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:
Apr. 07, 2009
Filed:
Oct. 25, 2005
Applicant:
Matthew Pratt, Boss, MO (US);
Inventor:
Matthew Pratt, Boss, MO (US);
Assignee:
The Doe Run Resources Corporation, St. Louis, MO (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C01B 17/96 (2006.01); C01D 5/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
A method for purifying heavy metal impurities (such as antimony, arsenic, iron, cadmium, and lead) from 28 to 38 weight percent aqueous crude sodium sulfate solution is achieved by adding ferric sulfate to the aqueous crude sodium sulfate solution to form a suspension, progressively neutralizing the suspension from a pH of less than 3.5 up to at least 6, and separating the ferric-sulfate-nucleated precipitate from the suspension. An oxidizing agent such as peroxide is optionally added to the suspension to augment adsorption of the heavy metals.