GB1344869A - Method and apparatus for making small ceramic sphres - Google Patents

Abstract

1344869 Spherodizing ceramic material COORS PORCELAIN CO 18 June 1971 28648/71 Heading B5A [Also in Division C1] Small ceramic spheres are made by forming a bed of powdered, preferably non-hydroscopic material, e.g. wax or alumina, on a work surface; discharging drops of ceramic slip on to the surface of the bed to form spheres; reforming the bed surface, e.g. by inverting it, and discharging further drops of ceramic slip to form more spheres. The powder is deposited from a hopper 42 on to a moving conveyer belt 34 and levelled off by a bar 46. Dry ceramic material such as alumina is fed to a ball mill 14 then milled with water in a wet ball mill 18 and passed to a holding tank 20 together with an agent such as magnesium sulphate where it is agitated to maintain it in suspension. The slurry is discharged through a first set of nozzles 30 which are set at an angle across the surface of the bed to deposit drops in staggered array. A radiant heater 50 dries the drops and the moving bed then rides up a ramp 52 and drops over the end so that the ceramic spheres fall on to the bottom and the powder forms into a bed over them. A second set of nozzles 32 and radiant heater 58 deposit and dry a second layer of ceramic spheres, the material then discharging on to a separator 60, the powder being returned to the hopper and the ceramic spheres taken through a set of sizing screens 62 and fired in a kiln. The ramp 52 (Fig. 2, not shown) comprises an adjustably inclined blade set across the belt surface and followed by a doctoring bar. The set of nozzles may be formed by inserting hollow needles through the wall of a plastics tube, inlet and return conduits being provided thereto (Figs. 3 and 4, not shown). Specification 1,344,870 is referred to.