Abstract: A process for producing cement clinker, having a preheating-, calcination and cooling zone, under addition of a secondary fuel, (retardedly)combustible components such as waste materials and/or conventional fuels being added in the zone between kiln inlet and calcination zone and then being subjected to an incomplete combustion and/or pyrolysis under addition of exhaust gases from the burning process.The gases thus formed are introduced into the calcination zone as secondary combustion gas together with the exhaust gas from the burning process and are burned there with tertiary air and optionally with conventional secondary fuel.The plant required for performing the process consists of a system of heat exchangers (2), a calcining kiln (3a), a burnin kiln (10) and a clinker cooler (13).The calcining kiln (3a) is provided with a means (4) for introducing tertiary air and/or oxygen preferably preheated (m) in the clinker cooler (13) and optionally with a means (15) for introducing a conventional fuel.

Abstract: The invention relates to a process for the utilization of waste substances containing combustible components and showing fluctuations in their composition and properties and to a device for carrying out the process.The improvement comprises effecting the volatilization, decomposition and incomplete combustion of the waste substances in a first process step which is immediately followed by a second process step in which formed pyrolysis gases are burned in a heating device for burning starting materials for building materials or inorganic binders.

Abstract: The present invention provides a method for producing a mixture of materials of differing compositions, particularly a mixture comprised of two burned, sintered, calcined, and/or heated inorganic components, the first of said components being subjected to a heating process, particularly a burning process, and the second and other components being heated to a temperature below the temperature to which the first component has been heated.

Abstract: A cement and process of producing the cement is disclosed wherein the cement comprises at least two clinkers, one being a Portland cement clinker of conventional composition and at least one other clinker of low-calcium content or marl clinker. This marl clinker is heated between 450.degree. C and 1250.degree. C and contains hydratizable mineral phases of low-calcium content and 0-30% by weight related to the marl clinker of glass phases.