Abstract: A rotary hearth for a kiln assembly in which the refractory material-bearing portion of the hearth is supported by a metal frame from below and is contained peripherally by a refractory buttress secured to the frame. In the preferred form of the invention, the refractory buttress comprises a lower layer of slightly circumferentially spaced buttress block and an upper layer of refractory rim tiles interlocking with the buttress blocks. The hearth is free of metal structural components in regions of high heat and thus free from the problems of cracking and jamming associated with assemblies of the prior art.

Abstract: A discharge chute assembly for a rotary calcining hearth in which a carriage movable radially along tracks carries one or more pairs of opposed rollers receiving a flange extending around the hearth. The carriage supports the chute to cause the chute to follow any radial fluctuations in the position of the hearth edge and thereby minimize spillage of material. The chute is disposed with its upper edge extending into an outwardly opening circumferential channel formed around the side of the hearth beneath the upper surface, further minimizing spillage.

Abstract: A process of and apparatus for cooling lime produced by calcining limestone and separating the lime dust from the heated air resulting from such cooling in which dust separators are placed inside and near the top of a cooling tower into which the hot lime is dumped. Cool air is drawn into the cooling tower near its bottom, flows up through falling lime and is then pulled into dust separators near the top of the tower. The lime dust caught by the separators falls down through tubes into a chute along with the rest of the lime which has cooled in the tower, and the heated air which comes out of the separator is piped out of the tower for use in the calcining process.