185 results about "Silicon tetrachloride" patented technology

The invention relates to a continuous production method of high-purity tetraethoxysilane, and belongs to the technical field of tetraethoxysilane preparation. The method comprises a raw material pretreatment stage and a purification and rectification stage: in the pretreatment stage, silicon tetrachloride and ethanol are subjected to an esterification reaction in a molar ratio of 1: (3-4) under the protection of nitrogen, the pH is adjusted to be neutral through triethylamine, and triethylamine hydrochloride is removed through reduced pressure distillation; then, a cerium oxide-molecular sieve composite adsorbent with the specific surface area larger than or equal to 800 m / g and the pore diameter of 2-5 nm is adopted for dehydration under the pressure of 0.8-1.2 MPa till the water content is smaller than or equal to 5 ppm, and volatile impurities are removed through high-purity nitrogen purging; in the purification stage, metal ions and Cl are synergistically removed through a titanate modified resin layer and a nano TiOtube layer, and then step-by-step separation is performed through a four-stage differential pressure rectifying tower. Through collaborative optimization of structural design of the composite adsorbent, construction of an organic-inorganic hybrid interface of the resin layer and pressure gradient rectification, 72-hour continuous production is achieved, the single-pass yield of the product is 92%, and the total amount of metal impurities is smaller than or equal to 5 ppb.

The invention discloses a method for recycling silicon industry by-product silicon tetrachloride based on gallium electrode electro-deposition, which is used for solving the problems of low solubility and crystal structure in the process of preparing silicon by an electro-deposition method. According to the method, a deep eutectic solvent system composed of 1, 3-dimethyl-2-imidazolinone and 1, 3-dimethylurea is adopted to efficiently absorb silicon tetrachloride in a green manner and prepare the electrolyte, and the electrolyte is converted into high-purity, uniform and compact silicon crystals by using a liquid gallium electrode electrodeposition technology, so that effective conversion from wastes to high-added-value materials is realized. Meanwhile, the low-toxicity eutectic solvent which is easy to prepare and has good biodegradability is adopted to replace traditional ionic liquid or other chemical reagents, so that the safety, the environmental protection property and the sustainability of the process are remarkably improved, and the treatment cost and the environmental burden are reduced at the same time.

The present invention discloses a method for separating nickel and iron from a nickel-iron alloy by chlorination roasting: (1) placing the nickel-iron alloy in a roasting furnace; (2) introducing a gaseous chlorinating agent into the roasting furnace for staged roasting to obtain roasting slag and a roasting gas phase; wherein the gaseous chlorinating agent is a mixture of chlorine and gaseous ferric chloride; and (3) condensing the roasting gas phase obtained in step (2) in stages to obtain solid ferric chloride and liquid silicon tetrachloride, respectively. The present invention controls the composition of the chlorinating agent during the chlorination roasting process to achieve selective and directional volatilization of iron into the gas phase while preventing nickel from being chlorinated. Thus, nickel and iron in the nickel-iron alloy can be separated in a single step, and the process flow is short.

The invention belongs to the technical field of silicon carbide coatings, and particularly relates to a method for quickly depositing a silicon carbide coating through CVD (Chemical Vapor Deposition), which comprises the following steps: pretreating a graphite substrate; debugging the equipment; placing the pretreated substrate in a reaction furnace, closing a furnace door, starting a vacuum system, pumping the pressure in the reaction furnace to-Pa, and reducing the interference of air in the furnace on the reaction; introducing a small amount of hydrogen into the reaction furnace, rapidly raising the temperature in the furnace to 800-900 DEG C, maintaining the temperature, then introducing a very small amount of silicon source and carbon source gas, and carrying out preliminary deposition on the surface of the substrate; and hydrogen, silicon tetrachloride and methane are sequentially introduced. The preparation method of the CVD silicon carbide coating can solve the problems of low deposition rate, long preparation period and the like when the existing CVD process is used for preparing the silicon carbide coating, so that the production efficiency can be greatly improved, the cost can be reduced, and the preparation method has important significance in promoting the application of the silicon carbide coating in more fields.

The invention relates to a preparation method of silicon dioxide-boron nitride nanobelt aerogel, which comprises the following steps: dissolving melamine and boric acid in a co-solvent of tert-butyl alcohol and hot deionized water, stirring and mixing, carrying out ultrasonic treatment, freeze-drying and the like to obtain a melamine-boric acid aerogel precursor, placing the precursor in a tubular furnace, and carrying out vacuum drying to obtain the silicon dioxide-boron nitride nanobelt aerogel. Pyrolyzing in an ammonia gas atmosphere to obtain boron nitride nanobelt aerogel; and placing the boron nitride nanobelt aerogel in a xylene solution containing tetraethoxysilane and silicon tetrachloride, taking out the boron nitride nanobelt aerogel, and drying the boron nitride nanobelt aerogel. And hydrolyzing and pyrolyzing in an inert atmosphere to form a silicon dioxide layer on the surface, thereby obtaining the silicon dioxide-boron nitride nanobelt aerogel. The silicon dioxide and boron nitride nanobelt aerogel is low in density and excellent in mechanical property and oxidation resistance.

The utility model provides a system for synthesizing trichlorosilane. The system for synthesizing trichlorosilane comprises a trichlorosilane synthesis reaction device, a first gas-solid separation unit, a first tail gas treatment unit, a silicon tetrachloride hydrogenation reaction device, a second gas-solid separation unit, a second tail gas treatment unit and a product separation and purification unit. According to the system, through the technological process of fusing the trichlorosilane synthesis reaction and the silicon tetrachloride hydrogenation reaction, efficient utilization of silicon powder, hydrogen and silicon tetrachloride is achieved, the investment and operation cost is saved, and meanwhile the raw material consumption is reduced.

The invention discloses a manufacturing process for synthesizing high-purity quartz sand by a silicon tetrachloride liquid-phase hydrolysis method, which comprises the following process steps in sequence: carrying out liquid-phase hydrolysis on silicon tetrachloride and water, and then washing, carrying out solid-liquid separation, drying, calcining, grinding and screening the hydrolysis product to finally obtain high-purity quartz powder, a heating process is carried out while solid-liquid separation is carried out, or the heating process is carried out between the washing process and the solid-liquid separation process; or a heating process is carried out while the washing process is carried out. The orthosilicic acid in the hydrolysate is easier to decompose into metasilicic acid due to heating; in this way, metasilicic acid almost completely exists during solid-liquid separation, only filter residues of metasilicic acid particles exist on the filter screen and are easy to transfer, and the problem that colloidal precipitated orthosilicic acid filter residues are difficult to transfer is solved. Loss of orthosilicic acid is avoided as far as possible, raw material consumption is reduced, preparation cost is reduced, and the filter screen is convenient to clean.

The electronic-grade silane gas continuous production preparation system comprises a cold hydrogenation treatment device, an inlet of the cold hydrogenation treatment device is connected with a raw material supply system, and an outlet of the cold hydrogenation treatment device is connected with a cold hydrogenation rectifying tower through a pipeline. The cold hydrogenation rectifying tower is sequentially connected with the boron and phosphorus removal adsorption column, the first-stage disproportionator, the first tower, the second tower, the second-stage disproportionator, the third tower and the fourth tower through pipelines, and electronic-grade silane in the fourth tower is used for being conveyed to a silane tank area; the first tower is used for removing silicon tetrachloride produced after the disproportionation reaction of the first-stage disproportionator; the second tower is used for separating the extracted chlorosilane material; the third tower is used for separating silane from chlorosilane; and the fourth tower is used for discharging light impurities and heavy impurities and conveying gas-phase electronic-grade silane into a silane tank area. The device and the method realize continuous, efficient and high-purity production of the electronic-grade silane gas, and have the advantages of low energy consumption, low cost, thorough impurity removal and the like.

The invention relates to the field of inorganic nonmetal powder materials, and discloses a preparation method of silicon nitride powder, which comprises the following steps: (1) mixing a surfactant, liquid ammonia and an organic solvent to form a to-be-reacted solution, and mixing the to-be-reacted solution with a silicon tetrachloride solution for substitution reaction to obtain a solution containing silicon imine suspended matters; the surfactant is selected from one or more of sodium dodecyl sulfate, polyvinylpyrrolidone, sodium stearate, sodium dodecyl benzene sulfonate, fatty acid methyl ester ethoxylate sulfonate, fatty acid sorbitan, polysorbate-20 and polysorbate-80; the surfactant is selected from one or more of sodium dodecyl sulfate, polyvinylpyrrolidone, sodium stearate, sodium dodecyl benzene sulfonate, fatty acid methyl ester ethoxylate sulfonate, fatty acid sorbitan, polysorbate-20 and polysorbate-80; (2) carrying out suspended matter extraction and impurity removal on the solution containing the silicon imine suspended matter to obtain silicon imine powder; (3) performing thermal decomposition on the silicon imine powder to obtain amorphous silicon nitride powder; and (4) crystallizing the amorphous silicon nitride powder to obtain the alpha-phase silicon nitride powder. The method can reduce the impurity content and agglomeration degree of the precursor so as to improve the quality of the silicon nitride powder.

The invention provides a photovoltaic glass surface self-cleaning coating and a preparation method thereof.The photovoltaic glass surface self-cleaning coating is prepared from a dehydrated organic solvent, 1-7 parts by mass of tetramethyl orthosilicate, 2-15 parts by mass of fluorosilane hydrophobic coupling agent, 10-20 parts by mass of silicon tetrachloride, 1-10 parts by mass of hydrophobic silane coupling agent, 5-15 parts by mass of dichloro (methyl) (3, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5- and 1-10 parts of 2, 3, 3-trifluoropropyl) silane and 1-10 parts of dimethyl dichlorosilane. According to the preparation method, tetramethyl silicate with relatively low reaction activity is used as a raw material to react with silicon tetrachloride to form an intermediate species with moderate activity, and then a linear chain polymer modification layer is pre-formed on the surface by utilizing the difference of reaction rates; a fluorosilane substance added in the coating also can participate in the reaction to form an organic silicon linear polymer with a fluorosilane side chain; in the recombination process of polysiloxane, perfluoro side chains with lower surface energy migrate to the surface of the coating; meanwhile, by adding the dichlorosilane coupling agent and the trichlorosilane coupling agent, the flexibility and hydrophobicity of the coating are improved.

The invention provides a silicon-carbon negative electrode material and a preparation method and application thereof, and belongs to the technical field of lithium ion battery negative electrode materials. The preparation method comprises the following steps: adding silicon tetrachloride and calcium carbide into a carbon tetrachloride solution, uniformly stirring, and transferring into a high-pressure reaction kettle for reaction to obtain a Si-C precursor; adding the obtained Si-coated C precursor into absolute ethyl alcohol and carrying out ball milling treatment; and carrying out suction filtration and drying on the material obtained by ball milling, calcining and carbonizing in inert gas, and cleaning the obtained product to obtain the silicon-carbon negative electrode material. The silicon-carbon negative electrode material prepared by the invention is used for preparing a negative electrode material of a lithium ion battery, has good cycle performance, has relatively high reversible specific capacity and first coulombic efficiency, and is excellent in overall electrochemical performance.

The present invention provides a method for preparing silica based on a liquid-liquid two-phase interface method, comprising the following steps: S1, providing an organic solution and water, wherein the organic solution includes an organic solvent and silicon tetrachloride; the volume ratio of the water to the organic solution is not less than 1 / 50; the molar ratio of the water to the silicon tetrachloride is not less than 4:1; the organic solvent is insoluble or slightly soluble in the water; S2, mixing the water and the organic solution to obtain a first treatment liquid; S3, aging the first treatment liquid to obtain a second treatment liquid; the second treatment liquid comprises an aqueous phase and an organic phase; S4, separating a primary silica product from the second treatment liquid; and calcining the primary silica product to obtain a silica product. The present invention prepares silica nanopowders with a high degree of spheroidization based on silicon tetrachloride and the liquid-liquid two-phase interface method, and the reaction is mild and low-risk.

The invention relates to a method and a system for preparing trichlorosilane from ferrosilicon, the method comprises the following steps: taking ferrosilicon, silicon tetrachloride and hydrogen as raw materials, fully reacting in a fluidized bed reactor to obtain trichlorosilane and FeSiy alloy, xlt; 40). The system comprises a fluidized bed reactor (200), a cyclone separator (300), a washing tower (400), a gas-liquid separator (500) and a coarse distillation tower (600). Compared with the prior art, the method has the remarkable characteristics that the silazite is used as a silicon source and is low in cost and easy to obtain, the reaction activity of trichlorosilane and FeSiy generated by reaction of the silazite, silicon tetrachloride and hydrogen is high, the utilization rate of silicon elements in the compound is high, no extra catalyst needs to be added in the co-hydrogenation reaction, meanwhile, the byproduct FeSiy alloy is produced, and the production cost is low.

The invention relates to the technical field of asphalt pavement materials, in particular to an RAP-steel slag emulsified asphalt cold recycled mixture volume expansion inhibition method. The method comprises the following steps: firstly, pretreating a selected steel slag sample, and preparing a silicon tetrachloride solution to soak the steel slag; then, the soaked steel slag is taken out and placed in a curing box to be cured, and the pH of the cured steel slag is adjusted; and finally, detecting the expansion rate of the RAP-steel slag emulsified asphalt cold-recycled mixture and the content of free calcium oxide in the RAP-steel slag emulsified asphalt cold-recycled mixture according to specifications, evaluating the volume expansion inhibition effect of the method on the cold-recycled mixture, and based on the further optimization scheme, providing the efficient volume expansion inhibition method for the RAP-steel slag emulsified asphalt cold-recycled mixture. Therefore, the steel slag can be better applied to the asphalt pavement, and the road performance is improved while the solid waste steel slag is fully utilized.

The invention discloses a cold hydrogenation quench tower energy recovery system and an operation mode, and the system comprises a quench tower, a vaporizer, a first-stage heat exchange system, a second-stage heat exchange system and a circulating water cooler, and layered energy recovery is realized through a three-stage cascade heat exchange structure: a high-temperature liquid-phase material discharged from a quench tower sequentially passes through a second-stage heat exchange system, a first-stage heat exchange system and a circulating water cooler to complete heat exchange, and meanwhile, a heating heat source is provided for silicon tetrachloride and hydrogen. Through the design of multiphase flow enhanced heat transfer, feed gas quality-divided heat exchange and tail liquid recovery, the system significantly improves the energy recovery rate, reduces steam consumption and raw material loss, enhances the operation stability of the system, and is suitable for efficient and energy-saving production of a cold hydrogenation process.

The application discloses an olefin polymerization catalyst and a preparation method thereof, and the olefin polymerization catalyst is used for preparing a polypropylene thermoplastic elastomer, and the olefin polymerization catalyst contains silicon tetrachloride modified silicon dioxide, a transition metal component and a non-transition metal component; the transition metal component is titanium tetrachloride and / or titanium alkoxy, and the non-transition metal component is a magnesium-containing compound. The olefin polymerization catalyst has high initial activity and overall activity, and polypropylene particles with high porosity are obtained. The catalyst can obtain a polypropylene thermoplastic elastomer with high rubber content in the synthesis process of the polypropylene thermoplastic elastomer.

The utility model provides a liquid removing device externally arranged on a silicon tetrachloride vaporizer, and aims to solve the technical problem that liquid is contained in a medium after silicon tetrachloride is vaporized in the prior art. The liquid removal device comprises: a tank body having an inlet, an outlet and an inspection port; the defoaming net is arranged in the middle of the tank body and located between the inlet and the outlet, and the interior of the tank body is divided into two spaces by the defoaming net; the blind plate covers the inspection opening; wherein the inlet is located at the bottom of the tank body, and the outlet is located above the inlet. The inlet of the tank body is connected with the outlet of the vaporizer, a medium obtained after vaporization of silicon tetrachloride needs to penetrate through the defoaming net, and liquid carried in the medium can be separated through the defoaming net. Besides, the inlet of the tank body is arranged at the bottom of the tank body, so that the separated liquid can fall into the vaporizer again under the influence of gravity for vaporization. According to the technical scheme, the influence on the production quality of polycrystalline silicon in the reduction furnace can be avoided, and the production energy consumption of the polycrystalline silicon is reduced.

The present invention provides a method for preparing silica based on the gas-liquid two-phase interface method, comprising the steps of: S1, providing an aqueous alcohol solution; S2, mixing an additive into the aqueous alcohol solution to obtain a reaction solution; the additive includes an alkali material; S3, loading silicon tetrachloride gas in the inert gas, and then controlling the inert gas to continuously aerate into the reaction solution; S4, stopping aerating into the reaction solution to obtain a termination solution; S5, aging the termination solution to obtain an aged solution; S6, separating the solid and liquid of the aged solution to obtain a primary silica product. The present invention prepares silica through the gas-liquid two-phase interface reaction of silicon tetrachloride, and overcomes problems such as fast hydrolysis rate and high danger of silicon tetrachloride by using the gas-liquid interface principle, and prepares silica with high dispersibility, spheroidization degree and purity, controllable morphology and uniform particle size distribution.

The invention discloses a chlorosilane raw material purification system and method for reducing donor and acceptor impurities in polycrystalline silicon, and belongs to the technical field of polycrystalline silicon production, the chlorosilane raw material enters a first rectifying tower for primary rectification separation, the tower kettle of the first rectifying tower is extracted and flows into a silicon tetrachloride raw material tank, and the tower top of the first rectifying tower is extracted and flows into a second rectifying tower; tower top produced liquid of the first rectifying tower is subjected to secondary rectifying separation in a second rectifying tower, tower bottom produced liquid of the second rectifying tower flows into a third rectifying tower, and tower top produced liquid of the second rectifying tower flows into a mixer; tower kettle produced liquid of the second rectifying tower is subjected to third-time rectifying separation in a third rectifying tower, and tower top produced liquid of the third rectifying tower flows into a fourth rectifying assembly; the tower top produced liquid of the third rectifying tower is subjected to fourth rectifying separation in a fourth rectifying assembly, tower bottom produced liquid of the fourth rectifying assembly flows into a chlorosilane storage tank, and product liquid is produced from the tower top of the fourth rectifying assembly; and the tower kettle produced liquid of the third rectifying tower is subjected to adsorption and impurity removal in the first adsorber, and flows into a chlorosilane storage tank after impurity removal.

The invention belongs to the technical field of cold hydrogenation synthesis, and particularly relates to a treatment method of slag slurry generated in a cold hydrogenation synthesis process, the slag slurry generated in the cold hydrogenation process is sequentially subjected to primary filtration, secondary diatomite precoating filtration, drying evaporation and rectification purification treatment, so that the recovery rate of chlorosilane (mainly silicon tetrachloride) is up to 99%, and the recovery rate of chlorosilane is up to 99%. Resource waste and environmental pollution are avoided, meanwhile, an alkali washing tank is omitted, the process is simplified, and energy consumption is reduced; in addition, physical separation (filtration, drying and rectification) and solid slag neutralization are adopted in the treatment method, no wastewater is generated, a matched sewage treatment system is not needed, and the environmental protection cost and energy consumption are remarkably reduced.

A system and method for separating aluminum trichloride from cold-hydrogenated silicon tetrachloride includes a pressure-reducing tank, a condenser, a first extraction tank, a second extraction tank, a clear liquid filter, and a clear liquid tank. The system is characterized by: a silicon tetrachloride inlet pipe at the top of the pressure-reducing tank; the bottom of the pressure-reducing tank being connected to the first and second extraction tanks via pipes; the bottoms of the first and second extraction tanks being connected to a dryer via pipes; the side walls of the first and second extraction tanks being connected to the clear liquid filter via pipes; the tops of the first and second extraction tanks being connected to the condenser via pipes; the bottom of the condenser having a liquid outlet pipe connected to the top of the clear liquid tank; and the bottom of the clear liquid tank having a silicon tetrachloride recovery pipe; and the clear liquid filter being connected to the liquid outlet pipe via a pipe. This invention improves the clogging situation of the entire cold hydrogenation system, solves the problem of long-term operation of the cold hydrogenation system, and reduces the equipment failure rate.

The invention discloses a trichlorosilane deep rectification composite impurity removal process, and belongs to the technical field of polycrystalline silicon production raw material purification. According to the process, deep purification of crude trichlorosilane is achieved through the steps of pre-protection and primary adsorption, directional rectification enrichment of methyl dichlorosilane narrow fractions, concentration, mixing with silicon tetrachloride, catalytic reaction rectification conversion, differential pressure thermal coupling rectification purification, double-tank parallel deep purification, tail gas treatment and the like. According to the method, the impurity methyl dichlorosilane difficult to remove is precisely separated through side extraction, the impurity methyl dichlorosilane is converted into a component easy to separate through a catalytic reaction, and the boron and phosphorus impurities are deeply removed in combination with differential pressure thermal coupling energy saving and double-tank alternate adsorption. The process can efficiently remove moisture, metals and key impurities boron and phosphorus, obviously improves the purity of the trichlorosilane product, realizes gradient utilization of energy and hydrogen circulation, and has the advantages of high purity, low energy consumption and continuous production.

This invention provides an activation method for a liquid fatty amine, a preparation process for the liquid fatty amine and silane, wherein the liquid fatty amine has a tertiary amine group; the activation method involves activating the liquid fatty amine with silicon tetrachloride; this method can significantly improve the catalytic effect of the liquid fatty amine, and the activated liquid fatty amine exhibits higher catalytic activity in the process of disproportionation of trichlorosilane to prepare silane, which can effectively reduce the reaction activation energy, increase the reaction rate, and improve the single-pass reaction efficiency and conversion rate.

The application provides a method for preparing chlorosilane by catalytic cracking of polychlorosiloxane, which comprises the following steps: adding high-boiling material, a chlorine source, a catalyst and a reducing agent into a reactor to generate silicon tetrachloride through a catalytic cracking reaction; the high-boiling material comprises at least one of polychlorosilane and polychlorosiloxane; the catalyst is a supported catalyst, the carrier material of the catalyst is a porous material, and the active component of the catalyst comprises at least one of copper, nickel, zinc and rare earth elements. The method can effectively open Si-Si bonds and Si-O bonds, and realize the cracking of high-boiling materials such as polychlorosilane and polychlorosiloxane generated in the production process of polysilicon, especially the cracking of oxygen-containing polychlorosilane. Under the joint action of the reducing agent, the catalyst and the silicon-based additive, the conversion rate of polychlorosiloxane is higher, and the energy consumption of the reaction can be effectively reduced.

The invention relates to a method for recovering silicon in the form of silicon tetrachloride, in which biochar having a silicon content of at least 1% by weight, expressed as% by weight of elemental silicon, is reacted with elemental chlorine at a temperature of 350 to 900 DEG C and the formed silicon tetrachloride is separated from the exhaust gas stream, preferably by condensation.

The invention discloses an environment-friendly chlorine-free polysilicate synthesis process. The process comprises the following steps: by taking silicon powder, alcohol and a silicate synthesis catalyst as raw materials, directly reacting at 120-180 DEG C to generate a silicate intermediate, and carrying out combustion treatment on byproduct hydrogen; and hydrolyzing the obtained intermediate at 40-80 DEG C under the catalysis of a chlorine-free immobilized hydrolysis catalyst, and carrying out condensation and activated carbon adsorption refining to obtain a polysilicate product. A traditional silicon tetrachloride route is thoroughly abandoned, introduction of chlorine elements is avoided from the source, no hydrogen chloride is generated in the reaction process, and environmental pollution and equipment requirements are greatly reduced; the method has the advantages of simple process, stable raw material source and high atom economy, can realize cyclic utilization of silicon powder and alcohol, and can flexibly produce polysilicate esters of different brands by regulating and controlling process conditions. The process has the advantages of cleanness, safety, low cost, high product purity and the like, and is particularly suitable for high-end fields with strict requirements on chlorine content.

The invention provides a method and a system for recovering chlorosilane in polycrystalline silicon process waste gas. The method for recovering the chlorosilane in the polycrystalline silicon process waste gas comprises the following steps: absorbing the process waste gas by using a silicon tetrachloride solution to obtain a chlorosilane mixed solution and intermediate waste gas; and adsorbing the intermediate waste gas by using an adsorbent to obtain lean gas and an adsorbent to be regenerated. According to the method for recovering chlorosilane in the polycrystalline silicon process waste gas, chlorosilane in the process waste gas can be recycled with lower energy consumption and cost, and the method has excellent economic benefits.

The invention provides a process for purifying and refining industrial grade titanium tetrachloride, which comprises the following steps of: removing main impurities such as silicon tetrachloride, vanadium oxychloride, aluminum chloride, ferric chloride and titanium oxychloride in a titanium tetrachloride crude product by adopting a rectification method and a chemical method, and condensing into a titanium tetrachloride liquid; carrying out degassing treatment on the titanium tetrachloride liquid; filtering the titanium tetrachloride liquid by using an ultrafiltration membrane; filtering the titanium tetrachloride liquid by using a nanofiltration membrane; and crystallizing the titanium tetrachloride liquid to obtain a finished product of which the purity reaches 99.99% and the total content of metal impurities is less than 5ppb. Main impurities in a titanium tetrachloride crude product are removed through a rectification method and a chemical method, then titanium tetrachloride liquid is filtered through an ultrafiltration membrane and a nanofiltration membrane, and metal impurities are efficiently removed through surface negative charges of the nanofiltration membrane, so that a titanium tetrachloride finished product with the purity reaching 99.99% and the total content of the metal impurities being smaller than 5 ppb is obtained. The process steps are simplified, and the titanium tetrachloride purification efficiency is improved.

The present invention discloses a method for selecting silicon powder particles suitable for a cold hydrogenated fluidized bed. The key points of the technical solution are to assume that the potential energy of the silicon powder in the bed is offset by the kinetic energy of the gas phase material, calculate the gas flow rate μ of the gas phase on the surface of the silicon powder in the fluidized bed; select the mesh size of the silicon powder particles according to the real-time rising gas flow rate, and maintain the bulk density in the fluidized bed at 200-2500 kg / m 3 The mesh ratio of all silicon powder particles fed into the fluidized bed is calculated. The present invention provides a method for selecting silicon powder particles suitable for a cold hydrogenated fluidized bed based on the amount of silicon tetrachloride vaporized and the rising gas velocity within the fluidized bed. The method is simple to calculate and easy to operate, making it suitable for use in cold hydrogenated fluidized bed production operations. It reduces the amount of metallic silicon powder particles carried out of the fluidized bed, prevents damage to the distributor, and achieves a high conversion rate.

The application relates to the technical field of battery material and resource recycling, and provides a process for preparing lithium-sulfur electrolyte raw materials based on waste salt, which comprises the following steps: taking industrial waste salt as a sulfur source, taking lithium-rich waste residue as a lithium source, taking waste carbon as a reducing agent, uniformly mixing the three with a binder, granulating, further calcining to obtain a mixture, mixing the obtained mixture with a solvent A, ball milling, solid-liquid separation, obtaining a liquid phase containing sulfides, subjecting the obtained solid phase to acid immersion treatment and condensation to obtain silicon tetrachloride, mixing and dissolving the liquid phase containing sulfides and lithium chloride, carrying out solid-liquid separation to obtain a solution containing lithium chloride and lithium sulfide, reducing and concentrating the solution containing lithium chloride and lithium sulfide to obtain a mixed product of lithium chloride and lithium sulfide, and further adjusting the proportion to obtain lithium-sulfur electrolyte raw materials. The application realizes the resource utilization of industrial waste salt and lithium-rich waste residue, reduces the preparation cost of lithium-sulfur electrolyte raw materials, simultaneously produces high-value silicon tetrachloride as a byproduct, and reduces waste emission.