Abstract: The invention relates to a method for processing steel slag to produce a hydraulic mineral binder with a high hardening potential and to recover iron. There is provision for this purpose to provide a feed product comprising steel slag with MnO. This feed product is further processed as a melt by introducing reducing agent into the melt. A lime saturation factor of between 90 and 110 is hereby to be achieved in the mineral melt portion. Subsequently the melt is cooled in a defined manner and elementary iron is mechanically separated from the solidified melt. The solidified melt is then supplied for use as hydraulic mineral binder. Furthermore the invention relates to a hydraulic mineral binder.

Abstract: The present invention teaches the method to use the sulfate or sulfites based raw materials, such as magnesium, calcium and other alkative earth sulfates or sulfites to produce the respective oxides in a carbon five basis, by using sulfur as the fuel and the reductant. The invention also utilizes renewable energy such as solar thermal or green electricity wherever possible. This approach provides a green process, of ultra-low carbon dioxide emission, for the production of magnesium, other alkaline earth metals and other material which requires alkaline earth oxide, such as in the production of carbon free Portland cement requiring lime. The invention also provides a useful outlet for waste streams leading to sustainable processes. The cost of the production of these precursors are kept low by concurrently producing a saleable by-product—sulfuric-acid.

Abstract: A method for secondarily synthesizing calcium sulphoaluminate mineral in Portland cement clinker is provided. The method includes adding gypsum into raw Portland cement, calcination, then heating twice to re-form calcium sulphoaluminate mineral that has decomposed at high temperature in the clinker. This method can increase the content of calcium sulphoaluminate mineral in the clinker. As a result, the advantages of the calcium sulphoaluminate mineral in the clinker may be obtained, such as improvement of the early stage performance and long-term performance of the cement clinker and increase in the quantity of mixture in the cement.

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: A process for making calcined gypsum in slurry or powder form. The process includes adding at least two types of crystal modifiers to the slurry. The first crystal modifier is to control crystal morphology of the calcined gypsum (such as succinic and/or malic acid). The second crystal modifier is to prevent or retard setting to control set time (such as tetrasodium pyrophosphate (TSPP)) to form a water stable product. An accelerator is typically added at the site of use for specific applications such as setting type joint compound, media casting, exterior/interior coating, and sprayable fireproofing. A composition made by the process and a kit for using the composition are also disclosed.

Abstract: Accordingly, the present invention provides an improved process for the production of Portland slag cement using granulated blast furnace slag, which comprises: (viii) forming of cement clinker by known process, (ix) ball-milling of cement clinker for a period ranging between 30-60 minutes in dry condition, (x) reducing size of granulated blast furnace slag by any process to obtain the size in the range between 210 to 100 ?m for using as feed for attrition mill, (xi) wet milling of granulated blast furnace slag for a period ranging between 5-15 minutes in an attrition mill using granulated blast furnace slag to water ratio in the range of 1:1 to 1:2 and granulated blast furnace slag to grinding bail ratio in the range of 1:5 to 1:15, (xii) removing water from the slurry obtained after attrition milling by known process, (xiii) drying of the obtained slurry by known process, (xiv) mixing intimately of: attrition milled slag obtain in step (vi) in the range of: 50 to 95% by weight ball-milled clinker obtain

Abstract: Accordingly, the present invention provides an improved process for the production of Portland slag cement using granulated blast furnace slag, which comprises: (viii) forming of cement clinker by known process, (ix) ball-milling of cement clinker for a period ranging between 30-60 minutes in dry condition, (x) reducing size of granulated blast furnace slag by any process to obtain the size in the range between 210 to 100 ?m for using as feed for attrition mill, (xi) wet milling of granulated blast furnace slag for a period ranging between 5-15 minutes in an attrition mill using granulated blast furnace slag to water ratio in the range of 1:1 to 1:2 and granulated blast furnace slag to grinding bail ratio in the range of 1:5 to 1:15, (xii) removing water from the slurry obtained after attrition milling by known process, (xiii) drying of the obtained slurry by known process, (xiv) mixing intimately of: attrition milled slag obtain in step (vi) in the range of: 50 to 95% by weight ball-milled clinker obtain

Abstract: Fluorgyp is converted to calcium sulfate by reacting sulfuric acid in the fluorgyp with calcium carbonate having a small particle size. The resulting product is useful as a set retarding agent for cement.

Abstract: Moisture conditioning building material is compound of diatomite, which contains 5%˜30% by weight in the range of grain size 2 micrometer˜100 micrometer, inorganic material and either or both of organic reinforcing fiber and inorganic fiber, and is obtained by depositing method.

Abstract: The present invention regards a particularly quick-setting Portland cement clinker containing calcium fluoro-aluminate (11CaO.7Al.sub.2 O.sub.3.CaF.sub.2) mixed with lime that has not undergone the burning process of the clinker.

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: A Portland cement clinker free of C.sub.4 A.sub.3 S having the following proportions of clinker phases, in % by wt.:--C.sub.3 S: 40 to 80--C.sub.4 AF: <20--C.sub.2 S: <30--C.sub.3 A: <20and a SO.sub.3 content from 1.0 to 3.0% by wt., based on the clinker, obtained by burning a mixture of raw materials containing CaO, SiO.sub.2, Al.sub.2 O.sub.3, Fe.sub.2 O.sub.3 and an additive containing SO.sub.3 at temperatures from 1200.degree. to 1350.degree. C. centigrade, the use thereof and a Portland cement.

Abstract: The invention relates to a method for manufacturing cement clinker whereby the raw meal is initially subjected to preparatory processing, e.g. by comminution, homogenization and/or drying, and, eventually, nodulized and burned, with the nodulization process itself taking place in a stationary burning reactor. By the method according to the invention a sulphatic compound is added to the raw meal in a sufficient quantity before introducing the raw meal into the stationary burning reactor or directly into the stationary reactor, e.g. through the combustion air or together with the fuel. The sulphatic compound may be selected among all types of sulphates which will not affect the properties of the finished cement. It is particularly advantageous to use calcium sulphate, either naturally occurring or industrial by-products and regular waste materials, e.g. used absorbent from dry exhaust gas desulphurization.

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 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: Methods for combining Class C fly ash into cementitious mixtures for producing concretes that are resistant to sulfate-containing environments. In one method, Class C fly ash is intergound with portland cement clinker and gypsum to produce a cementitions mixture, which, when combined with water and an aggregate produces a hardened concrete that is resistant to sulfate environments. Alternatively, portland cement clinker and gypsum are first interground and the resultant mixture is admixed with Class C fly ash to produce a cementitious mixture. Thie cementitious mixture, in combination with water and an aggregage, produces a hardened concrete that has improved resistance to sulfate environments. In other aspects, a concrete that is stable in sulfate environments is produced by admixing portland cement, Class C fly ash and water containing a source of ions selected from the group consisting of sulfate and hydroxyl anions.

Abstract: Acidic gases such as sulfur oxides are removed from a waste gas stream by passing it through a reverse jet scrubber in which a suspension of finely divided limestone is used as an absorption medium. The method is particularly adaptable for use in a cement manufacturing plant wherein the sulfur dioxides in the waste gases from the combustion of fossil fuels used for process heat are removed by passing them through a reverse jet scrubber that uses as an absorption medium a suspension of finely divided limestone derived from the powdered limestone feed to the cement-making process and wherein the calcium sulfate slurry formed by reaction of the sulfur oxides with the calcium carbonate in the absorption medium is returned to the limestone comminution step of the cement making process and thereby disposed of as an ingredient of the cement clinker.

Abstract: A method for manufacturing cement is described, by which gypsum is added to the clinker in the clinker cooler (3). Hereby it is obtained that the gypsum is dried in a safe, simple and inexpensive manner without substantial additional costs for establishment and operation.

Abstract: The present invention pertains to a portland cement clinker containing the following amounts of clinker phases, in wt. %:C.sub.3 S: 30 to 80,C.sub.4 A.sub.3 S: 5 to 30,C.sub.4 AF: <30,C.sub.2 S: <40,C.sub.3 A: <20,and an SO.sub.3 content between 2 and 8 wt. %, obtained by calcining a raw material mixture containing CaO, SIO.sub.2, AL.sub.2 O.sub.3, and Fe.sub.2 O.sub.3 in the presence of an additive containing SO.sub.3 and an additive containing fluorine at temperatures between 1,150.degree. C. and 1,350.degree. C.

Abstract: A flux composition for cement comprises mainly wollastonite. One of the compositions of the flux is wollastonite 99%, fluorite 5-15% and gypsum 30-35%. The flux is added during the preparation of the cement raw materials and comprises 1-10% of the admixture. Thus, the firing temperature firing time may be shortened, the consumption of coal may be decreased and manufacturing productivity of the cement may be improved. In addition, the compression strength and the binding strength of the cement are also improved.

Abstract: A cementitious composition capable of forming an early high strength cement when admixed with a liquid comprising a cementitious material of a specific chemical composition, surface area, and particle size distribution, the method of making such cementitious composition, and cements comprising said composition.

Abstract: This invention isolates in separate furnaces the three thermochemical processes required in manufacturing Portland cement and sulphur dioxide from a calcium sulfate source so as to yield improved pyrometallurgical treatment for each individual process. Separating these processes facilitates selection of the most kinetically suitable reactions by enabling the maintenance of optimum conditions for each process without compromising the thermal or kinetic efficiencies of the other processes.Only one fourth of the calcium sulfate is reduced to calcium sulfide in a separate ad hoc reduction furnace specifically designed for achieving enhanced reduction parameters which results in minimized reduction equipment size. Treating most of the calcium sulfate elsewhere works to avoid side reactions and allows Portland cement raw mix components to have an enhanced synergistic catalytic effect on reduction kinetics.

Abstract: A method of producing cement or concrete, comprising the step of adding fly ash to the cement or concrete at the production stage, the fly ash containing lime and reaction products from the reaction occurring between lime and sulphur oxides in connection with the desulphuration of flue gases. To avoid the disadvantageous effects of calcium sulphite and entringite reactions and to increase the used amount of fly ash containing desulphuration waste, the calcium sulphite is oxidized by hydrogen peroxide either before the production of cement or concrete or during the production.