411 results about "Ammonium metatungstate" patented technology

The invention discloses a preparation method of a rare-earth-based composite multi-component denitrification and dioxin removal catalyst. According to the preparation method, titanium dioxide (titanium white) and silicon powder as carriers and ammonium metatungstate, ammonium metavanadate, cerous nitrate and lanthanum nitrate as active components, the steps of mixing, kneading, molding, drying and roasting are carried out in the presence of auxiliary materials to prepare the catalyst, wherein the auxiliary materials include monoethanolamine, citric acid, ammonium hydroxide, lactic acid, stearic acid, glass fibers, macromolecular polymer fibers RP-CHOP, hydroxypropyl methyl cellulose, polyoxyethylene and water. The prepared catalyst can simultaneously decompose nitric oxides and dioxin and can improve the mercury removal efficiency of the existing smoke control device. The prepared catalyst is not only applicable to new power plants, but also suitable for the modification of a wet-method desulphurization device of an old power plant, 80 to 95 percent of HgO generated in a coal burning power plant can be oxidized to Hg<2+> by utilizing the prepared catalyst, and a majority of particle-state Hg<2+> can be removed by utilizing a dust removal device.

The invention discloses a preparation method of a high-strength and antioxidant rare-earth-based smoke denitration catalyst. The preparation method of the high-strength and antioxidant rare-earth-based smoke denitration catalyst comprises the following steps: by taking titanium dioxide and montmorillonite as carriers and ammonium metatungstate, cerous nitrate and lanthanum nitrate as active components, mixing, ageing, kneading, forming, drying and roasting with the accompanying of auxiliary materials. The auxiliary materials comprise ammonia water, lactic acid, citric acid, stearic acid, glass fiber, wood pulp, hydroxypropyl methyl cellulose, polyoxyethylene, monoethanolamine and water. The product prepared by the method is separated under a high SO2 smoke condition, nitric oxide in the smoke can be decomposed; meanwhile, the purpose of removing mercury and dioxin can be achieved. According to the preparation method of the high-strength and antioxidant rare-earth-based smoke denitration catalyst, the rare earth elements, namely cerium and lanthanum are used as the active components, so that the addition amount of vanadium is reduced, the toxicity of the product is reduced or the product is non-toxic product, the pressure of the post treatment of the product is reduced; the environmental protection pressure is reduced; the product is environmentally friendly; the product can be widely used in the field of thermal power plants, glass factories and chemical plants.

A nano-class RE-W particle contains RE oxide powder (CeO2, La2O3, or Y2O3) (0.5-30 wt%) and W (70-99.5 wt%), and is prepared through dissolving the ammonium metatungstate powder and RE oxide powder in water respectively, mixing, clarifying, dispersing it in liquid nitrogen by nitrogen sprayer for pre-freezing, vacuum freeze drying, and secondary reducing in hydrogen atmosphere. Its advantage is molecule-class mixing uniformly.

The invention discloses a fluorination catalyst, and a preparation method and a use thereof, and belongs to the field of chemical synthesis. The precursor of the catalyst is formed by blending 40-95mass% of a trivalent chromium compound with 5-60mass% of tungstate, wherein the trivalent chromium compound can be chromic oxide or chromium hydroxide, and the tungstate can be zinc tungstate, nickel tungstate, magnesium tungstate, aluminum tungstate, silicotungstic acid, ammonium tungstate, ammonium paratungstate or ammonium metatungstate. The fluorination catalyst has the advantages of high use temperature, high catalysis activity and long service life, and can be mainly used in reactions for preparing fluorinated alkenes through gas phase catalysis of fluorination of alkenyl halides at a high temperature.

The invention discloses a preparation method for TiO2-WO3 composite powder used as a catalyst carrier. The method comprises the following steps: dispersing the raw material metatitanic acid through beating, and adjusting the concentration of obtained slurry to be 15 to 25% on the basis of the mass percentage of TiO2; adding ammonia liquor into the slurry and adjusting the pH value of the slurry to be 6.5 to 9.0; filtering the slurry to obtain a solid phase filter cake; beating the solid phase filter cake again, and adjusting the concentration of obtained slurry to be 24 to 30% on the basis ofthe mass percentage of TiO2; adding an ammonium metatungstate solution in proportion, wherein, the proportion of addition amount of ammonium metatungstate is 4.0% to 10.0% with the mass of titanium dioxide as reference; directly pumping the slurry treated in the previous steps into a drying calcination apparatus for drying and calcining, and crushing blanking materials of a calcination kiln to obtain a finished product. The preparation method has the characteristics of low manufacture cost and a simple process; the prepared product has the advantages of a high specific surface area, high surface chemical activity, high catalysis efficiency and good processing performance.

The invention provides a method for synthesizing superfine tungsten trioxide all nanorods by use of a hydrothermal process. The method is used for preparing the superfine tungsten trioxide nanorods by taking ammonium metatungstate as a tungsten source, and citric acid and sodium sulfate in a specific ratio as composite catalysts, and by adjusting the pH value with hydrochloric acid and ammonium hydroxide, and finally, the superfine tungsten trioxide nanorods are analyzed by FESEM (Field Emission Scanning Electron Microscope), XRD (X-Ray Diffraction), TEM (Transmission Electron Microscopy) and HRTEM (High Resolution Transmission Electron Microscopy) analysis methods; an XRD analysis test result indicates that the prepared tungsten trioxide is in hexagonal crystal form WO3, the JCPDS (Joint Committee On Powder Diffraction Standards) card of the prepared tungsten trioxide is #33-1387, the diameter of the tungsten trioxide is about 30-60 nanometers and the maximum length of the tungsten trioxide is 2.5 microns. The maximum diameter-to-length ratio of the tungsten trioxide is 1:80. The superfine tungsten trioxide full nanorods prepared by the method are high-purity hexagonal crystal tungsten trioxide, the diameter of the nanorods is small and the distribution of rod shapes is even, and all superfine tungsten trioxide nanorods are present without particles in other forms.

The invention discloses a wear-resisting tungsten alloy and a preparation method thereof. The method includes the steps that firstly, aluminum nitrate, citric acid and ammonium metatungstate are adopted as raw materials and prepared into solutions, the solutions are mixed, a sol-gel reaction is carried out, and gel is dried and roasted to obtain Al2O3/WO3 mixed powder; then, the Al2O3/WO3 mixed powder is subjected to hydrogen reduction to obtain Al2O3/W mixed powder, and then the Al2O3/W mixed powder is subjected to ball milling with a planetary ball mill; finally, sintering is carried out to obtain the tungsten alloy. In the prepared tungsten alloy material, both the alumina grain size and the tungsten grain size are very small, the tungsten grain size is 0.5-2.1 micrometers, and the alumina grain size is 50-200 nanometers. The recrystallization temperature of the prepared tungsten alloy can reach 1600 DEG C or so. Compared with a pure tungsten material, microhardness is improved by 3-20%, and high-temperature wear resistance is improved by 5-15%.

The invention provides a preparation method of hollow porous tungsten oxide spheres and belongs to the field of functional materials. The method comprises the following steps of: dissolving ammonium tungstate and/or ammonium metatungstate in water and stirring thoroughly to produce a solution with concentration of 1 g/L to 200 g/L; preparing hollow powder of ammonium tungstate, ammonium metatungstate or a mixture thereof by the spray drying of spray-drying equipment; and putting the powder in an electric furnace, heating up to a temperature of 400 DEG C to 1000 DEG C, and preserving heat for 15 minutes to 180 minutes to obtain hollow porous tungsten oxide spheres. The method needs simple equipment, shortens the process flow, increases the preparation efficiency and is simple and feasible for preparing porous tungsten oxide nano-spheres. The specific surface area of the hollow porous tungsten oxide spheres prepared by the method reaches 15 m<2>/g to 30 m<2>/g. The preparation method has good prospects for industrial applications.

The invention discloses a preparation method of a wolfram carbide-carbon (WC-C) composite material with a large specific surface area. The method comprises the following steps of: putting the mixture of a wolfram source and metal powder into a quartz boat in the mass ratio of 1:(0.1-1) under the protection of nitrogen and transferring the mixture into a tubular furnace into which nitrogen is introduced, wherein the wolfram source is taken as a precursor and is ammonium metatungstate, ammonium paratungstate, sodium wolframate or wolframic acid, and the metal powder is Mg, Na or Al powder; and introducing CO serving as a carbonization gas into the tubular furnace at the flow speed of between 20 and 300 mini-liters per minute, performing reduction and carbonization in a programmed temperature raising mode, reacting, cooling to room temperature under the protection of nitrogen, putting a sample into acid solution, removing metal, filtering and drying so as to obtain black powder, namely the WC-C composite material. The preparation method of the invention is simple. The obtained WC-C composite material has the characteristics of high dispersibility and large specific surface.

The invention discloses a preparation method of a wide-temperature range rare earth-based composite oxide denitration catalyst. The preparation method comprises that titanium dioxide and montmorillonite as carriers, ammonium metatungstate, ammonium metavanadate, cerium nitrate and manganese oxide as active components and accessory materials are subjected to blending, ageing decaying, kneading, molding, drying and roasting to form the wide-temperature range rare earth-based composite oxide denitration catalyst, wherein the accessory materials comprise monoethanolamine, citric acid, ammonia water, lactic acid, stearic acid, glass fibers, wood pulp, hydroxypropyl methyl cellulose, polyoxyethylene, citric acid and water. The preparation method utilizes the rare earth-based composite oxide as an active ingredient, shortens catalyst activation time, effectively controls a SO2/SO3 conversion rate, improves a catalyst temperature adaptation capability, widens a catalyst use temperature range from 320-400 DEG C to 150-420 DEG C, has denitration efficiency more than 90%, and can carry out ammonia spraying denitration operation at a denitration area temperature of 150 DEG C when a boiler is started.

The invention relates to a honeycomb type selective catalytic reduction denitration catalyst and a preparation method thereof. According to the total mass of the catalyst, the catalyst comprises components of raw materials in percentage by mass as follows: 78%-84% of titanium dioxide, 4%-6% of clay, 0.5%-1.5% of an active component precursor, 4.5%-5% of a promoter precursor, 0.2%-0.5% of a static elimination agent, 0.1%-0.3% of a mold release, 0.1%-0.4% of an pH modifier, 0.3%-0.8% of a pore-forming agent, 4%-6% of a reinforcing agent and 1.8%-2.7% of a water retention binding agent, wherein the active component precursor is ammonium metavanadate, and the promoter precursor is ammonium metatungstate. A small quantity of the pore-forming agent, the reinforcing agent and the water retention binding agent is added, so that on one hand, the mechanical strength of the catalyst is improved, and the wear resistance of the catalyst is improved, and on the other hand, the specific surface area of the catalyst is increased, the activity of the catalyst can be improved and the contact area of the catalyst and NOx gas can be increased, and the conversion rate of the NOx is increased.

The present invention relates to improved preparation process of high purity chemical. High purity ammonium tetrathiotungstate is prepared through the reaction between ammonium metatungstate or tungsten trioxide and ammonium sulfate solution. Preparing high purity ammonium tetrathiotungstate in the said process of the present invention has ammonium sulfate amount near the required stoichiometric amount, mild reaction condition, short reaction period, less waste exhaust, high product yield, high product purity, and no need of treating virulent and effluvial hydrogen sulfide gas.

The invention discloses a denitration catalyst and a preparation method thereof. The preparation method comprises the following steps: preparing a precipitate mixture of titanium hydroxide and aluminium hydroxide; drying and roasting the precipitate mixture to obtain TiO2-Al2O3 compound oxide carrier powder; extruding, forming, sizing and drying the TiO2-Al2O3 compound oxide carrier powder, activated carbon powder, enamelled powder and an adhesive to obtain an activated carbon/TiO2-Al2O3 compound catalyst; dissolving ammonium metatungstate and ammonium metavanadate in oxalic acid to obtain first impregnation liquid; impregnating the activated carbon/TiO2-Al2O3 compound catalyst in the first impregnation liquid to obtain a V2O5-WO3/activated carbon/TiO2-Al2O3 compound catalyst; preparing second impregnation liquid; and impregnating the V2O5-WO3/activated carbon/TiO2-Al2O3 compound catalyst in second impregnation liquid to obtain the denitration catalyst. The denitration catalyst prepared by the method disclosed by the invention has relatively high denitration catalytic activity, is high in wear resistance and acid resistance and wide in active temperature region, and can recover waste heat while performs denitration treatment on to-be-treated flue gas.

The invention relates to a ceramic catalytic filter element for flue gas purification and a flue gas desulfurization and denitrification integrated dust removal method. The ceramic catalytic filter element is prepared from the following steps that a microporous alumina ceramic filter tube with a pore diameter of 40-80 microns is taken as a matrix; the matrix is immersed in a mixed sol made of zincacetate, and after the matrix is impregnated under a negative pressure, the matrix is roasted to obtain a modified matrix modified by zinc oxide; an equal volume impregnation method is adopted, and the modified matrix is impregnated with an mixed oxalic acid solution containing ammonium metavanadate and ammonium metatungstate, so that total loading mass of V2O5 and WO3 in pores of the matrix reaches 4.0%-6.0% to obtain an active matrix; the active matrix is immersed in a mixed sol made of Al2O3-SiO2-TiO2, the active matrix is dried and roasted after the active matrix is taken out, and a densefilm with a thickness of 0.2-0.6 millimeter and a pore diameter of 1-10 microns is formed on the outer surface of the active matrix to obtain the ceramic catalytic filter element. A denitrification catalyst of the ceramic catalytic filter element has the advantages of being strong in load, high in denitrification efficiency, long in service life and applicable to popularizing and using.

The invention discloses a preparation method of a cobalt-doped nano tungsten oxide negative electrode material and belongs to the technical field of lithium-ion batteries. The method comprises the following steps of adding ammonium metatungstate, cobalt nitrate and dimethyl imidazole to deionized water to prepare a mixed solution, carrying out vibration dispersion by using an ultrasonic generator, adjusting the pH value to 1-2, transferring the solution into a stainless steel reaction kettle, reacting at 170 DEG C for 4-6 days and naturally cooling to a room temperature; filtering the solution, washing the solution by using the deionized water and ethyl alcohol for multiple times and drying; putting the dried uniform powder into an aluminum oxide crucible, putting the aluminum oxide crucible into an atmosphere furnace and roasting in an air environment, wherein the roasting temperature is 500-600 DEG C and the heat preservation temperature is 1-2 hours; carrying out furnace cooling after roasting is completed to obtain a roasted product, namely the cobalt-doped nano tungsten oxide material; and taking out the product and grinding the product to obtain fine cobalt-doped nano tungsten oxide material. The cobalt-doped nano tungsten oxide material prepared by the method has the advantage of being small and uniform in particle size, the heat preservation time in the roasting process is relatively short, uniform and fine particles are ensured and growth of the particles is avoided.

The invention discloses a missile heavy-gravity tungsten alloy and a preparation method thereof, and belongs to the field of metal materials. The missile heavy-gravity tungsten alloy consists of the following alloy components in percentage by mass: 90.0%%-97.0% of tungsten, 0.1%-2.0% of zirconium oxide, 2.0%-9.9% of binding-phase nickel and iron, and inevitable impurities, wherein a mass ratio of the nickel to the iron is (3-4) to (2-1). The preparation method comprises the following steps: respectively dissolving ammonium metatungstate and zirconium nitrate into water, mixing to obtain mixed liquor, drying the mixed liquor to obtain power, roasting and reducing the powder to obtain composite tungsten powder; taking nickel powder and iron powder, carrying out ball-milling on the nickel powder and the iron powder after mixing, thereby obtaining a nickel-iron solid solution; mixing the composite tungsten powder with the nickel-iron solid solution to obtain mixed powder, and pressing and sintering the mixed powder to obtain the missile heavy-gravity tungsten alloy. According to the invention, high-temperature steady-phase ZrO2 is added into the tungsten alloy, a ZrO2 dispersed phase is fine and is uniformly distributed in a tungsten base body, so that the problem of poor mechanical property because of low compactness and uneven phase distribution of the missile tungsten alloy is solved; tensile strength of the tungsten alloy is higher than 1250MPa, and ductility of the tungsten alloy is higher than 17%; and the missile heavy-gravity tungsten alloy has the characteristics of high strength and high plasticity.

The invention relates to a technique and a system device for regenerating exhaust gas denitration catalyst, and belongs to the technical field of exhaust gas processing of coal-fired power plant. The processing steps includes cleaning the denitration catalyst in a recirculation state and performing activation and dehydration on the denitration catalyst in the recirculation state. The detergent is composed of polyacrylic acid, nonylphenol polyoxyethylene ether, fatty alcohol-polyoxyethylene ether and sodium ascorbate; temperature is controlled at 40 DEG C; the activate fluid is composed of oxalic acid, ammonium metavanadate, ammonium metatungstate; and methane acid used for controlling PH value is 1% wt. The processes of soaking, cleaning, activating, dehydrating and the like for regenerating catalyst are integrated to implement in one container or two, so that volume of regeneration system is remarkably reduced, regeneration procedure and operation steps are simplified, energy consumption is reduced by 50%, and air pollution caused by exhaust gas is avoided.