Abstract: In some embodiments, the invention provides a method for converting of a flue gas desulfurization (FGD) waste product to a gypsum-enriched product by fostering growth of sulfur oxidizing bacteria (SOB) in the FGD waste product. Also provided are isolated sulfur oxidizing bacteria cultures as well as kits comprising an isolated sulfur oxidizing bacteria culture and written instructions for fostering the growth of the isolated sulfur oxidizing bacteria culture in FGD waste product to product a gypsum-enriched product.

Abstract: Systems and methods for sequestering gas feed constituents and creating gas feed byproducts are disclosed. The systems and methods contemplate use of and processing of fluids using fluid energy transfer modules, scrubber unit(s), a slurry reaction vessel, a surge tank treatment vessel purifier(s) and a concentrator. Chemical solutions, solids etc. are regenerated and reused thereby increasing system and/or process efficiency and savings while also producing products for commercialization.

Abstract: A plant for producing cement clinker, comprising as viewed in the direction of materials flow, a heat exchanger to preheat raw meal, a downstream calciner to calcine the raw meal, a rotary kiln to sinter the calcined raw meal, and a clinker cooler to cool the sintered cement clinker. A combustion device which carbonizes, pyrolysis or burns difficult fuels, is embodied as a pot reactor or gooseneck reactor in an inverted U-shape, and is positioned upstream of the calciner on the flow path of the exhaust gases from the rotary kiln to the calciner, and has a gas outlet that opens out above a tertiary-air line of the clinker cooler into the calciner. As a result, it becomes possible to burn fuel which is lumpy and/or has poor ignitability, and the gases from incomplete combustion in the reactor are available in the calciner in gaseous form for further combustion.

Abstract: A method of manufacturing unitized formed mineral-based construction materials includes providing starting materials that include an aggregate, a cementing agent and water. The starting materials are mixed to achieve a mixture of the starting materials which is then placed into a form and cured to allow the mixture of starting materials to become a solidified unit. The solidified unit of the mixture of starting materials is defined by a minimum dimension of thickness, length, and/or diameter. The solidified unit of the mixture of starting materials is placed into a kiln which is then heated to a processing temperature of between about 1000° C. and about 1350° C. and maintained for a period of time of between about 10 minutes and about 60 minutes per centimeter of the minimum dimension of the solidified unit of the mixture of starting materials.

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 method of controlling the solubility of granular material by treating a precipitate comprising iron(II)sulphate monohydrate originating from titanium dioxide production, in which method the reaction temperature is allowed to increase at the most to a temperature of 120° C., to a plant for treating a precipitate comprising iron(II)sulphate monohydrate, to a product and its uses. A typical method according to the invention comprises the steps of mixing water to the reaction mixture in the said mixing apparatus, and keeping the amount of neutralizing agent sufficient to give a pH value from 1.5 to 4, preferably from 1.5 to 3, to the end product in order to obtain a granular material having a high soluble iron(II) content or keeping the amount of neutralizing agent sufficient to give a pH value ?9 to the end product in order to obtain a granular material having a low solubility.

Abstract: The method for reducing organic chlorine compounds in cement production facility is a method by which a quantity of organic chlorine compounds contained in powder is reduced in the cement production facility, and the method is provided with a heating step for heating the powder to separate the organic chlorine compounds from the powder or decompose the organic chlorine compounds and a gas thermal decomposing step for supplying heat-treated gas containing the organic chlorine compounds generated by heating the powder to a high temperature part of the cement production facility, thereby thermally decomposing the organic chlorine compounds contained in the heat-treated gas.

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: The invention provides a process for preparing a sulphur cement product comprising the following steps: (a) selectively oxidising hydrogen sulphide to elemental sulphur by contacting, in a reaction zone, a hydrogen sulphide containing feed gas and a molecular-oxygen containing gas with a particulate oxidation catalyst under selective oxidation conditions; (b) discharging a stream comprising liquid and/or solid elemental sulphur and particulate oxidation catalyst from the reaction zone; (c) admixing the stream comprising elemental sulphur and particulate oxidation catalyst with at least any one of elemental sulphur, a sulphur cement filler, a sulphur cement modifier, or aggregate at a temperature at which sulphur is molten; (d) solidifying the mixture obtained in step (c) by cooling it to a temperature below the melting temperature of sulphur to obtain the sulphur cement product.

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: An exhaust gas treatment method including: (A) a step of treating exhaust gas from cement manufacturing equipment by using a dust collector 9 to collect dust containing chlorinated organic compounds, and discharging the exhaust gas after the treatment by the dust collector 9, and (B) a step of charging all or part of the dust collected by the dust collector 9 into a place (e.g. a rotary kiln 5, a pre-calciner 6, and a cyclone 4d) having a temperature of at least 800° C. inside the cement manufacturing equipment. The remainder of the dust from step (B) maybe charged into a place (e.g. a raw material supply passage 3) having a temperature below 800° C. inside the cement manufacturing equipment, provided the amount of the remainder to be charged is smaller than a certain amount. Chlorinated organic compounds such as dioxins in the exhaust gas can be decomposed efficiently to be made harmless, merely by including simple and low-cost means (e.g. a dust feeding means 12, etc.).

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: A process and a device for eliminating harmful volatile elements, in particular chlorides and/or sulfates, contained in a stream of particle-laden fumes, in which a given fraction of at least 5% of the fumes, referred to as ‘by-passed fumes’, is extracted. The harmful elements of the by-passed fumes are caused to condense, at least with regard to their particles, according to a distribution that is a function of the fraction extracted, and the particles are filtered to isolate the harmful elements. At the time of filtering, the particles are separated into at least two fractions, one with a fine grain size and the other with a coarse grain size, using a separation selectivity adapted to the distribution of the elements in order for the coarse grain size faction to be poor in harmful elements and for the fine grain size fraction to be rich in harmful elements. Application to the production of cement clinker, in particular Portland cement clinker.

Abstract: A system for the manufacture of cement clinker from cement raw meal in which the off-gases of the cement clinker production line not only undergo denitrification but also undergo desulfurization, so that even sulfur-rich raw materials and fuels can be employed without exceeding the prevailing pollutant emission limits. A substream of the oversize material (30) discharged from the mixing chamber (29) of the precalcination stage (16) as solid sorbent may be combined with the off-gas (22) and/or with a partial gas discharge (38) of the rotary kiln off-gas in order to convert the sulfur oxides contained in those off-gases to calcium sulfate (34), which is subsequently separated from the system off-gas.

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: An apparatus for producing cement clinker using a high sulfur fuel includes a wet rotary kiln, at least one sulfur analyzer, a controller, and a burner. The wet rotary kiln has a first end and a second end and processes a slurry of a raw material mixed with a certain quantity of coarse grinded high sulfur fuel received at the first end to produce cement clinker. The sulfur analyzer is produces a measure of the sulfur content of the cement clinker. The controller receives the measure from the sulfur analyzer and controls a concentration of oxygen in the kiln based on the measured sulfur content in the clinker end product. The burner is installed in the kiln at the second end and operates to burn a high sulfur fuel.

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: Processes for making cement which when used to make concrete can stabilize the concrete against alkali-silica reactivity (ASR) from alkali containing components. The process includes adding lithium containing materials in the front of a cement kiln along with the cement starting materials in an amount sufficient to minimize ASR.

Abstract: The invention relates to an apparatus and a method for manufacturing clinker, such as cement clinker, in which the majority of the raw materials is present in a hydrous slurry.Initially, the slurry is dried in a gas suspension drier, and the raw materials are subsequently passed to a thermal unit in which the heating of the raw material is effected fairly quickly so that all organic compounds are destroyed in the thermal unit.Subsequent to being heated in the thermal unit, the raw material is directed to the kiln in which it is nodulized and burned into clinker.

Abstract: Sulfur oxides are removed from a preheater waste gas stream by reacting the sulfur oxides with lime recovered from the off gas stream in a calcining furnace. The method is particularly adaptable for use in a cement manufacturing plant wherein the sulfur dioxides in the waste gases result from the combustion of fossil fuels used for process heat.

Abstract: A process of treating dust from a cement manufacturing operation. The process comprises adding carbon bearing material to the dust catch from a cement manufacturing operation to form a mixture, which is formed into nodules and sizing the nodules to obtain a feed material having a selected size range. The nodules are directed as feed material to a fluidized bed which is maintained by passing air for combustion upwardly through a bed of material. The material is thermal processed within the fluidized bed in a reducing atmosphere by supplying fuel for combustion in the fluidized bed to maintain temperatures sufficient to volatilize alkali and sulfur compounds in the feed material and produce a product having an increased concentration of cement forming compounds and reduced alkali and sulfur compounds as compared to the feed material. The reduced clinker is then re-oxidized to minimize/reverse adverse color and mineralogy.

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: Processes for making cement which when used to make concrete can stabilize the concrete against alkali-silica reactivity (ASR) from alkali containing components. The process includes adding lithium containing materials in the front of a cement kiln along with the cement starting materials in an amount sufficient to minimize ASR.

Abstract: A method of reinforcing cement/concrete mixtures with alkali-intolerant reinforcements and/or aggregate, such as uncoated, common glass filament, plastic filament, fabric and roving made therefrom by reducing the pH of the mixture while in its plastic state, and/or after it has set and cured, to about 7. With a neutral pH, the alkali-intolerant reinforcements need not be coated to protect them from degradation. In the absence of alkalinity, the reinforcement and/or aggregate material bonds with the cement mixture to form a relatively stronger mixture, which can be shaped as desired, made part of permanently poured structures, cement boards and many other small and large products. By selecting appropriate and, if desired, different materials for the reinforcements and/or aggregate, the strength, flexibility, etc. characteristics of the product can be readily changed to adapt the product to the intended use. The pH is reduced by migrating such materials as CO.sub.2 and/or CO and O.sub.

Abstract: With the present invention, a feed preparation system for producing cement includes mixing raw materials with a source of potassium. The mixture is conveyed to feed preparation system where it is placed in condition for treatment in a fluidized bed reactor for thermal processing to produce cement clinker. The potassium combines with the SO.sub.2 generated in the process to form potassium sulfate solids that are filtered from the process gas stream before emission to the atmosphere to thereby reduce sulfur emissions from the fluid bed cement process. The starting material may include white cement raw meal, grey cement raw meal and cement kiln dusts.

Abstract: The invention relates to a method of producing cement clinker from fine-grained cement raw material which after preheating and calcining is burnt in a clinker burning zone divided into two stages and is then cooled. Optimum process conditions, particularly in the clinker burning zone, are achieved in that the calcined material is first of all heated to a temperature up to the region of the sintering temperature in a stage formed by a fluidized bed or spouted bed so that a build-up granulation of the material is brought about, whereupon the material thus heated is heated to the sintering temperature in a second stage of the clinker burning zone which acts as the finish-burning stage and tempered to the finishing burn.

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: A cement-type binding material suitable as a building material for use in the manner of a Portland cement including for underground work, or as a curing accelerating additive in mortar cement or masonry cement or in concrete or as a basic material for producing building components, is produced by mixing flue dust or flue ash with a product obtained by desulfurizing flue gases. The quantity of flue dust or ash is so measured than any free lime and lime being freed during an oxidizing and calcining treatment is completely bound to aluminates and silicates capable of reacting with water. The so produced intermediate multi-phase product is milled to a certain fineness and mixed with slag sand also milled to a certain fineness. The so obtained product is suitable for use in all instances where gypsum could not be used heretofore or could be used only under expensive protective measures.