528results about "Vanadium oxides" patented technology

The invention provides a method for preparing low-chromium low-potassium vanadium oxide by using a sodium vanadium solution, which comprises the following steps: S1) adjusting the pH value of the sodium vanadium solution to 10.5-11.0, and reacting with a chromium removal agent to obtain initial chromium removal slurry; s2) adjusting the pH value of the initial chromium removal slurry to 9.0-9.5, reacting with a silicon removal agent, and carrying out solid-liquid separation to obtain a filtrate; s3) reacting the filtrate with hydrogen peroxide, adding ammonium salt, precipitating vanadium, and performing solid-liquid separation to obtain ammonium metavanadate and primary vanadium precipitation wastewater; s4) adjusting the pH value of the primary vanadium precipitation wastewater to 6-7, reacting with ferrous sulfate, adding a complexing agent, mixing with the sodium vanadium solution, precipitating, and performing solid-liquid separation to obtain ammonium polyvanadate; and oxidizing and calcining the ammonium metavanadate to obtain the low-chromium low-potassium vanadium oxide. According to the method provided by the invention, the low-chromium and low-potassium vanadium oxide is prepared from the sodium vanadium solution, meanwhile, ammonium salt and vanadium in the primary vanadium precipitation wastewater are recycled, and the comprehensive production cost of the vanadium oxide is reduced.

The invention relates to the technical field of waste catalyst recovery, and particularly discloses a method for recovering valuable metals from a waste catalyst containing vanadium and molybdenum. Comprising the following steps: S1, heating and roasting the waste catalyst containing vanadium and molybdenum, continuously heating and roasting, and cooling to obtain a roasted material; s2, mixing the roasted material with a sulfuric acid solution A containing oxalic acid, and heating and leaching to obtain a leaching solution A and a residue A; mixing the residue A with a sulfuric acid solution B containing thiourea and ethylenediaminetetraacetic acid, heating, carrying out secondary leaching to obtain a leaching solution B and a residue B, and washing the residue B with an acid solution to obtain a washing solution; combining the leaching solution and the washing solution to obtain a combined solution; s3, adjusting the pH value of the mixed solution to 2.5-3, then adjusting the pH value to 4.5-5, adding a dimethylglyoxime alcohol solution, and heating to obtain a purified solution; uniformly mixing the purified liquid with the extraction liquid to obtain an organic phase containing vanadium and molybdenum; and S4, reverse extraction and product preparation. The ammonium molybdate and the vanadium pentoxide obtained in the invention have high purity, and the recovery rate of vanadium and molybdenum is high.

The invention provides a method for preparing vanadium pentoxide from iron-containing ammonium metavanadate, which comprises the following steps: S1) mixing iron-containing ammonium metavanadate with water to obtain ammonium metavanadate slurry; s2) mixing the ammonium metavanadate slurry with a complexing agent, adjusting the pH value to 1.5-2.5, carrying out iron dissolving reaction, and carrying out solid-liquid separation to obtain ammonium polyvanadate; 3, ammonium polyvanadate is calcined, and vanadium pentoxide is obtained.According to the method for preparing vanadium pentoxide from iron-containing ammonium metavanadate, the technical thought of acid dissolution-complexing iron removal is provided, the content of iron in vanadium pentoxide is effectively reduced, the process is simple, and the process cost is low.

The invention discloses a selective separation and resource utilization method of chromium in a sodium vanadium solution, which comprises the following steps: S1, measuring a predetermined volume of sodium vanadium solution, and heating to a predetermined temperature; s2, a preset amount of divalent manganese salt is added into the sodium vanadium solution, so that hexavalent chromium is subjected to a reduction reaction; s3, after the reaction is finished, carrying out solid-liquid separation and washing to obtain chromium and vanadium removed liquid and precipitates; s4, vanadium precipitation and calcination are conducted on the chromium and vanadium removal liquid, and a vanadium oxide product is obtained; and calcining the precipitate at high temperature to obtain the chromium-manganese oxide. According to the method, the sodium vanadium solution is used as a raw material, the divalent manganese salt is used as a reducing agent, hexavalent chromium is reduced into trivalent chromium, the trivalent chromium generates chromium hydroxide precipitate under the alkaline condition, vanadium is not reduced and is reserved in the solution, and efficient separation of vanadium and chromium is achieved; the dechromed vanadium liquid is subjected to vanadium precipitation and calcination, and a vanadium oxide product is obtained; after the precipitate is subjected to high-temperature calcination, chromium-manganese oxide is obtained and can be used for preparing chromium-manganese alloy, and resource utilization is achieved.

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 belongs to the field of hydrometallurgy, and particularly discloses a high-purity vanadium oxide electrode and a preparation method thereof. The method comprises the following steps: pre-treating the alkaline vanadium leaching solution by using an activated aluminum oxide adsorption column to obtain a pre-treated solution; adding a composite impurity removal agent taking modified lignosulfonate as a main agent into the pretreatment liquid for primary impurity removal to obtain primary impurity-removed filtrate; adding a calcium hydroxide suspension and a flocculating agent into the primary impurity-removed filtrate for secondary impurity removal to obtain secondary impurity-removed filtrate; purifying the secondary impurity-removed filtrate by using an ion exchange column to obtain a purified solution; ammonium salt is added into the purified liquid for vanadium precipitation, and ammonium metavanadate crystals are obtained; calcining the ammonium metavanadate crystal to obtain high-purity vanadium pentoxide; and preparing the high-purity vanadium oxide electrode by using the high-purity vanadium pentoxide. According to the scheme, the high-purity vanadium pentoxide is prepared by taking the alkaline vanadium leaching solution as a raw material through a multi-stage deep impurity removal process, and the high-purity vanadium oxide electrode is prepared by taking the alkaline vanadium leaching solution as the raw material.

The invention relates to the field of chemical industry, and discloses a method for preparing high-purity vanadium oxide by purifying ammonium vanadate, which comprises the following steps: adding a carbonate solution into ammonium vanadate, stirring, and heating to 75-95 DEG C to obtain a vanadium-containing return solution; keeping the temperature of the vanadium-containing return solution, and adding a calcium salt impurity removal agent to obtain a vanadium-containing purified solution and first-stage impurity removal slag; oxalate is added into the vanadium-containing purified liquid, the temperature of the vanadium liquid is kept, and deeply-purified vanadium liquid and second-stage impurity removal slag are obtained; cooling the deeply purified vanadium liquid to 5-35 DEG C, stirring and reacting, and then carrying out solid-liquid separation to obtain ammonium metavanadate and secondary vanadium precipitation supernatant; adding pure water into the ammonium metavanadate product, pulping, stirring, and heating to 80-95 DEG C to obtain a secondary return solution; the pH of the secondary return solution is adjusted to 1.6-2.0, the temperature is raised to 95-98 DEG C, and ammonium polyvanadate and a third-section vanadium precipitation supernatant are obtained; and drying the ammonium polyvanadate, raising the temperature to 500-600 DEG C in an oxidizing atmosphere, and carrying out heat preservation and calcination to obtain a vanadium pentoxide product. The method can be used for preparing a high-purity vanadium pentoxide product.

The invention relates to a preparation process and method for coating tungsten-doped vanadium dioxide nano-particles on the surface of silicon dioxide in a self-adsorption mode and application of the tungsten-doped vanadium dioxide nano-particles. The process sequentially comprises the steps of pretreatment of silicon dioxide and tungsten-doped vanadium dioxide particles and preparation of a core-shell structure formed by self-adsorption of the silicon dioxide and the tungsten-doped vanadium dioxide particles. The method comprises the basic operation procedures of grinding silicon dioxide microspheres, treating tungsten-doped vanadium dioxide particles with deionized water, setting stirring parameters and centrifugal parameters and the like. The invention also relates to application of the tungsten-doped vanadium dioxide and silicon dioxide core-shell structure prepared by using the self-adsorption method in adjustable transmittance and adjustable radiation capability in the fields of intelligent window energy-saving glass and radiation refrigeration. The problems that a traditional vanadium dioxide nanoparticle film is low in visible light transmittance, poor in near-infrared modulation capacity, adjustable in infrared radiance and the like are solved.

The invention provides a method for preparing high-purity vanadium pentoxide from carbonation leachate. The method comprises the following steps: S1) carrying out silicon removal on the carbonation leachate, and carrying out solid-liquid separation to obtain silicon-removed slag and silicon-removed liquid; s2) mixing the post-silicon-removal liquid with a complexing agent, and reacting to obtain a post-reaction liquid; s3) carrying out vanadium precipitation on the reacted liquid to obtain ammonium metavanadate and vanadium precipitation wastewater; s4) oxidizing and calcining the ammonium metavanadate to obtain high-purity vanadium pentoxide; the complexing agent is selected from one or more of ethylene diamine tetraacetic acid, disodium ethylene diamine tetraacetate and tetrasodium ethylene diamine tetraacetate. According to the method, the leaching solution obtained through the vanadium slag low-calcium roasting-carbonation leaching vanadium extraction technology serves as the raw material, ions such as iron, calcium and magnesium are controlled to enter the vanadium product through complexing, high-purity vanadium pentoxide with the low impurity content is obtained, the technological process is simple, implementation is easy, the cost is low, and the method is one of the methods for preparing high-purity vanadium pentoxide through the carbonation leaching solution.

An object of the present invention is to provide a negative thermal expansion material having better negative thermal expansion characteristics. The present invention is a negative thermal expansion material, comprising a copper vanadium composite oxide dissolving Li atoms and represented by the following general formula (1):(CuxMy)(VaPb)Ot. In the general formula (1), M represents a metallic element with an atomic number of 11 or more other than Cu and V, 1.60≤x≤2.40, 0.00≤y≤0.40, 1.60≤a≤2.40, 0.00≤b≤0.40, 5.00≤t≤9.00, 1.60≤x+y≤2.40, and 1.60≤a+b≤2.40.

The invention provides a vanadium dioxide composite electrode material and a preparation method and application thereof. The method comprises the following steps: taking vanadium leachate as a raw material, reacting with a reducing agent under the condition that the pH value is 2-6, mixing the obtained tetravalent vanadium solution with a precipitator, carrying out precipitation reaction, filtering, washing and drying the precipitate to obtain vanadium dioxide precursor particles, grafting a silane coupling agent with sulfydryl onto the surface of the vanadium dioxide precursor through coupling reaction, and carrying out vacuum drying to obtain the vanadium dioxide precursor. Silver ions are chelated under the action of sulfydryl, and silver elementary substances are deposited on the surfaces of vanadium dioxide precursor particles through reduction. And coating the composite slurry of the vanadium dioxide precursor and the carbon nanotube on the surface of a substrate, and calcining to obtain the vanadium dioxide composite electrode material. The vanadium dioxide composite electrode material is used as a negative electrode material of a battery, and the obtained battery is found to have excellent stability and reaction dynamic characteristics.

An object of the present invention is to provide a negative thermal expansion material having better negative thermal expansion characteristics. The present invention is a negative thermal expansion material, comprising copper vanadium composite oxide powder dissolving Al atoms and represented by the following general formula (1), CuxMyVzOt (1). In general formula (1), M represents a metallic element with an atomic number of 11 or more other than Cu, V, and Al, 1.60≤x≤2.40, 0.00≤y≤0.40, 1.70≤z≤2.30, 6.00≤t≤9.00, 1.00≤x+y≤3.00, and a molar number of the Al atoms in terms of atoms>a molar number of M atoms in terms of atoms if an M element is contained.

The invention discloses a microwave absorbing material of nitrogen-doped vanadium oxide and a preparation method thereof, the nitrogen-doped vanadium oxide is synthesized by combining a hydrothermal morphology control process with an annealing process for the first time, and the microwave absorbing performance of the nitrogen-doped vanadium oxide is systematically studied. The complex dielectric constant of the sample can be adjusted by adjusting the hydrothermal reduction pH value. When the pH value is 7, selective absorption of electromagnetic waves can be realized by adjusting the thickness of a sample, and the lowest reflection loss can reach 31.57 dB at 4.37 GHz. The reflection loss of the sample with the corresponding thickness in different frequency bands can be lower than 10dB, and the whole frequency range is almost covered. The excellent microwave absorption performance of the microwave absorption material of the nitrogen-doped vanadium oxide is attributed to the improvement of the conductivity in the nitrogen-doped double-phase vanadium oxide, good impedance matching and multiple reflection caused by a unique microstructure of the nitrogen-doped double-phase vanadium oxide. The microwave absorbing material of the nitrogen-doped vanadium oxide can be used as the absorbing requirements of different application scenes, and the corresponding thickness meets the absorbing requirements.

The invention discloses a preparation method of vanadium pentoxide and a vanadium pentoxide product, relates to the technical field of vanadium pentoxide production, and can improve the preparation efficiency of vanadium pentoxide and the recovery rate of vanadium pentoxide. According to the specific scheme, the method comprises the following steps: obtaining an enriched solution of vanadium pentoxide; after the enrichment liquid is pretreated, first enrichment liquid is obtained, and pretreatment comprises concentration adjustment and PH value adjustment; sequentially carrying out first impurity removal treatment and second impurity removal treatment on the first enrichment liquid to obtain a target enrichment liquid; and extracting the target vanadium pentoxide from the target enrichment liquid.

The invention discloses a method for preparing high-purity vanadium pentoxide from high-concentration sodium vanadium solution, which comprises the following steps: adjusting the pH value of the high-concentration sodium vanadium solution with acid, sequentially adding an inorganic ammonium salt and an organic ammonium salt, respectively reacting, carrying out solid-liquid separation to obtain vanadium-containing precipitate, dissolving the vanadium-containing precipitate, adding ammonium sulfate to prepare ammonium metavanadate, and filtering to obtain the high-purity vanadium pentoxide. And reducing ammonium metavanadate to prepare vanadium pentoxide. According to the method, introduction of more impurities due to hydrolysis in the vanadium precipitation process of the high-concentration sodium vanadium solution is effectively prevented. The method is simple in technological process, and does not need the procedures of impurity removal, high temperature and the like.

The invention provides a method for closed-loop preparation of high-purity vanadium pentoxide from ammonium metavanadate, and belongs to the technical field of metallurgy. The method comprises the following steps: carrying out acid-process vanadium precipitation on an ammonium metavanadate raw material to obtain ammonium polyvanadate; carrying out alkaline vanadium precipitation on the ammonium polyvanadate to obtain high-purity ammonium metavanadate; and roasting the high-purity ammonium metavanadate to obtain the vanadium pentoxide. The existing method for producing high-purity vanadium pentoxide from ammonium metavanadate mainly adopts a pure alkali method or an acid method for purification, and has the problems of high purification cost, repeated purification, incapability of closed-loop production, low purity and the like, the acid-alkali combined secondary crystallization method is adopted, closed-loop production is realized, the cost is low, no pollution is caused, vanadium pentoxide with the purity of 99.9% can be obtained, the additional value is increased, and the method is suitable for industrial production. And the requirements of high-end vanadium markets are met.

The invention belongs to the field of functional nano materials, and relates to a method for large-scale preparation of monoclinic phase vanadium dioxide nano powder, a heat insulation film and application of the heat insulation film, and large-scale preparation of the monoclinic phase vanadium dioxide nano powder is successfully achieved by combining a coprecipitation method with low-temperature calcination. The obtained product has excellent size uniformity (the average particle size is 65 + / -10 nm) and an adjustable phase change characteristic (61-68 DEG C). The polymer-based composite film prepared based on the nano powder shows excellent optical performance, and the method has the advantages of mild reaction conditions (less than or equal to 600 DEG C), controllable product morphology and phase transition temperature and the like, and provides a reliable solution for industrial production of nano functional materials for intelligent windows.

The invention provides a method for recovering silicon and metals from a waste catalytic cracking / catalytic cracking catalyst. The method comprises the following steps: carrying out hydrochloric acid acid leaching treatment on the waste catalytic cracking / catalytic cracking catalyst by using hydrochloric acid with the HCl concentration of 1-3 mol / L at 60-120 DEG C, and carrying out solid-liquid separation to obtain a leaching solution and loose microspheres; the leaching liquid is used for metal recovery; and reacting the loose microspheres with a hydrofluoric acid solution with the mass concentration of HF being 5-47%, introducing the generated gas into a sodium hydroxide solution with the mass concentration of sodium hydroxide being 5-40%, and removing a solid phase from the obtained product to obtain liquid sodium silicate. According to the method provided by the invention, high-efficiency and high-purity silicon recovery is realized through the cooperation of specific hydrochloric acid, hydrofluoric acid and sodium hydroxide treatment; and meanwhile, Ni, V, rare earth and Al components can be completely or almost completely leached into a leaching solution through specific hydrochloric acid treatment, and a foundation is laid for efficient recovery of the Ni, V, rare earth and Al components.

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 discloses a V6O13 nano material and a preparation method and application thereof, and belongs to the technical field of aqueous zinc ion batteries, the preparation method of the V6O13 nano material comprises the following steps: taking V2O5 as a vanadium source, and adopting a hydrothermal method to prepare an intermediate product; and the intermediate product is subjected to annealing treatment, and the V6O13 nanometer material is obtained. According to the preparation method disclosed by the invention, a hydrothermal-annealing synergistic strategy is adopted, firstly, an intermediate product is prepared by taking V2O5 as a vanadium source and adopting a hydrothermal method, and then, the V6O13 nano material with more complete lattice arrangement is obtained through high-temperature annealing, so that higher battery capacity and more stable long cycle life are realized, and a new scheme is provided for research on an aqueous zinc ion battery positive electrode material.

The invention belongs to the technical field of building glass and coating materials thereof, and discloses a one-step chemical synthesis method of W-VO2 (M) nano-particles and application of the W-VO2 (M) nano-particles in thermochromic smart windows.The method comprises the steps that firstly, ammonium metavanadate, hydrazine hydrate and ammonium metatungstate serve as raw materials, tungsten-doped M-phase vanadium dioxide nano-particles are chemically synthesized through a one-step hydrothermal method, and the tungsten-doped M-phase vanadium dioxide nano-particles are prepared; the obtained W-VO2 (M) nanoparticles are high in crystallinity, small in particle size (10-40nm), high in purity and low in phase change temperature; then, by taking a polyvinylpyrrolidone material as a parent material, uniformly distributing the W-VO2 (M) nanoparticles in PVP (Polyvinyl Pyrrolidone) to form a uniformly dispersed thin film; according to the application of the W-VO2 (M) nanoparticles in the thermochromic intelligent window, not only can high visible light transmittance be obtained, but also the solar energy regulation and control capability of the W-VO2 (M) nanoparticles can be improved, and the application of the W-VO2 (M) nanoparticles in the fields of the thermochromic intelligent window and radiation refrigeration is further promoted.

The invention belongs to the technical field of a VO2 low-dimensional structure growth process, and particularly relates to a chemical vapor deposition preparation method for realizing a natural bending VO2 nanowire with a controllable curvature radius. According to the method, a chemical vapor deposition system formed by a sliding rail type tube furnace is selected, a Si / SiO2 substrate is selected as a substrate, V2O5 powder is taken as a precursor, and controllable preparation of the bent VO2 nanowires with different curvature radiuses is successfully realized by comprehensively regulating and controlling growth parameters of chemical vapor deposition (CVD); the bottleneck that only conventional linear VO2 nanowires can be prepared through an existing chemical vapor deposition method is broken through. The bent VO2 nanowires with different curvature radiuses, which are prepared by the method disclosed by the invention, are relatively high in quality, good in crystallinity and uniformity, excellent in MIT characteristic and special in mechanical property. The method has the advantages of simplicity in operation, high repeatability, no toxic waste gas emission and the like, and is beneficial to large-scale popularization and application.

The invention relates to a preparation method of high-purity vanadium pentoxide, in particular to the field of high-purity vanadium pentoxide, which comprises the following steps: adding an impurity removal agent into a phosphorus-containing vanadium solution to remove impurities, and then carrying out solid-liquid separation to obtain filtrate; the obtained filtrate is sequentially subjected to first pH value adjustment, second pH value adjustment, ammonium salt vanadium precipitation, dehydration, calcination deamination and melting, and high-purity vanadium pentoxide is obtained; wherein the impurity removing agent is prepared from calcium salt and a flocculating agent; the final pH value of the first pH value adjustment is 4.5-5.5; the final pH value of the second pH value adjustment is 1.8-2.2. According to the preparation method provided by the invention, the vanadium in the vanadium liquid is efficiently recovered by matching the metallographic phase specific impurity removal process of the vanadium liquid with pH value adjustment, the purity of the obtained vanadium product is greater than or equal to 99.9%, and the recovery rate of the vanadium is greater than or equal to 98%.

The invention discloses pure inorganic stimuli-responsive sol as well as a preparation method and application thereof, inorganic sol with stimuli-responsive performance is prepared from an inorganic nano-material with positive electricity, and the technical problem of conversion from one-dimensional inorganic nano-material sol to gel is solved. Compared with a means of providing positive electricity for the one-dimensional inorganic nano material through a modification means, the one-dimensional inorganic nano material carrying the positive electricity only needs cheap inorganic matters in cost, and the convenience and cost of the one-dimensional inorganic nano material carrying the positive electricity have qualitative changes in further processing and practical application; the adjustment of the acting force between one-dimensional inorganic nano materials can be realized without replacing ligands, and the method has extremely high advantages in the aspect of realizing the sol-gel conversion capability of stimulation response. The method disclosed by the invention is relatively low in cost and simple and convenient to operate, and the prepared hydrogel not only has relatively good mechanical properties, but also has relatively good stimulation response capability, is a material capable of realizing comprehensive application, and is wide in application scene.

The invention discloses a three-dimensional porous carbon encapsulated V2O5 carbon fiber electrode constructed by in-situ growth and a preparation method and application thereof, belongs to the technical field of aluminum ion battery positive electrode materials, and aims to solve the problems that the intercalation and deintercalation dynamics of AlCl4 in a polyacrylonitrile (Pan)-based carbon fiber is blocked due to disordered graphite structure, and the performance of the Pan-based carbon fiber is influenced. And the material cannot be used as an effective electrode material to be applied to an aluminum ion battery system. According to the preparation method, an in-situ growth technology is adopted, a three-dimensional porous carbon substrate is grown on the surface of carbon fiber, then an orthorhombic system vanadium pentoxide (V2O5) nano material which has high theoretical specific capacity and can realize large-current charging and discharging is packaged in the three-dimensional porous carbon substrate, and the V2O5-based carbon fiber electrode is prepared. According to the electrode, the electrostatic interaction between Al < 3 + > ions and crystal lattices is effectively relieved, the structural advantages of the carbon fibers and the energy storage performance of V2O5 are fully combined, the energy storage effect of the aluminum ion battery is remarkably improved, and a new effective scheme is provided for development of aluminum ion battery electrode materials.

The invention discloses a process for extracting high-purity vanadium pentoxide from ammonium polyvanadate, and belongs to the technical field of nonferrous metallurgy. According to the process, efficient purification of vanadium pentoxide is achieved through the steps of sodium hydroxide dissolution, pH adjustment, gradient impurity removal, precise filtration, freezing-unfreezing circulation, high-purity water washing, centrifugal dewatering, two-stage firing and the like. In the process, the gradient impurity removal technology effectively reduces the content of impurities such as iron, sodium and the like, the precision filtration system ensures low residue of the impurities, the freezing-unfreezing circulation step further improves the crystal purity, and the two-stage firing process realizes directional conversion of the alpha-V2O5 crystal form. The purity of the obtained vanadium pentoxide product reaches up to 99.99% or above, the Na < + > content is smaller than or equal to 2 ppm, the Fe residue is smaller than or equal to 5 ppm, the alpha-V2O5 crystal form proportion is larger than or equal to 98%, the problems that in a traditional process, deep impurity removal is difficult, the product purity is insufficient, and crystal form conversion is incomplete are remarkably solved, and an effective technical approach is provided for preparing high-purity vanadium pentoxide.

A process produces high-purity vanadium chemicals from vanadium raw materials having high molybdenum contents. Molybdenum is selectively precipitated via vanadium from alkaline vanadate solutions using the following process steps: providing a molybdenum-containing alkaline vanadate solution, adding calcium hydroxide as a precipitant in portions while keeping the pH constant between 6 and 7 using acid, mixing the solution, solid-liquid separation of the resulting suspension, and further processing the low-molybdenum alkaline vanadate solution to produce a high-purity vanadium chemical having a molybdenum content of at most 500 ppm.

The invention discloses a production method of low-silicon low-aluminum tablet vanadium pentoxide, which belongs to the technical field of vanadium chemical metallurgy, and comprises the following steps: (1) impurity removal of a vanadium liquid: heating the vanadium liquid with steam, and sequentially adding concentrated sulfuric acid and aluminum sulfate to obtain the purified vanadium liquid; (2) precipitating and filtering: adding liquid ammonium sulfate and concentrated sulfuric acid into the purified vanadium liquid to adjust the pH value, heating by steam, washing by a vertical filter press, extruding, and drying by compressed air to generate ammonium polyvanadate; and (3) drying, calcining and melting: carrying out flash evaporation drying on the ammonium polyvanadate, calcining in a calcining furnace, melting in a melting furnace, and carrying out sheet casting to generate the sheet-shaped vanadium pentoxide with the silicon content and the aluminum content being less than or equal to 0.05% by mass. By means of the method, impurities entering the product are reduced, and the flaky vanadium pentoxide meeting the requirement for aviation alloy smelting is produced.

The invention relates to the field of vanadium and chromium separation, and particularly discloses a sodium vanadium solution treatment method which comprises the following steps: S100, adding an alkaline reducing agent into a sodium vanadium solution, and carrying out reduction of hexavalent chromium and selective precipitation reaction of trivalent chromium; s200, at the later stage of the reaction in the step S100, urea is added into a solution system, and a deep removal reaction of silicon and chromium is carried out; and S300, after the reaction in the step S200 is finished, solid-liquid separation is conducted, silicon-chromium slag and purified vanadium liquid are obtained, silicon-chromium oxide is obtained after the silicon-chromium slag is treated and can be used for smelting silicon-chromium alloy, and the purified vanadium liquid is subsequently used for preparing a high-purity vanadium oxide product. According to the method, the vanadium sodium salt solution obtained through a vanadium slag sodium salt roasting-water leaching process is used as a raw material, hexavalent chromium in the solution is reduced through an alkaline reducing agent, selective precipitation separation of hexavalent chromium and vanadium is achieved, and meanwhile urea is supplemented to conduct synergistic precipitation removal on silicon in the solution.

The invention provides metal ion intercalation vanadium dioxide as well as a preparation method and application thereof, belongs to the technical field of aqueous iron ion batteries, and aims to solve the technical problem of low energy density of an aqueous iron ion battery positive electrode material. The preparation method of the metal ion intercalation vanadium dioxide comprises the following steps: dispersing vanadium pentoxide, a reducing agent and a metal source into a solvent to obtain a mixed solution; and reacting the mixed solution to obtain the metal ion intercalation vanadium dioxide nanosheet. The synthesis method provided by the invention is a one-step hydrothermal method, the synthesis method is relatively simple, environment-friendly and relatively low in cost, and the prepared material is a relatively uniform nanosheet. The prepared metal ion intercalation vanadium dioxide nanosheet is used as a positive electrode material of an iron ion battery, 284.32 mAh g <-1 > can be provided under the current density of 0.1 A g <-1 >, and the average discharge efficiency is as high as 99%.