169 results about "Ammonium metavanadate" patented technology

The invention relates to the technical field of vanadium pentoxide preparation, and particularly discloses a preparation method of high-purity vanadium pentoxide, which comprises the following steps: S1, vanadium slag pretreatment: carrying out microwave activation on vanadium slag, and then carrying out ball milling and roasting to obtain clinker; the sulfuric acid-oxalic acid composite acid and the clinker are mixed and leached, the pH is adjusted after leaching is completed, and vanadium-containing leachate is obtained through filtering; s3, vanadium enrichment: heating the vanadium-containing leachate, adding a sodium carbonate solution while stirring, adjusting the pH value, preserving heat and curing, and then carrying out hot filtration to obtain vanadium-rich filter residues; s4, vanadium purification: mixing the vanadium-rich filter residues with a sodium hydroxide solution, stirring, introducing compressed air while stirring, and carrying out hot filtration after the reaction is finished, so as to obtain vanadium-rich filtrate; and S5, calcining: carrying out two-stage calcining on the ammonium metavanadate precursor to obtain high-purity V2O5. The preparation method is high in vanadium recovery rate, and the purity of the prepared V2O5 is 99% or above.

The invention discloses a preparation method of 5N specified-grade high-purity vanadium pentoxide, which comprises the following steps: step S1, taking high-purity ammonium metavanadate as a raw material, mixing the raw material with pure water in proportion, heating for dissolving, and cooling to obtain an ammonium metavanadate solution; s2, enabling the ammonium metavanadate solution to pass through a resin column for adsorption, and collecting column passing liquid; s3, carrying out vacuum concentration on the column passing liquid, cooling and crystallizing the obtained concentrated liquid, and carrying out suction filtration to obtain primary crystals; s4, mixing the primary crystal with pure water in proportion, heating, filtering, cooling filtrate, crystallizing, filtering and washing with water to obtain a secondary crystal; step S5, repeating crystallization operation for 1-3 times to obtain recrystallized ammonium metavanadate; and step S6, putting ammonium metavanadate into a porcelain baking tray, putting the porcelain baking tray into a calcining furnace, vacuumizing, calcining and cooling to obtain a 5N specified-grade high-purity vanadium pentoxide product. The method has the characteristics of simple principle, convenience in operation, high reliability and the like, and the purity of vanadium pentoxide is remarkably improved.

The invention provides a method for short-process all-component echelon recovery of a waste hydrogenation catalyst, and relates to the field of solid waste treatment. The recovery method of the waste hydrogenation catalyst comprises the following steps: roasting the waste hydrogenation catalyst and sodium carbonate to obtain a roasted product; the roasted product is leached with water, and leaching liquid and leaching residues are obtained; extracting the leaching solution by using an extracting agent to obtain a vanadium-molybdenum-containing organic phase, sequentially carrying out reverse extraction treatment on the vanadium-molybdenum-containing organic phase by using a strong alkaline reverse extraction agent and a weak alkaline reverse extraction agent to obtain a vanadium reverse extraction solution and a molybdenum reverse extraction solution, and carrying out vanadium precipitation treatment on the vanadium reverse extraction solution to obtain ammonium metavanadate; acidizing the molybdenum strip liquor to precipitate molybdenum to obtain ammonium molybdate; carrying out sintering treatment on the leaching residues and alkaline substances, leaching obtained calcine with water to obtain water leaching residues and filtrate, and carrying out aluminum precipitation treatment on the filtrate to obtain aluminum hydroxide, aluminum oxide or pseudo-boehmite; and reducing and smelting the water leaching residues to obtain the ferro-nickel alloy. According to the invention, multi-element comprehensive recovery of all components of vanadium, molybdenum, nickel, aluminum and sulfur can be realized, and high-value utilization of all components of the waste hydrogenation catalyst is realized.

The invention provides a method for preparing a nearly 3.5-valent vanadium electrolyte by reducing ammonium metavanadate with coke oven gas, which comprises the following steps: (1) reducing and calcining ammonium metavanadate in coke oven gas to obtain a reduced product; (2) carrying out replacement deamination on the reduced product in the step (1) to obtain a nearly 3.5-valent vanadium oxide, wherein the nearly 3.5-valent vanadium oxide contains V4O7; and (3) a mixed sulfuric acid solution and the approximately 3.5-valent vanadium oxide are subjected to a dissolution reaction, and the approximately 3.5-valent vanadium electrolyte is obtained. The process method disclosed by the invention is simple and easy to implement, the approximately 3.5 valence vanadyl sulfate electrolyte product with high vanadium concentration and low ammonia content can be obtained by taking the ammonium metavanadate and the coke oven gas as raw materials, and the application prospect is wide.

The invention discloses an anti-aging bronze powder pigment and a preparation method and application thereof in the technical field of bronze powder pigments, and the anti-aging bronze powder pigment takes copper-zinc alloy as a base material, and is sequentially connected with a composite chemical passivation layer, a functionalized organic-inorganic hybrid compact barrier layer and a surface super-hydrophobic layer through chemical bonding from inside to outside; wherein the composite chemical passivation layer is formed by treating a passivation solution containing phytic acid, ammonium metavanadate and sodium tungstate; the functionalized organic-inorganic hybrid compact barrier layer is constructed by a silane mixed solution containing 3-mercaptopropyltriethoxysilane, a reaction type ultraviolet light absorber Si-BP, a reaction type hindered amine light stabilizer Si-HALS and tetraethyl orthosilicate through a sol-gel process. Through the design of a multi-layer composite system, the aging resistance of the bronze powder is improved, and meanwhile, the optical decoration performance can be reserved to the maximum extent, so that the dual strict requirements of high-end outdoor applications such as automobile coatings on durability and visual texture can be met.

A system for plant-mediated synthesis and characterization of vanadium pentoxide (V2O5) nanoparticles, comprising a structurally integrated device configured to perform extraction, reaction, calcination and performance evaluation within a closed automated control loop, wherein the system includes: a basic chassis made of heat-insulated stainless steel, which houses a microcontroller-based central control unit; a bioextract preparation unit fluidically connected to a reactive mixing chamber, the bioextract preparation unit comprising a Soxhlet extractor with a borosilicate condenser, a thermostatically controlled heating jacket and a digital thermocouple to maintain extraction temperatures between 60°C and 70°C; a precursor feed vessel containing an ammonium metavanadate solution with a molarity between 0.1 M and 0.3 M, wherein this vessel is connected to the reaction mixing chamber via an electromagnetically actuated inlet valve and a precision peristaltic pump; a reaction mixing chamber with an inductive heating coil, a magnetic stirrer plate and a temperature and pH monitoring device configured to maintain a uniform reaction temperature of 70±2°C during the precursor-extract interaction; a calcination module consisting of a muffle furnace lined with refractory ceramic material and containing embedded nichrome heating elements controlled by a PID-controlled temperature controller to achieve a heating rate between 5 °C and 10 °C per minute up to a setpoint of 445±5 °C for combustion synthesis; an optical characterization module with integrated UV-VIS spectrometer, Fourier transform infrared analyzer and photoluminescence detector, each optically isolated and electronically connected to the control unit; and a photocatalytic and antibacterial test chamber fluidically connected to the output of the calcination module, the chamber comprising a UV irradiation array, an optical absorption sensor and a temperature-controlled bacterial incubation plate, the central control unit includes a programmable logic controller (PLC) configured to synchronize the operation of all submodules via feedback control loops, which receive data from temperature, pH and optical sensors, thereby automating the synthesis, analysis and testing of V2O5 nanoparticles.

The invention discloses a flocculent vanadium-doped MoN / CNT composite material and a preparation method and application thereof.The method comprises the steps that 1, ammonium molybdate is added into absolute ethyl alcohol to be dissolved, and a solution A is obtained; 2, adding 2-methylimidazole into deionized water, and dissolving to obtain a solution B; 3, adding the solution A into the solution B, stirring, carrying out suction filtration, separating out a precipitate, and drying to obtain a precursor I; 4, adding the precursor I into deionized water, and stirring to obtain a turbid solution; 5, ammonium metavanadate and polyvinylpyrrolidone are added into absolute ethyl alcohol, and a solution C is obtained; 6, adding the solution C into the turbid solution, stirring, carrying out suction filtration, separating out a precipitate, and drying to obtain a precursor II; 7, performing low-temperature sintering on the precursor II in an argon atmosphere to obtain a precursor III; and 8, mixing the precursor III with urea, and performing high-temperature sintering in an argon atmosphere to obtain the vanadium-doped MoN / CNT composite material which has high energy density and high conductivity and can endow an energy storage device with high rate capability and long cycle life.

The invention discloses a device and method for synthesizing a fourth-generation refrigerant R1235ze through photocatalysis of VDF, and belongs to the technical field of green chemical engineering. The core of the method is that a g-C3N4 / BiVO4 heterojunction photocatalyst is adopted to catalyze VDF to react with hydrogen chloride to generate R1234ze under the mild condition of 70-90 DEG C under the irradiation of simulated sunlight (AM1.5 G). The catalyst is prepared by taking melamine, bismuth nitrate and ammonium metavanadate as precursors and carrying out hydrothermal reaction and calcination treatment under specific conditions. The matched industrial system realizes the whole process integration from the continuous preparation of the catalyst to the online separation of the product. According to the method, the reaction temperature is successfully reduced to about 80 DEG C from traditional 400 DEG C or above, energy consumption is reduced by about 75%, CO2 emission is reduced by about 60%, meanwhile, the product selectivity is not lower than 93%, the quantum efficiency is not lower than 12%, the purity reaches up to 99.5% or above, and a subversive solution is provided for green and low-cost industrial production of R1234ze.

The invention discloses an L-cysteine doped ammonium vanadate positive electrode material, a preparation method thereof and application of the L-cysteine doped ammonium vanadate positive electrode material in an aqueous zinc ion battery, and belongs to the technical field of materials. The preparation method comprises the following steps: adding ammonium metavanadate and oxalic acid into deionized water, stirring and mixing, then adding L-cysteine, carrying out hydrothermal reaction on the obtained mixed solution, cooling to room temperature, carrying out centrifugal cleaning, and carrying out vacuum drying to obtain the L-NVO. L-NVO is prepared through a simple one-step hydrothermal method, L-cysteine is doped into the electrode material through further reaction, the introduction of L-cysteine not only enlarges the interlayer spacing of NVO, but also participates in the storage of zinc ions, increases the active sites of the zinc ions, effectively promotes the diffusion of ions and charge transfer, and improves the electrochemical performance of the electrode material. The conductivity of the material is improved, the internal resistance of the material is reduced, and the structural flexibility and stability of the material are maintained, so that the overall performance of the aqueous zinc ion battery is improved.

The present application relates to a kind of preparation methods of sulfur vanadium co-doped bismuth tungstate visible light catalyst, the catalyst is assisted by urea hydrothermal method, with sodium tungstate, bismuth nitrate, thiourea, citric acid, ammonium metavanadate, urea as raw material, configuration certain concentration of thiourea and citric acid aqueous solution as sulfur source;Configuration certain concentration of ammonium metavanadate aqueous solution as vanadium source.Sulfur source and vanadium source are mixed after drop by drop to be added to bismuth nitrate solution, after stirring, transfer to hydrothermal kettle, the hydrothermal kettle is placed in blast oven and hydrothermal treatment cooling, centrifugal separation product, washing and drying obtain sulfur vanadium co-doped BWO visible light catalyst.The method is obtained by one-step hydrothermal treatment flower cluster of bismuth tungstate nanosheet composition, simple process, low equipment requirement, the composite photocatalyst prepared has stronger response under visible light condition, has higher application value in pollution control, environmental protection, new energy preparation and other fields.

The invention discloses a process for preparing a V2O3 / ZnV2O3 total battery by simultaneously using vanadium oxide in a zinc ion battery as a positive electrode material and a negative electrode material, which comprises the following steps: reacting ammonium metavanadate with absolute ethyl alcohol by adopting a solvothermal synthesis method, washing, drying, and calcining in a tubular furnace to obtain V2O3; in the preparation process of the V2O3 positive electrode material, only V2O3, acetylene black serving as a conductive agent and PVDF serving as a binder are mixed in proportion and then are coated on graphite paper, other coating protection materials do not need to be introduced into a V2O3 / Zn negative electrode, and V2O3 is used as a protection layer to inhibit growth of zinc dendrites, relieve hydrogen evolution side reaction of the zinc negative electrode and reduce corrosion of zinc. Vanadium oxide V2O3 is directly used as a core positive electrode material, the zinc negative electrode coating is developed by utilizing the characteristics of the vanadium oxide V2O3, a material is formed, meanwhile, the performance optimization of the positive electrode and the negative electrode is realized, the used raw materials are simple and easy to obtain, the process is simple and easy to implement, and the preparation process is simple and easy to implement from V2O3 raw material synthesis to positive and negative electrode piece preparation to V2O3 / ZnV2O3 total battery assembly. And comprehensive improvement of positive and negative electrode performances of zinc ions is simultaneously realized by a single material.

The invention belongs to the field of magnesium ion battery positive electrode materials, and particularly relates to a preparation method of a magnesium ion battery positive electrode material BixVS4 composite material, which comprises the following steps: dissolving an organic reducing agent in N-methyl pyrrolidone, and stirring at room temperature; adding ammonium metavanadate, and stirring at 50-100 DEG C; adding thioacetamide, and continuously stirring; adding hydrochloric acid and stirring until the color of the solution becomes dark green; and adding bismuth nitrate pentahydrate, stirring, carrying out a hydrothermal reaction in a reaction kettle, cooling to room temperature, centrifuging, washing with deionized water and absolute ethyl alcohol for several times, and drying to obtain the BixVS4 composite material. The method has the advantages that VS4 is subjected to cation modification, high conductivity is provided by introduction of metal ions, and charge transfer is accelerated. Bi enters a VS4 crystal lattice, local charge rearrangement is caused, Van der Waals force between VS4 layers is weakened, rapid embedding and de-embedding of Mg < 2 + > are facilitated, and more active sites for embedding of Mg < 2 + > are provided.

This invention belongs to the field of materials technology, specifically relating to a calcium-doped ammonium polyvanadate cathode material, its preparation method, and its application in aqueous zinc-ion batteries. The preparation method includes: dissolving ammonium metavanadate and anhydrous calcium chloride in deionized water, adding hydrochloric acid to adjust the pH of the solution, continuing stirring to ensure thorough mixing, subjecting the mixed solution to a hydrothermal reaction, cooling to room temperature, centrifuging and washing, and vacuum drying to obtain Ca-NVO. This material prepares Ca-NVO via a simple one-step hydrothermal method, and further reactions can further convert Ca... 2+ Ca is doped into the electrode material. 2+ The introduction of Ca can serve as an interlayer support, improving the stability of the crystal structure, and Ca... 2+ It induces the formation of oxygen vacancies, improves reaction kinetics, increases reversible capacity, effectively promotes ion diffusion and charge transfer, improves the conductivity of the material, reduces its internal resistance, and maintains the structural flexibility and stability of the material, thereby enhancing the overall performance of aqueous zinc-ion batteries.

The invention relates to the technical field of denitration catalyst regeneration, in particular to a preparation method of a regenerated denitration catalyst based on a reconstructed bulk phase carrier. The preparation method comprises the following steps: carrying out ultrasonic treatment on the waste catalyst by using an ethylenediamine tetraacetic acid-hydrofluoric acid mixed solution to realize targeted detoxification; carrying out hydrothermal reaction on the detoxified carrier, titanium sol, cerous nitrate and zirconium nitrate, and roasting with nitrogen to complete bulk phase reconstruction; carrying out microwave-assisted gradient loading on ammonium paratungstate and an ammonium metavanadate-oxalic acid solution on the reconstructed carrier to obtain a precursor; and roasting and activating the precursor in a gradient atmosphere to obtain the regenerated catalyst. The catalyst prepared by the invention has high denitration efficiency, excellent sulfur poisoning resistance stability, good circulation performance and long service life, can realize efficient regeneration of the waste vanadium-titanium-based denitration catalyst, is suitable for the field of industrial flue gas denitration, and has significant application value.

The invention provides a high-purity and high-solubility vanadyl sulfate crystal and a preparation method and application thereof.The preparation method of the high-purity and high-solubility vanadyl sulfate crystal comprises the following steps that ammonium metavanadate or ammonium polyvanadate serves as a raw material and is roasted at the temperature of 600-900 DEG C under the inert gas protection and reducing atmosphere conditions, and vanadium oxide is obtained; dissolving the vanadyl sulfate in a mixed solution of pure water and sulfuric acid to obtain a high-concentration vanadyl sulfate solution or vanadyl sulfate slurry; the valence state of vanadium is adjusted to 3.9-4.1; cooling, crystallizing and filtering to obtain primary vanadyl sulfate crystals; dissolving the primary vanadyl sulfate crystal in pure water to obtain a vanadyl sulfate solution, and filtering; and adding sulfuric acid, adjusting the vanadium valence state of the solution to 3.99-4.01, cooling, crystallizing, and filtering to obtain the high-purity and high-solubility vanadyl sulfate crystal. The vanadyl sulfate crystal has the advantages of small particle size, high purity, good solubility and the like, and has good application prospects and large-scale popularization potential in the field of vanadium electrolyte.

This invention relates to a method for preparing carbon-modified vanadium sulfide lithium-ion battery anode materials using vanadium-containing oxalate. The steps are as follows: vanadium-containing oxalate and ammonia are mixed, heated and stirred, filtered, and the filtrate is collected; hydrochloric acid is added while heating and stirring until the pH reaches 7-9, filtered, and the filtrate is collected; hydrogen peroxide and ammonium sulfate are added sequentially while heating and stirring, kept at a certain temperature for a period of time, filtered, and solid ammonium metavanadate is collected and dried; the dried ammonium metavanadate, ammonia, and deionized water are mixed, thioacetamide and acetylene black are added sequentially, ultrasonically treated, heated and kept at a certain temperature, naturally cooled, and the solid obtained by filtration is washed and dried to obtain acetylene black composite vanadium tetrasulfide, which is the carbon-modified vanadium sulfide lithium-ion battery anode material. The carbon-modified vanadium sulfide lithium-ion battery anode material prepared by the method of this invention exhibits superior electrochemical energy storage effect and cycle stability, demonstrating excellent rate performance.

A method for preparing vanadium pentoxide by using ammonium metavanadate, comprising the following steps: (1) preparation of an oxidant loaded with ozone and chloromethyl polystyrene resin of graphene oxide; (2) heating and dissolving crude ammonium metavanadate in water, adjusting the pH value to 8-9 by using a sodium hydroxide solution after dissolving, filtering to obtain a sodium metavanadate solution; (3) heating the sodium metavanadate solution to 60-80 DEG C, adding the oxidant loaded with ozone and chloromethyl polystyrene resin of graphene oxide, stirring for more than 20 minutes, filtering to obtain a filtrate; (4) adding ammonium metavanadate crystals to the obtained filtrate for recrystallization, obtaining ammonium metavanadate precipitate, and performing solid-liquid separation and drying to obtain ammonium metavanadate crystals; (5) calcining the ammonium metavanadate crystals to obtain vanadium pentoxide. The purity of the obtained vanadium pentoxide is greater than or equal to 99.99%, and the sum of the content of tetravalent vanadium and trivalent vanadium is less than or equal to 0.003%.

The invention belongs to the technical field of hydrogen-sensitive materials, and particularly relates to a preparation method of a vanadium-containing modified tungsten oxide-titanium dioxide composite hydrogen-sensitive color-changing material, which comprises the following steps: S1, selecting ammonium metatungstate and ammonium metavanadate as raw materials, adding deionized water, stirring and dissolving, adding titanium dioxide, and carrying out ultrasonic dispersion and magnetic stirring for 30 minutes to form a uniform suspension; s2, drying the mixed solution obtained in the step S1 in a drying oven until the weight is constant, and calcining the dry powder in a muffle furnace; s3, weighing chloroplatinic acid, dissolving the chloroplatinic acid in deionized water, adding the dry powder obtained in S2 into the solution, uniformly stirring, drying, and calcining in a muffle furnace to form a Pt-loaded composite material; the color of the material prepared in the S3 turns into dark blue from light grey after meeting hydrogen. The whole preparation and detection process is high in efficiency, quick in response, simple in technological process and free of secondary pollution.

A preparation method of granular vanadium pentoxide comprises the following steps: (1) adding ammonium metavanadate into a mixed solvent, heating, stirring and dissolving to obtain a solution A; (2) adding ammonia water and sodium acetate into the solution A, removing impurities, and carrying out solid-liquid separation to obtain a vanadium-containing purified solution; (3) heating the vanadium-containing purified solution, carrying out gradient vanadium precipitation, and carrying out solid-liquid separation to obtain a vanadium precipitation mother solution and solid-phase ammonium polyvanadate; and (4) calcining the ammonium polyvanadate for deamination to obtain particle vanadium pentoxide. According to the invention, a mixed solvent of water, ethylene glycol and acetone is adopted to prepare vanadium pentoxide with uniform particle size and large particle size; sodium acetate is added in the impurity removal process, the molecular structure of the sodium acetate contains hydrophobic carbon chains, the sodium acetate is alkalescent in an aqueous solution, and granular vanadium pentoxide can be generated through catalysis; product particle size distribution is uniform; the vanadium pentoxide product with the purity larger than or equal to 99.99 wt% and the particle size larger than or equal to 150 micrometers is prepared, the particle size within the range of 180 micrometers to 200 micrometers is larger than or equal to 80%, and particle size distribution is uniform.

The invention relates to a preparation method of binuclear vanadyl oxalate SCR catalyst regeneration liquid, and belongs to the technical field of SCR catalyst regeneration liquid. The method comprises the following steps: adding oxalic acid dihydrate into water, and stirring for the first time until the oxalic acid dihydrate is completely dissolved to obtain an oxalic acid solution; adding ammonium metavanadate into the oxalic acid solution batch by batch, carrying out second stirring so as to carry out a chemical reaction, continuously introducing nitrogen into a chemical reaction system, and removing carbon dioxide generated by the chemical reaction so as to prepare a binuclear vanadyl oxalate complex solution; after the binuclear vanadyl oxalate complex solution is cooled to a set temperature, polyethylene glycol is added into the binuclear vanadyl oxalate complex solution for third stirring, and a primary regeneration solution is obtained; the primary regeneration liquid is filtered, and binuclear vanadyl oxalate SCR catalyst regeneration liquid is obtained; wherein the density of the binuclear vanadyl oxalate SCR catalyst regeneration liquid is 1g / cm < 3 > to 1.5 g / cm < 3 >, the molar concentration of vanadium is 1mol / L to 2.5 mol / L, and the pH value is 1.5 to 4.5.

The utility model relates to the technical field of ammonium metavanadate processing, and discloses ammonium metavanadate roasting furnace tail gas efficient recovery treatment equipment which comprises a reaction kettle, a first gas outlet frame fixedly installed on the upper surface of the reaction kettle, a reaction frame fixedly installed on the upper surface of the first gas outlet frame, and a second gas outlet frame fixedly installed on the upper surface of the reaction frame. An air outlet is fixedly formed in the upper surface of the second air outlet frame, a partition plate is fixedly installed on the inner wall of the air outlet, a rotating shaft is movably installed on the inner wall of the air outlet, and a movable plate is fixedly installed on the outer surface of the rotating shaft; through cooperative arrangement of a first air outlet frame, a reaction frame, a second air outlet frame, an air outlet, a partition plate, a rotating shaft, a movable plate, a baffle, an air return pipe, a first servo motor, an air quality detector, a shielding frame, a movable door and bolts, the effect of detecting air can be achieved, and the situation that the purified air is discharged before reaching the standard is avoided; the influence on the physical and psychological health of workers and surrounding residents is avoided.

The application discloses a preparation method and application of a nickel vanadate / carbon nanotube composite nanosphere. NiCl2.6H2O and nickel-plated carbon nanotubes are added into an ammonium metavanadate solution, and then anhydrous ethanol is slowly added. The mixture is heated at a temperature of 160-200 DEG C for 6-10 hours. The mixture is centrifuged and the precipitate is dried to obtain the nickel vanadate / carbon nanotube composite nanosphere. The nickel vanadate / carbon nanotube composite nanosphere is synthesized by a one-step hydrothermal method for the first time, and has high dispersion and uniform particle size. The unique CNT winding main body structure can provide an electrically conductive path for electron transmission. The ultra-small nickel vanadate nanoparticles are uniformly embedded on the CNT, which accelerates electron transmission and greatly reduces the transmission distance of lithium ions, and improves the electrochemical performance of the nickel vanadate / CNT composite nanosphere. The nickel vanadate / CNT lithium ion battery negative electrode material prepared by the method has good cycle stability and rate performance.

The application discloses a catalyst for synthesizing methanol, and a preparation method of the catalyst, which comprises the following steps: (1) adding gamma-Al2O3 powder into a salt solution corresponding to an alkaline earth metal, then adding triethanolamine, uniformly mixing, and placing in a muffle furnace for calcination to obtain a pretreated gamma-Al2O3 carrier; (2) firstly, immersing the pretreated gamma-Al2O3 carrier in a calcium nitrate solution, and drying the catalyst precursor after immersion; (3) dissolving copper nitrate, cesium nitrate and ammonium metavanadate in deionized water to obtain a mixed solution, immersing the catalyst precursor obtained in the step (2) in the mixed solution, slowly adding an acid solution to control pH after immersion for a period of time, until precipitation is generated, and then filtering, washing, drying and calcining to obtain the catalyst. The catalyst prepared by the method has high methanol selectivity and can maintain high stability in the case of being exposed to air for a long time.

The invention discloses a method for preparing vanadium pentoxide from vanadium slag and vanadium pentoxide. The method comprises the following steps that the vanadium slag is subjected to roasting, clinker leaching and purification in sequence, and purified liquid is obtained; extracting the purified liquid by using a CO3 < 2-> and / or HCO3 <-> type extraction agent to obtain a vanadium-containing organic phase; the vanadium-containing organic phase is subjected to reverse extraction through a reverse extraction agent, and vanadium-containing reverse extraction liquid is obtained; adding ammonium salt into the vanadium-containing strip liquor, cooling and precipitating to obtain ammonium metavanadate; and calcining the ammonium metavanadate to obtain vanadium pentoxide. According to the scheme, the purification liquid is separated in an extraction mode to obtain the vanadium-containing organic phase, meanwhile, the vanadium-containing organic phase is subjected to reverse extraction of vanadium through the mixed solution of the sodium carbonate, the ammonium carbonate and the ammonia water, the stability of the vanadium-containing reverse extraction liquid is improved through introduction of the sodium carbonate, and the problem that when the vanadium is subjected to reverse extraction through the mixed solution of the ammonium salt and the ammonia water is solved. The problems of device wall scabbing, pipeline blockage and the like caused by crystallization and separation of ammonium metavanadate are solved.

The application belongs to the field of photocatalytic material preparation, and aims at solving the problem of low photocatalytic efficiency. The preparation method comprises the following steps: firstly, pre-oxidized graphene is put into distilled water and uniformly dispersed by ultrasonic, so as to obtain an oxidized graphene suspension; bismuth nitrate and ammonium metavanadate are respectively dissolved in nitric acid and ammonia water to obtain two solutions A and B; under ultrasonic state, A and B are added into the oxidized graphene suspension and uniformly dispersed, and then a precursor solution is obtained after magnetic stirring; secondly, the precursor solution is loaded into a reaction kettle with a polytetrafluoroethylene lining, and the reaction kettle is kept at 110 DEG C for 24 hours; the reaction liquid is obtained after the temperature is reduced to 60 DEG C; thirdly, the precipitated solid phase material in the lower layer of the reaction liquid is collected, washed, dried and ground into powder, so as to obtain graphene oxide / BiVO4 composite photocatalytic nanoparticles. The preparation method is simple, and the graphene oxide / BiVO4 composite photocatalytic nanoparticles obtained by the method effectively improve the photocatalytic oxidation performance.

The invention discloses a Bayer process sodium aluminate solution comprehensive purification system and a Bayer process sodium aluminate solution comprehensive purification process wherein in an inorganic carnallite purification system, high-concentration forced-effect mother liquor is adopted for seed crystal salting-out, settling separation and filter pressing to obtain a primary purification filtrate; according to the organic matter crystallization, adsorption and purification system, after primary purification filtrate and low-concentration evaporation mother liquor are mixed and cooled, underflow of an organic matter settling tank serves as seed crystal, an adsorption auxiliary is added, and through the combined action of natural cooling precipitation and adsorption, the morphology of a crystallization product is controlled, and the settling and filtering performance is improved. And the vanadium salt purification system is used for further cooling and crystallizing the secondarily purified filtrate and extracting the vanadium element. The comprehensive purification system can perform step-by-step multiple purification on the Bayer process sodium aluminate solution, the influence of various impurities on the production system is reduced, the step-by-step purification can further solve the problem of difficult product treatment and purification, the recovery and extraction of the high-value vanadium-rich salt slag and the preparation of ammonium metavanadate are realized, and the method is suitable for industrial production. Meanwhile, various purified impurities are subjected to innocent treatment.

The application belongs to the technical field of wet vanadium extraction, and particularly relates to large-granularity ammonium metavanadate and a preparation method thereof. The preparation method comprises the following steps: (1) preparation of a vanadium-containing stock solution; (2) dissolving ammonium salt and high-molecular-weight polyethylene glycol in water, and adding alkali to adjust pH to obtain an ammonium salt solution; (3) adding low-molecular-weight polyethylene glycol to the vanadium-containing stock solution to obtain a modified vanadium-containing stock solution; (4) uniformly mixing the ammonium salt solution and the modified vanadium-containing stock solution, adjusting pH, and obtaining a mixture after reaction; and (5) filtering the mixture, washing the solid product, and obtaining large-granularity ammonium metavanadate. The low-molecular-weight polyethylene glycol mainly plays a role in reducing nucleation rate, and the high-molecular-weight polyethylene glycol has good adsorption and mainly plays a role in promoting crystal growth, so that the granularity of ammonium metavanadate is improved through the cooperation of polyethylene glycols with different molecular weights. The application has simple process, is environment-friendly, has no waste water and waste residue to be discharged, and is beneficial to industrial popularization and application.

The invention relates to the field of hydrometallurgy, and provides a high-purity ammonium metavanadate washing method which comprises the following steps: preparing oxalic acid into an acidic solution, and preparing ammonium bicarbonate into a weakly alkaline solution; adding the acid solution into the crude ammonium metavanadate, stirring or soaking and washing under a preset first temperature condition, and carrying out solid-liquid separation after washing to obtain primarily washed ammonium metavanadate; and adding the weakly alkaline solution into the primarily washed ammonium metavanadate, stirring or soaking and washing, and carrying out solid-liquid separation after washing to obtain the high-purity ammonium metavanadate. The ammonium metavanadate is washed, and impurities adsorbed on the surface of the ammonium metavanadate can be remarkably removed. The solvent is in full contact with the surface of the ammonium metavanadate, adsorbed impurities are dissolved or dispersed into the solvent, and a washing solution is separated from an ammonium metavanadate solid, so that the impurities on the surface are effectively removed, the content of the impurities in the ammonium metavanadate is further reduced, and the purity of a product is effectively improved. The method has high operability and is suitable for large-scale industrial production.

The utility model relates to the technical field of vanadium extraction from vanadium slag, and particularly discloses a vanadium extraction system for phosphorus-removed vanadium slag and ammonium metavanadate raffinate, which comprises a first dissolving tank for dissolving the ammonium metavanadate raffinate and a phosphorus-removed vanadium slag solution so that the ammonium metavanadate raffinate and the phosphorus-removed vanadium slag solution are subjected to chemical reaction to obtain phosphorus-removed vanadium slag slurry; the first separator comprises a first outlet and a second outlet and is used for carrying out solid-liquid separation on the phosphorus removal vanadium slag slurry to obtain first vanadium-containing filtrate and first residues, and the first vanadium-containing filtrate and the first residues are output through the first outlet and the second outlet respectively; the buffer tank is connected with the first outlet; the second dissolving tank is connected with the second outlet and is used for pulping and washing the first residue to obtain residue slurry; and the second separator is connected with an outlet of the second dissolving tank and comprises a third outlet and a fourth outlet, the third outlet is connected with the buffer tank, and the second separator is used for squeezing the residue slurry and then separating to obtain second vanadium-containing filtrate and second residues, and the second vanadium-containing filtrate and the second residues are output through the third outlet and the fourth outlet respectively. The device disclosed by the utility model realizes high-efficiency recovery of vanadium in dephosphorized slag and ammonium metavanadate raffinate.

According to the method for preparing the vanadium electrolyte through targeted impurity removal and one-step vanadium precipitation of the sodium-modified vanadium solution, high-purity ammonium metavanadate is prepared through targeted impurity removal of the sodium-modified vanadium solution, and calcination is conducted under the protection of inert gas of ammonium metavanadate, so that the consumption of auxiliary materials and the generation amount of waste water are greatly reduced; the manufacturing process cost of the vanadium electrolyte is effectively reduced; by adopting a two-time silicon removal mode, the use amount of a silicon removal agent is reduced while high-efficiency removal of chromium is realized, and the generation amount of silicon removal slag and the vanadium loss in the silicon removal process are reduced. In addition, the pH value of the liquid subjected to deep silicon removal is lower than that of the liquid subjected to chromium removal, so that the aluminum concentration of the liquid subjected to deep silicon removal can be effectively reduced, and conditions are created for improving the subsequent hydrolysis aluminum removal effect; the crude ammonium metavanadate is pulped and washed by adding a complexing agent, the content of cations such as potassium, sodium and calcium is reduced, the ammonium metavanadate is calcined under the protection of inert gas to obtain low-valence vanadium oxide, the acid solubility of the vanadium oxide is improved, and the consumption of a reducing agent in the preparation process of the vanadium electrolyte is reduced.