783 results about "Sodium tungstate" patented technology

The present invention provides a method of treating high-molybdenum tungsten mineral or tungsten slime by means of three-ion column exchange molybdenum-eliminating technology so as to obtain ammoniumpara-tungstate with high purity at low cost. The treating process includes grinding, alkali leaching, filtering and concentration to obtain sodium tungstate crystal; water dissolving, filtering and sulfurizing sodium tungstate; ion exchange to eliminate molybdenum; desulfurizing sodium tungstate liquid; ion exchange to elimiante impurity and desorbing tungsten with ammonia water and ammonium chloride solution to prepare ammonium tungstate solution; and evaporation to obtain ammonium para-tungstate crystal. The present invention has low cost.

The invention discloses a preparation method of a tungsten diselenide nanosheet, and belongs to the technical field of nanometer material preparation. The preparation method comprises the following steps of dissolving sodium borohydride into an organic solvent, and successively adding selenium powder and sodium tungstate to prepare a mixed solution; transferring the mixed solution to a reaction kettle, and performing reaction for 6 to 48 hours at 200 DEG C to 240 DEG C; after the temperature of the reaction kettle is naturally cooled to the room temperature, collecting black products through suction filtration; washing the product by deionized water and ethyl alcohol; freezing and drying the washed product to obtain the tungsten diselenide nanosheet. The invention provides the method for synthesizing the tungsten diselenide nanosheet in one step by a solvothermal method for the first time. The preparation method has the advantages that the raw materials are green and environment-friendly; the cost is low; the yield is high; the reaction condition is mild; the scale production can be realized. The high-crystallization tungsten diselenide nanosheet prepared by the method has the advantages that the size is great; the layer number is small; the distribution is uniform; the specific surface area is high; high application prospects are realized in the fields of catalysis, energy storage and the like.

The invention provides a novel wet separation method for separating and extracting metallic tungsten and molybdenum from molybdenum-removing slag produced by a sulfide method in the tungsten smelting, sequentially comprising: fully dissolving tungsten and molybdenum metallic elements by directly using (1-4)mol/L alkali solution under the conditions of agitation and temperature of 60 DEG C to 100DEG C to obtain an alkaline solution with a pH value of over 9 and then filter the alkaline solution; neutralizing the solution to have a pH value of 7.5 to 8.5 with (1-4)mol/L acid and filtering the solution; adjusting the acid to make the solution have a pH value of 2 to 3 at a temperature of under 60DEG C, then warming the solution to above 90DEG C and preserving the heat for 1 to 5 minutes, and cooling the solution to under 60DEG C for filtration, so as to obtain an acidulous tungstenic dilute solution and precipitation of molybdenum trisulfide; and gaining a sodium tungstate solution of (100-200)g/L by adopting the conventional process; and the method can effectively separate and extract valuable metals such as tungsten and molybdenum, and has advantages of stable and simple process and low treatment cost.

The invention belongs to the treatment technology of a black hard ceramic membrane on the surface of magnesium alloy, in particular relating to a treatment method of a black hard microarc oxidation ceramic membrane on the surface of magnesium alloy. The invention mainly solves the technical problems that the colour of a ceramic membrane treated by magnesium alloy microarc oxidation is white or grey white mostly and the deep colour and even black ceramic membranes can not be obtained in the prior art. The method provided by the invention comprises the steps that sodium phosphate, sodium fluoride, sodium hydroxide, sodium molybdate, potassium carbonate, sodium tungstate, copper sulphate and potassium dichromate are added into water and prepared into an alkaline electrolytic solution, and the solution is stirred for later use; and then magnesium alloy and a stainless steel plate are immersed into the alkaline electrolytic solution, the magnesium alloy is taken as an anode, the stainless steel plate is taken as a cathode, and microarc oxidation treatment is carried out until a compact black hard ceramic membrane grows in situ on the surface of the magnesium alloy.

The invention discloses a super-wide-temperature-range nickel-hydrogen battery. The battery comprises an iron shell as well as a nickel electrode, a hydrogen electrode, a diaphragm and an electrolyte solution mounted in the iron shell, wherein the nickel electrode takes foam nickel as a substrate material; the space in foam nickel is filled with a positive electrode active substance Ni(OH)2, a conductive agent, an additive and a binder; the hydrogen electrode takes a porous nickel-plated steel belt, a copper net or foam nickel as a substrate material; the porous nickel-plated steel belt, the copper net or foam nickel is coated with a negative electrode active substance, namely, hydrogen storage alloy powder, the conductive agent, the additive or the binder; and the electrolyte solution is a mixture of a potassium-rich alkaline aqueous solution and sodium tungstate or tungstic acid crystals. The invention furthermore discloses a manufacturing method for the super-wide-temperature-range nickel-hydrogen battery. According to the super-wide-temperature-range nickel-hydrogen battery disclosed by the invention, the ratio of 0.2C discharge capacity to normal-temperature capacity maximally can reach 70-80% in an environment with the temperature of -45 DEG C; and the ratio of 0.2C discharge capacity to normal-temperature capacity of the nickel hydrogen battery maximally can reach 85-95% in an environment with the temperature of 70 DEG C. Moreover, the manufacturing method is simple and suitable for large-scale production.

The invention discloses a silver-modified bismuth tungstate composite photocatalyst, its preparation method and an application thereof. Bismuth tungstate in the catalyst is granules with the particle size being 0.5-3 microns and the catalyst is composed of bismuth tungstate pieces, the length of which is 30-100 nm and the thickness of which is 5-10 nm. Silver granules with the particle size being 5-40 nm are modified on the bismuth tungstate pieces. The specific surface area of the catalyst is 10-30 m<2>/g. The preparation method comprises the following steps of: respectively adding bismuth nitrate into a nitric acid solution with stirring to obtain a bismuth nitrate solution and adding polyvinylpyrrolidone into a sodium tungstate solution with stirring to obtain a mixed solution, adding the bismuth nitrate solution into the mixed solution, placing in an enclosed state, keeping warm at 160-180 DEG C for 20-24 h, centrifuging, washing, drying to obtain a bismuth tungstate powder, adding the bismuth tungstate powder into a silver nitrate solution, stirring, drying, grinding into a powder, and roasting the powder to prepare the target product. The product can be used in water polluted by organic matters or heavy metal ions to perform visible light photodegradation.

The invention relates to a preparation method of square tungsten oxide nano powder, belonging to the field of inorganic non-metallic materials. The content thereof is as follows: tungstenic acid deposition obtained by the reaction of sodium tungstate and hydrochloric acid is used as a precursor, citric acid is used as an auxiliary reagent, hydrochloric acid is used to adjust pH value and nano tungsten oxide is grown in a high-pressure autoclave by heating. Heating mode can be microwave heating and resistance wire heating, and the nanocrystalline grown is square. The characteristic of the square tungsten oxide powder material is that: the size of the square tungsten oxide is between 80 and 150nm. The advantages of the method are that: the process is simple, the cost is low and the shape and size of the tungsten oxide crystal are hydrothermally controlled by the citric acid auxiliary.

The invention discloses a composite water treatment agent which comprises the following components in parts by mass: 15-45 parts of sodium tungstate, 5-25 parts of polyaspartic acid, 1-5 parts of zinc salt, 2-15 parts of sodium benzoate and 2-25 parts of carboxylate, wherein sodium tungstate is a corrosion inhibitor which is non-toxic, causes no environmental hazard and can generate the synergic corrosion inhibition function with polyaspartic acid. With addition of other assistants, the composite water treatment agent becomes a green composite water treatment agent which has excellent corrosion inhibition and scale inhibition effects, lower in cost, non-phosphorus, easily biodegradable and beneficial to environmental protection. In China, tungsten reserves and yield are abundant, so that the sufficient tungsten compounds can be provided, and the cost of the treatment agent is greatly lowered.

The present invention relates to a transition metal tungstate, and in particular to a method for preparing a BiOI / CdWO4 heterojunction composite photocatalyst. The method uses bismuth nitrate, sodium tungstate, potassium iodide and chromium acetate as raw materials for preparing the BiOI / CdWO4 heterojunction composite photocatalyst. The prepared nano-composite photocatalyst has excellent visible light catalytic activity, especially a sample supplemented with 1.5mmol of bismuth nitrate has the best activity in degradation of rhodamine B, and reaches degradation rate of 90% after 90min of visible reaction, and has higher degradation activity than pure BiOI and CdWO4.

The invention relates to a method for treating a waste hard alloy and particularly relates to a method for treating a waste hard alloy grinding material, mainly solving the problems of long nickel-cobalt leaching time, high oxidizing agent consumption, high equipment requirement, long process, high separation difficulty of cobalt and tungsten which are contained in the waste hard alloy grinding material and low purity of an obtained tungsten product in the prior art. The method comprises the following steps of: (a) soda calcination: mixing tungsten carbide filter residues with sodium carbonate and sodium nitrate, and then calcining to obtain a material I; (b) caustic soda leaching: leaching the material I by using liquid caustic soda with [OH-] of 0.5-2.0 mol/l to obtain a sodium tungstate-containing solution and cobalt-nickel-containing filter residues; (c) cobalt-nickel leaching: leaching the cobalt-nickel filter residues by using an acid solution with [H+] of 0.5-2.0 mol/l to obtain a cobalt-nickel-containing solution used for cobalt-nickel recovery; (d) tungsten recovery: adding acid to the sodium tungstate-containing solution to regulate the pH value to 5.0-8.0 to obtain a high-purity tungstic acid precipitate, and washing, drying and calcining to obtain high-purity tungsten trioxide. The method disclosed by the invention can be used for well solving the problems and is worthy of being applied and popularized.

The invention discloses a bismuth tungstate composite photocatalyst modified by a nitrogen-doped carbon quantum dot and a preparation method and application thereof. The composite photocatalyst is characterized in that bismuth tungstate is taken as a carrier, and is modified with the nitrogen-doped carbon quantum dot. The preparation method comprises the following steps: mixing bismuth nitrate, sodium tungstate and water, and stirring the mixture to obtain a bismuth tungstate precursor solution; mixing the bismuth tungstate precursor solution with a nitrogen-doped carbon quantum dot solution, and stirring the mixture to obtain a mixed solution; performing a hydrothermal reaction to obtain the bismuth tungstate composite photocatalyst. The composite photocatalyst has the advantages of environmental friendliness, high photo-induced electron-hole separating efficiency, high light absorbing efficiency, high photocatalysis activity, high photocatalysis stability and high corrosion resistance; the preparation method has the advantages of simple preparation process, low raw material cost, and easiness in controlling operation conditions. The composite photocatalyst is used for catalyzing degradation of antibiotic wastewater, and has the advantages of simple application method, high degrading efficiency and high repeatability, and has a very good practical application prospect.

The invention provides a high-efficiency and clean tungsten smelting method. The method comprises the steps of: carrying out electrolysis on an NaCl solution to obtain NaOH and H2 from a cathode chamber and obtain Cl2 from an anode chamber; leaching a tungsten mineral raw material by the NaOH solution obtained by electrolysis to prepare a sodium tungstate solution; treating and transforming the obtained sodium tungstate solution by the existing technology to obtain a ammonium tungstate solution; oxidizing and removing ammonia nitrogen in waste smelting water by the Cl2 obtained by electrolysis; and reducing a tungsten oxide by the H2 obtained by electrolysis, thereby preparing tungsten powder. The method can be used for efficiently treating the tungsten mineral raw material to prepare the tungsten powder; and the method can save cost and no ammonia-nitrogen waste water is discharged.

The invention discloses a method for preparing a morphology and constitution controllable WO3 nano sheet/g-C3N4 nano composite material, and belongs to the field of photocatalysts. The nano composite material is of a structure that WO3 nano sheets are uniformly distributed on layered g-C3N4 nano sheets. The nano composite material is simple in preparation process and is prepared by using a one-step method. The method comprises the following steps: by taking sodium oleate as a surfactant, firstly, dissolving the surfactant into a dilute nitric acid solution at certain temperature, adding g-C3N4, sufficiently dispersing the g-C3N4, slowly adding a sodium tungstate solution, and performing reaction for 120 minutes at 60 DEG C, thereby obtaining the WO3 nano sheet/g-C3N4 nano composite material. The nano composite material can be used as a photocatalyst for degrading MO, and has good catalysis effects and stability.

A process for alkaline decomposition of both scheelite and wolframite includes such steps as grinding and pressure-digestion of the two ores in NaOH solution respectively at 140-200 deg.C and under 0.3-1.1 MPa for 1-6 hr, diluting and filtering the decomposed scheelite to obtain a solution of sodium tungstate, and directly using it to decompose the wolframite while adding additive containing PO4 ions. Its advantages are high decomposition percentage (99%), and reduced pollution and low alkali consumption.

The invention relates to a synthesizing method of a heteropolyacid imidazolium salt catalyst. The method belongs to the technical field of chemical synthesis. According to the invention, sodium tungstate and phosphoric acid are adopted as raw materials. Through the steps such as phosphotungstic acid synthesis, sodium ion removing, phosphotungstic acid imidazolium salt preparation, filtering, and spray drying, heteropolyacid imidazolium salt is obtained. The ionic liquid heteropolyacid imidazolium salt catalyst synthesized with a liquid synthesis route has catalytic activity substantially better than that of a heteropolyacid catalyst prepared with a traditional method. At least, the catalyst has an excellent performance in a reaction for synthesizing PTMEG through tetrahydrofuran polymerization.

The invention discloses a preparation method of an ultrathin tungsten trioxide dihydrate nanosheet photocatalyst. The preparation method is characterized in that an organic-inorganic hybrid of an organic amine intercalation is prepared through solvothermal reaction. The preparation method comprises the steps of mixing 10 mL of a sodium tungstate solution of which the concentration is 1.0 mol/L with 90 mL of a hydrochloric acid solution of which the concentration is 3.0 mol/L for reaction, so as to obtain tungsten trioxide dihydrate block powder; mixing tungsten trioxide dihydrate powder with organic amine for reaction for 2 to 3 days at the temperature of 100 DEG C to 150 DEG C, so as to obtain the organic-inorganic hybrid of the organic amine intercalation; then, forming the tungsten trioxide dihydrate ultrathin nanosheet through organic acid liquid phase peeling; and mixing tungsten trioxide dihydrate of the organic amine intercalation with an organic acid solution, and carrying out liquid phase ultrasonic peeling to obtain the tungsten trioxide dihydrate ultrathin nanosheet. The method is simple and convenient in use and easy to operate, and the prepared tungsten trioxide dihydrate ultrathin nanosheet has relatively high photocatalytic activity.

The present invention is process of synthesizing guaiacol, and relates to the application of catalyst in catalytically synthesizing guaiacol through the solid phase alkylation reaction between catechol and methanol. The catalyst has active component of ammonium metatungstate, sodium tungstate, ammonium molybdenum, ammonium biphosphate, ammonium phosphate, ammonium chromate or silicotungstic acid; and carrier of active carbon, SiO2, ZnO, Al2O3, TiO2, BaCO3 or CaO; and active component supporting amount of 2.1-30.2 wt%. The process of synthesizing guaiacol has catalytic reaction temperature of 533-573 K, the molar ratio between catechol and methanol of 1/7-1/2.5, and catalyst amount of 0.84-2.8 weight portions. During the process, the mixed solution of catechol and methanol is fed to the pre-heater in the flow rate of 0.3-2ml/hr, gasified and reacted catalytically at the temperature of 533-573 K.

The invention discloses a zinc coat environmental-friendly passivation solution and a use method thereof. The passivation solution is formed by dissolving a solute consisting of a plurality of materials into deionized water, wherein the solute in the solution comprises the following components: 80-120g/L of sodium molybdate, 20-30g/L of sodium tungstate, 2-7g/L of titanyl sulfate, 5-10g/L of phytic acid, 15-50g/L of acrylic acid and 20-40g/L of hydrogen peroxide, wherein the pH value of the solution is regulated to 1.5-2.5 by using dilute acid. It is found that the zinc coat environmental-friendly passivation solution contains no chromium ions and thoroughly solves the problem of environment pollution brought by chromating; through salt spray test examination, a zinc coating plate passivated by the passivation solution has corrosion resistance approximately consistent with that of the traditional passivation solution; meanwhile, the use method is simple and easy.

The invention belongs to the technical field of photocatalytic materials, and particularly relates to a heterojunction nanosheet photocatalyst and a preparation method and application of the heterojunction nanosheet photocatalyst. A visible light responsive heterojunction photocatalytic material is prepared from silver nitrate, disodium hydrogen phosphate, nitric acid, ammonia water, and sodium tungstate as raw materials by utilizing a hydrothermal method and a precipitation method. The photocatalyst is made from a silver phosphate/tungsten oxide heterojunction photocatalytic material formed by tungsten oxide and silver phosphate, tungsten oxide is in a nanosheet shape, silver phosphate is in a particle shape, the silver phosphate nano-particles uniformly grow on the surfaces of the tungsten oxide nanosheets, and the molar ratio of tungsten oxide to silver phosphate is 1 to (0.3-1.8). The visible light responsive heterojunction photocatalytic material prepared by the method is used for degrading a methylene blue trihydrate dye, and the degradation rate can reach 97% after the degradation is carried out for 20 minutes.

The present invention provides one kind of electroplating apparatus for electroplating inner wall of copper tube for tubular crystallizer and the corresponding electroplating process. The electroplating apparatus includes electroplating solution storing tank, filter, relevant controller and pipeline; and the electroplating bath has tubular crystallizer copper tube as electroplating cathode, fixture sealing cover and anode titanium basket. The electroplating process includes the deoiling treatment of the inner surface of the crystallizer; and electroplating with W-Co electroplating solution comprising cobalt sulfamate, sodium tungstate, HCl, boric acid, lauryl sodium sulfate and AD486 to form coating of 0.1-1 mm thickness. The electroplating process can obtain W-Co alloy coating with small friction coefficient, high wear resistance, heat expansion coefficient near that of copper and no peeling off and production process produces easy-to-process effluent and no harmful gas.

The invention provides a method for preparing fluorine-mixed bismuth tungstate powder through a microwave hydrothermal method. The method comprises the steps as follows: with bismuth nitrate pentahydrate, sodium tungstate dehydrate and ammonium fluoride as raw materials, dissolving Bi(NO3)3.5H20 and Na2WO4.2H2O into deionized water according to the mole ratio of Bi:W of 2:1, adding a certain amount of NH4F, magnetically stirring the raw material at a room temperature to make the raw material be uniformly mixed so as to obtain a precursor solution for microwave hydrothermal reaction, transferring the precursor solution into a reaction kettle, adopting the microwave hydrothermal method to react the precursor solution at the temperature of 160 DEG C to 240 DEG C, and controlling the time for heat preservation for 60 minutes so as to obtain the fluorine-mixed bismuth tungstate powder. The method provided by the invention has the advantages of simple device, low temperature (about 200 DEG C), high efficiency (the reaction time is about 60 minutes), high powder reacting activity, simple technology, high efficiency, low energy consumption, low cost, environment protection and the like.