1504 results about "Vanadate" patented technology

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 discloses a preparation method of high-purity vanadium pentoxide. The method comprises the following steps of: a, grinding a vanadium-containing raw material, and removing iron; b, performing sodium roasting on the raw material treated in the step a, and leaching to obtain the vanadium-containing solution; c, removing cation impurities and anion impurities from the vanadium-containing solution obtained in the step b, and filtering to obtain the purified vanadium-containing solution; d, adding ammonium sulfate into the purified vanadium-containing solution to perform molybdenum precipitation treatment, filtering, washing and removing impurities to obtain vanadate precipitate; and e, pulping and filtering the vanadate precipitate, washing, further removing impurities in the vanadate precipitate, drying and roasting to obtain a vanadium pentoxide product. By virtue of the strict and effective impurity removal treatment, the purity of the vanadium pentoxide product can be increased, and can be over 99 percent.

The invention provides a composite smoke denitration catalyst capable of oxidizing zero-valence mercury. The catalyst is composite oxide V2O5-CeO2-WO3 / TiO2 or V2O5-CeO2-MoO3 / TiO2 based on TiO2 as a carrier, wherein the weight proportion is as follows: the weight percent of TiO2 is 75-100, the weight percent of V is 1-1.5, the weight percent of Ce is 1-5, and the weight percent of W or Mo is 7.5-8.5. The preparation method comprises the following steps: depositing Ce(OH)3 on nano TiO2; dipping ammonium vanadate / ammonium molybdate; and drying and roasting so as to obtain the catalyst; or dipping a commercial SCR (selective catalytic reduction) catalyst in a cerous nitrate aqueous solution, and then drying and roasting. The catalyst provided by the invention maintains the denitraiton efficiency of the original SCR catalyst and simultaneously the oxidation rate of zero-valence mercury is obviously improved, and divalent mercury ions are captured in subsequent dedusting equipment and wet desulphurization system; and the application temperature range of the catalyst is wide, the combination control of emission amounts of nitrogen oxides and mercury in smoke of a fuel coal power plant can be achieved on the promise that the smoke purification facility of the fuel coal power plant is not added.

The invention provides methods and compositions for improved in vitro culture of cells that make use of vanadate. The methods enhance cell survival thereby recovery of the polypeptide of interest produced in the cells is increased relative to cells grown without vanadate.

The invention relates to a titanium oxide supported ferric vanadate catalyst. The catalyst is composed of a TiO2 carrier, and a FeVO4 active constituent supported on the TiO2 carrier. In term of the mass of the catalyst as 100wt%, FeVO4 is 1.5-15 wt%, preferably 2.5-13.5 wt%, further preferably 8-10 wt%, and most preferably 9 wt%. According to the invention, the TiO2 supported FeVO4 catalyst is used for purifying fixed-source and movable-source nitric oxides in NH3-SCR (selective catalytic reduction) reaction for the first time; and moreover, the preparation method for the catalyst is simple and practicable, and easily realizes industrialized production. The FeVO4 / TiO2 catalyst disclosed by the invention is extremely excellent in anti-H2O-poisoning and anti-SO2-poisoning performances in the NH3-SCR reaction, and very suitable for practical application.

The invention relates to a catalyst for decomposing hydrogen sulfide by photocatalysis and a preparation method of hydrogen and liquid sulfur by employing same. The catalyst comprises a carrier, active component and assistant and has the characteristics that the carrier is one or more selected from vanadate, niobate and tantalate, the active component is one or more selected from alkali metal hydroxide, alkaline earth metal hydroxide, alkali metal nonmetal oxysalt, alkali metal nonoxysalt, alkaline earth metal nonmetal oxysalt and alkaline earth metal nonoxysalt and the assistant is lanthanide oxide or VIII group oxide. The catalyst of the invention can be used for preparing hydrogen and liquid sulfur so that the produced sulfur is easy to be separated from the catalyst, the catalyst can be recycled and the sulfur contained in hydrogen sulfide can be fully recycled, thus realizing the comprehensive utilization of hydrogen sulfide.

The invention relates to a method for preparing vanadic anhydride. It comprises following steps: employing ammonium vanadate, vanadic anhydride of technical grade or waste catalyst discharged in sulfuric acid preparation process; treating with ammonium hydroxide, sulfuric acid and ammonium chloride, washing with water; getting fine active vanadic anhydride; removing foreign matter with ammonium hydroxide, calcium hydroxide, sodium aluminate, sodium silicate, sulfuric acid and ammonium chloride; washing with water again; drying; calcing at 670 Deg. C and getting high-purity vanadic anhydride. The invention is characterized in that it makes use of current material to prepare chemical materials urgently needed by industrial production, and saves a large amount of foreigh exchange.

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 present invention is of zinc or zinc alloy coated steel for hot forming having an inorganic overlay covering the zinc or zinc alloy coating to prevent loss of zinc during heating and hot forming. In one embodiment, the inorganic overlay has a coefficient of thermal expansion greater than the coefficient of thermal expansion of zinc oxide. In another embodiment, the inorganic overlay has a compositional gradient interface with the zinc or zinc alloy coating. Preferably the inorganic overlay may be comprised of material selected from phosphates, oxides, nitrates, carbonates, silicate, chromate, molybdate, tungstate, vanadate, titanate, borate, fluoride and mixtures thereof. A method of preparing the steel for hot forming and a method for hot forming the steel are provided.

The invention discloses a method for preparing an environment-friendly micro-arc oxidation black ceramic film on an aluminum alloy surface, and the method comprises the following steps: firstly, pouring deionized water into an oxidation tank, weighing 1-10g / L of sodium hexametaphosphate, 1-3g / L of sodium silicate, 0.5-2g / L of potassium hydroxide, 0.2-2g / L of sodium fluoride and 0.5-20g / L of ferric ammonium oxalate in terms of the volume of the added deionized water, and uniformly stirring and mixing the sodium hexametaphosphate, the sodium silicate, the potassium hydroxide and the sodium fluoride to obtain a micro-arc oxidation base electrolyte; adding the weighed ferric ammonium oxalate into the base electrolyte, and stirring and mixing uniformly to obtain an aluminum alloy micro-arc oxidant solution; and then, sequentially carrying out surface deoiling and cleaning, water washing, aluminum alloy micro-arc oxidation, sealing and drying on the aluminum alloy to prepare the environment-friendly micro-arc oxidation black ceramic film on the aluminum alloy surface. By means of the preparation method disclosed by the invention, the problems of single color, limited application range, and environment pollution caused by a vanadate electrolyte, of the existing aluminum alloy ceramic film layer, are solved.

A catalyzed diesel particulate matter exhaust filter including a porous filter substrate for filtering the diesel particulate matter impregnated with a catalytic material which includes an alkaline earth metal vanadate and a precious metal.

The invention provides a controllable preparation method and an application of rare earth metal hydroxide or vanadate nano material by using an ionic liquid assisted hydrothermal method. The preparation method comprises the following steps of taking rare earth metal salt, metavanadate and sodium hydroxide as raw materials, mixing evenly, adding deionized water to form precipitate, adding mixed solution of imidazolium ionic liquid and anhydrous ethyl alcohol, stirring for 10-30 min, transferring into a hydrothermal reaction kettle, carrying out hydrothermal reaction for 1-8h under the temperature of 100-220 DEG C and obtaining rare earth metal hydroxide nano particles, nano rods or nano-wire materials. If the reaction time is prolonged to 16-148h, rare earth vanadate one-dimensional nano-wire and two-dimensional nanoflake materials can be prepared. The method provided by the invention can effectively adjust and control phases and features of rare earth metal hydroxide and vanadate nano materials, and has the advantages of mild reaction conditions, simple technique, low cost, high yield and the like, thus being hopeful to be widely applied in the fields such as luminescent devices, electrocatalytic components, permanent magnets, biological and medical industry and the like.

The invention discloses the methods of preparation for a superfine bismuth vanadate yellow pigment, the characteristics of its bismuth nitrate, partial vanadate or vanadate are the main raw material. Through controlling of its appropriate pH and temperature to get the Ultra-fine particles,which composed of bismuth vanadate yellow pigments.well by adding surfactant or changing vanadium source, itcan further control particle morphology, which were prepared by a diameter of 50-150 nm spherical particles, 100-200 nanometer length, width 50-100 nanometers Flake Vanadate Bismuth or length of 200-300 nm rod bismuth vanadate. The preparation of this invention is a simple process, and can be controlled morphology, the bismuth vanadate can meet the needs of different occasions, which can be widely used in the automotive topcoat, ink, paint and other requirements for a higher size area.

The invention belongs to the chemical engineering field, in particular relates to a method for preparing ammonium polyvandata with vanadium-containing solution. The method uses the vanadium-containing solution produced with the traditional sodium roasting-water immersing technology as the raw material. First, vanadium combines with added calcium compounds and produces calcium vanadate, which reacts with ammonium bicarbonate and transfers vanadium into the solution but transforms calcium into more insoluble calcium carbonate; the ammonium polyvandata is produced with the separated solution under appropriate pH and heating conditions. After redissolution of calcium vandata, the ammonium bicarbonate containing less than 0.1percent of SUM (Na2O+K2 O) can be obtained. The ammonium bicarbonate can be used for production of vanadium trioxide and vanadium pentoxide with exceedingly low contents of potassium and sodium; and the ammonia content of vanadium-precipitation waste water is only 60percent to 75 percent of vanadium-extraction waste water in traditional technologies. The invention has very promising application prospect.

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.

A process for preparing V2O3 includes such steps as adding the powdered ammonium vanadate or V2O5 into the furnace pipe of an externally heated fluidized furnace, filling industrial gas in the furnace pipe while heating it to 600-650 deg.C, reducing reaction for 3-9 min, and cooling in the condition of isolating air.

The invention belongs to the technical field of chemical materials, and relates to a treating fluid and a method for preparing vanadium-zirconium composite conversion coatings with self-repairing performance on aluminum alloy surfaces through the same. The method includes the steps of firstly preparing the treating fluid containing fluorozirconate, metavanadate, sodium fluoride, nitrate, an accelerate and an additive; then putting an aluminum alloy after surface pretreatment into a working fluid made of the diluted treating fluid for 2min-10min; and finally subjecting the aluminum alloy to washing, drying and cooling to obtain the vanadium-zirconium composite conversion coatings. The preparation process is simple, heavy metals such as hexavalent chromium and nickel are not contained, the environment is friendly, the conversion coatings of the aluminum alloy after a conversion coating treatment are dense and high in binding force, metal ions in the conversion coatings can bond with base metal under a corrosion environment and provided with a certain self-repairing performance, and the treating technology of vanadium-zirconium conversion coatings can effectively replace chromate treatment on aluminum alloy surfaces.

The invention discloses a method for recovering vanadium in vanadium-titanium magnetite ore. The method comprises the process steps of: (1) mixing, pelletizing or briquetting, vanadium-titanium magnetite ore, a calcium additive and an adhesive, drying and oxidizing roasting to obtain roasting clinker; (2) performing carbonation leaching on the roasting clinker by utilizing leaching solution containing CO3<2->, and performing solid-liquid separation to obtain calcium-contained iron ore slag and chrome-vanadium-contained dissolving solution; and (3) adding a reagent with NH4+ into the dissolving solution for ammonia settlement, so as to obtain ammonia vanadate, or adding acid liquor into the dissolving solution, and directly acidifying to obtain V2O5. By adopting calcified roasting-carbonation leaching, the vanadium in the vanadium-titanium magnetite ore is recovered, obtained sintered pellets containing the calcium-contained iron ore slag can be directly applied to blast furnace smelting; and therefore, the problem of recovering the vanadium in the vanadium-titanium magnetite ore is effectively solved, and subsequent blast furnace smelting is not influenced. After the vanadium is recovered by using the method, chromium can be recovered from obtained crystallizing mother solution; and therefore, the vanadium-titanium magnetite ore is effectively and comprehensively utilized.

A method for extracting vanadium and chromium from materials containing the vanadium or / and the chromium is characterized by comprising the following steps: taking salt and alkali of alkali metal or the alkali of the alkali metal as an oxidation transformation medium of the materials containing the vanadium or / and the chromium; carrying out treating for 0.5-6 hours at the temperature of 160-600 DEG C under the effect of an oxidizing agent and enabling the vanadium and the chromium in the materials to be converted into soluble vanadate and soluble chromate; carrying out water leaching to obtain leaching liquor containing the vanadium or / and the chromium; adding a precipitant A in the leaching liquor containing the vanadium or / and the chromium to selectively precipitate the vanadium at first, and adding a precipitant B to precipitate the chromium to obtain vanadium-rich residues and chromium-rich residues; and then separating and recycling the vanadium and the chromium from the vanadium-rich residues and the chromium-rich residues respectively. The vanadium and the chromium are separated and recycled effectively, and moreover, the effect of removing impurities simultaneously is achieved; liquor obtained after chromium precipitation is subjected to oxidization regeneration, evaporated and concentrated to obtain media, and the media are returned to an oxidation transformation procedure for the materials containing the vanadium or / and the chromium and are recycled. The method has the advantages of the simple technology, easiness and convenience in operation, the good vanadium and chromium separating effect, a high metal recovery rate, low production cost, environmental friendliness and the like, and is suitable for industrial application of extracting the vanadium and the chromium from the materials containing the vanadium or / and the chromium.

The invention relates to a method for recovering nonferrous metals from a waste denitration catalyst, and specifically relates to a method for recovering vanadium and tungsten from a tungsten containing vanadium-titanium based waste denitration catalyst. The method mainly comprises the following steps: crushing and grinding the catalyst, adding hydrogen peroxide to enable part of vanadium oxide to form pervanadic acid, and filtering to obtain a filter cake and a filtrate containing pervanadic acid; after heating the filtrate, filtering again to obtain V2O5, and mixing and circulating to use a novel filtrate and hydrogen peroxide; adding alkali liquor to the filter cake, stirring and heating, leaching the residual vanadium in form of metavanadate and leaching tungsten in form of metatungstate; filtering to obtain mixed liquor of metavanadate and metatungstate; adding ammonium salt into the mixed liquor to separate out ammonium metavanadate precipitate, further filtering to obtain an ammonium metavanadate filter cake and a third filtrate, and adding a concentrated acid into the third filtrate to separate out tungstic acid precipitate. The method and process provided by the invention are simple, and when metavanadate and tungstic acid are leached, calcination is avoided, so that the energy consumption is low, the solid-liquid reaction is good in contact, and the recovery rates of vanadium and tungsten are high.

A method wherein a methanol-containing gas stream is passed in contact with a catalyst comprising a supported or unsupported bulk vanadate catalyst in the presence of an oxidizing agent for a time sufficient to convert at least a portion of the methanol to formaldehyde (CH2O).

The invention discloses an efficient vanadium extraction method by performing alkali roasting on vanadium mineral. The method comprises the following processing steps of: (1) mixing the vanadium mineral with sodium hydroxide or potassium hydroxide for pellet fabrication, and oxidizing and roasting pellets at the temperature of 300-700 DEG C to obtain roasted clinker; (2) leaching the roasted clinker using water or aqueous alkali corresponding to the step 1, and then carrying out solid-liquid separation to obtain leaching residue and a vanadium dissolution solution; and (3) cooling and crystallizing silicon-removed vanadium digestion solution to obtain vanadate. The alkali roasting is used by the method provided by the invention, because alkali can function as a caking agent in the aggregating process, the caking agent can be saved; not only is the roasting temperature reduced largely and process flow largely shortened, but also no waste gas, ammonia-nitrogen wastewater and the like are discharged, as well as a leachate can be recycled; and a silicate phase can be directly destroyed to promote the destroy and the oxidization of a vanadium phase, and the oxidative enveloping and the leaching hindering of the silicate phase to the vanadium can be prevented so that the efficient vanadium leaching can be realized and the leaching rate can reach more than 95%.

The invention relates to a method for extracting vanadium and chromium from vanadium-containing steel slag by high-alkalinity potassium hydroxide, and belongs to the technical field of metallurgy. The invention adopts a technical scheme that: the steel slag together with water and potassium hydroxide is added into a reactor, the mixture is decomposed under normal pressure, and then the obtained reaction slurry is cooled and diluted by a diluent to obtain mixed slurry containing the potassium hydroxide, potassium vanadate, potassium silicate, potassium chromate and tailings; the alkalinity of the potassium hydroxide in the mixed slurry is controlled to be more than or equal to 100g / L, the mixed slurry is filtered and separated while the temperature is kept to be 80 to 130 DEG C to obtain the tailings and vanadium and chromium-containing water solution. The method has the advantages that: the high-temperature roasting is avoided, the reaction time is shortened, the single high-efficientextraction and simultaneous extraction of the vanadium and the chromium are realized; atmospheric pollutant as Cl2, HCl, dust, SO2 and the like caused by roasting are effectively avoided in the vanadium extraction process; and compared with the conventional roasting process, the generated amount and the discharged amount of waste water are effectively reduced, and clean production is realized.

The invention relates to a synthesis method of an alkaline earth metal vanadate micro / nano material by utilizing microwave radiation. According to the method, with an alkaline earth metal salt and ammonium metavanadate as the raw materials and distilled water as a solvent, the alkaline earth metal vanadate micro / nano material is prepared in a microwave radiation heating mode in the presence of a structure directing agent. The synthesis method is characterized in that: the microwave heating efficiency is high, and the phase and morphology of the product are effectively controlled through the adjustment and control of the raw material properties or the structure directing agent, ultimately the high-efficiency functional nano material is acquired; and the synthesis method has the significant advantages of no temperature and concentration hysteresis, high operability, mild reaction conditions, simple process, and the like and the microstructure of the product is controllable. The invention also provides valuable experience for the application of the metal vanadate micro / nano material in the fields of energy storage and conversion, sewage treatment, photocatalysis, biomedicine, etc.

A sealing glass of a low melting point glass composition which is a phosphate glass that contains transition metal wherein the glass contains 15 to 35% of BaO and Sb2O3 (in total) and the ratio by weight of BaO to Sb2O3 or Sb2O3 to BaO is 0.3 or less. Particularly the transition metal is vanadium and the glass contains V2O5 of 45 to 60 wt % as vanadium oxide and P2O5 of 15 to 30 wt % as phosphorus oxide. The bonding material is a mixture of a filler and a vanadate-phosphate glass that contains V2O5 as the main ingredient and the glass contains V2O5 of 45 to 60%, P2O5 of 20 to 30%, BaO of 5 to 15%, TeO2 of 0 to 10%, Sb2O3 of 5 to 10%, and WO3 of 0 to 5%. The particle size of the filler is in the range of 1 to 150 μm and the ratio of filler is 80% by volume or less of the adhesive glass.

The invention discloses a method for processing a multi-metal alloy. The method comprises the following steps of firstly, carrying out oxygen-enriched pressure leaching on the multi-metal alloy containing nickel, cobalt, tungsten, molybdenum, vanadium, and iron in the sulfuric acid system to selectively leach nickel and cobalt in the multi-metal alloy; precipitating a leaching solution containing nickel and cobalt through an alkaline substance to obtain a nickel-cobalt residue product; pressurizing the leaching residue containing molybdenum, vanadium, tungsten and iron, adding a small amount of ammonium persulfate, leaching with sodium hydroxide and after the leaching is completed, carrying out solid-liquid separation to obtain a leaching solution containing tungsten, molybdenum and vanadium; adjusting the pH of the leaching solution containing tungsten, molybdenum and vanadium with hydrochloric acid, adding a vanadium-precipitating agent so that vanadium is precipitated in a form of ammonium vanadate and firing ammonium vanadate to obtain a vanadium pentoxide product; and adsorbing tungsten and molybdenum in the vanadium-precipitated solution with anion resin and backwashing to obtain a high-concentration ammonium tungstate and ammonium molybdate solution, evaporating and crystallizing to obtain a mixed product of ammonium tungstate and ammonium molybdate. The processing method is simple in flow, the required device is less and simple, the device investment is low and simple in operation and the method is easy to promote.

The invention relates to a combined chemical-electrochemical method for preparing an all-vanadium redox flow battery electrolyte. The method adopts a solid or solution containing soluble vanadate, especially vanadium slag leachate obtained after steel-making with vanadic titano-magnetite, for production of a high-purity high-concentration vanadium electrolyte. The method is characterized in that a vanadyl sulfate electrolyte with a sulfuric acid concentration of 1 to 6 mol / L and a vanadium concentration of 1 to 5 mol / L can be prepared through impurity removal, acidic vanadium precipitation, multiple alkaline leaching and vanadium precipitation, calcination and reduction, an electrochemical process is cooperatively used so as to prepare a 3.5-valent or 3-valent vanadium electrolyte, and after electrolysis, the vanadium electrolyte of a positive electrode can be repeatedly used through chemical reduction. The method provided by the invention can treat the vanadium slag leachate and the solid or solution containing soluble vanadate and has the advantages of simple process flow, mild reaction conditions, substantially reduced cost, etc.; and the prepared high-purity high-concentration vanadium electrolyte is especially applicable to an all-vanadium redox flow battery.

The invention discloses a method for preparing hollow spherical porous BiVO4 with the aid of a surfactant, which comprises the following steps of: under a stirring condition, dissolving bismuth nitrate and ammonium meta-vanadate in 2 mol / L solution of nitric acid in a molar ratio of bismuth nitrate to ammonium meta-vanadate to nitric acid of 1:1:10; adding polyvinylpyrrolidone (PVP) and carbamide into the mixed liquid in a molar ratio of bismuth nitrate to PVP to carbamide of 1:0.0075-0.0125:3; transferring the mixed liquid to a stainless steel self-pressure reactor of which the lining is teflon and the volume filling degree is 50 percent, and to a thermostat to perform hydro-thermal treatment for 30 hours at the temperature of 100 DEG C; cool a product naturally to room temperature after the product is taken out; drying the product for 24 hours at the temperature of 60 DEG C; and finally calcining the product in a muffle furnace to obtain hollow spherical porous BiVO4 particles with a monoclinic scheelite structure. The method has the characteristics of cheap raw materials, simple process, controllable appearance and crystalline phase structure of the target product particles and the like.