Abstract: In cement clinker production installations, especially with short rotary tubular kiln, in order to find a way in which the thermally highly stressed rotary kiln intake chamber can be protected from overstress and therewith the entire production installation can be reliably operated it is proposed, according to the invention, to introduce directly into the rotary kiln intake chamber, a finely granular non-preheated substance usable in the cement clinker production process, to suspend or disperse it there in the rotary kiln exhaust gas and thereby to continuously cool the kiln intake chamber, and to discharge the heated finely granular substance with the exhaust gas from the kiln intake chamber and to add it to the process raw meal or direct it elsewhere.

Abstract: A method and plant for burning sludge or filter cakes during the cement clinker manufacture where the cement is manufactured in known manner by the cement raw meal being preheated, calcined and burned into clinker with subsequent cooling of the clinker and where the sludge is dried and finely divided prior to burning. The drying heat is provided by feeding hot raw meal from either the preheater or a separating cyclone installed in connection with the calciner to the drier unit, which may be a drier crusher. Applicable types of sludge include sewage sludge, beaching earth, paper sludge, fibre rejects, combustible chemical residues, e.g. waste derived from the manufacture of nylons and pesticides, and drill sludge resulting from oil exploration.

Abstract: Processes and systems for producing cementitious materials from ferrous blast furnace slags. Processes comprise mixing of a source of CaO with molten slag flowing from at least one slag tap hole of a blast furnace. Sufficient CaO is mixed with the molten slag to raise the ratio of CaO to SiO.sub.2, the C/S Ratio, of the slag to between about 64 1.06 and 1.25, while maintaining the Base Number of the molten slag less than about 1.55. The slag is then water granulated and ground to a predetermined degree of fineness. An activator then is added to the ground granulated slag. The C/S Ratio of the granulated slag determines the degree of fineness to which the granulated slag must be ground to achieve a desired hydration rate in the resultant cementitious material. Cementitious materials with C/S Ratios in this range may be ground less finely, yet possess the same hydration rates, as other more finely ground cementitious materials.

Abstract: Waste sludge that contains water, solids and oil, is mixed with a filter aid that has filter aid characteristics and a heating value of at least 1,000 Btu/lb. The admixture obtained is subjected to filtration yielding a high-Btu combustible material, useful as fuel. This combustible material, optionally after drying to remove water, is very suitable for use as fuel in a cement kiln.