35 results about "Chromium Compounds" patented technology

The invention relates to a method for preparing a catalyst. A process for preparing a catalyst comprising: a) contacting (i) a silica support, (ii) a titanyl compound, (iii) a chromium-containing compound, and (iv) an optional solvent to form a first aqueous mixture comprising a pre-catalyst and a reaction medium comprising from about 1 wt% to about 99 wt% water; b) heat treating the pre-catalyst by heating to a temperature of from about 400 DEG C to about 1000 DEG C for a time of from about 1 minute to about 24 hours to form a catalyst. A method of making a catalyst comprises contacting a hydrated support material comprising silica with a chromium-containing compound to form a first aqueous mixture comprising a chromized support; contacting the first aqueous mixture comprising the chromized support with a solution comprising (i) a solvent and (ii) a titanyl compound to form a second aqueous mixture comprising a pre-catalyst; and heat treating the pre-catalyst to form the catalyst.

This invention relates to the field of chromium slag resource utilization technology, specifically to a method for pre-reduction enhanced oxidation extraction of chromium from chromium slag, comprising: S1, mixing calcium-free roasted chromium slag, carbonaceous reducing agent, and sodium carbonate in a mass ratio of 1:(0.4~0.9):(0.05~0.25) and pressing them into shape to obtain a chromium slag preform; S2, under an inert atmosphere, reducing and roasting the chromium slag preform at 850~1050℃ for 30~150 min to generate sodium chromite, and cooling it to room temperature with the furnace to obtain a pre-reduced chromium slag mixture; S3, under an oxygen-containing atmosphere, oxidizing and roasting the pre-reduced chromium slag mixture at 850~1050℃ for 30~150 min to convert trivalent chromium into water-soluble hexavalent chromium compounds, and air-cooling it to room temperature to obtain a roasting product; S4, stirring and leaching the roasting product in an acidic solution, separating the solid and liquid to obtain a leaching residue and a leachate containing hexavalent chromium. The pre-reduction stage enables lattice reconstruction and micropore optimization, creating favorable reaction conditions for the subsequent oxidation stage, thereby significantly improving the oxidation conversion efficiency of chromium.

Provided is a method for producing monofluoroethane, which enables production of monofluoroethane from ethylene and hydrogen fluoride at a high conversion rate even under mild reaction conditions. This method for producing monofluoroethane comprises reacting ethylene gas with hydrogen fluoride gas in the presence of a catalyst to obtain monofluoroethane. The catalyst contains a chromium compound, which is at least one selected from chromium fluoride and chromium oxyfluoride.

The invention relates to an austenitic stainless steel food-grade pipe welding spot cleaning passivator. The austenitic stainless steel food-grade pipe welding spot cleaning passivator comprises the following components in parts by mass: 0.2-1.2 parts of a complexing agent, 0.5-2.5 parts of a sealing agent, 9.5-18 parts of organic acid, 1-5 parts of an oxidizing agent, 1-5 parts of a coordination agent, 0.2-2 parts of a corrosion inhibitor, 0.4-1.5 parts of an active agent and 64.8-87.2 parts of water. Through compounding of the whole materials, after a stainless steel workpiece is cleaned and passivated, no heavy metal is left on the surface of the workpiece, the corrosion resistance of the surface of the workpiece can be improved, the service life of the workpiece is prolonged, harmful gas, acid mist and toxic substances are not generated in the process of cleaning and passivating the workpiece, and the service life of the workpiece is prolonged. The austenitic stainless steel cleaning and passivating agent is safe and environment-friendly to use, and solves the problems that in the process of cleaning and passivating austenitic stainless steel products by adopting a pickling and passivating method in the market, acid mist is formed, nitrogen dioxide polluting the atmosphere is generated, chromium compounds with high toxicity are generated, and the health of operators is harmed and the environment is polluted.

This invention relates to the field of metallurgical technology, specifically to an ultra-low yield strength ratio, high-phosphorus, atmospheric corrosion-resistant steel and its preparation method. The preparation method includes: placing a cut billet into a slow-cooling pit, with the initial slow-cooling temperature ≥500℃ and the final slow-cooling temperature not lower than 300℃; heating the slow-cooled billet, controlling the billet's exit temperature from the furnace to 1140~1170℃, and the furnace time coefficient to be 10~11 min / cm; employing a two-stage rolling process, with the billet undergoing the first stage of rolling after descaling, and the surface temperature of the rolled piece at the start of the second stage of rolling being T2=(T+1600 / H-1.8H)℃, and the rolled steel plate not being water-cooled; and then placing the rolled steel plate between steel plates at 500~600℃ for at least 48 hours to achieve stacking cooling. This invention utilizes a fine, uniform microstructure and phosphorus and chromium compounds to improve the material's corrosion resistance, meeting the requirements for corrosion resistance and high toughness of steel used in building and engineering structures in coastal atmospheric environments.

The insulating coating of the grain-oriented magnetic steel sheet contains no chromium compound but contains a phosphate, and the content of the phosphate is 0.5% or more and less than 2.0% as measured by the nuclear magnetic resonance method 31 The P-NMR spectrum was subjected to Gaussian fitting in the range of 16 to -90 ppm, and the proportion of the peak area of the structure to the total peak area was more than 0% and 10% or less. 0 The P-NMR spectrum was subjected to Gaussian fitting in the range of 16 to -90 ppm, and the proportion of the peak area of the structure to the total peak area was more than 0% and 10% or less.

The invention discloses a method for preparing syndiotactic polystyrene through transition metal catalysis. According to the method, an aryl ether-transition metal chromium compound is adopted to catalyze styrene to polymerize so as to prepare syndiotactic polystyrene. According to the preparation method of the compound, an aryl ether compound reacts with tetrahydrofuran chromium trichloride to obtain a chromium complex, then the chromium complex and aluminum alkyl form a catalytic system, bulk polymerization is performed in styrene to obtain syndiotactic polystyrene, and the syndiotactic polystyrene has the advantages of good stereoselectivity and high activity.

The invention discloses a chromium-doped garnet broadband near-infrared stress luminescent material as well as a preparation method and application thereof. The preparation method comprises the following steps: respectively weighing a lutetium-containing compound raw material, a gallium-containing compound raw material and a chromium-containing compound raw material according to a general formula Lu3Ga5 (1x) O12: 5xCr < 3 + >, uniformly grinding the raw materials, pre-sintering, cooling to room temperature, grinding and uniformly mixing, calcining at high temperature, cooling to room temperature along with a furnace, and grinding to obtain the chromium-doped garnet broadband near-infrared stress luminescent material. The chromium-doped garnet broadband near-infrared stress luminescent material Lu3Ga5 (1x) O12: 5xCr < 3 + > disclosed by the invention has good stress luminescence self-recovery performance and shows broadband emission in a near-infrared range, and the full width at half maximum (FWHM) is greater than 120 nm. The material has a low-threshold excitation characteristic, can meet the requirement of mechanical imaging in a living body, and can be used for preparing a stress luminescent film suitable for mechanical detection of skeleton joints.

The present invention relates to a solid catalyst system comprising a chromium compound, a metal compound, an aluminum compound and a silica support, wherein the silica support has an average particle size in the range of > 20 to < 50 pm, a pore volume in the range of > 1.7 ml / g to < 3 ml / g, and a surface area in the range of > 400 m 2 / g to < 800 m 2 / g, and wherein the aluminum alkoxide compound has the formula R1-Al-OR2, wherein R1 is selected from (C1-C8)alkyl, and OR2 is selected from (C1-C8)alkoxy.

The present invention relates to a photomask blank comprising a transparent substrate and a chromium-containing film. The chromium-containing film consists of a chromium compound layer formed of a chromium compound comprising Cr, N and optionally O and having a composition with a Cr content of > 30 at%, a total content of Cr + N + O of > 93 at% and fulfilling the formula: 3Cr ≤ 2O + 3N. The first composition is: an atomic N / Cr ratio of > 0.95, a Cr content of > 40 at%, a total content of Cr + N of > 80 at% and an O content of ≤ 10 at%.

The present invention relates to a ligand compound, an organochromium compound, a catalyst composition containing the organochromium compound, and a method for oligomerizing ethylene using the same, which exhibit high catalytic activity and high selectivity for 1-hexene and 1-octene, and which can oligomerize ethylene with excellent efficiency.

Methods for making a supported chromium catalyst are disclosed, and can comprise contacting a silica-coated alumina containing at least 30 wt. % silica with a chromium-containing compound in a liquid, drying, and calcining in an oxidizing atmosphere at a peak temperature of at least 650° C. to form the supported chromium catalyst. The supported chromium catalyst can contain from 0.01 to 20 wt. % chromium, and typically can have a pore volume from 0.5 to 2 mL / g and a BET surface area from 275 to 550 m2 / g. The supported chromium catalyst subsequently can be used to polymerize olefins to produce, for example, ethylene-based homopolymers and copolymers having high molecular weights and broad molecular weight distributions.

The application provides a purification method of a chromium-containing mixed salt, the mixed salt comprising sodium carbonate, sodium bromide and a heavy metal chromium compound, in the method, a high-purity sodium bromide aqueous solution is prepared from the mixed salt and chromium salt is recovered, and the method comprises the following steps: preparing a crude sodium bromide solution, preparing a chromium removal agent by using a barium compound or a calcium compound, removing chromium from the crude sodium bromide solution by using the chromium removal agent and collecting a filtrate A; and treating the filtrate A to obtain a high-purity sodium bromide aqueous solution. In the method, the sodium carbonate in the crude sodium bromide solution is all converted into sodium bromide; by using the method, the chromium in the sodium bromide is removed and converted into barium chromate or calcium chromate products; the obtained sodium bromide no longer contains the heavy metal chromium and can be directly used for preparing high-purity sodium bromide or preparing a sodium bromide aqueous solution.

The present invention relates to a ligand compound having a novel structure, which exhibits high 1-hexene and 1-octene selectivity while exhibiting high catalytic activity and enables ethylene oligomerization with excellent efficiency, an organic chromium compound, a catalyst composition containing the organic chromium compound, and a method for ethylene oligomerization using the same.

The present invention relates to a ligand compound, an organochromium compound, a catalyst composition containing the organochromium compound, and a method for oligomerizing ethylene using the same, which exhibit high catalytic activity and high selectivity for 1-hexene and 1-octene, and which can oligomerize ethylene with excellent efficiency.

An insulating coating composition for electrical steel sheets according to an embodiment of the present invention comprises 100 parts by weight of metal phosphate, 33 to 110 parts by weight of nano-silica with a particle size of 1 to 50 nm, 45 to 325 parts by weight of micron-sized silica with a particle size of 0.5 to 50 μm, 28 to 215 parts by weight of nitrate, 10 to 100 parts by weight of boron compound, and 8 to 110 parts by weight of chromium compound.

The disclosure provides a catalyst composition for the oligomerization of ethylene to produce one or more linear alpha olefins, the catalyst composition including a chromium compound, a heteroatomic multidentate ligand having an NPNPN backbone, wherein each P is an optionally substituted phosphino group and each N is an optionally substituted amino group, a methylaluminoxane, and triethyl-aluminum.

The invention discloses a broadband near-infrared stress luminescent material without pre-irradiation as well as a preparation method and application of the broadband near-infrared stress luminescent material. The material is La < 3 > Ga < 5-5x > GeO < 14: 5x > Cr < 3 + >, wherein x is greater than or equal to 0.0025 and less than or equal to 0.02; the crystal structure belongs to a P321 trigonal system structure, and the active ion is Cr < 3 + >. The preparation method comprises the following steps: respectively weighing a lanthanum-containing compound raw material, a gallium-containing compound raw material, a germanium-containing compound raw material and a chromium-containing compound raw material, uniformly grinding the raw materials, grinding, pre-sintering, calcining, cooling to room temperature along with a furnace, and grinding to obtain the near-infrared stress luminescent material without pre-irradiation. The material disclosed by the invention shows broadband emission in a near-infrared 1 region range, and has good self-energy-supply performance, the stress luminescence intensity can be self-recovered, and the stress luminescence intensity can be kept at a considerable level even if force circulation times are continuously applied for multiple times. The material can be used for preparing a stress luminescent film suitable for biological physiological parameter detection.

The invention provides an environment-friendly sulfur-corrosion-resistant ceramic coating and a preparation method thereof, and belongs to the technical field of corrosion resistance and corrosion prevention. The ceramic coating comprises the following components: 15-25 parts of silica sol; 5 to 10 parts of an aluminum dihydrogen phosphate solution; 3 to 8 parts of potash water glass; 18 to 25 parts of zirconium oxide; 2-5 parts of boron nitride; 3-8 parts of silicon carbide whiskers; 5 to 10 parts of aluminum oxide; 4-8 parts of mica powder; 2 to 4 parts of yttrium-stabilized zirconium oxide; 1-3 parts of fumed silica; 15 to 25 parts of deionized water; and 0.1 to 0.5 part of a polyether modified organic silicon leveling agent. A more stable composite inorganic bonding network is constructed through the silica sol, the aluminum dihydrogen phosphate and the potash water glass, the finally obtained coating has extremely low porosity, excellent anti-permeability, excellent sulfuric acid and sulfur vapor corrosion resistance and outstanding thermal shock resistance and wear resistance, toxic chromides in traditional coatings are abandoned, and the coating is environmentally friendly and free of pollution. The invention provides a novel protective material which is more environment-friendly, longer in service life and environment-friendly.

This invention relates to a highly selective ethylene tetramer Cr(III) metal catalyst system and its application method. The catalyst system comprises: a chromium compound; a ligand with the general structural formula (Ph2)P-X-P(Ph2); and an activator or co-catalyst, wherein the chromium compound is one of an organic salt, inorganic salt, coordination complex, or organometallic complex of trivalent chromium. The ethylene tetramer Cr(III) metal catalyst system and its application method provided by this invention improve upon existing PNP chromium-based catalysts, increasing the selectivity for 1-octene, reducing waxy products, and maintaining high activity.

The present invention relates to a catalyst, a preparation method therefor and the use thereof, belonging to the technical field of catalysts. The catalyst comprises a chromium compound, a diaryloxy compound and an ether compound, the molar ratio of the chromium compound to the diaryloxy compound being1:1-1:100, and the molar ratio of the diaryloxy compound to the ether compound being 1:1-1:600. The catalyst in the present invention at least comprises one chromium compound, at least one metal Mg-containing diaryloxy compound and at least one ether compound, and can highly selectively catalyze an ethylene trimerization reaction, thereby improving the reaction activity of the catalyst and increasing the yield. In the ethylene trimerization reaction, the catalyst in the present invention is activated by an alkyl aluminum cocatalyst, the catalyst is capable of catalyzing ethylene trimerization reactions under high-temperature and high-pressure conditions, and the content of waxy by-products is at a relatively low level.

This invention belongs to the field of petrochemical catalysis technology and relates to a method for the selective trimerization of ethylene to 1-hexene. The key feature is that the selective trimerization of ethylene to 1-hexene is catalyzed by a quaternary system of chromium compounds, pyrrole ligands, trialkylaluminum, and chloride auxiliaries, and the reaction is carried out in a cyclohexane solvent. This invention provides a high-boiling-point cyclohexane inert organic solvent for the catalytic system. Compared with known solvents in the catalytic system, using cyclohexane as a solvent not only helps reduce the generation of volatile organic compounds during 1-hexene production but also simplifies the separation process of 1-hexene and other α-olefins, reducing separation energy consumption and thus lowering the production cost of 1-hexene and other α-olefins. Furthermore, using cyclohexane as a solvent in the selective trimerization of ethylene is expected to reduce solvent costs, as cyclohexane can be produced in large quantities using benzene hydrogenation alkylation.

A vanadium-chromium electrolyte, a method for preparing the same, and a redox flow battery composed thereof are provided. The vanadium-chromium electrolyte includes active substances and a free acid, the free acid acts as a proton conductive agent after ionization, and the active substances contain at least vanadium ions and chromium ions. The present disclosure further provides the method for preparing the vanadium-chromium electrolyte, which includes the following steps: dissolving a vanadium compound with a free acid, and obtaining a mixed solution of the free acid and vanadium ions through filtering; electrolytically reducing vanadium to an average valence state of 3.5 to 4 valence; adding a chromium compound, dissolving through stirring, and implementing a filtering; and adding pure water and an auxiliary reagent to adjust concentration, and preparing the vanadium-chromium electrolyte.

The present invention relates to a ligand compound having a novel structure, which exhibits high 1-hexene and 1-octene selectivity while exhibiting high catalytic activity and enables ethylene oligomerization with excellent efficiency, an organic chromium compound, a catalyst composition containing the organic chromium compound, and a method for ethylene oligomerization using the same.

The invention relates to an electrically insulating coating composition for grain-oriented electrical steel based on aluminum and magnesium phosphates and silica sol. The claimed composition has the following ratio of components: 20-40 wt.% of aluminum and magnesium phosphates; 20-45 wt.% of silica sol; 0.01-2 wt.% of a modifying additive in the form of zirconium silicate ZrSiO4, 0.1-3 wt.% of potassium orthovanadate K3VO4, 0.1-3 wt.% of vanadyl hydroxide phosphate VOHPO4 and 0.1-2 wt.% of manganic oxide hydroxide MnO(OH); and up to 100 wt.% of water. As a result, the electrically insulating coating does not contain chromium compounds (CrIII and CrVI) and exhibits high resistance to corrosion and moisture, excellent adhesion to metals, good appearance and high resistivity coefficient.

The invention relates to a catalyst and a preparation method and application thereof, and belongs to the technical field of catalysts, the catalyst comprises a chromium compound, an aromatic dioxy compound and an ether compound; the molar ratio of the chromium compound to the aryl dioxy compound is (1: 1)-(1: 100); the molar ratio of the aryl dioxy compound to the ether compound is (1: 1)-(1: 600). The catalyst at least contains one chromium compound, at least one aryl dioxy compound containing metal Mg and at least one ether compound, and can catalyze ethylene trimerization reaction with high selectivity, so that the reaction activity of the catalyst is improved, and the yield is increased. In the ethylene trimerization reaction, the catalyst provided by the invention is activated by an aluminum alkyl cocatalyst, the catalyst can catalyze the ethylene trimerization reaction under the conditions of high temperature and high pressure, and the content of waxy byproducts is at a relatively low level.

A catalyst composition process for olefin oligomerization is provided. The catalyst composition includes a chromium compound, wherein the chromium compound has at least one substituted or unsubstituted phosphate ligand, a ligating compound, and a cocatalyst. The catalyst composition for olefin oligomerization of the disclosure includes a specific chromium compound (such as a chromium-containing phosphate compound).

Methods of synthesizing chelated chromium are described herein. These methods may include the step of combining a chromium precursor and a reducing agent to provide a reduced chromium compound, wherein the chromium precursor includes Cr (VI) and the reduced chromium compound includes Cr (III). The method may also include the step of combining the reduced chromium compound and a ligand to provide chelated chromium. In some embodiments, the methods described herein are particularly useful for the synthesis of CrEDTA or CrPDTA.

The application provides a preparation method of a magnesium-chromium gas-permeable element. The application adopts a multi-stage particle grading and a magnesium-chromium compound system, coarse particles ensure the skeleton strength, fine powder and micro powder optimize the pore structure and the inter-particle bonding strength, a specific silica sol binder strengthens the interface bonding, the high gas permeability and the high strength are considered, the problems of low strength and short service life of traditional products are solved, meanwhile, micron-level through curved pores are formed through high-temperature sintering, the pores are uniformly distributed, the blowing bubbles are fine and dense, the purification effect of molten steel is improved, the curved channels increase the penetration resistance of molten steel, the molten steel is not easy to penetrate and is not easy to be cut, the service safety is greatly improved, the magnesium-chromium matrix has high refractoriness and strong slag erosion resistance, the binder and the raw material have good matching, the strength is high at high temperature, the matrix is not collapsed, the thermal shock stability and the slag erosion resistance are significantly improved, the service life is greatly improved compared with traditional products, and the replacement frequency is reduced.