2086 results about "Cement kiln" patented technology

The invention describes an activated supersulphated aluminosilicate binder containing aluminosilicates, calcium sulphate and an activator containing alkali metal salts, wherein the aluminosilicates are selected from the group consisting of blast furnace slag, clay, marl and industrial by-products such as fly ash with the proviso that the Al2O3 content is greater than 5% by weight, wherein blast furnace slag is present in an amount exceeding 35% by weight and clay, marl and/or fly ash is present in an amount exceeding 5% per weight and wherein cement kiln dust in an amount of from 3 to 10% by weight is added to the mixture as an activator and calcium sulphate is used in an amount exceeding 5% by weight.

The present invention includes methods of cementing in subterranean formations using cement kiln dust in compositions having reduced Portland cement content. An embodiment of a method comprises placing a sealant composition that comprises cement kiln dust and is essentially free of Portland cement in a subterranean formation; and allowing the sealant composition to set.

An alternative cover for landfill may be formed from a slurry mixture of water, cementitious binder, adhesion enhancing admixture and fiber. These constituents may be mixed and applied to cover landfilled wastes, granular material piles or for soil erosion control. The cover will harden to minimize water infiltration, wind blown dust, odor and affinity to birds, flies and other insects. The water may include tap water, landfill leachate and wastewater. The binder may include Portland cement, blended cement, cement kiln dust, class C fly ash, and/or calcium sulphate hemihydrate. The adhesion enhancing admixture includes water-dispersible polymers. The fibers may comprise shredded paper or wood or plastic fibers.

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.

The present invention provides cement compositions that comprise water, high alumina cement, a soluble phosphate, and cement kiln dust. The cement compositions optionally may be foamed with a gas. Methods of cementing also are provided that comprise: providing the cement composition; introducing the cement composition into a location to be cemented; and allowing the cement composition to set therein. The location to be cemented may be above ground or in a subterranean formation.

A process for sequestering carbon dioxide from the exhaust gas emitted from a combustion chamber is disclosed. In the process, a foam including a foaming agent and the exhaust gas is formed, and the foam is added to a mixture including a cementitious material (e.g., cement-kiln dust, lime kiln dust, or slag cement) and water to form a foamed mixture. Thereafter, the foamed mixture is allowed to set, preferably to a controlled low-strength material having a compressive strength of 1200 psi or less. The carbon dioxide in the exhaust gas reacts with hydration products in the controlled low-strength material and in turn sequesters the carbon dioxide.

The disclosure provides methods and systems for sequestering and/or reducing sulfur oxides, nitrogen oxides and/or carbon dioxide present in industrial effluent fluid streams. A solid particulate material comprising a slag component, a binder component (distinct from the slag component), and optionally water is formed and then contacted with the effluent fluid stream to reduce at least one of the sulfur oxides, nitrogen oxides, and/or carbon dioxide. The contacting of the effluent stream may occur in a packed bed reactor with the solid dry particulate material. Methods of reducing pollutants from exhaust generated by combustion sources, lime and/or cement kilns, iron and/or steel furnaces, and the like are provided.

The invention provides an SCR (selective catalytic reduction) catalyst for denitrating low-temperature smoke of a cement kiln and a preparation method thereof. The SCR catalyst is characterized in that by adjusting the technological conditions such as proportions of active components, mass ratio of carriers and active components, calcining temperature and the like, a composite metal oxide which is formed by one or more metal elements out of manganese (Mn), ferrum (Fe), copper (Cu), cerium (Ce), lanthanum (La), bismuth (Bi), niobium (Nb), tantalum (Ta) and the like is loaded on a carrier by adopting an impregnation method, and tungsten and molybdate are used as active assistants. The active components in the SCR catalyst are uniformly distributed on the surface of the carrier in an unformed shape, the low-temperature activity of the catalyst is improved by utilizing the synergistic effect of multiple metals, the SCR catalyst is particularly suitable for the denitration of the smoke which is discharged from a dust collector on the tail of the cement kiln, the denitration rate can reach higher than 70 percent at the temperature of 80 DEG C, the denitration rate is higher than 90 percent in the temperature range of 125 DEG C to 200 DEG C, and the toxicity resistance is strong.

The invention discloses a low temperature denitration catalytic addictive and a preparation method thereof, and belongs to the field of low temperature denitration catalyst. According to the low temperature denitration catalytic addictive, TiO2-SiO2 is taken as carrier, manganese oxide (MnOx) is taken as active substance, and cerium oxide (CeO2), nickel oxide (NiO) and iron oxide (FeOx) are taken as auxiliary agents. The preparation method comprises following steps: TiO2-SiO2 composite carrier is prepared by sol-gel method; loading of CeO2, NiO or FeOx is realized by one-step dipping; and then the low temperature denitration catalytic addictive is obtained by calcination. The low temperature denitration catalytic addictive possesses high low-temperature denitration catalytic efficiency, wide active temperature window, and relatively high alkali metal poisoning resistance. TiO2-SiO2 is low in cost, and specific area of TiO2-SiO2 is larger than that of pure TiO2 carrier, so that it is beneficial for dispersion of active substances on the surface of TiO2-SiO2, and stability of the active substances. Auxiliary agent NiO or FeOx are capable of increasing low-temperature activity and alkali metal poisoning resistance of the low temperature denitration catalytic addictive, so that the low temperature denitration catalytic addictive is suitable for denitration in dedusted cement kiln at low temperature or even under conditions with unstable temperature.

The invention discloses a special castable for a kiln outlet, which belongs to the field of refractory materials. According to the invention, the special castable comprises the following components in percentage by weight: 8-25% of silicon carbide, 10-30% of andalusite, 20-35% of corundum, 5-15% of spinel powder, 5-10% of zircon mullite powder, 1-5% of zirconium diboride, 1-5% of silicon nitride,5-15% of alumina micropowder, 3-6% of pure calcium aluminate cement, 0.5-1% of explosion-proof fiber and 0.06-0.2% of sodium tripolyphosphate, which is an additive. By using the special castable for the kiln outlet, disclosed by the invention, the phenomenon of poor wear resistance, block falling and the like in the kiln outlet can be effectively improved; the service life of the cement kiln outlet can be largely prolonged; and the special castable for the kiln outlet, disclosed by the invention, has the advantages of high temperature resistance, heat shock resistance, wear resistance, high strength, irreversible micro expansion and the like.

The invention discloses a special pouring material for a kiln opening and belongs to the field of a refractory material. The special pouring material comprises the following components by weight percent: 10-25% of silicon carbide, 15-30% of andalusite, 20-35% of corundum, 5-15% of spinel powder, 5-10% of zircon mullite powder, 5-15% of aluminum oxide micro powder, 3-8% of silicon micro powder, 2-5% of pure calcium aluminate cement, and 0.5% and 0.2% of anti-explosion fibers and sodium tripolyphosphate serving as additives. The special pouring material is capable of efficiently improving the wear resistance and avoiding the hot peeling phenomenon of the cement kiln coal injection pipe, has the characteristics of high temperature resistance, heat vibration resistance, wear resistance, high strength, irreversible micro inflation, and the like, and is capable of greatly prolonging the service life of the cement kiln coal injection pipe.

In one example of an embodiment of the invention, a method for producing an aggregate is disclosed comprising mixing sewage sludge from a waste water treatment facility with a non-coal combustion ash silicoaluminous waste material, agglomerating the mixture to form an agglomerate, and pyroprocessing the agglomerate to form an aggregate. The waste material may comprise municipal solid waste incinerator bottom ash, incinerator fly ash, incinerator filter dusts, cement kiln dusts, waste glass, blast furnace slag, kiln dusts, and/or granite sawing residues, for example. The method may further comprise milling the waste material prior to mixing. Preferably, the milling is wet milling. Pyroprocessing of the agglomerate may take place in a rotary kiln. The resulting aggregate may be a lightweight or a normal weight, sintered or vitrified aggregate. Aggregates and methods for making aggregates of high and low calcium silicoaluminous materials are also disclosed.

The invention relates to a complex combination alumina-carborundum-(carbon) series amorphous fire proof material, and the formula comprises: 36 to 32 percent of 8-3mm corundum or bauxite, 18 to 26 percent of 3-1mm corundum or bauxite, 10 to 22 percent of 1-0.0088mm corundum or bauxite, 0 to 15 percent of 1-0.088mm carborundum, 0 to 3 percent of 1-0.0088 spherical asphalt, 0 to 20 percent of d90 less than 0.088mm corundum or bauxite, 0 to 20 percent of d90 less than 0.088 carborundum, 0 to 3 percent of d90 less than 0.088mm high-carbon materials, 0 to 5 percent of alpha alumina micro powder, 1 to 8 percent of alumina hydrate, 1 to 6 percent of silicon ash, 0 to 2 percent of calcium aluminate cement, 0.05 to 0.4 percent of plus super-plasticizer (polycarboxylic acids+sulfonated naphthalene formaldehyde polymer+sulfonated melamine polymer), 1 to 6 percent of plus polypropylene acid series latex and 1 to 6 percent of plus water. Compared with low-cement aluminum carborundum carbon material, the material has good anti-corrosion performance. Therefore, the service life of a kilneye of a cement kiln and a main groove slag line of a blast furnace can be prolonged when a product is combined by the complex combination alumina-carborundum-(carbon) series amorphous fire proof material instead of the cement.

The invention discloses wear corrosion resistant castable prepared from a bauxite-based homogenous material and a preparation method thereof, which belong to the technical field of castable refractory. In the invention, by using the characteristics of the bauxite-based homogenous material, such as homogeneous chemical components and structure, stable performance, mulite main crystal phase, small linear change, high high-temperature strength and certain flexibility due to mutual insertion of micro crystals and the like, the shortcomings of low middle-temperature strength and poor wear resistance and alkali corrosion resistance of the conventional high-aluminum bauxite castable are overcome, and the problems of low middle-temperature strength, poor wear resistance and poor alkali, chloride and sulphur corrosion resistance of the conventional high-aluminum and corundum castable are effectively solved. The wear and corrosion resistant castable with high middle-temperature performance is prepared. The wear corrosion resistant castable and the preparation method thereof have the advantages of small fluctuation of water adding amount in construction, stable usability, reduction rate of partial corrosion, prolonged service life and wide application to a kiln hood, a grate cooler, a tertiary air duct and a decomposing furnace of a dry process cement kiln and relative parts of other ceramic and petrified thermo-technical kilns and the like.

The invention relates to a composite bonding wear-resistant castable refractory, which can be used for high-temperature kiln engineering. The amorphous castable refractory which is normal in coagulation, quick in hardening, low in porosity, high in strength and high in abrasive resistance is prepared from silica sol serving as a bonding agent, aluminate cement serving as a curing agent, alumina micro powder and wollastonite which serve as a compact agent, heat resistant steel filters serving as a reinforcing agent and corundum and alumina which serve as an aggregate. The composite bonding wear-resistant castable refractory is suitable for positions such as air pipeline elbows for the cogeneration of cement kilns, cyclone cones and linings for triple air pipe gates which are easy to wear in high-temperature kilns.

Alternate fuels and method of using the alternate fuels for replacing all or part of conventional fuels used to heat a riser duct, calciner or kiln in a cement making process.

The invention provides efficient, inexpensive, and environmental friendly catalysts and catalyst systems. The catalysts can be used to catalyze esterification and/or transesterification reactions, for example, for the preparation of biodiesel. Kiln dust, such as cement kiln dust (CKD) or lime kiln dust (LKD) can be used to convert a variety of feedstock acids and/or esters to biodiesel in high yield under mild conditions. The CKD and LKD catalyst systems are recyclable esterification or transesterification catalysts that can be used to prepare biodiesel, such as methyl soyate, from various feedstocks, including vegetable oils and animal fats.