and filtrate is returned to the process.