836 results about "Sodium tungstate dihydrate" patented technology

The invention discloses a method for extracting tungsten, titanium and vanadium from a waste SCR (selective catalytic reduction) catalyst, which comprises the following steps: crushing the waste SCR catalyst, adding a strongly alkaline solution, and reacting; filtering, separating, then adding strong acid into the sodium tungstate and sodium vanadate mixed solution, and reacting to obtain tungstic acid and a sodium salt and vanadic acid mixed solution; regulating the pH value of the sodium salt and vanadic acid mixed solution until precipitate is separated out, thus obtaining ammonium vanadate; then adding sulfuric acid into the tungsten-and-vanadium-removed SCR catalyst, and reacting to obtain a titanyl sulfate solution and solids such as aluminum slag and the like; then adding water into the titanyl sulfate solution, and hydrolyzing to obtain titanic acid and a waste acid solution; and finally, respectively calcining the obtained ammonium vanadate, tungstic acid and titanic acid to obtain vanadium pentoxide, tungsten trioxide and titanium dioxide. According to the invention, tungsten, titanium and vanadium can be extracted from the SCR catalyst through the reaction with strong alkali and strong acid at a low temperature, the equipment requirement is low, the energy consumption is low, some products having added values can be coproduced, and no secondary pollution is generated, thereby facilitating popularization and application.

The invention provides a method for preparing pure ammonium paratungstate (APT) from crude Na2WO4 solution containing NaOH, P, As, Si, Sn and other impurities. The method comprises the following steps of crystallizing tungsten into Na2WO4 crystals through concentration, separating NaOH from impurities, redissolving and acidifying the Na2WO4 crystals till the pH of the crystals is between 2.0 and 6.0, adsorbing the crystals by use of macroporous weak alkaline anion exchange resin, desorbing the crystals by use of NH4OH, obtaining (NH4)2WO4 solution, performing evaporation crystallization and obtaining the APT. Under the condition that the crystallization rate is between 88 and 90 percent, the P, the As and the Si contained in the APT are all less than 10*10. The method has the outstanding advantage of small amount of discharged wastewater (mainly liquid after exchange), namely the volume of the discharged liquid after the exchange is one third to one twenty-fifth of that of liquid before the exchange; in addition, the discharged liquid after the exchange contains no detrimental impurities and is easy to control.

The invention proposes a kind of hydrothermal method used for preparing light catalyzing material with visible light active nano crystal Bi2WO6 powder. The method makes bismuth nitrate and sodium tungstate as raw materials, prepare them into mixed solution, then add into reacting kettle and have hydrothermal treatment for 10 - 48 hours at 100 - 200 Deg. C, take out reacting kettle, after the system cooled to room temperature, repeatedly wash the got output to neutral with deionized water, then dry in vacuum condition, finally through 100 -1000 heat treatment for 0.5 -10 hours, we can obtain light catalyzing material with visible light active nanometer crystal Bi2WO6 powder. The method has such advantages as low synthesizing temperature, large specific surface area of obtained simples and small grains. The prepared material can not only show light catalyzing activeness in ultraviolet, but also show light catalyzing activeness in visible light bound as sunlight or indoor lamplight.

The invention discloses a fluorination catalyst, and a preparation method and a use thereof, and belongs to the field of chemical synthesis. The precursor of the catalyst is formed by blending 40-95mass% of a trivalent chromium compound with 5-60mass% of tungstate, wherein the trivalent chromium compound can be chromic oxide or chromium hydroxide, and the tungstate can be zinc tungstate, nickel tungstate, magnesium tungstate, aluminum tungstate, silicotungstic acid, ammonium tungstate, ammonium paratungstate or ammonium metatungstate. The fluorination catalyst has the advantages of high use temperature, high catalysis activity and long service life, and can be mainly used in reactions for preparing fluorinated alkenes through gas phase catalysis of fluorination of alkenyl halides at a high temperature.

The invention relates to a preparation method of acipimox for treating hyperlipidemia, belonging to the field of medicines. The invention provides an acipimox synthesis process which is simple and easy to operate. The preparation method comprises steps of with 2, 5-dimethylpyrazine as a raw material, carrying out nitrogen oxidation, reaction with acetic anhydride and alkaline hydrolysis to obtain 2-hydroxymethyl-5-methylpyrazine; directly oxidizing a post-treatment fluid by using 2,2,6,6-tetramethyl-1-piperidinyloxy/sodium hypochlorite/potassium bromide to obtain 5-methylpyrazine-2-carboxylic acid, wherein the post-treatment fluid is not needed to be dried and concentrated; oxidizing 5-methylpyrazine-2-carboxylic acid by using hydrogen peroxide/sodium tungstate to obtain acipimox.

The invention provides a synthesis method of tungsten trioxide, belongs to the technical field of inorganic synthesis chemistry, and particularly relates to the synthesis method of the tungsten trioxide. The synthesis method comprises the following steps of: taking sodium tungstate dihydrate and sodium chloride as raw materials; utilizing hydrochloric acid to adjust a pH (Potential of Hydrogen) value of a reaction system to adjust the pH value to 1.5-3.0; carrying out hydrothermal reaction at 170-190 DEG C for 22-28 hours; and washing, centrifuging and drying to obtain tungsten trioxide powder. The obtained tungsten trioxide powder has different shapes and different photoelectric properties. According to the synthesis method disclosed by the invention, a one-step hydrothermal synthesis method is adopted, so that the operation is simple, the repetitiveness is good and the raw material cost is low; and the pH value is simply adjusted to obtain the tungsten trioxide powder with the different shapes and the different photoelectric properties, and the photocatalytic degradation efficiency on an organic dye is higher.

The invention discloses a hydro-thermal synthesis method of a visible light photocatalyst mesoporous Bi2WO6. The hydro-thermal synthesis method comprises the following steps of: dissolving bismuth nitrate into a salpeter solution and stirring so as to obtain a solution A; dissolving sodium tungstate in deionized water and stirring so as to obtain a solution B; dropwisely adding the solution B in the solution A under intense agitation, adding a template agent and stirring so as to obtain a mixing solution, transferring the mixing solution to a reaction kettle an inner container of which is made of polytetrafluoroethylene, and carrying out a 180-degree thermostatic reaction for 24h, so as to obtain white precipitate; and washing for 2-3 times respectively by utilizing deionized water and absolute ethyl alcohol, and carrying out natural air-drying on a product so as to obtain a target object. The hydro-thermal synthesis method provided by the invention has the advantages that the process of the synthesis method is simple, the cost is low, the reaction is mild, the morphology of the product is good, the photocatalytic degradation efficiency is high, and the product is easy to recover, a prepared Bi2WO6 photocatalyst is of a three-dimensional flower shape assembled by nanosheets and has a mesoporous level structure, the Bi2WO6 photocatalyst has high catalytic activity on Rhodamine B, different template agents are adopted so as to have different influences on the degradation and morphology of the product, and the comparison phenomenon is obvious.

Synthesis of pyridine-N-oxide is carried out by preparing sodium tungstate into carrier phosphate-tungstic acid by wetting method, vacuum drying to generate anhydrous product, putting anhydrous product and carrier into container, formulating solution by deionized water, agitating to remove water content, drying at high-temperature, activating to obtain catalyst, putting catalyst and pyridine into flask, oxidation reacting by hydrogen peroxide, filtering out catalyst and decompress distilling to obtain the final product. It's simple, fast and cheap and has less solvent.

The invention discloses a method for preparing nanometer bismuth tungstate by utilizing a fused salt method. According to the method, bismuth nitrate and sodium tungstate are adopted as raw materials, potassium nitrate/sodium nitrate and lithium nitrate are utilized as a fuse salt system, the raw materials are mixed and added into a molten salt system in a crucible, and the nanoscale bismuth tungstate powder is obtained through reaction. According to the method, the uniform mixing of raw material on a molecule scale can be realized, and the nanoscale bismuth tungstate powder with high purity is obtained. The method provided by the invention has the advantages that the equipment is simple, the technological process is short, the operation is simple, the product performance is excellent, and the method has an extensive application prospect.

The invention discloses a preparation method of a tungsten disulfide nanorod. The method comprises the following steps that sodium tungstate, hydroxylamine hydrochloride and thiourea are dissolved in water according to the molar ratio of 1 to (1.5-3) to (3-5) to form a solution, a mixed surfactant is added to the solution, the mixed surfactant is composed of CTAB, CTAC and F127 which are mixed according to the molar ratio of 1 to (1.5-3) to (0.6-1.8), the solution is moved into a stainless steel reaction kettle, and a reaction is conducted for 10-24 h at the temperature ranging from 170 DEG C to 200 DEG C. For the prepared tungsten disulfide nanorod, the diameter ranges from 20 nm to 100 nm, the length ranges from 200 nm to 350 nm, the maximum length difference is smaller than 150 nm, the length distribution is centralized, the size uniformity is good, and the dispersity is good; meanwhile, the prepared tungsten disulfide nanorod has the unexpected visible light absorption property and the wide application prospect in the photocatalytic aspect.

The invention discloses a preparation method of a WO3/C3N4 mixed photocatalyst. The preparation method comprises the following steps: taking sodium tungstate and sodium chloride as the raw materials, preparing WO3 through a hydrothermal method, subjecting the WO3 to an ultrasonic dispersion treatment to obtain processed WO3; taking urea as the raw material, burning urea to obtain C3N4 in one step, subjecting C3N4 to an ultrasonic dispersion treatment to obtain processed C3N4; mixing the processed WO3 nano powder and processed C3N4 by a mechanical means and ultrasonic waves in sequence, washing the mixture, subjecting the mixture to a centrifugal treatment, and finally drying the mixture at a temperature of 70 to 80 DEG C to obtain the WO3/C3N4 composite photocatalyst. Under the same conditions, the catalytic degradation rate of rhodamine B of the provided photocatalyst is increased by 8%, compared with that of a conventional WO3/C3N4 composite photocatalyst, which is prepared through a grinding method; moreover, the catalytic time is shorter, and one hour after the starting of the catalytic reactions, the catalytic degradation rate of rhodamine B can reach 99%.

The invention relates to an anodization closing method for improving the corrosion resistance of an aluminum alloy. The method comprises a step of aluminum surface pretreatment, a step of aluminum product anodization, a step of preparation of a supersaturated sodium molybdate solution or an aqueous sodium tungstate solution, a step of adjusting the pH value to 5.5-6.5, a step of primary closing at 70-100DEG C for 10-30min, a step of preparing a supersaturated aqueous La2(CO3)3 or Pr2(CO3)3 solution, a step of adjusting the pH value to 5.5-6.5, a step of secondary closing at 70-100DEG C for 10-30min, a step of cleaning, and a step of drying to complete the process. The method adopts a double closing technique to substitute single-time closing of a traditional technology, so the corrosion resistance of the aluminum alloy product is substantially improved; the sodium molybdate or sodium tungstate solution is adopted to carry out the primary closing; and rare earth carbonate is adopted to substitute nickel and cobalt salts to carry out the secondary closing, so the surface compactness of the aluminum alloy is greatly improved, and the corrosion resistance of the product is improved; and the method has the advantages of simple making technology, low equipment requirement and harmlessness to the environment.

The invention provides a chromium-free passivation solution as well as preparation and using methods thereof. The passivation solution is prepared by dissolving a solute composed of multiple substances into deionized water, wherein the solute in the solution comprises the following raw materials according to the ratio: 60-80g/L of sodium molybdate, 5-10g/L of sodium tungstate, 2-7g/L of ethanol, 15-50g/L of acetic acid, 20-40g/L of hydrogen peroxide, 5-10g/L of ethylenediaminetetraacetic acid disodium and the balance of water. The chromium-free passivation solution is firm in adhesive force, low in porosity and corrosion-resistant.

The invention discloses a technology for producing tungsten trioxide by prilling and roasting of tungsten slag. The technology is characterized by comprising the following steps of: (1) baking tungsten slag and then adding blind coal, mixing and crushing the tungsten slag and the blind coal, and then adding lime mud, sodium carbonate and water, priling in a priling disc to prepare the mixed tungsten slag balls; (2) putting the mixed tungsten slag balls into an open hearth kiln to carry out semi-enclosed insulated roasting so as to obtain a tungsten slag clinker; (3) soaking the tungsten slag clinker, and carrying out ion exchange to obtain high-concentration sodium tungstate mother liquor; (4) removing the impurity of the high-concentration sodium tungstate mother liquor, and then filtering, precipitating, leaching the sediment, dewatering and baking the sediment to obtain a calcium tungstate product. The tungsten slag, the blind coal, the lime mud and recycling wastewater are adopted as roasting agents to replace soda ash and burning acid with high price and large consumption for the traditional technology-wet firing method, so that the tungsten production cost of each metal ton is reduced by***, and the transformation rate of WO3 is improved by 25%; the chronic diseases of sodium-process rotary kiln roasting and caking shovel kiln stop production are successfully solved, and about 50% of energy consumption is saved on the traditional technology and wet firing production.

The invention relates to an environmentally friendly composite corrosion and scale inhibitor for circulating cooling water, which comprises polyepoxysuccinic acid, poly aspartic acid, benzotriazole, sodium gluconate and sodium tungstate according to a mass ratio of (1- 2.5): (3 -5): (1-2): (10-25): (3-5). The composite corrosion and scale inhibitor provided by the invention has the characteristics of no phosphorus, biodegradability, and less dosage of medicament, can be suitable for high-salt-content and high-hardness water and the like, is an environmentally friendly water stabilizer which has good corrosion inhibition, scale inhibition dispersion performances for a circulating cooling water system.