Composition for producing phosphine gas

Abstract

A metal phosphide composition is disclosed for generating a mixture of phosphine and diluent gas(es), presented ready for use in a hydrolysis process or apparatus in the form of a free-flowing particulate metal phosphide material composed of loose particles of said metal phosphide essentially free of metal phosphide dust, essentially free of hydrolysis retarding agents and essentially free of hydrophobic substances in the form of coatings or hydrophobizing additives. In use the hydrolyzable metal phosphide, preferably magnesium phosphide, is released directly into liquid water under an atmosphere of gas inert to phosphine. The generated mixture of phosphine and inert carrier gas, e.g. CO.sub.2, can be used as such or is diluted into a gas mixing chamber with air to a concentration below the ignitability limit before being used in fumigation. The composition is manufactured by reacting a finely divided metal, selected from the group consisting of aluminum, calcium and magnesium with yellow phosphorus in an inert gas atmosphere and in the presence of a catalyst. Throughout the reaction batch and throughout the process, once reacting has commenced, a temperature is maintained within the range of 350.degree. C. to 550.degree. C. The metal phosphide is withdrawn as a particulate free-flowing material and is packaged ready for use in phosphine generation in such free-flowing condition, essentially free of dust, essentially free of hydrolysis retarding agents and essentially free of hydrophobizing substance in the form of coating or hydrophobizing additives, in a gastight container.

Dependencies are inferred from the claim text.