88 results about "Chromium trioxide" patented technology

The invention relates to a preparation method of 2-(2-amino-5-bromo-benzoyl) pyridine, which comprises the following steps: by taking 1, 2-diphenyl-1H-benzimidazole (I) as a starting material, oxidizing under the action of chromium trioxide and acetic acid to obtain N-[2-(2-pyridinecarbonyl) phenyl] benzamide (II), hydrolyzing the N-[2-(2-pyridinecarbonyl) phenyl] benzamide (II) under the action of sulfuric acid to obtain 2-(2-aminobenzoyl) pyridine (III), and reacting the 2-(2-amino-5-bromo-benzoyl) pyridine (III) with the 2-(2-amino-5-bromo-benzoyl) pyridine (III) to obtain the 2-(2-amino-5-bromo-benzoyl) pyridine. And (III) performing substitution reaction with NBS in DCM to obtain the target product 2-(2-amino-5-bromo-benzoyl) pyridine. The method has the advantages of mild reaction conditions, higher product purity, high yield, simplicity and convenience in operation, low cost and easiness in industrialization.

The invention discloses a preparation method and application of a carbon dioxide hydrogenation catalyst, and belongs to the field of hydrogenation catalysis. The vanadium slag is used as a raw material, a leaching solution containing silicon, chromium and vanadium is obtained through sodium salt roasting, an aluminum source is added to remove the silicon element, meanwhile, an ordered mesoporous carbon material is added, and silicon and aluminum elements are converted into an ordered mesoporous composite oxide which is used as a hydrogenation catalyst carrier; an indium salt, a cerium salt and a nickel salt are dissolved in ethanol and mixed with the carrier for isopyknic impregnation to obtain the hydrogenation catalyst; and carrying out chromium and vanadium separation on the silicon-removed leaching solution to obtain chromium sesquioxide and the all-vanadium redox flow battery electrolyte. The catalyst has a regular pore structure, ordered mesopores provide a confinement effect, dispersion and anchoring of active components are facilitated, and the activity of the catalyst is remarkably improved.

The application relates to the field of fireproof bricks, and discloses a baking-free fireproof brick and a preparation method thereof. The baking-free fireproof brick comprises iron tailings, cement, fly ash, a functional additive, fine aggregate, quartz sand, a chromium aluminum phosphate binder, a water reducing agent and water. The functional additive is prepared by using aluminum chloride hexahydrate and alkaline silica sol as raw materials, ammonium molybdate tetrahydrate as a catalyst, growing mullite whiskers on the surface of silicon carbide fibers through vacuum impregnation and heat treatment, modifying the prepared composite silicon carbide fibers through 3-(methacryloxy) propyl trimethoxysilane, and then copolymerizing the modified composite silicon carbide fibers with acrylic acid and 4-hydroxybutyl vinyl ether. The chromium aluminum phosphate binder is prepared by using aluminum hydroxide, phosphoric acid and chromium trioxide as raw materials and calcium hydroxide as a curing agent. The baking-free fireproof brick prepared through the synergistic effect of the components has high compressive strength and bending strength, small water absorption and good baking-free fireproof and heat insulation performance.

The present disclosure relates to the synthesis of Vitamin K2 bearing varying prenyl side chains. The synthesis comprises the reaction of phenyl sulfone of tert-butyl dimethyl silyl (TBDMS) protected mono prenyl menadiol with prenyl halides bearing varying prenyl units in the presence of the phase transfer catalyst followed by reductive desulphonation to yield TBDMS ether of Vitamin K2. The TBDMS ether is then oxidized in the presence of chromium trioxide and periodic acid to yield the corresponding Vitamin K2.

The present invention relates to a high-entropy rare earth chromate high-temperature negative temperature coefficient thermistor material, belonging to the field of semiconductor sensors, and aims to solve the existing perovskite structure high-temperature NTC material. Under high temperature environment, the Cr element in the system will volatilize in the form of gaseous CrO3, showing poor high-temperature aging stability. The high-temperature negative temperature coefficient thermistor material uses lanthanum trioxide, neodymium trioxide, samarium trioxide, europium trioxide, gadolinium trioxide and chromium trioxide as raw materials, and undergoes wet three-dimensional vibration ball milling, powder calcination, cold isostatic pressing, and high-temperature sintering to obtain a perovskite structure (La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 G 0.2 )CrO3 thermosensitive material. The electrical performance parameters of this series of materials are: B 0℃ / 1300℃ =2044±1.42%K,ρ 1300℃ =1.45×10 3 ±1.73%Ω·cm. The high-entropy rare earth chromate high-temperature negative temperature coefficient thermistor (La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 G 0.2 )CrO3 has excellent negative temperature coefficient characteristics in the temperature range of 0~1300℃, and shows good high temperature aging stability at high temperatures (the resistance drift rate is only 4.35% after aging for 500 hours at 1300℃).

The invention discloses a method for preparing brown aluminum oxide by smelting chromium-aluminum spinel. The method comprises the following steps: crushing the chromium-aluminum spinel into chromium-aluminum spinel particles; the chromium-aluminum spinel particles and the carbon particles are mixed, and a mixture is obtained; putting the mixture into an electric arc furnace for bottoming and compacting; electrifying and smelting by using a three-phase graphite electrode; after smelting is completed, cooling water is continuously introduced into the electric arc furnace for cooling for a period of time, and then natural cooling is conducted; and disassembling the furnace, cleaning and separating brown aluminum oxide and high-carbon chromium metal, and packaging. According to the method, chromium trioxide in the chromium aluminate spinel is reduced into high-carbon metal chromium by adopting a carbon reduction smelting method, so that most of chromium trioxide is removed, a generated aluminum-containing product meets the impurity-containing requirement of brown aluminum oxide, and the high-carbon metal chromium is conveniently separated from the brown aluminum oxide by utilizing the characteristic that the density of the generated high-carbon metal chromium is greater than that of the brown aluminum oxide; the technological process is greatly simplified, and the production cost is saved.

The invention discloses a chromium-site high-entropy chromium lithium titanate material as well as a preparation method and application thereof, and belongs to the technical field of electrochemical energy storage materials. The crystal structure of the chromium-site high-entropy chromium lithium titanate material is a single spinel solid solution phase, and the chemical general formula of the chromium-site high-entropy chromium lithium titanate material is Li (Cr < 1-x-y-z-w > V < x > Fe < y > Mn < z > Al < w >) TiO4. According to the preparation method, chromium trioxide serves as an oxidizing agent, carbohydrate serves as a reducing agent, and rapid synthesis is achieved through a one-step combustion method. The process is simple and efficient, and the prepared chromium-site high-entropy chromium lithium titanate material has relatively high specific capacity and excellent cycling stability and can be applied as a lithium ion battery negative electrode material. According to the invention, the problems of limited theoretical capacity and poor rate capability of the existing chromium lithium titanate material are effectively solved, and a new way is provided for developing a high-performance lithium ion battery negative electrode material.

The application provides an aluminum material protection water-based paint and a preparation method thereof, and belongs to the technical field of paints. A monomer A is prepared by condensation of maleic acid through an ionic liquid, and copolymerization of hexafluorobutyl acrylate hydroxyethyl ester and butyl acrylate to obtain a polymer; a solution is prepared by stirring and mixing phosphoric acid, chromium trioxide and aluminum dihydrogen phosphate; a suspension is prepared by mixing water and magnesium oxide; the suspension is added dropwise into the solution to react, magnesium powder and the polymer are added, a dispersing agent and a leveling agent are added, and the mixture is uniformly mixed to obtain the aluminum material protection water-based paint. The aluminum material protection water-based paint prepared by the application has good corrosion resistance, good adhesion, good mechanical properties and hardness, good antibacterial, flame-retardant and high-temperature resistance, improved leveling and film-forming properties of the paint, reduced coating film defects, and a wide application prospect.

The invention discloses a magnesium oxide-containing high-performance composite crucible for smelting an aluminum-lithium alloy and a preparation method of the magnesium oxide-containing high-performance composite crucible, and belongs to the technical field of refractory materials. The preparation method comprises the following steps: mixing aluminum oxide, calcium aluminate, boehmite, magnesium oxide, chromic oxide, calcium fluoride, modified zirconium powder, aluminum oxide and a 5wt% aluminum dihydrogen phosphate solution to obtain a mixed material, and sealing and standing the mixed material to obtain a first mixed material; adding the first mixture into a mold, and carrying out static pressure treatment to obtain a blank; and carrying out gradient sintering on the green body to obtain the magnesium oxide-containing high-performance composite crucible. According to the prepared high-performance composite crucible containing magnesium oxide, the synergistic effect of the modified zirconium powder and various functional oxides is taken as a core, and a unique process is combined, so that the corrosion resistance is improved, and the problem of material deterioration caused by high activity of lithium element is solved.

The invention discloses a high-performance Q345 composite board and a preparation method thereof.The high-performance Q345 composite board comprises a Q345R steel substrate and an embedded coating embedded in the surface of the Q345R steel substrate, the embedded coating comprises a spherical material and a Q345R steel substrate material, and the spherical material comprises, by weight, 98.91%-99.68% of a sharp crystal structure, 0.32%-0.86% of chromic oxide and 0-0.23% of nano zinc oxide. The Q345 composite board disclosed by the invention has good high-temperature strength, hydrogen embrittlement resistance and low-temperature toughness.

The invention discloses a ferrochrome liquid decarburization method based on partial roasting and step-by-step vacuum, and belongs to the technical field of ferroalloy smelting. During operation, only part of ferrochrome raw materials and powder need to be ground into powder and roasted into the endogenous oxidizing agent mainly comprising chromic oxide; then, in a vacuum induction furnace, the blocky ferrochrome and part of the oxidizing agent are molten to form a liquid molten pool, the oxidizing agent reacts with carbon in the melt through the process of combining step-by-step stepped vacuumizing and adding of the remaining oxidizing agent in batches, generated CO is rapidly pumped away by a vacuum system, and therefore deep decarburization is achieved. The method effectively solves the technical bottlenecks that a traditional oxygen blowing method cannot produce micro-carbon ferrochrome, and a vacuum solid-state method is tedious in raw material treatment and too long in decarburization period.

The invention discloses a light conversion material, an eye-protection screen protection film and a preparation method of the eye-protection screen protection film, and relates to the technical field of nano luminescent materials. The inorganic metal oxide or the inorganic non-metal oxide and the quantum dots are connected through a cross-linking material, and the inorganic metal oxide or the inorganic non-metal oxide is selected from nano silicon oxide, nano aluminum oxide, nano zinc oxide, nano zirconium oxide, nano calcium oxide, nano sodium oxide, nano manganese heptoxide or nano chromium trioxide; the particle size of the inorganic metal oxide or the inorganic non-metal oxide is 2-100 nm; the cross-linking material is selected from a silane coupling agent or a bifunctional ligand. The light conversion material and the eye protection screen protection film provided by the invention can prolong the service life of the nano luminescent material and maintain the stability of the light conversion efficiency of the light conversion material after long-term use.

The present application relates to a kind of gray glass composition and car window glass.The above-mentioned gray glass composition includes base component and coloring component, and the mass percentage of coloring component in gray glass composition is as follows: total iron Fe2O3 1.3%~2.5%, titanium dioxide TiO2 100ppm~800ppm, chromium trioxide Cr2O3 100ppm~500ppm, cobalt oxide CoO 100ppm~400ppm, selenium Se 10ppm~50ppm and tin oxide SnO2 10ppm~50ppm.The above-mentioned gray glass composition has the comprehensive performance of low visible light transmittance, low infrared transmittance, low ultraviolet transmittance, low solar direct transmittance, and also has the neutral gray tone that satisfies visual comfort, also has great economic advantage.

The present invention relates to the technical field of ladle castables, and specifically discloses a slag-resistant ladle castable, which includes: a green body and a protective layer coated on the surface of the green body; the raw materials of the green body include, by mass: 40-70 parts of corundum aggregate, 10-20 parts of corundum fine powder, 5-15 parts of aluminum-magnesium spinel, 5-15 parts of activated alumina micro-powder, 1-5 parts of polystyrene microspheres, 1-3 parts of aluminate cement, and 1-2 parts of polycarboxylate water reducer; the raw materials of the protective layer include, by mass: 5-15 parts of activated alumina micro-powder, 1-3 parts of chromium trioxide, 1-2 parts of titanium dioxide, 1-2 parts of bismuth germanate powder, 1-2 parts of pretreated nickel ferrite micro-powder, and 1-3 parts of polyvinyl alcohol; the pretreated nickel ferrite micro-powder is nickel ferrite micro-powder coated with rare earth zirconate on the outside. The obtained ladle castable has high strength, excellent slag erosion resistance, and excellent structural stability, and can meet the long-term use of the ladle lining structure in the high-temperature molten steel erosion environment.

The invention relates to the technical field of inorganic adhesive production, and particularly discloses a preparation method and application of phosphate-based adhesive. According to the invention, trivalent chromium ions are introduced into the phosphoric acid solution or the aluminum-containing phosphoric acid solution through an electrolytic method to obtain the phosphate-based adhesive, so that the use of chromium trioxide is completely avoided, the generation of harmful substances in the production process is reduced, the burden of treating and disposing the harmful substances is also avoided, and the green environmental protection property of the production process is improved; meanwhile, no by-product is generated in the reaction process, the atom utilization rate of the chemical reaction is greatly increased, and efficient atom economy is achieved; moreover, the metal chromium is converted into trivalent chromium ions through an electrolytic method, so that additional chemical reagents are avoided, the utilization efficiency of raw materials in the reaction is improved, and the generation of waste materials is reduced. According to the preparation method of the phosphate-based adhesive, the technological process is simplified, energy consumption and material consumption are reduced, the preparation method is more environmentally friendly and economical, and industrial production is easier to achieve.

This invention provides a phosphate-based adhesive and its preparation method, belonging to the field of inorganic adhesives. The invention involves mixing a phosphoric acid solution with an aluminum source for an acid-base neutralization reaction to obtain a neutralized product; mixing the neutralized product with a trivalent metal halide for a metathesis reaction to obtain the phosphate-based adhesive; and providing a curing agent to obtain the phosphate-based adhesive. This invention incorporates heteroions into the aluminum phosphate adhesive system in the form of trivalent metal halides, eliminating the need for a reduction reaction and allowing direct use of the trivalent metal. The preparation method is simple, efficient, and easily scalable for industrial production. Furthermore, this invention limits the trivalent metal halide to one or more of chromium halides, iron halides, scandium halides, iridium halides, lanthanum halides, ruthenium halides, osmium halides, gallium halides, and molybdenum halides, expanding the range of heteroions and eliminating the need for highly toxic chromium trioxide, thus improving the safety of the preparation method.

The present invention discloses a high-performance copper alloy for electronics and its preparation method, which relates to the technical field of electronic materials. In the present invention, copper alloy is modified by nano silver and nano tin. Under high-temperature conditions, the molten metals penetrate each other, fill the gaps between particles to make their connection tighter, thereby improving the electrical conductivity and mechanical properties of the matrix. Then, under the condition of high oxygen pressure, alloy powders mainly composed of aluminum, chromium, and tungsten carbide are melted and solidified through laser energy radiation to carry out metallurgical bonding with the matrix. First, a chromium trioxide oxide film is formed on the surface of the matrix, which reduces the oxygen activity at the oxide film interface, promotes the formation of a dense, complete and continuous aluminum oxide protective film by aluminum. Then, tungsten carbide therein forms a nucleation core, which refines the surrounding structure, improves the mechanical properties of the coating, and enhances the high-temperature oxidation resistance of the matrix.

The invention discloses a preparation method of a medical intermediate 6-methoxy-1-tetralone, which comprises the following steps: S1, carrying out hydrogenation reduction on 2-naphthol under the action of a catalyst and a promoter to prepare 5, 6, 7, 8-tetrahydro-2-naphthol; s2, 5, 6, 7, 8-tetrahydro-2-naphthol and an oxidizing agent X are subjected to a reaction, and 6-hydroxy-3, 4-dihydronaphthalene-1-one is prepared; s3, enabling the 6-hydroxyl-3, 4-dihydronaphthalene-1-ketone to react with a methylation reagent in an alkaline environment, so as to prepare 6-methoxyl-1-tetralone, and enabling the 6-hydroxyl-3, 4-dihydronaphthalene-1-ketone to react with a methylation reagent in an alkaline environment; wherein the oxidizing agent X comprises at least one of oxygen, hydrogen peroxide, tert-butyl hydroperoxide, potassium permanganate, tetrabutylammonium perchlorate, pyridine chlorochromate, 2, 3-dichloro-5, 6-dicyanobenzoquinone, chromium trioxide, ceric ammonium nitrate, potassium persulfate, 1, 4-benzoquinone and chloranil; the feeding molar ratio of the oxidizing agent X to the 5, 6, 7, 8-tetrahydro-2-naphthol is (1.0 to 2.5): 1.0. The method has the advantages of mild reaction conditions, high molar total yield, high purity, low cost and toxicity of raw materials, less discharge of three wastes, and clean process, and is suitable for industrial production.

This invention provides a refractory ceramic matrix material for smelting furnace linings and its preparation method, belonging to the technical field of ceramic refractory materials. The material includes coated modified fused magnesia aggregate, ceramic sand aggregate, surface-coated magnesia fine powder, γ-phase alumina micropowder, aluminum dihydrogen phosphate solution, alkaline silica sol, pre-reacted spinel precursor, and zirconium boride micropowder. The coated modified fused magnesia aggregate is prepared by mixing fused magnesia, silicon carbide composite powder, chromium trioxide powder, and phenolic resin powder, followed by sintering. Silicon carbide powder and magnesia powder are mixed, and a silicon nitride layer is deposited on the particle surface to obtain silicon carbide composite powder. The surface-coated magnesia fine powder is magnesia fine powder with alumina coated on the particle surface. The pre-reacted spinel precursor is prepared by preparing a mixed salt solution of magnesium nitrate hexahydrate and aluminum nitrate nonahydrate with deionized water, reacting, aging, and heat-treating. The ceramic sand aggregate is made of zirconium oxide. The allocation and use of each layer achieves a balanced improvement in performance.

The invention relates to a solid catalyst system comprising a first chromium compound, a second chromium compound, a reaction product of an alkyl aluminium compound and a nitrogen containing compound and a silicon oxide support, wherein the first chromium compound is chromium trioxide or a compound convertible to chromium trioxide, the second chromium compound is a slilylchromate compound and the nitrogen containing compound is a cycloalkylamine compound having the general formula: R3—NH2, wherein R3 is selected from C3-C8 cycloalkyl groups.

The present application relates to the technical field of ceramic preparation, and specifically to an intelligent preparation method for an anti-corrosion ceramic, the method comprising: pouring deionized water into a stirred reactor, sequentially adding fluorozirconic acid, nitric acid, ethanol; chromium trioxide; zirconium nitrate and sodium fluoride; reducing agent; ammonium molybdate and complexing agent; silane coupling agent and stirring to obtain an anti-corrosion ceramic. The present application aims to analyze whether chromium trioxide has reacted completely based on the two aspects of color change and temperature change, and then adjust the amount of ethanol added, control the stirring time, ensure the conversion of hexavalent chromium to trivalent chromium, and enhance the corrosion resistance of the film layer.

This invention discloses a ceramic clay composition, ceramics, and their applications, relating to the field of ceramic technology. The ceramics of this invention are obtained by sequentially processing the ceramic clay composition through a process of material conditioning, sieving, casting, air drying, oven drying, and sintering. The introduction of specific proportions of ceramic waste A and B, modified particles with a gallium-coated cuprous oxide core and an alumina shell, and high-entropy oxide solid solutions generated from the reaction of hafnium dioxide, tantalum pentoxide, niobium pentoxide, titanium dioxide, zirconium dioxide, chromium trioxide, and carbon powder, as well as chromium heptacarbonide, into the ceramic clay composition gives the ceramics prepared from the ceramic waste excellent fracture toughness, flexural strength, wear resistance, high-temperature resistance, and self-healing ability. Therefore, this invention has broad application prospects.

The invention is applicable to the field of preparation of rare earth ceramic pigments, and provides a preparation method of a rare earth ceramic pigment for building wall surfaces, which comprises the following steps: S1, weighing industrial neodymium oxide and aluminum oxide in equal proportion, adding water, mixing and grinding to obtain slurry A; s2, weighing yttrium oxide and aluminum hydroxide in equal proportion, adding water and chromium sesquioxide, and mixing and grinding to obtain slurry B; s3, mixing the slurry A obtained in the step S1 and the slurry B obtained in the step S2 to obtain slurry C; and S4, the slurry C is poured into a drying cylinder to be dried, a stirring mechanism is arranged in the drying cylinder to stir and heat the slurry C, and a spiral conveying mechanism in the drying cylinder drives the slurry C to be vertically conveyed. The problems that in a traditional drying process, due to the fact that the conveying speed is not matched with the heating uniformity, the drying efficiency is low, and materials are heated unevenly are solved.

The invention relates to a thermosensitive material for ultrafine continuous thermocouples, wherein the weight percentage of each component is: 10-15% of aluminum oxide, 15-18% of ferric oxide, 15-18% of chromium oxide, 20-24% of manganese carbonate, 5-10% of cobalt oxide, and the balance is magnesium oxide. The thermosensitive material of the invention has high temperature measurement accuracy, a temperature measurement range between room temperature and 800°C, and a temperature measurement accuracy of ±5°C. The thermosensitive material of the invention can be used to prepare ultrafine continuous thermocouples, with a diameter between 0.5mm and 1.0mm and a minimum bending radius between 1mm and 10mm. The thermocouple can be used to measure the temperature of automotive lithium batteries, is more convenient to fit lithium batteries, can be wrapped around the surface of automotive lithium batteries for temperature measurement, and has no temperature measurement dead angle.

The invention discloses a high-entropy rare earth chromate negative temperature coefficient thermal sensitive ceramic material as well as a preparation method and application thereof, belongs to the field of high-temperature thermal sensitive sensors, and aims to solve the stability problem of chromium-based perovskite in high-temperature long-term use, especially the problem of electrical property reduction caused by Cr element volatilization. The thermal sensitive ceramic material with the negative temperature coefficient is prepared by the following steps: respectively mixing raw materials including lanthanum trioxide, neodymium oxide, samarium trioxide, europium oxide, gadolinium oxide and chromium sesquioxide with dysprosium oxide, holmium oxide, yttrium oxide and erbium oxide according to a stoichiometric ratio; and carrying out wet ball milling, drying, powder calcination, cold isostatic compaction and high-temperature sintering to obtain the perovskite structure (La1 / 6Nd1 / 6Sm1 / 6Eu1 / 6Gd1 / 6M1 / 6) CrO3 thermal sensitive ceramic material, and M is Dy, Ho, Y or Er. The electrical property parameters are as follows: B 25 DEG C / 1500 DEG C is equal to 1927-2011 K, rho 1500 DEG C is equal to 1.29 * 10 < 2 >-1.60 * 10 < 2 > omega.cm, and good high-temperature aging stability is shown at high temperature (the resistance drift rate after aging for 500 hours at 1500 DEG C is less than 4.6%).

The present application relates to the technical field of preparation of oxygen reference electrode materials, and in particular to a method for optimizing the preparation process of oxygen reference electrode materials. It includes: obtaining the mass m1 of polyvinyl alcohol to be added, the mass m2 of chromium trioxide, the mass m3 of ferric oxide, and the mass m4 of chromium powder; inputting m1 into a first preset model to obtain the stirring speed v1 and the stirring duration t1 of the mixed solution after the chelating dispersant is added; inputting m1, m2, and m3 into a second preset model to obtain the speed e1 of adding chromium trioxide and ferric oxide to the modified solution and the stirring speed v2 of the modified solution after adding chromium trioxide and ferric oxide; inputting m1, m2, m3, and m4 into a third preset model to obtain the speed of adding chromium powder to the dispersed solution and the stirring speed of the dispersed solution after adding chromium powder; preparing oxygen reference electrode materials according to the dispersed solution. The present invention can improve the performance of the prepared oxygen reference electrode material.

The application discloses a method for separating vanadium and chromium elements from vanadium slag, which comprises the following steps: (1) roasting the vanadium slag with sodium carbonate, mixing and roasting the vanadium slag and the sodium carbonate at a certain temperature to convert vanadium and chromium elements in different valence states in the vanadium slag into the highest valence state; (2) low-temperature leaching, leaching the roasting product obtained in the first step with calcium salt and water at low temperature to obtain a calcium chromate crude liquid and a calcium vanadate leaching residue; (3) acid leaching and vanadium precipitation, separating residual chromium in the calcium vanadate leaching residue to obtain a vanadium-containing filter cake; (4) preparing vanadium pentoxide, adding water to the filter cake obtained in the third step, adding NaOH and (NH4)2SO4 to adjust the pH, and then performing water bath heating to obtain polyvanadic acid ammonium precipitate, which is dried and calcined to obtain V2O5 powder; and (5) preparing chromium trioxide, adjusting the pH of the chromium solution obtained in the second step, adding Na2SO3, reducing Cr 6+ to Cr 3+ , combining Cr 3+ with OH ‑ to form Cr(OH)3 precipitate, filtering, and calcining to obtain Cr2O3.

The application relates to the field of acetonitrile preparation, and aims to solve the problems of complicated acetonitrile impurity removal process and energy consumption, and provides a production method of a catalyst for acetonitrile preparation, which comprises the following steps: S100, 25-45 parts of pseudo-boehmite, 10-15 parts of activated carbon, 5-7 parts of chromium trioxide and 2-8 parts of P123 are mixed, then aging is carried out at 30-55 DEG C for 3-8 h, granulation is carried out to obtain a preform, and the particle size of the preform is 50-80 nm; S200, the preform is sintered at 500-550 DEG C for 2-4 h and sintered at 1100-1200 DEG C for 6-8 h to obtain a carrier; S300, 100-150 parts of the carrier, 1-3 parts of a noble metal precursor, 12-18 parts of chitosan and 600-800 parts of deionized water are mixed to obtain a mixed solution, the mixed solution is heated to reflux at 100-130 DEG C for 5-8 h under stirring, and then evaporative drying is carried out at 115-135 DEG C for 0.5-2 h to obtain the catalyst. The catalyst provided by the application can effectively inhibit the occurrence of a side reaction, reduce the ammonia gas consumption, and also can utilize the hydrophilic property of the catalyst to make the removal of an impurity layer, such as a carbon deposition layer, on the surface of the catalyst more simple during catalyst regeneration.

The application relates to a preparation method of a chromium dioxide nanowire array, and belongs to the technical field of inorganic nonmetal material preparation. The steps comprise the following: filling a chromium trioxide aqueous solution into nanopores of a porous alumina template by a vacuum impregnation method; drying the chromium trioxide aqueous solution in the nanopores of the template by a vacuum drying method; placing the dried template into an autoclave, sealing the autoclave after high-pressure pure oxygen with a pressure of 10-15 Mpa is filled into the autoclave; and heating the autoclave to 390-400 DEG C for 30 minutes, so that the chromium dioxide nanowire array is obtained. The preparation process is simple and easy to operate, and long chromium dioxide nanowire arrays can be prepared in porous alumina templates with various pore diameters.

The application relates to the technical field of acid etching agents, and discloses a hydrofluoric acid acid etching agent and a preparation method thereof, wherein the hydrofluoric acid acid etching agent comprises the following components in parts by weight: 70-75 parts of hydrofluoric acid, 40-45 parts of carrageenan, 25-30 parts of a humectant, 35-40 parts of chromium trioxide and 125-130 parts of water. Through the technical scheme, the problems of easy oxidation, complex raw materials, complicated preparation process and low stability of the acid etching agent in the prior art are solved.