Abstract: Generally rough sphere-shaped work pieces made of fragile material are ground into more uniform spheres. The rough spheres are fed into a holding plate having a channel cut into the bottom side of the plate with a width slightly larger than the largest diameter of the rough spheres. A movable abrasive surface is positioned adjacent to the bottom side of the holding plate. As the rough spheres move through the holding plate which can be vibrated, they move in contact with each other and with the abrasive surface. The finally formed spheres leave the plate where they are collected. It is a further embodiment green spheres which are treated in a sintering process with hydrogen gas have tungsten oxide particles applied to the surface of the spheres prior to and during sintering so that the particles remain separated and apart.

Abstract: An improved halogenator process and system is provided which significantly and economically decreases the level of impurities in the processing of various refractory metals and their halides and particularly hafnium tetrachloride which is condensed from gases produced by the chlorination of Zircon.