Abstract: Normally reject sponge metal fines, especially those produced by the crushing and screening of a regulus of zirconium and/or hafnium metal sponge, are added to the initial reduction charge of the metal tetrachloride and magnesium metal, and the so-modified charge is then passed through the conventional reduction and vacuum distillation steps to produce a regulus of the metal that has the reject fines incorporated therein by sintering.

Abstract: The pyrophoric fines inevitably resulting from the crushing of zirconium and/or hafnium or other exotic metal fines, such as titanium and uranium, are brought into contact with molten magnesium or a molten mixture of magnesium and magnesium chloride in the usual vacuum distillation furnace so that their surfaces are wetted by the molten material, after which furnace temperature is dropped to solidify the molten material about the fines. Furnace temperature is then raised to that required to vaporize the magnesium and magnesium chloride, whereupon sintering of the fines takes place over a period of time.