Abstract: The disclosure discloses a method for preparing calcium oxide using multistage suspension preheater kiln. The steps of the method are: (1) the limestone powder is fed to the multistage suspension preheater kiln for preheating to 800° C. to 900° C.; (2) A preheated material is fed to a decomposition furnace, and calcined at 900° C. to 1100° C. for 25 s to 35 s; (3) A calcined material is fed to a rotary kiln, and calcined at 1100° C. to 1300° C. for 25 to 35 minutes, and finally cooled to obtain calcium oxide.

Abstract: An object of the present invention is to separate CO2 gas generated in a cement-manufacturing facility in a high concentration and recover the CO2 gas. The present invention includes: feeding a cement material before calcination and a heat medium which has a particle diameter larger than that of the cement material and has been heated to the calcination temperature or higher in a medium-heating furnace (14), to a mixing calciner (12); and recovering the CO2 gas generated by the calcination of the cement material. The heat medium circulates between the medium-heating furnace and the mixing calciner. Another aspect of the present invention includes: feeding a cement material before calcination to a regenerative calciner (112) which has been heated to the calcination temperature or higher and has stored heat therein; and recovering the CO2 gas generated by the calcination of the cement material.

Abstract: In the method according to the invention for operating a cement plant, the raw meal is preheated in a preheating zone, the preheated material is precalcined in a calcining zone and the precalcined material is finally sintered in a sintering zone. The cement plant is operated in such a manner that the precalcined material which is supplied to the sintering zone has an SO3 concentration of at least 5.5% by mass and a CaSO4 proportion of at least 75%, preferably 90%, of the total salt content.

Abstract: The invention relates to a process for manufacturing cement clinker in a plant having a cyclone preheater, a precalcination reactor, a rotary furnace and a clinker cooler. In the process, the flue gases from the furnace are conducted to the precalcination reactor, or even to the cyclone preheater. According to the invention, the precalcination reactor is fed with an oxygen-rich gas, the nitrogen content of which is less than 30%, constituting the sole oxygen source for said reactor, and a portion leaving the cyclone preheater is recycled into the plant so as to obtain a suitable flux necessary for suspending matter in said preheater, while the other portion, rich in carbon dioxide, is adapted for the purpose of a treatment for limiting the amount of carbon dioxide discharged into the atmosphere, such as particularly sequestration.

Abstract: The invention relates to a process for manufacturing clinker from a raw mix, implementing the following: preheating of the raw mix by combustion flue gases; precalcination of the raw mix; and calcination of the precalcined raw mix in a rotary kiln, in which process the precalcination and the calcination in the rotary kiln produce combustion flue gases that contain CO2, in which the combustion flue gases created by the precalcination undergo a CO2-removal treatment without said flue gases mixing with the combustion flue gases created by the calcination in the rotary kiln.

Abstract: In the method according to the invention for producing cement clinker, raw cement meal is preheated in a preheater, the preheated raw cement meal is precalcined in a calciner and the precalcined raw cement meal is burnt in a kiln, fuel and combustion air having an oxygen content of at least 75 mol % being used in the calciner, and the raw cement meal being precalcined in a fluidised bed in the calciner. The exhaust gases occurring in the kiln are delivered to the preheater, bypassing the calciner, and the exhaust gases of the calciner are delivered to a CO2 preparation device.

Abstract: The invention relates to a process for manufacturing cement clinker in a plant having a cyclone preheater, a precalcination reactor, a rotary furnace and a clinker cooler. According to the invention, the flue gases produced by the rotary furnace are separated from the gases from the preheater so as not to mix them, the precalcination reactor is fed with an oxygen-rich gas and a portion of the gases leaving the cyclone preheater is recycled into said precalcination reactor, or even into the preheater so as to obtain a flux suitable for suspending matter in the preheater. The non-recycled other portion of the gases, rich in carbon dioxide, is adapted for the purpose of limiting the amount of CO2 discharged, by means such as sequestration means.

Abstract: The invention relates to a process for manufacturing cement clinker in a plant having a cyclone preheater, a precalcination reactor, a rotary furnace and a clinker cooler. In the process, the flue gases from the furnace are conducted to the precalcination reactor, or even to the cyclone preheater. According to the invention, the precalcination reactor is fed with an oxygen-rich gas, the nitrogen content of which is less than 30%, constituting the sole oxygen source for said reactor, and a portion leaving the cyclone preheater is recycled into the plant so as to obtain a suitable flux necessary for suspending matter in said preheater, while the other portion, rich in carbon dioxide, is adapted for the purpose of a treatment for limiting the amount of carbon dioxide discharged into the atmosphere, such as particularly sequestration.

Abstract: Described is a method as well as a plant for the simultaneous production of electricity and cement clinker by which method cement raw meal is calcined in a calciner (4) subject to simultaneous supply of fuel and combustion air and subsequently burned into cement clinker in a kiln (5), and where some of the heat contained in the exhaust gases from the calciner (4) is utilized to generate electricity by means of a boiler section (18). The method and plant are peculiar in that the combustion air supplied to the calciner (4) does not contain alkali or chloride, and in that the temperature of the exhaust gases used to generate electricity is at least 500° C. Coating formations formed on the boiler tubes due to the condensation of alkali and chloride vapours can be avoided, while, at the same time, the efficiency with which thermal energy can be converted into electrical energy can be increased.

Abstract: In a method for pretreating charges contaminated with carbon carriers such as, for instance, carbon-carrier-contaminated earths, soils, rocks or minerals having low calorific values for use in clinker kilns, the mentioned charges are introduced into a reactor (8) and heated or dried with gases. The heated gases are drawn off at temperatures below 1250° C., preferably between 700 and 900° C., and the heated or dried charge is separately discharged at temperatures between 500° C. and 1000° C., wherein the temperatures are set and maintained to stabilize the temperature distribution within the reactor (8) by controlling the supply of fresh air, the supply of water or water vapour, by controlling the feed rate of the charge and/or of process gases such as, e.g., tertiary air as well as, if required, by burning fuels. The gases drawn off from the reactor (8) are at least partially recirculated into the reactor (8) and/or supplied to a precalcining stage and/or a preheating stage of the clinker kiln (1).

Abstract: To provide a cement clinker production line with a calcining stage which is connected upstream of the rotary tubular kiln and has an integrated calcining combustion chamber, with formation of a CO-containing reduction zone whose size and length and reduction potential can be adapted with simple means to different NOx contents contained in the rotary kiln exhaust gas and/or different types of material and pellet sizes of the secondary fuels used in the calcining combustion chamber, the calcining combustion chamber may have an upper, raw-meal-free reducing zone with a feed for secondary fuels arranged at the upper side of the combustion chamber, and first tertiary partial airstream with sub-stoichiometric fuel combustion for the purpose of gasifying the secondary fuels, and the combustion chamber may have a lower zone, the inflow for at least one raw meal partial stream and one second tertiary partial airstream being arranged in the junction region of the upper raw-meal-free, reducing zone and the lower zone, t

Abstract: A method of making cement clinker in a wet rotary kiln that includes providing raw material at the front of the kiln and adding a second group of materials for processing at an intermediate location along the kiln. This second group may include materials that improve the clinker and requires less energy to produce. A kiln system that employs this method and a cement clinker made by the method.

Abstract: In order to make sure, for cement clinker production lines with blown injection of dispersible solid fuels such as, for example, coal dust, into the calcinator which is provided with fuel, that an open flame does not occur at the fuel injection point, it is proposed according to the invention that the fuel is fed into a meal intake box that has a sloping raw meal chute and deflector slide and is arranged on the outside of the calcinator and connected to it through a wall opening and the fuel is pre-mixed with the pre-heated raw meal there, and then introduced via the deflector slide into the reaction section of the calcinator in order to form a gas-raw meal-solid fuel-suspension that is uniformly distributed.

Abstract: The invention relates to a process for the manufacture of cement, whereby a metal oxide known for its catalytic action in the reduction of nitrogen oxides NOx, selected from the group consisting of CuO, Co3O4, Mn3O4, Fe2O3, SnO2, NiO, ZnO, V2O5 and TiO2 is injected into the cement plant kiln flame and/or the precalcination zone flame if there is one.

Abstract: A lower heat exchanger for preheating powdered raw materials has a system of cyclones. The exchanger is divided into a high temperature part and a low temperature part, mutually interconnected with an interconnecting tube of hot gas. Lowest member of low temperature part is a counter current shaft exchanger having an input under the level of hot gas output from the highest cyclone of high temperature part. Heated-up powdered raw material is transported from the low temperature part into the high temperature part by a transport tube, to which the hot gas stream is led. To this stream, powdered raw material from the output of counter current shaft exchanger is led. To the output tube arranged between the input chamber of a rotary kiln and the first cyclone of high temperature part, the inputs for fuel, combustion gas, hot gasses, and/or precalcined raw material are ended.

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: The present invention concerns a process for the production of cement clinker in rotary kilns with substitution of primary raw materials and fuels by use of residual materials containing minerals and combustible parts with moisture contents of up to about 65% without predrying. The process makes possible a material and/or thermal utilisation of residual materials in the case of saving of the clay and fuel sources and relief of dumping with simultaneous lowering of the emissions, above all NO.sub.x, in the cement rotary kiln.

Abstract: A method for producing portland cement includes adding stabilized electric arc furnace dust (EAFD) to the raw materials fed into the feed end of a rotary cement kiln to form a cement clinker. The untreated EAFD is preferably stabilized by forming a mixture of water, lime, and a cementitious reactant consisting of untreated electric arc furnace dust. Preferably, dolomitic lime is used and ferrous sulfate is added to the mixture. The stabilized EAFD, which is so soft that no grinding is necessary, may be nonetheless passed through the grinding mill along with the cement raw materials (excluding stabilized EAFD), combined with the raw materials after the raw materials are ground, or delivered directly to the rotary cement kiln in a stream separate from the cement raw materials. The stabilized EAFD serves as an inexpensive iron source in place of iron ore, mill scale, coal ash, or others.

Abstract: The invention relates to a method and a plant for manufacturing mineralized portland cement clinker. The method and plant provides for preheating, calcining, burning and finally cooling the clinker. The mineralizer may e.g. be gypsum, fluorine, or a waste product containing these or other mineralizers. The mineralizer is added to the feedstock after the feedstock has been fed to the process, preferably after the cyclone which handles the feed to the calciner, i.e. the last cyclone in the preheater, or the lowermost preheater stage in a plant which does not incorporate a calciner.

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: The present invention is an improved process for preparing a portland cement composition where the process comprises heat calcining a mixture comprising a source of calcium and a source of silicon to form clinker. The improvement comprises providing to the process a silicon containing product resulting from the hydrolysis of chlorosilicon by-product as at least a portion of the source of silicon.

Abstract: An aqueous composition comprising an active ingredient, a volatile organic compound and water, which is homogenized so that at least 90% by weight of the active ingredient are in particles of less than 1.0 micron in diameter, may be used to deliver an active ingredient. Suitable active ingredients include, but are not limited to, mold releases, coatings, solvents and reactive compounds.

Abstract: A rotary cement kiln is operated with predried paper sludge in a secondary combustion period. The predrying of the paper sludge from a moisture content of about 50% by weight to a moisture content of about 30% by weight is effected with flue ga from the inlet end of the rotary kiln.

Abstract: A method for producing a hydraulic binder using partially calcined raw meal entrained in the kiln off gases. The raw meal flow form the lowermost cyclone is interrupted at or near the junction of the meal chute, kiln inlet and riser duct. This flow interruption causes turbulence in the partially calcined meal facilitating dust entrainment in the gas. The splash plate can be selectively adjusted to entrain more or less raw meal. The entrained meal is drawn off from the riser duct through a kiln bypass duct, processed and hydrated to convert the calcium oxide in the meal to calcium hydroxide.

Abstract: A method for producing building sheets containing cement, inert materials and additives and reinforced with plastic mesh, starting from a cement mix which does not contain more water than that desired in the formed sheet prior to hardening, the necessary fluidity of the cement mix being obtained by adding a fluidiser.The apparatus and method are therefore simplified.