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US 6,296,824 B1Granted
Method for producing rare earth oxysulfide powder
AssigneeSiemens Aktiengesellschaft
InventorJuergen Leppert
Life of this patent
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Abstract
In a method for producing rare earth oxysulfide powder, reduction of rare earth oxysulfate to rare earth oxysulfide powder ensues under a protective gas with a reducing agent which is hydrogen or carbon monoxide, or a hydrocarbon gas such as methane or propane.
Claims17
A method for producing rare earth oxysulfide powder comprising the steps of:
- producing a suspension of at least one rare earth oxide in water;
- adding an additive, per mol of said rare earth oxide, to said suspension selected from the group consisting of one mol sulfuric acid and a dissolved sulfate of the rare earth of said at least one rare earth oxide in amount corresponding to one mol of sulfuric acid, and thereby obtaining a precipitate from said suspension;
- calcining said precipitate to obtain a rare earth oxysulfate;
- and
- reducing said rare earth oxysulfate to form rare earth oxysulfide powder.
2 more elements
Dependencies are inferred from the claim text.