28 results about "Chromium sesquioxide" patented technology

The invention provides near-infrared adjustable double-perovskite type mechanoluminescence fluorescent powder as well as a preparation method and application of the near-infrared adjustable double-perovskite type mechanoluminescence fluorescent powder. The expression general formula of the double perovskite type mechanoluminescence fluorescent powder is Sr2M1-xSbO6: xCr < 3 + >, wherein M is Al, Ga, Sc, In or Y; x is equal to 1%-7%. The preparation process of the fluorescent powder comprises the following steps: a, weighing strontium carbonate, an oxide of M, antimony pentoxide and chromium sesquioxide according to the element proportion in the chemical general formula Sr2M1-xSbO6: xCr < 3 + >; b, mixing the weighed raw materials, and uniformly grinding to obtain a mixture; and c, carrying out high-temperature calcination on the obtained mixture to obtain the near-infrared adjustable double perovskite type mechanoluminescence fluorescent powder. By regulating and controlling the components of the substrate, the emission main peak can be adjusted from 780nm to 946nm. The fluorescent powder provided by the invention can show a self-recovery near-infrared stress luminescence characteristic without pre-irradiation under continuous stress stimulation, is simple to prepare and convenient for industrial batch production, and has a wide application prospect.

The invention relates to a method for preparing vanadium, chromium, aluminum and silicon products through gradient separation of vanadium shale. According to the technical scheme, silicon in the vanadium shale alkaline leaching solution is removed through a sulfuric acid precipitation method, and a desilicication solution and a siliceous precursor I are obtained; washing the siliceous precursor I with sulfuric acid, washing with water and calcining to obtain white carbon black; carrying out vanadium-chromium co-extraction on the desilicication liquid by adopting an amine extraction agent to obtain a vanadium-chromium organic phase; carrying out vanadium-aluminum extraction separation on the washing liquid by adopting an amine extraction agent to obtain a vanadium-rich organic phase and an aluminum-containing raffinate; the vanadium-rich organic phase and the vanadium-chromium organic phase are mixed, vanadium-chromium separation is achieved through step-by-step reverse extraction, and vanadium-rich liquid and chromium-rich liquid are obtained; adjusting the pH value of the aluminum-containing raffinate to precipitate aluminum hydroxide, and calcining to obtain aluminum oxide; carrying out ammonium salt vanadium precipitation on the vanadium-rich liquid to obtain ammonium polyvanadate, and calcining to obtain vanadium pentoxide; and reducing the chromium-rich liquid, adjusting the pH value, precipitating chromium hydroxide, and calcining to obtain chromium sesquioxide. The method is high in leaching rate, small in slag amount, high in product purity and high in recovery rate.

The invention relates to the field of refractory materials, in particular to a high-erosion-resistance refractory material based on boron nitride modification and a preparation method of the high-erosion-resistance refractory material. The problem that an existing refractory material is poor in erosion resistance is solved. The refractory material is prepared by taking zirconium dioxide, silicon dioxide, calcium oxide, ferric oxide and aluminum oxide as matrixes and adding samarium lanthanum magnesium aluminum composite gel powder and boron nitride loaded chromium sesquioxide, magnesium nitrate, aluminum nitrate, samarium nitrate, lanthanum nitrate and citric acid form gel, high-temperature treatment is performed to obtain the samarium lanthanum magnesium aluminum composite gel powder, and the samarium lanthanum magnesium aluminum composite gel powder is added to the boron nitride loaded chromium sesquioxide. Boron nitride is loaded with chromium sesquioxide after being treated by tannic acid, the corrosion resistance of the material is enhanced through the synergistic effect of all the components, and the material is suitable for high-temperature furnaces, high-temperature reactors and other industrial environments needing high-temperature resistance and high corrosion resistance.

The invention discloses a petuntse composition, ceramic and application, and relates to the technical field of ceramic. The ceramic disclosed by the invention is obtained by sequentially carrying out ageing treatment, sieving treatment, injection molding, airing, drying and sintering treatment on a petuntse composition. The petuntse composition comprises a ceramic waste material A, a ceramic waste material B and modified particles with gallium-coated cuprous oxide as a core and aluminum oxide as a shell in a specific proportion. And the components such as a high-entropy oxide solid solution generated by the reaction of hafnium oxide, tantalum pentoxide, niobium pentoxide, titanium dioxide, zirconium dioxide, chromium sesquioxide and carbon powder, and chromium heptacarbide are introduced, so that the ceramic prepared from the ceramic waste has excellent fracture toughness, bending strength, wear resistance, high temperature resistance and self-repairing ability. Therefore, the method has a wide application prospect.

The invention relates to the field of fused zirconia corundum bricks, and discloses a production method for regulating and controlling internal stress of fused zirconia corundum bricks, which comprises the following steps: preparing raw materials; melting in an electric furnace: putting the prepared raw materials into the electric furnace for melting; ventilating in stages in the melting process; preparing a mold for casting; after casting is completed, demolding and annealing are conducted; the raw materials comprise the following components in parts by weight: 50-65 parts of aluminum oxide; 25 to 35 parts of zirconium oxide; 8 to 12 parts of silicon dioxide; 0.5 to 2 parts of chromium sesquioxide; 0.5 to 1.5 parts of magnesium oxide; and 3-5 parts of scandium oxide. By adding scandium oxide and utilizing the characteristic that scandium oxide stabilizes a tetragonal phase, high-temperature phase change of zirconium oxide is effectively inhibited, and stress is reduced. Meanwhile, scandium oxide is used for refining grains, enhancing the grain boundary strength and reducing high-temperature stress concentration, so that the high-temperature stability of the fused zirconia corundum brick is improved, brittle fracture is avoided, and the thermal stability and durability are enhanced.

The invention belongs to the technical field of solid waste recycling and wastewater treatment, and particularly relates to a method for treating chromium-containing wastewater by adopting organic amine flue gas desulfurization residues. According to the method, the organic amine flue gas desulfurization slag is adopted as a reducing agent, hexavalent chromium is reduced into trivalent chromium, the trivalent chromium is separated from water in a precipitate form, and the precipitate is roasted to obtain chromium sesquioxide powder with relatively high purity in supernate; hexavalent chromium and total chromium can reach the national standard. According to the method, the treatment cost of the hexavalent chromium wastewater and the flue gas desulfurization slag is remarkably reduced, and meanwhile, the resource utilization of the flue gas desulfurization waste in a waste-to-waste manner is also realized.

The invention belongs to the technical field of plastic waste treatment, and particularly relates to a degradation and recovery method of a polyester material. The degradation and recovery method of the polyester material provided by the invention comprises the following steps: mixing the polyester material, a catalyst and a hydrogen donor, and then carrying out ball milling to obtain dimethyl terephthalate; the catalyst comprises copper chromite or chromium sesquioxide; the hydrogen supply reagent is methanol. According to the invention, copper chromite or chromium sesquioxide is taken as a catalyst, methanol is taken as a hydrogen donor, molecular chains can be activated, molecular chain breakage and strong mixing of reactants can be promoted under the action of mechanical force of ball milling, and the activation energy of reaction can be reduced due to good catalytic performance of the catalyst, so that efficient degradation of the polyester material under mild conditions is promoted. The degradation and recovery method provided by the invention does not need additional heating, is simple in process and low in energy consumption, can highly selectively degrade the polyester material into dimethyl terephthalate, and has remarkable high efficiency and economical efficiency.

The invention discloses a preparation method of a double perovskite oxide Sr2CrReO6 with high purity. According to the method, strontium carbonate and rhenium heptoxide are taken as raw materials and are subjected to high-temperature reaction under the protection of argon to synthesize an intermediate product; then mixing with chromium sesquioxide and elemental chromium powder, and carrying out high-temperature reaction under a vacuum tube sealing condition to obtain a crude product; and finally, carrying out heat treatment for multiple times in an inert atmosphere, and removing an impurity phase to obtain high-purity Sr2CrReO6 powder. By optimizing the temperature and time of the high-temperature reaction and introducing the heat treatment step, the impurity content is remarkably reduced, and the product purity is improved. According to the compact ceramic prepared from the high-purity powder through a spark plasma sintering technology, the antisite defect is 13.5%, the Curie temperature reaches 610 K, and the saturation magnetization is 0.84 microB / f.u. The method is easy and convenient to operate, low in equipment requirement, high in safety and suitable for laboratory-scale high-quality material preparation.

The invention relates to the field of electronic materials, and particularly discloses a low-gradient zinc oxide varistor and a preparation method thereof. The invention relates to a low-gradient zinc oxide piezoresistor disc, which is prepared from the following raw materials in parts by weight: 88 to 96 parts of zinc oxide, 1.5 to 3 parts of antimony trioxide, 2 to 5 parts of bismuth trioxide, 0.2 to 1.8 parts of nickel oxide, 0.1 to 0.9 part of cobalt sesquioxide, 0.1 to 0.4 part of manganese oxide, 0.02 to 0.07 part of chromium sesquioxide, 0.15 to 0.18 part of lithium acetate, 1.2 to 1.8 parts of dispersing agents, 1.8 to 2.5 parts of binding agents, 0.12 to 0.15 part of aluminum nitrate and 0.001 to 0.003 part of silver nitrate. Under the synergistic effect of all the components, by adjusting the use ratio of all the components, the potential gradient of the resistor disc can be reduced, the large-current endurance capacity of the resistor disc is improved, and the change of electrical performance after impact is reduced.

The invention discloses a method for preparing a sodium sulfate solution and chromic oxide of different grades from chromium-containing sodium hydrogen sulfate, which comprises the following steps: calcining the chromium-containing sodium hydrogen sulfate at high temperature to obtain a solid product and a gas product; putting the solid product into a pulping tank, adding water, pulping and dissolving until the solid product is completely dispersed, preparing a feed liquid, and carrying out filter pressing to obtain a primary filter-pressed filter cake and an acidic solution; adding alkali into the acidic solution for neutralization, preserving heat and curing, and then carrying out filter pressing to obtain a secondary filter-pressed filter cake and a slightly acidic solution; washing and filter-pressing the primary filter-pressed filter cake, and calcining to obtain low-grade chromium sesquioxide; and washing the secondary filter-pressed filter cake, carrying out filter pressing, and calcining to obtain the high-grade chromium sesquioxide. The invention provides the method for efficiently recycling the by-product chromium-containing sodium hydrogen sulfate in the production process of chromic anhydride, the problem of poison of wastes is solved, the process is simple and easy to operate, environmental protection benefits and economic benefits are considered, and the method is suitable for industrial production.

The invention belongs to the technical field of welding materials and laser welding processes, particularly discloses a SiC / Al-based composite material laser welding method based on active agent micro-filling and preset titanium foil assistance, and further provides a welding active agent which comprises the following components in percentage by mass: 1%-10% of titanium dioxide, 1%-10% of aluminum oxide, 1%-10% of aluminum oxide, 1%-10% of aluminum oxide and the balance of aluminum oxide. 5%-15% of cerium oxide; 26%-36% of sodium hexafluoroaluminate; 16%-26% of chromium sesquioxide; and 23%-55% of spherical silicon powder. And a better welding effect can be obtained when the welding rod is matched with a micro-filling material titanium foil for use. According to the method, the aluminum-based composite material and the base material are preset at the weld joint, the weldability of the aluminum-based composite material can be effectively improved, the required laser heat input is reduced, the tensile strength of the obtained joint reaches 54.4% of that of the base material, the process steps are simplified, the requirements for equipment and base material pretreatment are reduced, and the method has remarkable industrial application value.

The invention provides high-temperature reduction flame iron body porcelain and a preparation method thereof, and the iron body porcelain is prepared from the following chemical components in percentage by mass: 66.8 to 72.6 percent of silicon dioxide, 15.5 to 21.7 percent of aluminum oxide, 1.77 to 7.82 percent of total iron, 1.04 to 2.59 percent of magnesium oxide, 0.04 to 1.67 percent of calcium oxide, 0.06 to 0.1 percent of sodium oxide, 1.28 to 3.58 percent of potassium oxide, 0.1 to 0.85 percent of titanium dioxide, 0.02 to 0.03 percent of manganese oxide, 0.02 to 0.15 percent of scale pentoxide and barium oxide. 0.02% of chromium sesquioxide, and 1t of chromium sesquioxide; 0.006%, the content of nickel is 1t; the aluminum alloy comprises the following components in percentage by weight: 0.002% of aluminum, 0.002%-0.003% of copper, 0.006%-0.008% of strontium and 0.02% of zirconium, and the ignition loss is 4.05%-8.42%. According to the high-temperature reduction flame iron body porcelain and the preparation method thereof, the chemical composition is accurately controlled, so that the high-temperature reduction flame iron body porcelain has good physical and chemical properties, and meanwhile, a porcelain body is endowed with relatively high hardness and heat resistance; due to the proper iron content, the porcelain body has unique color and luster, the strength of the porcelain body is enhanced, and the problems of cracking, deformation and the like are effectively reduced.

The invention discloses an Nb-Cr-Al ternary intermediate alloy and a preparation and application method thereof. The Nb-Cr-Al ternary intermediate alloy is prepared by taking aluminum as a reducing agent, niobium pentoxide and chromium sesquioxide as oxidants, calcium fluoride as a slag former and potassium chlorate as a heat generating agent through smelting by adopting a metallothermic reduction method; the Nb-Cr-Al ternary intermediate alloy is evenly mixed with sponge titanium, aluminum shots and Cr70Al alloy in proportion and pressed into an electrode block, then a plasma beam welding box is used for welding the electrode block, a primary electrode is manufactured, vacuum consumable electric arc melting is conducted through a vacuum consumable electric arc furnace, Ti-Al-Nb-Cr alloy is obtained, and the Ti-Al-Nb-Cr alloy is obtained. The high-melting-point Nb-Al intermetallic compound is effectively prevented from appearing in the cast ingot, the uniformity of chemical components of the cast ingot is guaranteed, the stability of the structure and performance of the alloy is guaranteed, and the metallurgical quality and the yield of the cast ingot are effectively improved.

The invention belongs to the technical field of solid waste recycling and wastewater treatment, and particularly relates to a method for combined treatment of organic amine flue gas desulfurization residues and chromium-containing wastewater. According to the method, organic amine flue gas desulfurization residues are used as a reducing agent, phosphoric acid is used for controlling the pH value of wastewater, hexavalent chromium is reduced into trivalent chromium under the acidic condition, meanwhile, desulfurization ash is converted into a melamine phosphate flame-retardant material, and trivalent chromium is separated from water in a precipitation form under the neutral condition; and roasting the precipitate to obtain chromium sesquioxide powder with relatively high purity, and separating and recovering excessive phosphate radicals from the wastewater in the form of calcium phosphate. While the flue gas desulfurization slag and the chromium-containing wastewater are treated, melamine phosphate, chromium trioxide and calcium phosphate byproducts can be recovered, the treatment cost of the wastewater and solid wastes is reduced, and cyclic utilization of resources is realized.

The present invention discloses an antibacterial and antiviral ceramic glaze and a method for preparing a ceramic product, belonging to the technical field of ceramics. The antibacterial and antiviral ceramic glaze comprises the following components: silicon oxide, aluminum oxide, iron oxide, magnesium oxide, potassium oxide, sodium oxide, titanium oxide, manganese oxide, phosphorus pentoxide, sulfur trioxide, barium oxide, zinc oxide, cobalt tetroxide, nickel oxide, chromium sesquioxide and lithium oxide. The prepared antibacterial and antiviral ceramic product has excellent antibacterial and antiviral properties and excellent glaze strength.

The present application relates to the technical field of firebrick, in particular to a kind of chrome-zirconia corundum composite brick for waste incinerator grate furnace, the composite brick includes the following components by weight parts: white corundum powder 60-75 parts, chromium sesquioxide 7-14 parts, zirconia-silicon carbide composite powder 12-20 parts, magnesium oxide 2-5 parts, kaolin 3-6 parts, binder 1-4 parts;The zirconia-silicon carbide composite powder is made from the following raw materials by weight parts: tetraethyl orthosilicate 0.8-2 parts, anhydrous ethanol 2.5-6 parts, nano zirconia 0.8-1.5 parts, sucrose 2-3 parts, trimethoxysilane 0.4-1 part, deionized water 5.5-6.5 parts.The composite brick of the present application has high density, few internal defects, excellent refractory performance, small deformation under high temperature environment, excellent corrosion resistance, and the damage of incineration slag to the composite brick is small, which can effectively reduce the occurrence of fracture phenomenon and improve the service life of incinerator.

The application discloses a phosphoric acid-containing graphene oxide modified high-temperature anticorrosion ceramic coating material and a high-temperature anticorrosion ceramic coating and belongs to the technical field of high-temperature ceramic coating. The coating material preparation raw material comprises a high-temperature anticorrosion ceramic masterbatch and a phosphoric acid-containing graphene oxide dispersion solution, and the masterbatch components are as follows: 20-30% of silicate adhesive; 10-20% of nano-aluminum nitride; 5-10% of boron nitride; 1-5% of talcum powder; 5-10% of zirconium boride; 10-25% of chromium sesquioxide; 10-20% of aluminum oxide; 1-5% of cerium oxide; and the balance of water. The phosphoric acid-containing graphene oxide dispersion solution is directly applied to the high-temperature ceramic coating material, on the one hand, the problem of utilization of wastewater containing phosphoric acid prepared by a chemical method is solved, and on the other hand, the graphene oxide is used as a hydrophilic two-dimensional network structure to improve the properties of the coating, such as high-temperature resistance, oxidation resistance, high strength, high-temperature gas erosion resistance and the like, in cooperation with the high-temperature anticorrosion ceramic masterbatch.

The invention discloses a method for preparing a chromic oxide and sodium sulfate solution from chromium-containing sodium hydrogen sulfate, which comprises the following steps: preparing chromium-containing sodium hydrogen sulfate into a sheet by a sheet preparation machine, and calcining to obtain a calcined product; adding the calcined product into water to prepare a feed liquid, then adding sodium hydroxide for neutralization to prepare a mixed solution of chromic hydroxide and sodium sulfate, carrying out heat preservation and curing, then carrying out filter pressing to obtain a filter cake, then washing and carrying out filter pressing on the filter cake to obtain a chromic hydroxide filter cake, and carrying out filter pressing to obtain a filtrate which is a sodium sulfate solution; and calcining the chromium hydroxide filter cake to obtain chromium sesquioxide. According to the resource utilization method for the by-product chromium-containing sodium hydrogen sulfate in the chromic anhydride production process, the chromium-containing sodium hydrogen sulfate is converted into chromium sesquioxide and sodium sulfate solutions with high additional values, the problem of poison of waste is solved, and efficient recycling of chromium and sodium hydrogen sulfate is achieved; in addition, the method is simple in process, low in cost and suitable for industrial production.

The invention relates to the field of metallurgy, and provides a vanadium-chromium precursor alloy for hydrogen storage and a preparation method thereof.The method comprises the steps that vanadium pentoxide, chromium sesquioxide, aluminum particles and a slag former are mixed to obtain a mixed furnace burden; the mixed furnace burden is put into a furnace body to be smelted in advance, ignition smelting and electrified refining are carried out, and an alloy cake is obtained; and putting the alloy cake into a water tank for water quenching, soaking for a preset time, and then crushing and screening to obtain the vanadium-chromium precursor alloy. According to the method, the aluminothermic reduction formula and process are deeply optimized, and the high-quality vanadium-chromium alloy is directly prepared from the oxide. The oxygen content and the impurity level in the alloy can be effectively reduced, the alloy purity is remarkably improved, accurate regulation and control of vanadium and chromium components can be achieved, the subsequent hydrogen storage alloy synthesis requirement is met, rich slag generated after refining can be returned to the technological process to be reused, the resource utilization rate is greatly increased, and the production cost is reduced.

The present application belongs to the technical field of ceramic surface treatment, and particularly relates to a ceramic surface protective agent and a preparation method and use method thereof. The ceramic surface protective agent comprises, in parts by weight, 79-92 parts of a condensate, 2-5 parts of an intermediate, 1-3 parts of an emulsifier, 3-8 parts of a zirconium sol, 0.5-2 parts of a nano filler, and 1-3 parts of a hardening agent. The condensate is solid paraffin, the intermediate is glycerol or 1,2-propanediol, the nano filler is a mixture of one or more of zirconium oxide, yttrium sesquioxide and chromium sesquioxide, and the hardening agent is polyethylene wax. The present application aims to develop a new type of ceramic protective agent and a preparation method and use method thereof, greatly improve the corrosion resistance of ceramic plates, and simultaneously have excellent antifouling performance.

The invention relates to the technical field of preparation of high-purity chromium metal, in particular to a preparation method of high-purity chromium metal. The method comprises the following steps: (1) preparing a chromium trichloride solution; (2) purification: purifying the prepared chromium trichloride solution by an ion exchange method; (3) performing spray pyrolysis to prepare chromium sesquioxide; (4) gas-solid separation; and (5) chromium sesquioxide is reduced to prepare high-purity metal chromium. The method comprises the following steps: preparing a chromium trichloride solution by using metal chromium of 3N5, purifying the chromium trichloride solution by using an ion exchange method to remove heavy metal impurities in the chromium trichloride solution, and performing spray pyrolysis on the purified chromium trichloride solution to prepare high-purity chromium sesquioxide powder. Metal and interstitial element impurities such as oxygen, nitrogen and the like and low-melting-point metal impurities in the chromium sesquioxide are removed through a reduction method, and the purity of the prepared high-purity metal chromium reaches 99.999% or above. The preparation method is simple in process and few in control parameters, and the prepared chromium metal is high in purity.

The present invention relates to the application of a Cr₂O₃ - modified CoOx catalyst in direct electrolysis of natural seawater for hydrogen production. The Cr₂O₃ - modified CoOx catalyst grows on a titanium felt substrate, and the loading and area of the cathode and anode are the same. The loading is 2.0 - 6.0 mg cm⁻², and the catalyst area is 4 - 12 cm². The titanium felt loaded with the cathode and anode catalysts and the Nafion 115 / 117 proton membrane are heat - pressed to obtain a membrane electrode. The heat - pressing temperature is 90 - 120 °C, the heat - pressing pressure is 4 - 8 MPa, and the heat - pressing time is 0.5 - 1.5 min. By using the Cr₂O₃ - modified CoOx catalyst in the present invention, hydroxide ions can be preferentially enriched around the anode and chloride ions can be excluded, effectively avoiding harmful chlorine chemical reactions. The present invention uses natural seawater without pretreatment and without adding strong base, greatly reducing the production cost and simplifying the production process.

The application provides an antioxidant low-abrasion heat-resistant steam turbine blade coating and a preparation method thereof, and relates to the technical field of material surface treatment, and comprises the following components in mass ratio: nickel-cobalt-chromium-aluminum-yttrium alloy 20-30 parts, zirconia-yttria-alumina composite ceramic 30-40 parts, hafnium powder and rhenium powder mixture 10-15 parts, chromium sesquioxide 5-10 parts, rare earth oxide 3-5 parts, cerium dioxide 2-4 parts, silicon dioxide 3-5 parts, titanium carbide 5-8 parts, and zirconium boride 2-4 parts; the nickel-cobalt-chromium-aluminum-yttrium alloy and the zirconia-yttria-alumina composite ceramic are used in the application, a stable oxide film can be formed at high temperature, the further diffusion of oxygen is effectively prevented, the rare earth oxide and the cerium dioxide can promote the repair and stability of the oxide film, the antioxidant capacity of the coating is improved, and the blade can maintain good performance in a high-temperature environment for a long time.

The invention provides an antioxidant low-wear heat-resistant turbine blade coating and a preparation method thereof, and relates to the technical field of material surface treatment. Comprising the following components in parts by mass: 20-30 parts of nickel-cobalt-chromium-aluminum-yttrium alloy, 30-40 parts of zirconium oxide-yttrium oxide-aluminum oxide composite ceramic, 10-15 parts of hafnium powder and rhenium powder mixture, 5-10 parts of chromium sesquioxide, 3-5 parts of rare earth oxide, 2-4 parts of cerium dioxide, 3-5 parts of silicon dioxide, 5-8 parts of titanium carbide and 2-4 parts of zirconium boride. The nickel-cobalt-chromium-aluminum-yttrium alloy and the zirconium oxide-yttrium oxide-aluminum oxide composite ceramic are adopted, a stable oxidation film can be formed at a high temperature, further diffusion of oxygen is effectively prevented, rare earth oxide and cerium dioxide can promote repair and stability of the oxidation film, the oxidation resistance of the coating is improved, and the service life of the coating is prolonged. And the blade can keep good performance for a long time in a high-temperature environment.

The invention provides a method for preparing chromium sesquioxide powder by taking chromium-containing wastewater as a raw material, and belongs to the field of sewage treatment. The method for preparing the chromium sesquioxide powder by taking the chromium-containing wastewater as the raw material comprises the following steps: mixing the chromium-containing wastewater and a pH regulator, carrying out precipitation reaction, and then carrying out solid-liquid separation to obtain a dichromate solution; the pH value of the precipitation reaction is 2-4; after the dichromate solution flows through weak base anion resin to be treated, hexavalent chromium adsorption saturated resin is obtained; ammonia water is adopted to analyze the hexavalent chromium adsorption saturated resin, and a mixed solution is obtained; the mixed solution is a mixed solution of ammonium chromate and ammonium dichromate; the mixed solution is sequentially subjected to evaporation concentration, spray drying and calcination, and chromium sesquioxide powder is obtained. The method provided by the invention is simple in preparation steps, the obtained chromium sesquioxide powder is uniform in particle size, the purity can reach 99.6%, and the purity requirement of pigment-grade chromium sesquioxide is met.

The invention discloses a preparation method of a nickel-chromium intermediate alloy for a nickel-based superalloy, which comprises the following steps of: 1, mixing chromium sesquioxide powder, carbon powder, nickel protoxide powder and a dispersing agent, wrapping by adopting a plurality of layers of nickel foils, and pressing in a mold to obtain a carbon thermal reduction reaction block; step 2, melting an electrolytic nickel plate under a vacuum condition to obtain a nickel melt, carrying out carbon thermal reduction on the carbon thermal reduction reaction block in an inert atmosphere, then mixing the nickel melt with the carbon thermal reduction reaction block subjected to carbon thermal reduction, and carrying out alloy smelting; 3, cooling after casting to obtain a nickel-chromium intermediate alloy; the invention further discloses a preparation device of the nickel-chromium intermediate alloy for the nickel-based high-temperature alloy. According to the preparation method, chromium sesquioxide serves as the raw material, the carbon thermal reduction and alloy smelting coupling technology is adopted, impurities in the alloy melt are removed on the basis that the chromium reduction rate is guaranteed, the purity of the nickel-chromium intermediate alloy is effectively improved, and the preparation method is suitable for the technical field of intermediate alloy preparation.

The invention belongs to the technical field of high-temperature alloys, and particularly relates to a nickel-chromium intermediate alloy and a preparation method and application thereof. The preparation method of the nickel-chromium intermediate alloy provided by the invention comprises the following steps: mixing chromium sesquioxide, first oleic acid and a first dispersing agent, and carrying out first coating to obtain modified chromium sesquioxide; mixing nickel protoxide, second oleic acid and a second dispersing agent, and performing second coating to obtain modified nickel protoxide; mixing the modified chromium sesquioxide, the modified nickel protoxide, aluminum, a cooling agent, a grain boundary purifying agent and a slag former to obtain a mixed material; the mixed material is subjected to an aluminothermic reduction reaction and then subjected to induction melting and casting, and a nickel-chromium intermediate alloy is obtained; the aluminothermic reduction reaction is carried out in a protective atmosphere, and the induction melting is carried out in a hydrogen atmosphere. The nickel-chromium intermediate alloy prepared according to the preparation method provided by the invention is relatively low in impurity content and relatively low in burning loss rate.

The invention relates to the technical field of high-performance special ceramics, in particular to a low-thermal-conductivity chromium niobate ceramic and a preparation method thereof. The molecular formula of the chromium niobate is CrNbO4, and the chromium niobate is prepared from the following raw materials in parts by mole: 1.00 to 1.05 parts of chromium sesquioxide and 0.98 to 1.00 parts of niobium pentoxide. The preparation method comprises the following steps: mixing raw materials under the condition of ethanol and zirconium oxide ball-milling beads to obtain uniformly mixed slurry; filtering, drying and sieving the slurry to obtain mixed powder; calcining and sintering the mixed powder to obtain the chromium niobate ceramic. Through analysis, the chromium niobate ceramic has the characteristics of high relative density, high bending strength, high hardness and low heat conductivity, the relative density is 95% or above, the melting point is not lower than 1750 DEG C, the bending strength is 180 MPa or above, the hardness is 10 GPa or above, and the room-temperature heat conductivity is 1.2 W.m <-1 >. K <-1 > or below. The preparation method of the low-thermal-conductivity chromium niobate ceramic material has the advantages of simple and convenient process, easiness in large-scale production, high practicability and the like, and has a wide application prospect.