466 results about "Chromium oxide" patented technology

The invention relates to a modified chrome corundum ramming material and a preparation and construction process thereof, and belongs to the technical field of chrome corundum ramming materials. The ramming material comprises a material A, a material B and a material C, wherein the material A comprises chrome corundum aggregate, titanium dioxide coated aluminum oxide microspheres, calcium sulfide dehydrate and silicon carbide porous microspheres; the material B comprises chromium oxide-zirconium oxide composite nano powder, sodium thiosulfate pentahydrate, tricalcium phosphate and hexagonal boron nitride flaky crystals; and the material C comprises an aluminum dihydrogen phosphate-magnesium hydroxide compound, a calcium fluoride-aluminum oxide co-melt and a silane coupling agent. The preparation process comprises the steps of pretreatment of all the components, preparation of composite powder and layered preparation. The construction process comprises the steps of pretreatment, wet-process mixing, layered ramming, negative-pressure permeation, medium-temperature reaction, spraying curing, integral firing and the like. Generation of hexavalent chromium can be effectively inhibited, the thermal shock resistance, the mechanical strength and the heat-conducting property of the material are remarkably improved, and the material has the advantages of being good in environment friendliness, long in service life, excellent in construction performance and the like.

The invention provides a method for preparing an iron-chromium electrolyte and electronic-grade ferrous chloride by using a stainless steel waste liquid. The method comprises the following steps: firstly, adding elemental iron and / or elemental chromium into the stainless steel waste liquid to obtain a chromium-containing ferrous chloride solution; then, sulfide is added, and nickel is removed; adding iron powder to increase the pH value to obtain chromium hydroxide precipitate and a ferrous chloride solution; dissolving chromic hydroxide in hydrochloric acid to obtain a chromic chloride solution; purifying the ferrous chloride solution to obtain an electronic-grade ferrous chloride crystal; and finally, adding a chromium chloride solution, the electronic-grade ferrous chloride crystal and hydrochloric acid according to a certain proportion, and stirring and mixing to obtain the iron-chromium electrolyte. The ferrous chloride prepared by the steps is relatively high in purity and less in waste; meanwhile, the prepared electrolyte is good in electrical property, low in attenuation rate and low in cost, the purpose of comprehensive recycling of resources is achieved, and the general trend of technical improvement is met.

The invention discloses wear-resistant ceramic glaze water and a method for preparing a ceramic product, and relates to the technical field of ceramic products. The problems that in the prior art, mixing is not uniform, abrasion resistance is insufficient, adhesive force is poor, and production cost is high are solved. The prepared glaze water can form a compact and uniform glaze layer structure through reasonable proportioning of aluminum oxide, zirconium oxide and nano silicon dioxide, so that a ceramic product shows excellent wear resistance, the wear resistance coefficient of the ceramic product reaches 0.8 or above, and titanium oxide, chromic oxide and boric oxide are added, so that the high-temperature stability of a glaze layer is enhanced, and the service life of the ceramic product is prolonged. According to the invention, the glaze layer is not cracked, does not fall off and does not change color in complex environments such as high temperature, acid-base, impact and the like, the quality and appearance effect of the finished product are remarkably improved by matching with a segmented firing process, the performance of the ceramic product is improved, the stability and operability of production are also ensured, and the production cost is reduced. Wide application prospects are realized.

The invention relates to the field of refractory materials, in particular to a dry ramming mass for an intermediate frequency furnace and a preparation method thereof.The dry ramming mass is prepared from, by weight, 45-55 parts of fused corundum, 8-12 parts of fused magnesia, 15-20 parts of tabular corundum, 3-5 parts of fused spinel, 3-4 parts of activated aluminum oxide, 1-2 parts of silicon carbide, 1-2 parts of silica sol and 0.5-1 part of boric acid. 3.5-4.5 parts of a binding agent and 3-5 parts of an anti-penetrating agent; wherein the anti-penetrating agent is chromium oxide coated nickel aluminate microspheres. The invention solves the two major problems of easy penetration and thermal shock peeling of the traditional furnace lining, is especially suitable for harsh smelting environments of high manganese steel, stainless steel and the like, and has long service life and convenience in construction.

The invention relates to the technical field of alloy processing, and discloses a high-performance corrosion-resistant nickel-based alloy plate and a preparation method thereof, and the method comprises the following steps: raw material preparation, smelting treatment, casting treatment, hot rolling treatment, solution treatment, aging treatment and surface passivation treatment. According to the invention, when a composite acid system is adopted for passivation treatment, the concentration of chromium / molybdenum atoms in a passivation film is optimized and balanced due to the specific ratio of nitric acid to chromic acid, a chromium oxide provides a compact passivation barrier, and a molybdenum oxide endows the film layer with a self-repairing characteristic to synergistically inhibit pitting nucleation; meanwhile, nano titanium dioxide particles pretreated by silane are embedded into the passivation film in situ under the action of ultrasonic oscillation, organic pollutants adsorbed on a film layer can be decomposed by the photocatalytic characteristic of the nano titanium dioxide particles, the local corrosion effect of a battery caused by dirt coverage is avoided, and the performance of the battery is improved through double upgrading of components and the structure of the passivation film. And the alloy plate has excellent pitting corrosion resistance and fouling resistance in a chloride ion-containing medium.

The present invention relates to a preparation method of a self-propagating anti-corrosion and wear-resistant coating for a boiler water wall, belonging to the technical field of high-temperature protective coatings. The preparation steps are as follows: (1) Aluminum powder, iron(III) oxide powder, chromium oxide powder, zirconia fine powder, alumina fiber, heat-conducting filler and flux are ball-milled and mixed to obtain a mixed powder; (2) The mixed powder and sodium silicate binder are mixed evenly to obtain a suspension slurry; (3) The surface of the boiler water wall is treated by sandblasting; (4) A precoating is made on the surface of the boiler water wall; (5) A sodium silicate layer is made on the precoating; (6) A magnesium strip is ignited to initiate a self-propagating reaction to obtain a protective layer; (7) The protective layer is removed to obtain a self-propagating anti-corrosion and wear-resistant coating on the surface of the boiler water wall. The sodium silicate used as the binder obtains a dense self-propagating anti-corrosion and wear-resistant coating, and the self-propagating anti-corrosion and wear-resistant coating has good thermal conductivity, uniform thickness, excellent mechanical wear resistance and good corrosion resistance.

An optical component includes a substrate and an anti-reflective film. The substrate has an aspherical surface through which light passes. The anti-reflective film is disposed at least on the aspherical surface and includes a nanostructure layer and an intermediate layer. The nanostructure layer includes ridge-like protrusions that are non-directionally extended. A bottom of the ridge-like protrusions is closer to the substrate than a top of the ridge-like protrusions. The ridge-like protrusions gradually taper from the bottom toward the top. An average structural height of the ridge-like protrusions ranges from 108 to 368 nm. The intermediate layer is between the nanostructure layer and the substrate. A main component of the nanostructure layer is aluminum oxide. The nanostructure layer includes a metallic doping agent at least partially distributed inside the ridge-like protrusions. The metallic doping agent includes at least one of titanium, vanadium, chromium, titanium oxide, vanadium oxide, and chromium oxide.

Provided is a surface-treated steel sheet that can be produced without the use of hexavalent chromium and that combines excellent film corrosion resistance, coating corrosion resistance, film wet adhesion, coating secondary adhesion, and weldability. At least one side of the surface-treated steel sheet includes a Ni-containing layer, a metallic Cr layer on the Ni-containing layer, and an oxidized Cr layer on the metallic Cr layer. The water contact angle is 50° or less, and the total atomic ratio to Cr of K, Na, Mg, and Ca adsorbed on the surface is 5.0% or less.

The invention provides a piston rod with a self-lubricating coating and a preparation method of the piston rod. The piston rod comprises a substrate and a chromic oxide layer which are arranged in a stacked mode. The chromic oxide layer comprises a chromic oxide inner layer and a chromic oxide film layer which are arranged in a stacked mode, the chromic oxide inner layer is located in the direction close to the substrate, and the density of the chromic oxide film layer is higher than that of the chromic oxide inner layer; the surface of the chromium oxide layer is provided with at least one pit, and each pit is filled with lubricating filler. According to the piston rod with the self-lubricating coating, the compact chromium oxide film layer has high corrosion resistance and abrasion resistance and can effectively block and isolate grease with corrosion property from immersing, and therefore it is guaranteed that the bonding strength of the chromium oxide layer and a substrate is not affected by corrosion factors; in addition, at least one pit is formed in the surface of the chromium oxide layer, the lubricating filler can be filled in the pit, a good lubricating effect is achieved, and therefore the lubricating performance of the piston rod is further improved.

The invention relates to the technical field of water-based propylene ink, and discloses high-stability water-based propylene ink and a preparation method thereof.The high-stability water-based propylene ink is prepared from, by mass, 30-35 parts of pigment, 10-15 parts of modified dispersing agent, 2-5 parts of modified nano chromic oxide, 1-2 parts of resin, 0.5-1 part of anti-settling agent and 40-50 parts of solvent. Acrylic resin formed by modified cellulose, acrylic acid and itaconic acid serves as a dispersing agent of the water-based propylene ink, the motion resistance of pigment sinking can be increased, the pigment sinking phenomenon is further prevented, and the stability of the water-based propylene ink is remarkably improved; the side chain of the acrylic resin can be adsorbed into the cavity structure of carboxymethyl-beta-cyclodextrin in the modified cellulose, so that the stability of the acrylic resin in the water-based propylene ink can be further enhanced, and the effect of preventing the pigment from settling can be better exerted; tannic acid in the modified nano chromic oxide contains a large number of hydrophobic benzene rings, so that the water resistance of the water-based propylene ink can be enhanced.

The application discloses a kind of high-performance coiled material powder coating and preparation method thereof, belong to powder coating technical field, the application is by the compounding of organosilicon modified epoxy resin and carboxyl-terminated polyester resin, after organosilicon modification, the segment of introduction-Si-O-Si in system has high flexibility, and synergistic effect with nano calcium carbonate, it is helpful to balance the adhesion and flexibility of coating, grafting modification graphene oxide, active chromium oxide is added again, can obviously improve the mechanical strength of coating;After then, phosphite group is grafted onto graphene oxide, and is applied in the present powder coating system, can form three-dimensional network structure in system, chemical bond effect, not only can improve its crosslinking stability in system, and the sheet structure of graphene oxide, also can play certain barrier property, can also give coating longer weather resistance, and active chromium oxide synergistic effect is further improved, and the weather resistance and corrosion resistance of coating.

The invention provides an application of a composite coating formed by titanium oxide and chromium oxide in hydrogen resistance, which comprises the following steps: substrate preparation: cutting a metal sample into a metal substrate, pretreating the surface of the metal substrate, polishing, cleaning and drying; cr2O3-10% TiO2 composite powder is adopted, the composite powder is heated to be in a molten or molten state, and under traction of plasma high-speed flame flow, the composite powder impacts the surface of the base body in an accelerated mode and deposits to form the ceramic coating. According to the application of the composite coating formed by the titanium oxide and the chromium oxide in hydrogen resistance, the hydrogen permeation current is reduced, so that the hydrogen resistance of the coating is enhanced.

The invention belongs to the technical field of EBSD sample preparation of heterogeneous materials, and particularly relates to an EBSD sample preparation method of an Al7075 / Al6061 bimetal composite cast ingot. According to the method, mechanical grinding and polishing and argon ion polishing are combined for EBSD sample preparation, during mechanical grinding and polishing, aluminum oxide polishing paste is selected for rough polishing, aluminum oxide or chromium oxide polishing paste is selected for fine polishing, and finally cerium oxide polishing paste is selected for fine polishing, so that crystal lattices with complete and distortionless sample surface layers are obtained as far as possible, and the defects such as trailing are reduced to the maximum extent; the optimal surface characteristics are provided for subsequent argon ion polishing, and meanwhile, the calibration rate of an Al7075 / Al6061 bimetal composite cast ingot EBSD sample prepared through the method is not lower than 90% in combination with the optimal argon ion polishing process parameters.

The invention provides a catalyst for synthesizing N-methylaniline and a preparation method thereof, the catalyst comprises an active component, a carrier and an auxiliary agent, the active component comprises oxygen-containing compounds of copper, zinc and chromium, the carrier is gamma-alumina subjected to surface hydroxylation treatment, and the auxiliary agent is a cerium-molybdenum bimetallic alloy. The preparation method comprises the following steps: loading the active component on the hydroxylation carrier through ultrasonic impregnation, drying, further loading the cerium-molybdenum auxiliary agent, and carrying out reduction alloying and roasting activation to form the composite catalyst. The catalyst is a regular cylinder, has the diameter of 4-6mm and the length of 4-6mm, has an optimized pore structure and surface properties, and is suitable for methylation reaction of aniline and methanol. According to the method, the dispersity of active components is improved through modified chromic oxide, the mass transfer efficiency is enhanced through a hydroxylation carrier, the synergistic catalysis effect of cerium-molybdenum alloy is combined, the reaction activity and selectivity are remarkably improved, meanwhile, side reactions are inhibited, the stability is enhanced, and the method can be widely applied to industrial production of N-methylaniline.

The invention discloses a high-performance coiled material powder coating and a preparation method thereof, and belongs to the technical field of powder paints.The high-performance coiled material powder coating has the advantages that organosilicon modified epoxy resin and carboxyl-terminated polyester resin are compounded, a-Si-O-Si-chain segment is introduced into a system after organosilicon modification, the flexibility is high, and the high-performance coiled material powder coating has a synergistic effect with nano calcium carbonate; the adhesive force and the flexibility of the coating are balanced, and the mechanical strength of the coating can be obviously improved by adding the grafted modified graphene oxide and the active chromic oxide; then, phosphite ester groups are grafted to the graphene oxide, the graphene oxide is applied to a powder coating system, a three-dimensional network structure and chemical bonding can be formed in the system, the crosslinking stability of the graphene oxide in the system can be improved, and a certain barrier property can be achieved due to the flaky structure of the graphene oxide; and the coating is endowed with long-acting weather resistance, and the weather resistance and the corrosion resistance of the coating are further improved through the synergistic effect with the active chromic oxide.

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 discloses a preparation method and application of a sodium-ion battery positive electrode material, and relates to the technical field of sodium-ion batteries, and the preparation method comprises the following steps: (1) dissolving a compound containing a Cr element in water, adding the solution into a reaction kettle, gradually dropwise adding a NaOH solution, after the reaction is completed, gradually adding a chitosan hydrochloride aqueous solution into the reaction kettle according to a certain ratio, and stirring to obtain a mixed solution; after reacting for a certain time, filtering, washing and drying to obtain chitosan-coated chromium hydroxide Cr (OH) 3 (at) CS; (2) blending the Cr (OH) 3 (at) CS prepared in the step (1) with a sodium source according to a certain molar ratio, sintering the mixture under protective gas, and then grinding and sieving to obtain a carbon-coated sodium chromite positive electrode material NaCrO2 (at) C; the sodium-ion battery has good electrochemical performance and cycle performance, and the sustainable development of the sodium-ion battery industry is promoted.

The invention provides self-recovery chromium ion doped oxide mechanoluminescence fluorescent powder as well as a preparation method and application thereof. The chemical general formula of the self-recovery mechanoluminescence fluorescent powder is Al2 (1-x) O3: 2xCr < 3 + >, wherein x is equal to 0.3%-5%. The preparation method of the self-recovery mechanoluminescence fluorescent powder comprises the following steps: a, respectively weighing aluminum oxide and chromium oxide according to the molar ratio of each element in the chemical general formula Al2 (1-x) O3: 2xCr < 3 + >; b, grinding and uniformly mixing the weighed raw materials, and firing in air at the temperature of 1300 DEG C for 6 hours; and c, taking out the fired sample, and uniformly grinding to obtain the chromium ion doped oxide mechanoluminescence fluorescent powder. According to the chromium ion doped oxide mechanoluminescence fluorescent powder disclosed by the invention, a measured emission band main peak is located at 694 nm and is located at a biological first window (600-900 nm), and the chromium ion doped oxide mechanoluminescence fluorescent powder is expected to be used as a near-infrared mechanoluminescence biological probe; and the fluorescent powder has the advantages of no need of pre-irradiation and instant self-recovery of luminescence.

The application provides a temperature self-compensation strain sensor sensitive layer composite material and a preparation method thereof, and belongs to the technical field of functional materials. The composite material is prepared from raw materials including the following mass percentages: metal nanoparticles 25-35%, insulating oxide nanoparticles 2-3%, dispersing agent 0.1-0.5%, and the balance solvent; the metal nanoparticles have a positive temperature coefficient of resistance; and the insulating oxide nanoparticles include aluminum oxide nanoparticles, silicon oxide nanoparticles, zirconium oxide nanoparticles or chromium oxide nanoparticles. The composite material provided by the application can be used as a sensitive layer of a temperature self-compensation strain sensor, can avoid strain signal disturbance caused by environmental temperature changes, can make the strain sensor have a temperature self-compensation function, and can further simplify the system of the strain sensor without using an external circuit and without changing the size and structure of the strain sensor.

The invention discloses a halogen anion doped chromic oxide electrocatalyst and a preparation method and application thereof, and belongs to the technical field of new energy materials and electrochemical catalyst.The preparation method of the electrocatalyst comprises the steps that soluble chromium salt and polyvinylpyrrolidone are dissolved in a mannitol solution and then mixed with a soluble halogen salt solution, stirring is conducted, and the electrocatalyst is obtained; preparing to obtain a mixed solution; in a closed environment, heating the mixed solution at 160-180 DEG C for 6-24 hours to perform hydrothermal reaction, obtaining a reaction product after the reaction is finished, and then calcining in an air atmosphere to prepare the powdery halogen anion doped chromic oxide electrocatalyst, according to the method, the local structure, the spinning state, the energy band and the like of chromic oxide are regulated and controlled through the doped halogen anion ligand, the OER catalytic activity of the chromic oxide is optimized, the process is simple, and the method has good application prospects in the water electrolysis technology.

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 discloses red phosphorus master batch as well as a preparation method and application thereof. The red phosphorus master batch comprises the following components in parts by weight: 50-70 parts of a red phosphorus flame retardant; 30 to 50 parts of a toughening agent; 1-4 parts of a stabilizing aid; wherein the stabilizing aid comprises one or more of zinc oxide, calcium oxide, chromic oxide, hydrotalcite, metazirconic acid or magnesium oxide. According to the invention, the toughening agent with a specific content is adopted to coat the red phosphorus flame retardant, and the stabilizing aid is added, so that the content of phosphine in the red phosphorus master batch in the use process can be effectively reduced, and when the red phosphorus master batch is added into the nylon resin, the prepared nylon composite material has relatively low phosphine content and relatively good flame retardant property.

The invention discloses oxide modified copper powder and a preparation method and application thereof, and relates to the technical field of 3D printing. The oxide modified copper powder comprises a core layer and a shell layer located on at least part of the surface of the core layer, the core layer is made of copper powder, the shell layer is made of oxide, and the oxide comprises at least one of chromium oxide, aluminum oxide, magnesium oxide, yttrium oxide and cerium oxide. The copper powder is subjected to coating modification through the oxide, the laser absorption capacity of the copper powder can be effectively improved, then the compactness of a copper powder printing device is improved, meanwhile, the copper powder printing device keeps good electrical conductivity and thermal conductivity, and the device printed by using the oxide modified copper powder is suitable for being applied to multiple fields.

The invention relates to the technical field of thermal-shock-resistant refractory materials, and discloses a thermal-shock-resistant refractory material for a melting furnace and a preparation method of the thermal-shock-resistant refractory material. Comprising the following operation steps: step 1, uniformly mixing fused cast fused alumina zirconia, white corundum, aluminum oxide, chromic oxide and modified iron oxide, adding a modified polycarbosilane binder, heating to 250-300 DEG C, and mixing for 20-40 minutes to obtain a mixed material; 2, the mixed material is subjected to hot pressing treatment for 3-4 hours, and a blank is prepared; and sintering at 1600-2000 DEG C for 20-30 hours to obtain the thermal shock resistant refractory material.

Magnetic particles with a highly reflective protective membrane (300), comprising: a magnetic core (100), a shell (200) formed on the outer surface of the magnetic core (100), having a multi-layer structure and comprising a first shell (210) made of a dielectric material, and a second shell (220) made of metallic material, formed on the outer surface of the first shell (210) and being a multi-layer membrane in which two or more layers (221, 222, 223) of mutually different metallic materials are stacked on top of each other, and a highly reflective protective membrane (300) which is in contact with the second shell (220) and is formed on the outer surface of the shell (200), wherein the highly reflective protective membrane (300) comprises a multi-layer structure comprising a low refractive index membrane (310) formed on the outer surface of the shell (200) and having an optical thickness between 0.15 to 0.35 of the wavelength, and a high refractive index membrane (320) formed on the outer surface of the low refractive index membrane (310) and having an optical thickness between 0.15 to 0.35 of the wavelength, the dielectric material is one or more materials selected from a group comprising titanium dioxide, aluminum oxide, calcium carbonate, zirconium oxide, magnesium fluoride, zinc oxide and zinc sulfide, the metallic material is one or more materials selected from a group comprising copper, nickel, gold, platinum, silver, aluminum and chromium, the low refractive index membrane (310) consists of one or more materials selected from a group comprising silicon dioxide, magnesium fluoride, polystyrene, polymethyl methacrylate, polystyrene-co-butadiene, vanadium pentoxide, cadmium oxide, polyisobutylene and polyethylene, and the high refractive index membrane (320) consists of one or more materials selected from a group comprising titanium dioxide, aluminum oxide, zinc oxide, zirconium oxide and chromium oxide.

The invention relates to the field of vanadium and chromium separation, and particularly discloses a method for removing impurities phosphorus, chromium and silicon in a sodium modified vanadium solution, which comprises the following steps: S100, adjusting the pH value of the sodium modified vanadium solution to enable the pH value of a solution system to be 8.0-9.0 at room temperature to obtain a pretreated sodium modified vanadium solution; s200, heating the pretreated sodium vanadium solution, sequentially adding a reducing agent and a polyelectrolyte into the solution while stirring, and carrying out phosphorus and chromium removal reaction while stirring; s300, after the removal reaction of phosphorus and chromium is carried out for a period of time, adding a silicon removal agent, and carrying out a removal reaction of silicon; and S400, after the silicon removal reaction is finished, standing sedimentation and solid-liquid separation are carried out, impurity-removed slag is washed with water and then merged into the filtrate, and purified vanadium liquid is obtained. According to the method, firstly, glucose is adopted to selectively reduce hexavalent chromium into trivalent chromium under the weakly alkaline condition, pentavalent vanadium is not reduced, the trivalent chromium forms chromium phosphate and chromium hydroxide precipitates in a weakly alkaline solution, and meanwhile, the chromium removal efficiency is improved in a polyelectrolyte coagulation mode.

The application discloses a preparation method of vanadium-doped and high-hydrated mangan-chromian spinel monocrystal under high temperature and high pressure. The cylindrical mangan-chromian spinel sample is prepared by taking solid rose triangular rhombic manganese carbonate crystal, solid chromium (III) acetate hydroxide crystalline powder, solid vanadium (IV) acetylacetonate oxide powder, solid oxalic acid powder, solid bixbyite powder, solid chromium hydroxide powder and liquid dilute nitric acid as starting raw materials; two pieces of water source sheets are made from the bixbyite powder and the chromium hydroxide powder with a weight ratio of 4:1; the two pieces of water source sheets are placed at two ends of the cylindrical mangan-chromian spinel sample and then are placed into a double-capsule structure experimental sample bin with an inner layer sleeve being a graphite tube and an outer layer sleeve being a gold-palladium alloy tube; the high temperature and high pressure reaction is carried out to obtain the mangan-chromian spinel monocrystal; and the preparation technology blank of the vanadium-doped and high-hydrated mangan-chromian spinel large-particle monocrystal under the current high temperature and high pressure conditions is solved.

A preparation method of a 7B04 aluminum alloy surface in-situ synthesis microparticle enhanced thermal control function film layer can effectively improve the density of the film layer, meanwhile, the film layer is high in infrared emissivity and good in thermal control function, and comprises the steps that firstly, the 7B04 aluminum alloy surface, copper oxide and chromic oxide are pretreated, then a micro-arc oxidation electrolyte is prepared, and the 7B04 aluminum alloy surface is subjected to in-situ synthesis; the pretreated 7B04 aluminum alloy is placed in a stainless steel electrolytic cell of micro-arc oxidation equipment, then the micro-arc oxidation electrolyte is added into the stainless steel electrolytic cell, micro-arc oxidation treatment is conducted on the aluminum alloy through a micro-arc oxidation power source, the electrolyte is continuously stirred in the oxidation treatment process, and the aluminum alloy is subjected to micro-arc oxidation treatment; and finally, obtaining an in-situ synthesized microparticle reinforced thermal control functional film layer on the surface of the 7B04 aluminum alloy, washing the film layer with deionized water, and naturally airing the film layer to obtain the 7B04 aluminum alloy. The composition of the micro-arc oxidation electrolyte is designed, in the growth process of a micro-arc oxidation film layer, copper chromite black particles are synthesized in situ through chemical reaction, the particles and the film layer are metallurgically bonded, and the method has actual application and popularization value.

The invention relates to the technical field of lithium batteries, and discloses a positive electrode material based on core-shell structure carbon-coated chromic oxide and a preparation method of the positive electrode material. Comprising the following steps: S1, uniformly mixing chromium oxide, conductive carbon and a binder; granulating at the temperature of 150 to 160 DEG C by a spraying method; sintering at the temperature of 190-450 DEG C for 12-24 hours to obtain a chromic oxide active material; and S2, sequentially adding the chromic oxide active material, the modified conductive material and the composite binding material into a solvent, grinding and uniformly mixing to obtain the positive electrode material. The chromium oxide active material comprises the following raw materials in parts by mass: 90-99 parts of chromium oxide, 0.1-5 parts of conductive carbon and 1-3 parts of a binder, the D50 of the chromic oxide is CrO3 with the particle size of 5-6 microns; the conductive carbon comprises one or more of carbon nanotubes, graphene, carbon fibers and conductive carbon black; the binder comprises polyacrylic acid.

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.