Pyrite Cathode Material for a Thermal Battery.
Patent, Filed 7 Feb 91, patented 29 Sep 92,
DEPARTMENT OF THE NAVY WASHINGTON DC
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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 deg-455 deg 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 deg-550 deg 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 deg C in the presence of sulfur while continuously mixing to prevent sintering and agglomeration.
- Electrochemical Energy Storage
- Geology, Geochemistry and Mineralogy
- Properties of Metals and Alloys
- Inorganic Chemistry