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:
Sep. 29, 1992
Filed:
Feb. 07, 1991
J Paul Pemsler, Lexington, MA (US);
John K Litchfield, Bedford, MA (US);
The United States of America as represented by the Secretary of the Navy, Washington, DC (US);
Abstract
High purity synthetic pyrite is produced in a two-step and also in a one-step sulfidation reaction of iron powder. In a two-step process, a hydrogen-annealed iron powder is first reacted with molten sulfur at a temperature of from about 200.degree.-455.degree. C., while subjecting the reaction mass to mixing for a period sufficient to convert the iron powder to pyrrhotite, which is then reacted in a second step with sulfur vapor at a temperature of from about 420.degree.-550.degree. C., while subjecting the reaction mass to mixing for a period sufficient to convert the pyrrhotite to substantially pure pyrite. In a one-step process, iron powder is gradually heated from room temperature to about 550.degree. C. in the presence of sulfur while continuously mixing to prevent sintering and agglomeration.