Abstract: A composite sliding surface bearing consisting of a backing layer of steel, a bearing alloy layer which consists of aluminum and has been applied to said backing layer, and a sliding surface layer which consists of zinc phosphate and has been deposited on said bearing alloy layer. The backing layer of steel is provided on its outside surface in a thickness between 0.5 and 5 .mu.m with a metallic protective layer in order to ensure a firm retention in the bearing housing.

Abstract: In order to reduce the wear and to facilitate the replacement, a nozzle block comprises a mounting plate which is connected to the kiln shell, a nozzle tube which extends in the mounting tube and defines a clearance with the mounting tube and with the kiln lining, an abutment surface provided at the lower end of the nozzle tube and engaged by the orifice plate and which is clear of the body of the nozzle tube, a retaining tube which extends in the nozzle tube and defines a clearance with the nozzle tube and with the orifice plate, a gas feed duct attached to the side of the mounting tube and a cover on the mounting tube.