Removal of phosphine contaminant from carbon monoxide gas mixtures
AssigneeFMC Corporation
InventorsTheodore F. Munday, David Goldstein, John Walden
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Abstract
A method for removing small concentrations of phosphine contained in a carbon monoxide gas mixture by preferentially oxidizing the phosphine, in which the phosphine is oxidized with air at a temperature of from 500.degree. C. to 800.degree. C. to form phosphorus pentoxide, which is recovered from the gas mixture preferably as phosphoric acid.
Claims11
A method for preferentially removing phosphine from off-gas generated in the electric furnace production of elemental phosphorus, which off-gas is a gas mixture essentially free of elemental phosphorus and containing at least 85% by volume carbon monoxide and containing phosphine in an amount less than 1% by volume which comprises:
- (a) preheating the carbon monoxide gas mixture to a temperature of about 500.degree. C.;
- (b) introducing an amount of oxygen into the gas mixture sufficient to oxidize the phosphine to phosphorus pentoxide;
- (c) maintaining the gas mixture in a reaction zone at a temperature of from about 500.degree. C. to about 800.degree. C. for a period of time sufficient to oxidize the phosphine to phosphorus pentoxide without substantial concurrent oxidation of the carbon monoxide;
- and
- (d) recovering the entrained phosphorus pentoxide reaction product from the gas mixture.
Dependencies are inferred from the claim text.