1785 results about "Ammonium metavanadate" patented technology

The invention discloses a regeneration fluid for an SCR denitration catalyst, which comprises the following components: 0.001 to 1 weight percent of penetration enhancer JFC, 0.001 to 1 weight percent of surfactant OP-10, 0 to 1 weight percent of peregal, 0.6 to 4 weight percent of ammonium metavanadate, 5.5 to 12.5 weight percent of ammonium paratungstate, 0 to 6.5 weight percent of ammonium paramolybdate, and the balance of deionized water and acid. The regeneration fluid has the advantages that the regeneration fluid can also supplement active ingredients during the washing, and the activity recovery of the catalyst after the regeneration is up to between 90 and 105 percent; a nonionic surfactant is added into the regeneration fluid, so that the regeneration fluid improves the cleaning capability on the catalyst and cannot cause the damage to a catalyst carrier and other effective ingredients; and the regenerated catalyst fully can continue to be normally used, and the service life can reach more than 95 percent of that of a new catalyst.

The invention discloses recovery process of honeycomb type selective catalytic reduction (SCR) waste catalyst. The process includes the following steps: a, preprocessing the SCR waste catalyst and leaching at the high temperature and under high pressure; b, adding hydrochloric acid into leaching liquid, adjusting pH, and removing impurities; c, adding hydrochloric acid into the leaching liquid, reacting, calcining and preparing rutile titanium dioxide; d, preparing ammonium paratungstate; e, preparing ammonium metavanadate; and f, recycling and treating waste water. Main products of ammonium paratungstate, ammonium metavanadate and rutile titanium dioxide obtained in the process are high in purity and recovery rate. By-products of silicon magnesium slags, salty mud, high-concentration sodium chloride liquid and barium sulfate dregs are high-purity harmless useful goods. The process is free of harmful secondary pollutant emission, environment-friendly and capable of circulating, has high economical and social benefit and is practicable.

The invention discloses a process for producing vanadic anhydride by vanadium slag. The steps of the process comprise as follows: a, adding alkali metal salt in the vanadium slag, and mixing with each other uniformly, a mixture is obtained. b, laying the mixture obtained by step a into a calcining furnace to oxidize and calcine, vanadium slag grog is obtained. c, the calcined vanadium slag is discharged out of the furnace, fast cooling and performing water immersion. d, filtering the mixture obtained by step c, filter liquor is obtained. e, removing impurities in the filter liquor. f, adjusting the pH value of the filter liquor obtained by step e, adding ammonium salt to precipitate vanadium and filtering the filter liquor, then, ammonium peroxovanadate filter cake and ammonium metavanadate filter cake are obtained. g, calcining the filter cake after vanadium precipitation obtained by step f, and vanadic anhydride is obtained, wherein the content of the vanadic anhydride in the vanadium slag used in step a is 2.0%-8.0%. The invention has the advantages of simple and easy, low facility request, convenient operation and low cost, further, the residual quantity of the vanadic anhydride in waste slag is 0.55%-1.0%, which has fine economic benefit and social benefit.

The invention which relates to a method for preparing high purity vanadium pentoxide through using ammonium metavanadate belongs to the wet metallurgy field. The method comprises the following steps: heating and dissolving crude ammonium metavanadate in water, adjusting the pH value to 8-10 with an alkali after dissolving, adding an impurity removing agent to remove impurities, filtering to obtain a sodium metavanadate solution, adding ammonia water or an ammonium salt to the sodium metavanadate solution to precipitate to obtain an ammonium metavanadate precipitate, dehydrating the ammonium metavanadate precipitate, carrying out water washing on the precipitate through using a dilute ammonium salt solution, dehydrating after the wash washing, and roasting to obtain the high purity vanadium pentoxide. Vanadium pentoxide produced through adopting the method of the invention has the advantages of high purity and less impurities, and completely satisfies production requirements of high-end products; and the method of the invention has the advantages of short process flow, simple equipment, low cost and high benefit, and is suitable for the large-scale industrial production.

The invention relates to a method for recovering tungsten trioxide and ammonium metavanadate from a selective catalytic reduction (SCR) denitration catalyst. The method comprises the following steps of: crushing the SCR denitration catalyst, sieving to obtain catalyst powder, mixing with sodium carbonate, and stirring fully and uniformly; putting the mixed powder into a sintering furnace, and sintering to obtain a sintered material; keeping temperature for 1 hour, and sieving to obtain sintered material powder; pouring warm water, so that Na2WO4 and NaVO3 in the sintered material powder are dissolved fully, filtering, and removing precipitates to obtain a mixed solution of Na2WO4 and NaVO3; regulating the pH value to be 6.5-7.5, adding an ammonium bicarbonate solution or an ammonium chloride solution, and precipitating ammonium metavanadate precipitate; filtering, washing by using a diluted ammonium bicarbonate solution for 2 to 3 times, washing by using 30 percent ethanol for 1 to 2 times, and drying to obtain an ammonium metavanadate finished product; and converting the Na2WO4 in the residual solution into ammonium paratungstate, evaporating the residual solution to obtain ammonium paratungstate crystals, and calcining to obtain the tungsten trioxide. By the method, the ammonium metavanadate and the tungsten trioxide can be recovered, and the discharge of pollutants is reduced.

The invention belongs to the chemical material field, in particular to a titanium-base multicomponent catalyst used for the denitrification of power plant flue gas SCR and a preparation method thereof. The catalyst comprises a catalyst carrier TiO2 accounting for 80-99wt percent of the total content, and the active components of 1-5wt percent of V2O5, 5-15wt percent of WO3 and 1-5wt percent of oxide of molybdenum or cerium or manganese according to the total content. The catalyst also comprises the other components of 0-5wt percent of MoO3, 0-5wt percent of CeO2 and 0-5wt percent of MnO3. The preparation process is: ammonium metananadate, ammonium paratungstate and titanium dioxide are mixed in water solution and are dried, calcined and sieved to obtain the catalyst. The catalyst has the advantages of active temperature region of 240-480 DEG C, high denitration efficiency, and good SO3 poisoning resistance. Added SO2 has almost no influence on the activity of the catalyst.

The invention relates to a method for extracting vanadium pentoxide from vanadium slag, belonging to the field of vanadium metallurgy. In order to solve the technical problem, the invention provides a method for extracting vanadium pentoxide from vanadium slag with less environment pollution. The method comprises the following steps of: a. smashing the vanadium slag, and removing metal iron to obtain the refined vanadium slag; b. baking the refined vanadium slag at 800-1000 DEG C to obtain grog; c. adding the grog into alkali liquor for leaching, and filtering with hot to obtain vanadium-containing solution and tailings; d. removing impurity in the vanadium-containing solution, reducing the temperature of the impurity-removed and vanadium-containing solution to be less than 35 DEG C, crystallizing and filtering to obtain Na3VO4.5-12H2O crystalloid and filtering mother liquor thereof; and e. dissolving the Na3VO4.5-12H2O crystalloid by adding water, treating with an acid ammonium salt precipitation method to obtain ammonium poly-vanadate or ammonium metavanadate, and dehydrating, deaminizing and melting the ammonium poly-vanadate or the ammonium metavanadate to obtain the vanadium pentoxide.

The invention relates to a preparation method of an SCR denitration catalyst, which comprises the following steps: (1) Al2O3 sol is prepared, which comprises the steps that hot ammonia, the Al2O3 is added in drops into the ammonia and then HCI is added and the mixture is stirred; (2) Al2O3-SiO2-TiO2 composite sol is prepared, which comprises the steps that tetratethoxy-silane, butyl titanate, deionized water are sequentially put into ethanol to be aging and then the sol prepared by step (1) is adding to be stirred and aging; (3) vector is coated, which comprises the steps that cordierite honeycomb immersed into the sol of step (2) and the raffinate in a channel is cleaned, dried and roasted after being taken out; (4) active component impregnating solution is prepared, which comprises the steps that lanthanum nitrate, ammonium metavanadate and ammonium paratungstate are dissolved into the deionized water after being mixed together and oxalate acid is added to be aging; (5) the active component is loaded, which comprises the steps that the vector of the step (3) is immersed into the impregnating solution of the step (4) and then the raffinate in the channel is cleaned to be dried and roasted. The invention also relates to the denitration catalyst which is prepared by the method.

The invention relates to a recovery method for an SCR waste flue gas denitration catalyst, and adopts a hydrometallurgy process. After the SCR waste flue gas denitration catalyst is smashed and subjected to pre-calcination treatment, a NaOH solution is added according to a ratio for dissolution. After the catalyst is dissolved, solid-liquid separation is performed, sulfuric acid is added into the obtained precipitation, and the precipitation is steeped, precipitated, hydrolyzed, subjected to salt treatment, and calcinated to obtain TiO2. Sulfuric acid is added into the solution obtained from the first solid-liquid separation to adjust the pH value, excess ammonium nitrate is added to precipitate vanadium, and second solid-liquid separation is performed. Ammonium metavanadate obtained from filtration is subjected to pre-calcination to obtain a V2O5 finished product. Hydrochloric acid is added into the solution obtained from the second solid-liquid separation to adjust the pH value, and NaCl is added to obtain sodium tungstate. The sodium tungstate is subjected to purification, filtration, ion exchange, and other processes to separate impurities, and subjected to evaporative crystallization to obtain a sodium tungstate finished product. The method provided by the invention is simple in technology, general in equipment, easily available in raw material, low in cost and high in recovery rate.

The invention discloses a preparation method of high-purity vanadium pentoxide. The preparation method comprises the following steps of: returning and dissolving coarse vanadium in aqueous alkali, and filtering the solution to remove metal impurities, which are subjected to precipitation reaction with the aqueous alkali, in the coarse vanadium, thus obtaining a primary returned solution; slowly pouring the primary returned solution into a sulfuric acid solution, adjusting the pH value of the solution to be 1.0-2.0 to obtain a liquid-solid mixture, and performing solid-liquid separation on the liquid-solid mixture; filtering and washing precipitates obtained from the solid-liquid separation of the mixture, and returning and dissolving the mixture into the aqueous alkali, thus obtaining a secondary returned solution; adding ammonium sulfate into the secondary returned solution for precipitating vanadium, and filtering the solution to obtain ammonium metavanadate; and processing the ammonium metavanadate to obtain the high-purity vanadium pentoxide. The preparation method adopting multiple stages of returned dissolving can be used for effectively removing the metal canon impurities of the vanadium pentoxide, and further obtaining the high-purity vanadium pentoxide with the metal canon impurity contents of less than 0.001% and the vanadium pentoxide content of 99.99%.

The invention relates to a method for preparing a low-temperature SCR (selective catalytic reduction) denitration catalyst, and belongs to the technical field of catalysis. The denitration catalyst has a good nitric oxide removal rate, water resistance and sulfur resistance when the temperature of flue gas ranges from 150 DEG C to 250 DEG C. The method includes dissolving ammonium metavanadate, transition metal salts and titanium and tungsten powder in water; and drying and calcining the mixed liquor to prepare the low-temperature SCR denitration catalyst. The prepared catalyst is good in low-temperature activity, and can keep the good nitric oxide removal rate, the water resistance and the sulfur resistance at the temperature ranging from 150 DEG C to 250 DEG C. In addition, owing to the high activity and poison resistance at the temperature ranging from 150 DEG C to 250 DEG C, the catalyst can be applied to the field of flue gas after the flue gas flows via dust catchers of thermal power plants and flue gas, with the temperature ranging from 150 DEG C to 250 DEG C, of industrial furnaces and the like, and denitration catalyst technology and application breakthrough is realized.

The invention discloses a visible light responsive pucherite-graphene composite photocatalyst and a preparation method thereof. The composite photocatalyst is prepared by compositing pucherite and graphene according to the mass ratio of (1:2)-(1:5). The preparation method comprises the following steps of: putting graphite oxide into a mixed solution of water and ethanol for ultrasonic dispersion,respectively adding bismuth nitrate and ammonium metavanadate into ethanol for stirring, and finally mixing the three systems and regulating the pH to be greater than 7; then, transferring the mixed system into a hydrothermal kettle for reacting; and after the reaction is finished, centrifugally separating, washing and drying the product to obtain a leaf-shaped pucherite-graphene composite photocatalyst. In the invention, by using graphene as a template, the leaf-shaped pucherite-graphene composite photocatalyst is prepared by a hydrothermal synthesis method. The pucherite-graphene composite photocatalyst prepared by the method disclosed by the invention has better application prospect and economic benefit in the aspect of sewage treatment.

The invention relates to a method for recovering non-ferrous metals from waste denitration catalysts, particularly relates to a method for recovering vanadium, tungsten and titanium from a waste vanadium-tungsten-titanium-based denitration catalyst, belonging to the field of non-ferrous metal recovery technologies. The method mainly comprises the steps of preparing the catalyst into powder with the grain size being smaller than 100 meshes, and adding concentrated alkali liquor; heating to react vanadium, tungsten and titanium with alkali, so as to produce slightly-soluble titanate, water-soluble vanadate and tungstate; filtrating to obtain a titanate filter cake, wherein titanate or titanic acid can be prepared from the filter cake; adding ammonium salt into a filtrate so as to precipitate ammonium metavanadate, and filtrating to obtain ammonium metavanadate and a new filtrate; adding concentrated acid into the new filtrate, thereby preparing solid tungstic acid. The method has the advantages of simple process, low energy consumption, good solid-liquid reaction contact, high vanadium, tungsten and titanium recovery rate, and the like.

The invention discloses a recovering chemical product method with a V, Cr, Fe and P industrial muck in the chemistry field, which comprises the following steps: roasting raw materials; heating and leaching the clinkers; separating ferric oxide from the solution containing V, Cr, Fe and P; crystallizing the solution in order to removing to P; removing P deeply; removing Si; adjusting the acidity of the solution containing V and Cr; extracting V; extracting V reversely; settling V; roasting metammonium vanadate; reducing Cr; settling chromic hydroxide; separating chromic hydroxide from sodium sulfate; removing NH3; getting sodium sulfate crystallization; purifying sodium sulfate mother liquor; adsorbing V, Cr, tertiary sodium phosphate solution with rough tertiary sodium phosphate refining resin and reacting with phosphoric acid; drying and roasting sodium tripolyphosphate; getting V, Cr, Fe and P from the industrial muck containing V, Cr, Fe and P and separating the secondary product of ammoniacal liquor and sodium sulfate in the heat exchange procedure. The invention saves the energy, which adapts to an industrial appliance.

The invention relates to a method for preparing high-purity vanadium from heteropolyacid impurities in an amine extraction mode. Generally an ordinary vanadium solution is doped with impurities such as chromium, silicon, phosphorus, tungsten, molybdenum and arsenic, if acid is added into the solution, heteropolyacids such as phosphorus tungsten, phosphorus vanadium tungsten, silicon tungsten, phosphorus molybdenum tungsten, silicon molybdenum tungsten, molybdenum vanadium arsenic and tungsten arsenic can be formed, the impurities in the solution are removed by carrying out compounding synergic extraction on the heteropolyacids in the ordinary vanadium solution by using amines and a synergist so as to obtain a purified vanadium-containing raffinate, subsequently the vanadium-containing raffinate is evaporated and concentrated to be the concentration that each liter of the solution contains 40g vanadium, ammonium salt is further added into the concentrated liquid to obtain ammonium metavanadate solid, vanadium pentoxide with the purity greater than 99.9% is obtained through washing in pure water, drying and calcining in an oxygen atmosphere, the organic phase after the heteropolyacid is extracted is subjected to reverse extraction by using an alkali solution so as to form a heteropolyacid water phase, and the organic phase is recycled and circulated. The method has low requirement on equipment, and is simple to operate, key extraction agents are good in thermal stability and not sensitive in acid and alkali, and a recycling and circulating method is simple and easy to be industrialized.

The invention discloses a method for regeneration and resource utilization of a waste honeycombed denitrification catalyst. The method comprises the following steps of: crushing, grinding and sieving the waste catalyst; loading a mixture of the powdered catalyst and sodium carbonate into a sintering furnace to produce Na2WO4 and NaVO3, dissolving completely, adjusting the pH value to separate ammonium metavanadate precipitates, filtering, applying the remaining liquid to ammonium paratungstate extraction, washing the precipitates and oven-drying to obtain ammonium metavanadate, and making ammonium paratungstate crystals and tungsten trioxide. The regeneration method of the SCR catalyst comprises the following steps of: performing water-washing, pickling, activation and drying on the catalyst. The method for producing titanium pigment from the waste catalyst as raw material comprises the following steps of: performing pulverization, acidolysis and extraction on the waste catalyst, performing plate-frame pressure filtration; performing concentration, hydrolysis and suction-filtration on the catalyst, washing and blanching with sand leaching water, calcining, grinding and packaging. The method disclosed by the invention can effectively restore the activity of a deactivated catalyst and prolong the service life of the deactivated catalyst, which not only reduce the operating cost of a thermal power plant but also save the valuable rare earth resources.

The invention discloses a method used for preparing ammonium metavanadate from vanadium slag via ammonium salt leaching. The method comprises following steps: (1) vanadium slag is subjected to pre-oxidation so as to obtain a calcined product; (2) the calcined product is subjected to leaching with an ammonium salt aqueous solution, and liquid-solid separation is carried out; and (3) a liquid obtained via step (2) is subjected to cooling crystallization and separation so as to obtain ammonium metavanadate crystals. The method is high in vanadium leaching efficiency; leaching solution impurity content is low; ammonium metavanadate can be obtained via cooling crystallization; waste water contains no mirabilite; subsequent processes, such as purifying, vanadium precipitation, and waste water treatment, are simplified; technical cost is low; operation is simple; and the method is clean, and no pollution is caused.

The invention discloses a method for synthesizing a vanadium acid zinc micro/nanowire material by adopting a hydrothermal method. In the method, ammonium metavanadate and zinc nitrate are used as reaction materials, distilled water is used as a solvent, a surfactant is used for controlling a microstructure, and the vanadium acid zinc micro/nanowire material with a regular appearance can be prepared under a hydro-thermal condition. The technology has the advantages of simplicity in operation, feasibility, controllable experimental condition, good repeatability, suitability for mass production and the like; and the synthesized material can play an important and positive role in multiple fields such as electrode material, photoluminescence, gas sensing and the like.

The invention provides a denitration catalyst and a preparation method thereof. The denitration catalyst comprises: by weight, 40 to 45 parts of nano-titanium dioxide, 6 to 8 parts of nano-silica, 0.5 to 4 parts of ammonium metavanadate, 0.5 to 4 parts of ammonium paratungstate, 0.5 to 2 parts of Acesulfame K (A.K) sugar, and 3 to 5 parts of one or two moulding auxiliary agents. In the invention,trough the introduction of A.K sugar, the denitration catalyst has an excellent denitration performance and through the introduction of rare earth elements, an anti-poisoning performance of the denitration catalyst is improved greatly; the A.K sugar in the denitration catalyst has a binding effect and can improve effectively a mechanical property and a strength of the denitration catalyst thus ananti-crushing property of the denitration catalyst is improved and the problem that a denitration catalyst adopted by the prior art can be crushed frequently in use is solved.

The invention relates to a method for extracting V2O5 from stone coal vanadium ores, which is characterized in that the stone coal vanadium ores are grinded, subjected to high-temperature roasting, and directly leached out by a dilute sulfuric acid; slag is washed and filtered by water; and a leached solution is extracted by extract containing an N235 extractant, and subjected to back-extraction, ammonium metavanadate precipitation, filtration, washing, deamination and roasting to obtain the V2O5. The method greatly reduces pollution of waste gas and waste water. Compared with the prior salt roasting (sodium modification) technology, the technology has a reasonable design structure, high comprehensive utilization rate of resources, proper material consumption, strong controlled ability of the process, high product quality and high automation degree of the technological flow, and is convenient for large-scale industrial production. The technology does not have exact demands on the raw ores and has good adaptability. The overall yield of the technology is high, reaches more than 85 percent, is on the advanced level in China currently, and is improved by approximately 25 percent compared with the overall yield of sodium modification roasting technology of other vanadium smelting plants in Hunan province.

The invention relates to a method for recycling vanadium and molybdenum from a waste petroleum catalyst, and belongs to the technical field of petrochemical industry. The method comprises air-burning and ball-removing, ball-milling, soda roasting-water leaching, aluminum removing, molybdenum precipitating and enriching molybdenum by ion exchange. The method specifically comprises the following steps: firstly, igniting sticky oil in the waste catalyst in air to burn carbon and oils in the waste catalyst; then, oxidizing the vanadium and nickel in the forms of porphyrin compounds in the waste catalyst into vanadium oxide and nickel oxide, converting most of the molybdenum into molybdenum oxide, wherein the waste catalyst subjected to air-burning and oil-removing is more beneficial for crushing, and the crushed waste catalyst and a certain proportion of sodium carbonate are mixed, and are roasted at a high temperature; leaching roasted materials by hot water, dissolving sodium salts of the vanadium and the molybdenum into water to obtain a solution, filtering the solution, introducing the filtered solution into a leaching solution, introducing a little aluminum into the leaching solution, regulating the pH value of the solution to remove aluminum; regulating the pH value of the solution to 8-9, adding ammonium chloride, precipitating and separating out the vanadium in the form of ammonium vanadate; and concentrating vanadium-precipitated solution by adopting an ion exchange process and enriching an ammonium molybdate solution.

The present invention is wet process of extracting vanadium and/or molybdenum form waste petrochemical catalyst alumina carrier containing V, Mo and other elements. The wet process includes high-temperature deoiling the catalyst in natural granularity, mixing with sodium carbonate, high-temperature oxidation and roasting in a kiln or furnace to obtain water soluble sodium vanadate and sodium molybdate; countercurrent water soaking of the chamotte to obtain solution containing V and Mo in certain concentration, adding calcium salt and magnesium salt to eliminate P and other impurities, addingammonium salt solution into the clear solution to obtain ammonium metavanadate, decomposing and melting ammonium metavanadate to obtain V2O5 product; adding acid to the supernatant and organic phase extraction of Mo, ammonia water reverse extraction to obtain ammonium molybdate, and adding acid to precipitate ammonium tetramolybdate or molybdate product.

The invention discloses a preparation method of a denitration catalyst. The method comprises the following steps: (1) with an intermediate product of metatitanic acid from a titanium dioxide factory as a raw material, washing with dilute nitric acid, weak aqua ammonia, deionized water respectively to remove impurity ions so as to prepare metatitanic acid slurry; (2) orderly adding ammonium tungstate, ammonium molybdate and ammonium metavanadate into the metatitanic acid slurry, beating the mixture by ultrasonic wave, adjusting the pH of the slurry to 4.0-6.5 by an acid; (3) allowing the mixed slurry to stand, drying to obtain the catalyst powder; (4) compacting and molding the catalyst powder into honeycomb by a mold, performing heat treatment at 200-600 DEG C for 4-10 hours to obtain the denitration catalyst of the invention. The method for preparing the denitration catalyst of the invention has low cost and simple process, and the denitration catalyst can increase the conversion rate of NO. The denitration catalyst of the invention can realize a conversion rate of NO in power plant flue gas flue gas components of up to above 97% at a reaction temperature of 350 DEG C.

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 relates to a denitrifying catalyst and a preparation method thereof as well as a flue gas denitrifying method. The preparation method of the denitrifying catalyst comprises the following steps: mixing, aging, drying and calcining, wherein in the mixing step, ITAC-14-7A, CTAC-115, stearic acid, deionized water, ammonia, lactic acid, glass fiber, wood pulp, water, an ammonium metavanadate solution, carboxymethyl cellulose and polyoxyethylene are mixed by a mixer. The denitrifying catalyst prepared by the method has high-efficiency denitrifying efficiency.

The invention discloses a method for preparing a BiVO4 film with photocatalysis performance by using a sol-gel method. The method comprises the following steps of: respectively preparing a precursor solution A and a precursor solution B by taking bismuth nitrate pentahydrate (Bi(NO3)3.5H2O) and ammonium metavanadate (NH4VO3) as raw materials and taking citric acid as a solvent, preparing BiVO4 sol by mixing the precursor solution A with the precursor solution B; and coating the BiVO4 sol to a treated FTO (Fluorine-doped Tin Oxide) glass substrate surface in a spinning manner by adopting a spin coating method so as to form a film, and carrying out pre-annealing and annealing treatment on the film formed after spin coating, thereby obtaining the BiVO4 film fixed on the FTO glass substrate surface. According to the method for preparing the BiVO4 film with the photocatalysis performance by using the sol-gel method, the pure-monoclinic-phase BiVO4 film is prepared by combing the sol-gel method with the spin coating method, the prepared BiVO4 film has certain photocatalysis activity under visible light irradiation, meanwhile, the problem of immobilization of a BiVO4 photocatalyst is solved, and then, the separation, recovery and reuse of the BiVO4 photocatalyst are realized.

The invention relates to a method for preparing a flue gas SCR (Selective Catalytic Reduction) denitration catalyst. The method comprises the following steps of: mixing ammonium metavanadate, oxalic acid, manganese salt and water for preparing a mixture solution, adding titanium dioxide powder into the mixture solution, heating in water bath and stirring, and obtaining mixed sol by standing at room temperature; putting the mixed sol into a microwave oven, heating and drying by utilizing microwave radiation; and putting dried solid into a muffle furnace for burning. According to the method disclosed by the invention, a temperature window of the SCR catalyst can be broadened to a low-temperature direction, the problems of low denitration efficiency at low temperature and narrow temperature window of a commercial catalyst are solved; compared with the traditional drying method, the microwave radiation heating and drying method has the advantages that low-temperature SCR denitration activity of the composite catalyst can be increased to a large extend, when the activity temperature is up to 250 DEG C, the denitration efficiency of the catalyst prepared by the traditional drying method is up to 51.9%, and the denitration efficiency of the catalyst can be increased by 31.7 percentage points and can be up to 83.6% by the microwave radiation heating and drying method.