Process and apparatus for producing phosphine-containing gas

A process for generating a mixture of phosphine and diluent gas or gases, wherein a hydrolysable metal phosphide selected from the group consisting of magnesium phosphide, aluminum phosphide and calcium phosphide is contacted with liquid water in a generating space, whereby the metal phosphide is hydrolysed to release phosphine which is withdrawn from the generating space and is, in the event that the phosphine withdrawn from the generating space has an ignitable composition, diluted from the time of its generation to its reaching its locality of use with a diluent gas to a composition which is non-ignitable under the conditions of use, wherein the metal phosphide is released into the liquid water in a free-flowing particulate form, composed of loose metal phosphide particles predominantly in a particle size range of about 0.1 mm to 2.5 mm, essentially free of metal phosphide dust substantially smaller than 0.1 mm and of hydrolysis retarding agents and essentially free of hydrophobic substance in the form of coatings or hydrophobising additives, and, in the event that dilution commences already in the generating space, under an atmosphere comprising a carrier gas inert to the phosphine, forming at least part of the diluent gas.