147results about "Calcium aluminates" patented technology

The invention discloses a high-efficiency clean resource utilization method for quadratic aluminum dust. The method comprises the following steps: performing low-temperature roasting treatment on quadratic aluminum dust, removing harmful elements such as nitrogen, carbon and fluorine, pulping, washing, desalting and dehydrating the quadratic aluminum dust, removing sodium salt, potassium salt andother impurity components, washing brine and evaporating and crystallizing by utilizing flue gas waste heat. The purified quadratic aluminum dust can serve as a raw material to be directly utilized, and after the quadratic aluminum dust is mechanically mixed with auxiliary materials (calcium-based, silicon-based and magnesium-based), an aluminum based inorganic material is prepared at a high temperature, and the sintering exhaust gas realizes up-to-standard discharge by virtue of dust removal and dry defluorinated purification. According to the technology in the invention, the quadratic aluminum dust can be safely, cleanly and efficiently treated and converted into the high-value aluminum based inorganic material to the greatest degree, and environmental-friendly treatment and high-value resource utilization of the quadratic aluminum dust can be realized.

To provide a method for preparing a mayenite type compound having electroconductivity imparted. A method for preparing an electroconductive mayenite type compound, which comprises melting a raw material containing Al and at least one element selected from the group consisting of Ca and Sr, holding the melt in a low oxygen partial pressure atmosphere having an oxygen partial pressure of not higher than 10 Pa, followed by cooling or annealing in a low oxygen partial pressure atmosphere or in atmospheric air for solidification, thereby to replace oxygen present in cages by electrons in a high concentration.

A method of producing a CO₂ adsorbent and CO₂ adsorbents. The method including the steps of: (a) producing a mixture of at least one calcium salt and at least one metal support cation in at least one solvent; (b) drying the mixture to produce a solid containing a calcium metal salt; and (c) calcining the dried solid to produce a sorbent of calcium oxide dispersed in a porous metal support.

The invention discloses a technology method used for producing poly aluminium chloride and calcium aluminate. The technology method comprises following steps: 1, ash stir frying is carried out, and metal aluminum is recycled so as to obtain secondary aluminum ash; 2, the secondary aluminum ash is subjected to deamination processing so as to obtain a deaminated aluminum ash slurry; 3, the deaminated aluminum ash slurry is subjected to defluorination processing so as to obtain a defluorinated aluminum ash slurry; 4, the defluorinated aluminum ash slurry is filtered so as to obtain a filtrate anda filtration residue, wherein the filtrate is a poly aluminium chloride solution; and 5, the filtration residue is washed until the pH value is 7, is uniformly mixed with a calcium based auxiliary material, drying and high temperature reaction are carried out, after reaction, cooling, crushing, and grinding processing are carried out so as to obtain calcium aluminate. According to the technologymethod used for producing poly aluminium chloride and calcium aluminate, secondary aluminum ash is subjected to complete harmless processing, so that high efficiency resource utilization of secondaryaluminum ash is realized, and the produced products possess better economical benefit.

Provided is a method for preparing an electroconductive mayenite type compound with good properties readily and stably at low cost without need for expensive facilities, a reaction at high temperature and for a long period of time, or complicated control of reaction.

A method for preparing an electroconductive mayenite type compound comprises a step of subjecting a precursor to heat treatment, wherein the precursor contains Ca and/or Sr, and Al, a molar ratio of (a total of CaO and SrO:Al₂O₃) is from (12.6:6.4) to (11.7:7.3) as calculated as oxides, a total content of CaO, SrO and Al₂O₃ in the precursor is at least 50 mol %, and the precursor is a vitreous or crystalline material; and the method comprises a step of mixing the precursor with a reducing agent and performing the heat treatment of holding the mixture at 600-1,415° C. in an inert gas or vacuum atmosphere with an oxygen partial pressure of at most 10 Pa.

Disclosed is a 12CaO.7Al₂O₃ compound, a 12SrO.7Al₂O₃ compound, or a mixed crystal compound of 12CaO.7Al₂O₃ and 12SrO.7Al₂O₃, which contains a negative hydrogen ion (H⁻, H²⁻, H₂⁻ at a concentration of 1×10¹⁸ cm⁻³ or more. A negative hydrogen ion comprising a primary component of a hydride ion is incorporated into C12A7 (12CaO.7Al₂O₃), so that a function of being converted from an insulative material to an electrically conductive material in a sustained manner by means of irradiation with light can be exhibited even in the normal atmosphere at a room temperature. The present invention also provides a solid electrolyte capable of conducting a negative hydrogen ion, and means for releasing a hydride ion from the inside of a solid into a gaseous phase using an electric field.

Provided is a process for producing an oxide which includes an electrically conductive mayenite type compound and has an electron density of at least 1 * 1018/cm3, starting from a combination of a calcium compound and aluminium compound, or a compound which includes calcium and aluminium with a molar ratio of calcium oxide and aluminium oxide as equivlent oxides in the range 9:10 to 14:5, wherein the process for producing an oxide includes a step of heating and holding the starting material at 900-1300 DEG C to produce a calcined powder which includes at least one oxide selected from a group comprising calcium aluminate, calcium oxide and aluminium oxide, and a step of heating and holding the aforementioned calcined powder at least 1200 DEG C and less than 1415 DEG C, in a reducing atmosphere in an atmosphere of an inert gas with a partial pressure of oxygen of no more than 1000 Pa or in a vacuum atmosphere.

The invention discloses a method for preparing calcium aluminate by utilizing aluminum ash and acetylene sludge. The method comprises the following steps: performing catalytic hydrolysis, acidolysis and washing on aluminum ash so as to prepare high-purity aluminum ash powder; performing ball-mill mixing on the high-purity aluminum ash powder and acetylene sludge, performing compression molding onthe mixed powder, and sintering in a sintering furnace to prepare an active calcium aluminate bulk material; crushing and performing ball milling, thereby obtaining the high-activity calcium aluminaterefining agent. The calcium aluminate refining agent prepared by the method disclosed by the invention is excellent in property, and standard requirements of calcium aluminate YB/T4265-2011 for a steel-making slag remover are met. The method disclosed by the invention solves the pollution problems of the aluminum ash and acetylene sludge hazardous/solid wastes to the environment, realizes resource utilization, and has excellent environmental, economic and social benefits.

The invention discloses a method for preparing high-purity calcium aluminate by using a rotary kiln. The method comprises the following steps: uniformly mixing a calcium-containing compound and an aluminum-containing compound according to a molar ratio of elemental Ca to elemental Al of (1: 1.5) to (1: 4) to obtain a raw material; adding pulverized coal into the raw material, and uniformly mixing;sending a mixture into the rotary kiln, sintering at 1350-1500 DEG C for 0.5-1 hour, and cooling to obtain a clinker; milling and pressing the clinker for 0.5-1.5 hours by using a ball mill; and screening by using a screening device to obtain powdery granules, namely the high-purity calcium aluminate. By the method, the steps are simple, operation is easy, the production steps are simplified, theproduction time is shortened, the production efficiency is improved, and industrial production can be achieved.

The invention relates to an alkaline waste liquor recycling method capable of being used for recycling mold release waste liquor in the aluminum profile production process and belongs to the technical field of environmental protection. The method comprises the steps that after the mold release waste liquor is filtered in a pressed mode, refined lime slurry is used for reacting with sodium aluminate in the mold release waste liquor, then aluminum in the mold release waste liquor is removed by means of solid-liquid separation, obtained alkali liquor is added into solid caustic soda to improve concentration, then the alkali liquor can return to be used in the mold release process, and generated calcium aluminate precipitate can serve as high-quality coagulant to be used for treating acid waste water. The method has the advantages of being low in cost and achieving total recovery and zero emission, working procedures and adopted equipment are simple, and the method is an ideal recycling method for the mold release waste liquor of the aluminum profile factory.

Provided is a method for preparing an electroconductive mayenite type compound with good properties readily and stably at low cost.

A production method of an electroconductive mayenite type compound comprising a step of subjecting a precursor to heat treatment, is a method for preparing an electroconductive mayenite type compound, comprising a step of subjecting a precursor to heat treatment; wherein the precursor is a vitreous or crystalline material, which contains Ca and Al, in which a molar ratio of (CaO:Al₂O₃) is from (12.6:6.4) to (11.7:7.3) as calculated as oxides, and in which a total amount of CaO and Al₂O₃ is at least 50 mol %, and wherein the heat treatment is heat treatment comprising holding the precursor at a heat treatment temperature T of from 600 to 1415° C. and in an inert gas or vacuum atmosphere with an oxygen partial pressure P_O2 in a range of

• • P_O2≦10⁵×exp[{−7.9×l0⁴/(T+273)}+14.4] in the unit of Pa.

The embodiment of the invention provides a technology and production system for producing aluminum acid calcium powder by using aluminum ash. The technology comprises the steps that after being brokenand screened, the aluminum ash is evenly mixed with limestone in a predetermined proportion, and a mixed raw material is obtained; the mixed raw material is subjected to ball milling to obtain mixedraw material powder; the mixed raw material powder is subjected to preheating decomposition to obtain a decomposed mixed raw material; the decomposed mixed raw material is sintered to obtain sinteredblocks; the sintered blocks are cooled, ground and screened in sequence to obtain the aluminum acid calcium powder. The production system for producing the aluminum acid calcium powder by using the aluminum ash comprises a raw material preparation device, a raw material calcination device and a clinker processing device. Fluorides, nitrides and other harmful substances in the aluminum ash are bound with calcium ions by using the processing technology and the production system to be prepared into harmless substances, the aluminum ash can be processed into the harmless substances to protect theenvironment, moreover, the aluminum acid calcium powder produced by using the method is a main raw material for preparing an efficient water treatment agent, and the economic and environmental benefits are significant.

The invention discloses a process method for preparing high-purity calcium aluminate and polyaluminum chloride. The method comprises the following steps: allowing secondary aluminum ash to undergo a hydrolysis catalytic reaction, carrying out solid-liquid separation through a bag type vacuum filter press so as to obtain a primary liquid phase and a primary solid phase, allowing the primary liquidphase to be precipitated through saturated lime water so as to generate calcium fluoride, wherein pure water can be used for the hydrolysis catalytic reaction of the aluminum ash, then allowing the primary solid phase to undergo acidolysis through industrial waste hydrochloric acid, carrying out filtering through a filter press so as to obtain a secondary liquid phase and a secondary solid phase,allowing the secondary liquid phase to undergo a polymerization reaction so as to generate the polyaluminum chloride, carrying out pressure filtration and spray drying with a spray tower so as to prepare solid powdery polyaluminum chloride, completely grinding the secondary solid phase and limestone through a ball mill, sending ground secondary solid phase and ground limestone into a rotary kiln,and carrying out high-temperature calcination so as to obtain the calcium aluminate. The method provided by the invention has the characteristics of low cost, easily-available raw materials, simple production process, high product purity, no secondary pollutants, significant social benefits and economic benefits, etc.

The present invention relates to a mayenite-type compound containing Ca, Al and oxygen, wherein part of the Ca atoms are replaced by at least one kind of atoms (M) selected from the group consisting of Be, Mg and Sr. The M/(Ca+M) atomic ratio is 0.01 to 0.50, and at least part of the free oxide ions contained in the mayenite-type crystal structure are replaced with anions of an element having an electron affinity smaller than that of oxygen.

The invention relates to a method for preparing tricalcium aluminate by the aid of spark plasma sintering techniques. The method includes analyzing raw materials which are pure calcium carbonate CaCO3 and pure gamma-phase aluminum oxide gamma-Al2O3; carrying out ball-milling on the pure calcium carbonate and the pure gamma-phase aluminum oxide and then controlling the heating rates and the cooling rate of a spark plasma sintering furnace under the conditions of vacuum degrees of (30-50) Pa, pulse ratios (ON/OFF) of (6/1-48/8) and axial pressures of (1-3) kN; fetching samples out of the spark plasma sintering furnace when the temperatures of the samples are reduced and reach (60-90) DEG C and grinding the samples to obtain particles with the sizes smaller than 20 micrometers so as to obtain the tricalcium aluminate. The method is simple and convenient, and the synthesis efficiency is improved by (10-20) times as compared with the traditional method. The method has the advantages of speediness, high efficiency and energy conservation.

If a conductive mayenite compound having a large specific surface area is obtained, the usefulness thereof in respective applications is remarkably increased. A conductive mayenite compound powder having a conduction electron density of 10¹⁵ cm⁻³ or more and a specific surface area of 5 m²g⁻¹ or more is produced by: (1) a step for forming a precursor powder by subjecting a mixture of a starting material powder and water to a hydrothermal treatment; (2) a step for forming a mayenite compound powder by heating and dehydrating the precursor powder; (3) a step for forming an activated mayenite compound powder by heating the compound powder in an inert gas atmosphere or in a vacuum; and (4) a step for injecting electrons into the mayenite compound through a reduction treatment by mixing the activated mayenite compound powder with a reducing agent.

The invention discloses a method for preparing calcium aluminate by synergistic treatment of high-magnesium aluminum ash and fly ash, which comprises the following steps: carrying out wet ball milling on high-magnesium aluminum ash, fly ash and quick lime, and sequentially carrying out washing, solid-liquid separation and roasting treatment on the ball-milled material to obtain a calcium aluminate product. According to the method, a calcium aluminate series product capable of being used for iron and steel smelting desulfurization is obtained by taking the aluminum ash generated in the aluminum smelting processing process as a raw material, so that the comprehensive utilization of hazardous wastes is realized, a relatively high economic value can be obtained, and the method is simple to operate and environment-friendly, and meets the industrial production requirements.

There is provided a C12A7 compound capable of selectively and reversibly clathrating X⁻ ions, such as active oxygen radicals, with improved controllability. The C12A7 compound clathrating OH⁻ ions and On⁻ at a concentration of 2×10¹⁹ cm⁻³ or less can be prepared by subjecting a mixed material containing Ca and Al to a solid phase reaction at a firing temperature not lower than 1200° C. and lower than 1449° C. in a dry oxygen atmosphere having an oxygen partial pressure of 0.1 atm or more and a water vapor partial pressure of 10⁻³ atm or less, keeping the resultant product at a temperature of 1200° C. or higher, and cooling rapidly. The C12A7 compound is heat-treated to clathrate OH⁻ ions at a concentration of 2×10¹⁹ cm⁻³ or less, and On⁻ at a high concentration of more than 2×10¹⁹ cm⁻³. The compound can reversibly clathrate or release On⁻ ion radicals through the elevation or lowering of the temperature thereof in a temperature range of 300 to 850° C. The compound is useful for an oxidation catalyst, an anti-bacterial agent, an ion conducting material, an electrode for a solid-electrolyte fuel cell, and the like.

The invention relates to calcium aluminate powder with high dissolution rate. The calcium aluminate powder comprises components in percentage by weight as follows: 55%-60% of bauxite, 5%-10% of boron oxide and 30%-40% of limestone, and the sum of the components is 100%. The process for preparing the calcium aluminate powder from the components comprises the following steps: the components are weighed, ground into powder and mixed uniformly; the uniformly mixed material is stirred and mixed with warm water at 30-35 DEG C in the weight ratio of the mixed material to the warm water being 1:1.5, a product is placed into a furnace for calcination with gas as fuel at the temperature of 1,050-1,100 DEG C, and granular calcium aluminate is obtained after retention for 30 min; granular calcium aluminate is ground by a mill, and the calcium aluminate powder with high dissolution rate is obtained. The conventional raw material formula is changed, the calcination temperature in a production process is reduced, boron oxide is added as a mineralizer, and meanwhile, gas replaces pulverized coal to be taken as the fuel, so that the problems that the bauxite and the limestone of the raw materials are not mixed sufficiently, reaction time is longer, more energy is consumed and the like in the traditional production process of the calcium aluminate powder are solved effectively.

The invention discloses a method for synchronously activating, inerting, removing impurities and melting calcium aluminate by using low-magnesium aluminum ash, wherein the method comprises the steps: carrying out wet ball milling on a mixed raw material of the low-magnesium aluminum ash and a calcium-containing additive, and sequentially carrying out solid-liquid separation, drying and roasting treatment on the ball-milled material to obtain a calcium aluminate series product. According to the method, the calcium aluminate series product capable of being used for iron and steel smelting desulfurization is prepared from the low-magnesium aluminum ash generated in the aluminum smelting machining process, comprehensive utilization of hazardous waste is achieved, high economic value can be obtained, and the method is easy to operate, low in cost, environmentally friendly and capable of meeting the industrial production requirement.