Abstract: The system includes a raw material predrying kiln, a preheating kiln, a reduction rotary kiln, a cooling rotary kiln, a ball mill, a magnetic separator, a reduced iron powder drying kiln, a blank prefabricator, a blank drying kiln, a sintering furnace, a fused salt electrolysis tank, a titanium cleaning device, a filtering device, a vacuum dryer, a waste heat boiler, and a steam turbine generator. In the present disclosure, a high-temperature flue gas produced by the reduction rotary kiln is directly used to preheat a raw material. The CO-containing high-temperature flue gas discharged by the reduction rotary kiln and the CO discharged at the fused salt electrolysis stage are recovered and used for power generation and steam production of the waste heat boiler. Due to a low moisture content of the flue gas, a low-temperature flue gas obtained after the waste heat recovery is used for drying.

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: The disclosure relates to a method to produce electricity in a cement clinker production utilizing a kiln and/or a precalciner as combustion chambers to generate electricity, the method including: a. supplying fuel to the precalciner and/or the kiln in a quantity corresponding to at least 110% of a heat value requirement for clinker production operation of the precalciner and/or the rotary kiln per unit weight of clinker, respectively; b. bypassing a portion of hot flue gases from at least one of (i) the kiln and/or (ii) the precalciner; c. leading hot flue gases to a heat recovery steam generator producing steam; d. producing electricity with a power island including a steam turbine equipped with an electrical generator.

Abstract: A method and plant for reducing mercury (Hg) and other metal emissions including injecting a chemical reagent into the process in such a way as to convert elemental mercury into a mercury compound that is more readily captured using normal particulate control equipment associated with kilns, smelters, furnaces, and boilers of cement plants and other industrial plants.

Abstract: A method of producing cement clinker including the steps of preheating raw meal comprising calcium carbonate in a preheating stage that is preheated by the exhaust gases of a sintering stage connected downstream in the direction of the gas flow, neutralizing the preheated raw meal, sintering the raw meal into cement clinker in a sintering stage, and cooling the cement clinker from the sintering stage in a cooling stage that cools the cement clinker with a gas. The exhaust gases of the sintering stage are combined with the exhaust gases of the neutralization, and the combined exhaust gases are conducted in an open gas circuit. The CO2 emissions are substantially reduced over known systems with CO separation, and the formation of nitrogen oxides by the combustion of atmospheric nitrogen in the oxidative environment of the sintering stage burner is almost completely prevented.

Abstract: The invention relates to a process and a plant for producing cement clinker and for purifying the off-gases formed thereby, wherein cement raw meal is preheated in a preheater by means of hot off-gases and then optionally precalcined, the preheated and optionally precalcined cement raw meal is burnt in a rotary kiln to form cement clinker, the cement clinker is cooled in a cooler, the hot off-gases used in the preheater are used in a raw mill for treating the cement raw meal, the dust content of a dust-containing mill off-gas thereby formed is reduced in a separating device to less than 5 g/Nm3, preferably less than 1 g/Nm3, alkali hydrogen carbonate and/or alkali carbonate is added to and mixed with the mill off-gas whose dust content has been reduced to less than 5 g/Nm3, and the mixed gas thereby formed is subsequently fed to a process filter for separation of dust laden with pollutants.

Abstract: The present invention relates to an apparatus and a method for the selective non-catalytic reduction (SNCR) of NOx in industrial cement production plants. In particular, the method according to the present invention provides for the atomization of an aqueous solution containing the reagent by introducing it into the gas to be treated that is at a high temperature, thus achieving the simultaneous and immediate evaporation of the water and gasification of the reagent. Thanks to this method, there is achieved improved performance of the non-catalytic reduction process of NOx while using the same reagent or, specularly, the same performance with a lesser amount of reagent being required, with consequent reduction of the costs.

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: A method for treating cement kiln dust is provided. The method includes the steps of receiving cement kiln dust (CKD) from a kiln; heating the collected CKD; forming a gas stream of vaporized metal and CKD by sufficient heating to separate at least one heavy metal from the collected CKD stream to create a cleaned CKD stream and a metal stream; providing a water soluble alkaline-earth metal polysulfide; combining the heavy metal stream with the water soluble alkaline-earth metal sulfide to create a combined stream; and removing at least a portion of one heavy metal from the combined stream.

Abstract: A system and method of using a double-effect-reactor to dispose incinerated flue gas and improve cement yields. The double-effect-reactor features an incinerated reaction chamber and a gas-solid suspension mixing chamber. The system includes the double-effect-reactor, a high temperature dust-arrester, a system for recovery of thermal energy and dust removal, a triple valve, and an independent chimney. Also disclosed is a method in which combines the double-effect-reactor with a cement production system.

Abstract: The invention relates to a process and a plant for producing cement clinker and for purifying the off-gases formed thereby, wherein cement raw meal is preheated in a preheater by means of hot off-gases and then optionally precalcined, the preheated and optionally precalcined cement raw meal is burnt in a rotary kiln to form cement clinker, the cement clinker is cooled in a cooler, the hot off-gases used in the preheater are used in a raw mill for treating the cement raw meal, the dust content of a dust-containing mill off-gas thereby formed is reduced in a separating device to less than 5 g/Nm3, preferably less than 1 g/Nm3, alkali hydrogen carbonate and/or alkali carbonate is added to and mixed with the mill off-gas whose dust content has been reduced to less than 5 g/Nm3, and the mixed gas thereby formed is subsequently fed to a process filter for separation of dust laden with pollutants.

Abstract: In accordance with the present invention, there is provide and device and method to facilitate the treatment of chlorine bypass dust while preventing increases in chemical cost and concentrations of heavy metals in clinker, and ensuring stability in quality of cement, and to treat chlorine bypass exhaust gas while avoiding coating troubles in a cement kiln etc., and preventing heat losses in a preheater etc., without degradation of clinker production amount.

Abstract: Systems, methods and processes teach by specific examples how the cost of sequestering carbon dioxide (CO2) can be totally offset and turned into profits during coal powered electricity generation from revenue and co-benefits. The process is provided whereby fly ash-carbon mixtures, or de-volatilized coal char, or anthracite coal culm is co-fired in an air-cooled, slagging combustor with limestone or similar slag fluxing materials converts the ash into cementitious slag with properties similar to ground granulated blast furnace slag.

Abstract: During the production of cement clinker by preheating cement raw meal in a preheater and calcining and sintering the preheated cement raw meal, the exhaust gases which are produced during the calcination and the sintering process are used for preheating and are subsequently cleaned in an SCR catalytic convertor. There are used during the clinker production replacement fuels which contain carbon-containing odorous substances and/or ammonia-containing compounds which are previously dried, wherein a drying exhaust gas which is produced during the drying operation and/or exhaust vapour condensate being used at least partially for exhaust gas quenching upstream of the SCR catalytic convertor, and the carbon-containing odorous substances and/or ammonia-containing compounds in the drying exhaust gas and/or exhaust vapour condensate being converted on the SCR catalytic convertor.

Abstract: A process for the production of cement which includes the calcination of calcium carbonate-containing raw meal in a calciner heated by combustion of a carbon-containing fuel with a gas including oxygen and from 0 to 80% by volume of carbon dioxide, and substantially free of nitrogen, and isolating the gas produced by combustion and calcination in the calciner.

Abstract: Manufacturing methods and plants for carrying out methods of manufacturing cement clinker including diverting gases from a separation cyclone for a calcined cement material. The diverted gases are cooled to a temperature of 850° C. or less by introducing raw cement materials into the diverted gas stream.

Abstract: Provided herein are compositions and methods including hydraulic cement, supplementary cementitious material, and/or self-cementing material. Methods for making the compositions and using the compositions are provided.

Abstract: A method and apparatus for reducing discharges into the atmosphere of mercury pollutants associated with dry process, precalciner cement manufacturing is shown. Raw feed meal used in cement production is heated in a special heating chamber to drive off volatile mercury pollutants, such as elemental mercury and mercury oxides. Preferably, the feed meal is heated to a temperature of at least 175° C. The gases that are driven off flow are then cooled to condense the mercury pollutants causing them to be adsorbed on carbon particles injected into the gas flow. The carbon particles containing the condensed mercury pollutants are then filtered out of gas flow, for example, using a fabric filter. The gas flow may be burned to destroy other volatile pollutants such as hydrocarbons and/or ammonia.

Abstract: A cement kiln chlorine/sulfur bypass system wherein the equipment cost is suppressed and the sulfur included in a combustion gas bled from a cement kiln is separated and effectively utilized. The cement kiln chlorine/sulfur bypass system comprises an air bleed means for bleeding a kiln exhaust gas passage, which runs from the end of the cement kiln to a bottom cyclone, of a part of the combustion gas, a separating means for separating dust in the gas bled by the air bleed means into coarse particles and fine particles, and a wet dust collector for collecting dust from the gas containing the fine particles separated by the separating means. The separating means is preferably a classifier in which the cut size is changeable. The wet dust collector is preferably a mixing scrubber.

Abstract: A method to efficiently reduce lead content of cement without exerting influence upon quality of the cement. The method comprises the steps of: controlling O2 concentration of combustion gas in an inlet end of a cement kiln to 5% or lower and/or CO concentration thereof 1000 ppm or more; extracting a part of combustion gas from the cement kiln and collecting dust contained in the combustion gas; and collecting lead from the dust collected. With this, the area where raw material temperature in the cement kiln is between 800° and 1100° can be turned into reducing atmosphere to sharply increase volatilization rate of lead, and collection of lead from the dust allows lead content of cement to efficiently be reduced without exerting influence upon quality of the cement.

Abstract: Methods and systems for converting waste heat from cement plant into a usable form of energy are disclosed. The methods and systems make use of two heat source streams from the cement plant, a hot air stream and a flue gas stream, to fully vaporize and superheat a working fluid stream, which is then used to convert a portion of its heat to a usable form of energy. The methods and systems utilize sequential heat exchanges stages to heat the working fluid stream, first with the hot air stream or from a first heat transfer fluid stream heated by the hot air stream and second with the flue gas stream from a second heat transfer fluid stream heated by the hot air stream.

Abstract: The carbon monoxide and hydrocarbon content of flue gas in a cement clinker production apparatus is lowered by feeding a high velocity stream of hot oxygen into the flue gas. Methods and apparatus for producing the hot oxygen stream are disclosed.

Abstract: Described is a method for manufacturing cement clinker by which method cement raw meal is preheated and burned in a plant comprising a cyclone preheater (1) and a kiln (5). The method is peculiar in that that at least a portion of the raw meal is extracted from the cyclone preheater (1), that this raw meal is introduced into a separate unit (21) in which it is given a retention time under oxidating conditions provided by means of a gas stream for forming SO2 and for expelling organic carbon, that the formed SO2 and the expelled organic carbon are subsequently discharged from the separate unit (21) entrained in the gas stream for further treatment in a subsequent process stage, and that the raw meal is reintroduced into the cyclone preheater (1). Hereby is obtained an effective reduction of the VOC, CO as well as the SO2 emission without necessitating utilization of additional energy for heating.

Abstract: Described is a method as well as a plant for preheating particulate or pulverulent material such as cement raw meal or similar material in a cyclone preheater (1), comprising at least two cyclone stages, each comprising a riser duct (2a, 2b, 2c, 2d) and a cyclone (1a, 1b, 1c, 1d). The method is peculiar in that a portion of the material which is fed to at least one cyclone stage is introduced to the first part of the riser duct, viewed in the direction of travel of the exhaust gases, and is heated from a temperature of maximum 450° C. to a temperature of at least 550° C., and in that the remaining material which is fed to the same cyclone stage is introduced into the last part of the said riser duct. As a result, there will be a reduction in the amount of SO2 which is discharged from the cement plant preheater as emission, without a simultaneous increase in energy consumption.

Abstract: A method and apparatus for reducing air pollutants associated with dry process, precalciner cement manufacturing is shown. Raw feed meal used in cement production is heated in a special heating chamber to drive off volatile compounds, such as organic materials and salts of ammonia. Preferably, the feed meal is heated to a temperature of at least 350° F. The gases that are driven off flow to the precalciner where they are combusted and rendered harmless. Heat is provided by diverting at least a portion of the exhaust gases from the cement pyroprocessing kiln to the special heater. The raw feed meal is indirectly heated using a heat exchange wall between the feed meal and the kiln exhaust gas flow. In addition, abase-containing material such as lime or precalcined feed meal, may be added to the raw feed before treatment meal to promote the breakdown of inorganic ammonium compounds, thereby releasing gaseous ammonia which is also destroyed upon subsequent combustion.

Abstract: A process is disclosed for producing cement clinker, comprising the steps of: a) providing a mixture of ground calcareous materials and ground argillaceous materials; b) heating the mixture of step a) to a temperature sufficient to calcine and fuse the ground materials to form the cement clinker, and thereby producing an exhaust gas containing CO2; c) catalysing the hydration of at least a portion of the CO2 contained in the exhaust gas and producing a solution containing bicarbonate ions and hydrogen ions; and d) adding to the solution obtained in step c) metal ions, and adjusting the pH of the solution to precipitate a carbonate or said metal. Preferably, the metal ions are Ca++ obtained from the dissolution of a material selected from the group consisting of CaCl2, cement kiln dust and sea salts and the carbonate is CaCO3 which is advantageously recycled into the process by adding the CaCO3 to the mixture of step a). A cement plant for performing this process is also disclosed.

Abstract: In a method of producing cement clinker and electricity, cement raw mix and hydrocarbon are fed in a circulating fluidized bed boiler (1). Therein cement raw mix is calcined and steam is produced. Gas and solids out of the fluidized bed enter a cyclone (8), the solids being separated therein and returned to the bed. Part of those solids are first cooled down in a solids heat exchanger (9) producing steam. Fly ash consisting predominantly of lime and gas escaping the cyclone are passed through a heat exchanger (28, 33) and a filter (37). Hot bed material is discharged from the circulating fluidized bed and is ground with additives, then blended with lime being separated in the filter (37), then supplied to a rotary kiln (16), wherein the solids are clinkered. The produced steam is fed to a steam turbine island (42).

Abstract: A method and apparatus for heat treatment of fine-grained material. In order to reduce the nitrogen oxide content of the exhaust gas from the combustion zone, a region of the calcination zone is operated under reducing conditions and ammonia-containing additives are introduced into the calcination zone. In this case, at least the predominant proportion of the ammonia-containing additives is only added in a region of the calcination zone in which the secondary combustion of the combustion products which are formed in the section operated under reducing conditions but are not completely reacted out is largely concluded.

Abstract: The invention in its various embodiments includes an apparatus and a method for improving combustion in a cement kiln system. The apparatus in one embodiment includes a precalciner and an oxygen source coupled to the precalciner. The method in one embodiment includes introducing oxygen into the precalciner of a cement kiln system.

Abstract: In order to create a process for the economical production of cement clinker in a cement clinker production line with a raw meal preheater, a precalcination stage, a rotary tubular kiln and a clinker cooler, in which the total oxygen excess required for all firing points, i.e., the ratio of total oxygen to total fuel, also designated as &lgr; value, is to lie as low as possible, it is proposed according to the invention, to continuously measure the content of CO and/or (unburned) hydrocarbons and/or other combustion products in the exhaust gas path of the precalcination stage and, in dependence on this measurement value, to perform a regulating intervention on the amount of an oxidation agent and/or catalyst to be injected into the precalcination stage.

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 an apparatus to reduce NOx emissions in the exhaust gas from installations that form NOx as a result of combustion processes, such as the production of cement clinker, in which the NOx decomposition occurs in the temperature range from approximately 450° C. to approximately 850° C. and in an oxidizing atmosphere with a fuel-air ratio (Lambda) approximately equal to 1.

Abstract: In a method for reducing the amount of chloride components in cement clinker kilns at least a portion of the chloride-containing gases is removed from the kiln chamber. The gases are guided into a condenser whereby the gas temperature is maintained at a value above the condensation temperature of the chloride components. The chloride components are then cooled on cooled condensation surfaces of the condenser to a value below the condensation temperature. The cleaned gases are removed from the condenser and preferably returned into the kiln chamber. The condensation surfaces are continuously or discontinuously cleaned, and the removed chloride crystals are taken out of the condenser.

Abstract: The invention relates to the production of cement clinker from cement raw material using a preheating zone, a calcination zone, a heating zone in which the calcined material is further heated whilst avoiding the formation of a molten phase, as well as a clinker burning zone and cooling zone from which part-quantities of the hot exhaust air are delivered as combustion air together with proportions of fuel to the clinker burning zone, the heating zone and the calcination zone. A reliable further heating while avoiding incrustations is achieved in the heating zone by constructing this zone in the manner of a flue stream reactor to which calcined material, fuel and combustion air are delivered in the lower end region of a rising first treatment zone at one point in each case and from which the heated material is precipitated essentially by the effect of gravity overlaid with centrifugal action.

Abstract: The invention relates to the heat treatment of fine-grained material which is first of all preheated in a multi-stage cyclone preheater, then further heated in a calcination zone, next finally burnt in a kiln and then cooled. Preheated material and tertiary air are delivered to the reaction chamber of the calcination zone in order to maintain therein a reducing atmosphere for reduction of the NO.sub.X content in the kiln exhaust gases. For the purpose of good adjustability of the reaction temperature in the reaction chamber and for the purpose of a space-saving construction, the preheated material from the second-lowest preheating stage as well as tertiary air are introduced at the bottom into the reaction chamber and an adjustable part-quantity of the preheated material from the third-lowest preheating stage is introduced into an upper region of the calcination zone.

Abstract: Cement and elemental sulfur are produced by forming a moist mixture of a flue gas desulfurization process waste product containing 80-95 percent by weight calcium sulfate hemihydrate and 5-20 percent by weight calcium sulfate hemihydrate, aluminum, iron, silica and carbon, agglomerating the moist mixture while drying the same to form a feedstock, and calcining the dry agglomerated feedstock in a rotary kiln. Sulfur dioxide produced during the calcination is cooled and contacted with hydrogen and carbon monoxide to reduce the same to elemental sulfur.

Abstract: Cement is produced by forming a moist mixture of a flue gas desulfurization process waste product containing 80-95 percent by weight calcium sulfite hemihydrate and 5-20 percent by weight calcium sulfate hemihydrate, aluminum, iron, silica and carbon, agglomerating the moist mixture while drying the same to form a feedstock, and calcining the dry agglomerated feedstock in a rotary kiln. Sulfur dioxide released from the calcium sulfite hemihydrate and calcium sulfate hemihydrate during calcination may be used to produce sulfuric acid, while heat recovered in the process is used to dry the agglomerating feedstock.

Abstract: The present invention relates to a method for dry desulfurizing flue gases from rotary cement kilns, for which additives suitable for binding SO.sub.2, such as quick lime and/or dry calcium hydroxide, are supplied to the kiln, the additive being introduced into a flue gas-carrying zone at the kiln head at a injection angle of 2.degree. to 12.degree. to the axis of the kiln and at an injection velocity of 20 to 80 m/sec.

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: Disclosed is a method and an apparatus for the heat treatment of lime sludge (CaCO.sub.3) to form burnt lime (CaO). In the method of the present invention a lime sludge feed is entrained in and thereafter dried in a gas flash dryer means to produce a dried lime sludge. The dried lime sludge is separated from the gases and thereafter is fed to a rotary kiln in which the dried lime sludge is converted to active burnt lime. In order to maintain the flow of gas in the flash dryer means at a predetermined velocity in order to entrain all the lime sludge feed in the gas flow, an adjustable portion of the separated gases are recycled through the flash dryer means.

Abstract: A bypass system is provided for a long cement kiln. The long cement kiln includes a cylindrical rotary vessel in which a kiln gas stream flows countercurrent to in-process mineral. The bypass system includes an annular bypass plenum, a port in the wall of the rotary vessel in gas flow communication with said plenum, and a draft tube for preventing passage of in-process mineral through said port. A blower fan induces flow of at least a portion of the kiln gas stream to form a bypass stream through the draft tube and the port and into the annular bypass plenum. The bypass system also includes an apparatus for mixing controlled amounts of ambient air with the bypass stream to cool the kiln gas bypass stream and to precipitate alkali fume in the kiln gas bypass stream before it passes through the draft tube and the port in the wall of the rotary vessel to reduce build up of condensed alkali inside the draft tube.

Abstract: In a kiln plant for burning clinker from mineral raw materials, such as cement raw materials, and comprising a kiln (1), a precalciner (4), a preheater (6, 7, 8) and a flue gas filter (31), part of the kiln flue gases is diverted from the precalciner and the preheater via a bypass (20-30), the bypassed amount of flue gas being subjected to a preceding quenching in a chamber (21), humidified with water and cooled in a reactor (23), thereby causing the chlorides and alkalis in the bypassed gas to deposit upon dust particles which together with material dust in the gases are precipitated from the latter in a separator (25). The bypassed flue gas thus being almost purified of harmful compounds is then fed to the filter (31) or recirculated to the bypass in such manner that at least part of the precipitated compounds and material dust from the reactor (23) and the separator (25) is returned to the reactor for renewed treatment in same.

Abstract: The invention relates to a method of purifying the exhaust gases from plants for the production of cement clinker, in which the filter zone through which the exhaust gases flow contains at least one adsorption stage in which an adsorbent is provided which is suitable for fixing NH.sub.x compounds, heavy metals and/or trace pollutants, at least a proportion of the adsorbent being removed from the adsorption stage at specific intervals of time and introduced into the final burning zone and/or preheating zone. By such a method the NO.sub.x content of the exhaust gases is significantly reduced, and at the same time heavy metals and trace pollutants are eliminated from the exhaust gases.

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.