Ball milling spherical particles

Fe, Ti, Ni, and Cu in ball or vibrational mills particles are obtained in the form of irregular polyhedra on milling such alloys as Fe—Al, Al—Ni—Co, and Al—Si—Fe in vortical mills, the particles have a plate-like shape. On the condensation of nickel and iron carbonyls spherical particles are formed in the reduction of metals (W, Mo, Fe, Ni, Co, Cu, Pt, Sn, Ag, Au, etc.) from their salts or oxides, and also on electrolysis of salt melts or solutions, the metal particles produced have the shape of dendrites. 

Lead is used to make the active materials as well as the grids. The lead must be highly refined (usually virgin or primary lead) to preclude contamination of the battery. It is described as corroding-grade lead in ASTM specification B29." Lead is oxidized by either of two processes—the Barton pot or the ball mill. In the Barton pot process, a fine stream of molten lead is swept around inside a heated pot-shaped vessel, and oxygen from the air reacts with fine droplets or particles to produce an oxide coating around each droplet. Typical Barton pot oxides contain 15 to 30% free lead, which usually exists as the core of each fine leady oxide spherically shaped particle. Barton pots are available in a variety of sizes up to 1000 kg/h output. 

It was pointed out by Tait that the rapid initial increase in the rate of polymerization, with both the spherical magnesinm chloride and magnesium ethoxide catalyst, decayed rapidly in the same way as ball-milled magnesiiun chloride catalysts. The loss of activity was presnmably dne to the small particles or fragments becoming blocked with polymer. 

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