Abstract: The manufacture of Portland cement clinker by (1) forming an intimate mixture by intergrinding (a) unsintered Portland cement raw materials and (b) a low volatile carbonaceous fuel such as coke breeze having a high ignition temperature, (2) passing the intimate mixture through a set of preheating cyclones wherein it is preheated prior to passing into a calcining zone, and (3) passing the mixture into said calcining zone wherein said intimate mixture (a) is maintained in a substantial fluidized condition, and (b) is heated rapidly up to a calcination temperature to accomplish calcination of the Portland cement raw material and the ignition of the carbonaceous fuel.

Abstract: A combination burner has a burner pipe for pulverized fuel beside a burner chamber for fluid fuel. A plurality of retractable nozzles mounted in a retractable housing inside the chamber are connected to a plurality of fluid fuel sources. Primary air may be controlled in varying amounts to both burner pipe and burner chamber. Nozzles may be angled with respect to burner pipe to provide supportive flame.