Abstract: The emission of halogens and sulfur dioxide and the formation of water-soluble compounds of heavy metals are suppressed in the pyrolysis of waste in a carbonization zone at a temperature in the range from 300.degree. to 600.degree. C. by adding a fine-grained basic material to the waste prior to completion of the pyrolysis of the waste in the carbonization zone.

Abstract: Carbonate-containing sinterable material, e.g. for cement clinker, is calcined in a rotary kiln and then cooled in a grate cooler. The material is subjected to preheating in a suspension preheater and then to precalcination in an upright precalcining installation. The fuel for the latter is introduced through nozzles into a substantially oxygen-free crude power exhaust gas suspension and after turbulent mixing of the fuel with this suspension a stoichiometric quantity of combustion air is introduced so that a flameless combustion occurs in the turbulent mixture. Thereafter the solids enter the rotary kiln for the final calcination.

Abstract: A method of operating a milling installation to regulate the fineness of the milled product, in which the milled product emerges from the output side of a mill, e.g. a ball-type tube mill, and material to be milled is introduced at the opposite side of the mill. According to the invention, the mass output rate dm/dt or m of the product is continuously or discontinuously measured and this measurement is used to control the rate of mass output at the output side of the mill so that the output rate is held substantially constant. The invention is applicable to a through-flow (continuous open-circuit) mill in which a fresh starting material is continuously introduced into the mill and to the circulating system (continuous closed-circuit mill) in which the output of the mill is delivered to a classifier which separates the fine product from a coarse component which is recycled to the mill.