79 results about "Ultra high purity" patented technology

The invention relates to the technical field of PSA (Pressure Swing Adsorption) hydrogen extraction, in particular to a hydrogen purification process based on a PSA device, which comprises the following steps: raw material gas is firstly decompressed and enters the PSA device, a product hydrogen after impurity removal is sent to the outside, desorbed gas of the PSA device is pressurized by a desorbed gas compressor and is sent to a first-section shift converter, the raw material gas enters an adsorption tower in an adsorption state, and the desorbed gas enters a second-section shift converter; under the action of a special adsorbent, CO, N2, CH4O, CH4, AR and other components in the raw material gas are adsorbed, and high-purity H2 flows out of the tower top, is subjected to pressure stabilization metering through a regulating valve and then is sent out. According to the hydrogen purification process based on the PSA device, residual impurities can be deeply removed by using two-stage pressure swing adsorption, additionally arranging a two-stage adsorption tower and performing post-treatment detection on hydrogen, the impurity content required by high-purity hydrogen needs to be controlled at a ppm level, the purity of the hydrogen can stably rise to 99.99% or even higher through two-stage PSA, and the purity of the hydrogen is greatly improved. The use standard of ultra-high-purity hydrogen in the production of semiconductors and photovoltaic cells is met, and the process stability and the yield of products are guaranteed.

The invention discloses a preparation method of an ultra-pure hydroxylamine aqueous solution, and relates to the field of organic chemistry and chemical industry production. The method comprises the following steps: reacting electronic-grade hydroxylamine salt with organic alkali in a proper solvent to generate hydroxylamine, then separating and removing salt and unreacted hydroxylamine in a reaction solution through a mercaptopyridine ion exchange modified membrane, and finally concentrating the solution into 50wt% ultra-high-purity hydroxylamine aqueous solution by adopting reduced pressure evaporation or multi-effect evaporation. The process has the characteristics of high efficiency, environmental protection, simplicity and easiness in operation, effectively improves the purity, yield and separation efficiency of hydroxylamine, and meets the strict requirements of electronic grade hydroxylamine on purity and metal ion content.

The invention discloses electronic-grade hafnium oxide and a preparation method and application thereof, and relates to the technical field of high-dielectric-constant materials, and the preparation method comprises the following steps: carrying out chlorination reaction on crushed coarse hafnium oxide and graphite powder to prepare coarse hafnium tetrachloride; purifying the crude hafnium tetrachloride by adopting a molten salt purification method and / or a hydrogenation purification method to prepare high-purity hafnium tetrachloride; the method comprises the following steps: introducing high-purity hafnium tetrachloride into a sublimation furnace, introducing oxygen and an AlCl3 gas-phase catalyst into the sublimation furnace, and oxidizing the high-purity hafnium tetrachloride into hafnium oxide particles and chlorine; and dechlorinating the hafnium oxide particles through a fluidized bed to obtain the electronic-grade hafnium oxide. The hafnium oxide prepared by the preparation method not only has electronic-grade ultra-high purity, but also overcomes various defects of synthesis by using hafnium tetrachloride water; and the technological process is simple, the production efficiency is high, and the production cost is low.

The invention relates to the field of graphene preparation, and discloses a layer number controllable graphene material preparation process which comprises the following steps: S1, substrate selection: selecting a copper surface or nickel surface substrate, and putting the copper surface or nickel surface substrate into a chemical vapor deposition reaction chamber; s2, raw material preparation: selecting ultra-high-purity natural flaky graphite, and putting the pretreated ultra-high-purity natural flaky graphite into a reaction chamber; s3, reaction precursor: introducing hydrogen and argon into the reaction chamber, and adjusting to preset conditions; s4, reaction condition adjustment: adjusting the temperature and atmosphere to gasify the graphite and deposit the graphite into graphene; and S5, cooling and transferring: spraying a protective layer after cooling, drying, and then transferring to a target substrate. Through the technical scheme of temperature staged regulation and control and hydrogen concentration dynamic regulation, the deposition process of carbon atoms on the substrate is more controlled, the number of growth layers is more stable, the carbon dissolution and precipitation rate is effectively balanced, random accumulation of a multi-layer structure is avoided, and the application of the multi-layer structure in a high-precision electronic device is more reliable.

The invention provides an ultra-pure thorium fluoride production process which comprises the following steps: preparing a nanoscale ThF4.xNH4F precursor through a gas-liquid-solid three-phase reaction, atomizing an ammonium fluoride solution into microdroplets by adopting ultrasonic atomization, and carrying out synergistic reaction with gaseous ammonium fluoride and a liquid-phase thorium nitrate solution; a microwave-plasma synergistic fluorination reaction is adopted, and the precursor is heated in a high-purity inert atmosphere to generate crude thorium fluoride; according to the ultra-pure thorium fluoride production process provided by the invention, the purity of thorium fluoride is remarkably improved through the technical means of preparation of a nanoscale precursor through a gas-liquid-solid three-phase reaction, microwave-plasma synergistic fluorination, multi-stage sublimation combined with graphene-based nano trapping membrane purification, intelligent process control, by-product closed-loop recovery and the like; the impurity content is low, and the requirements of nuclear reactor fuel substrates and high-end optical coatings on ultra-high purity are met. The method has the advantages of high yield, high process stability and small purity fluctuation among batches, and the production efficiency and the product consistency are obviously improved.

The invention relates to the technical field of high-purity quartz purification methods, in particular to a high-purity quartz green low-consumption purification method which comprises the following steps: S1, plasma-assisted crushing pretreatment; s2, complex acid leaching-microwave synergistic impurity removal; s3, fluidized chloridizing roasting; s4, nano bubble water washing-targeted adsorption; s5, performing vacuum heat purification; according to the purification method of the high-purity quartz, the step of complex acid leaching-microwave synergistic impurity removal is adopted, highly toxic hydrofluoric acid in a traditional chemical acid leaching method is abandoned, and the toxicity of waste liquid is greatly reduced; compared with a traditional high-temperature chlorination method which needs a high temperature of 1300 DEG C or above, the method adopts fluidized chlorination roasting, so that the roasting temperature is reduced by 500 DEG C, and the energy consumption is reduced by 40%; nano-bubble ultrapure water is adopted for ultrasonic cleaning, the cleaning efficiency can be improved by 50%, and residual impurities are effectively removed; through innovative design and synergistic effect of all the steps, ultra-high purity of SiO2 with the purity being greater than or equal to 99.996% is realized, and meanwhile, environmental protection, energy conservation and consumption reduction as well as industrial stable production are taken into consideration.

The present invention belongs to the technical field of the extraction of total bamboo leaf flavonoids, and relates to a method for preparing an ultra-high-purity nanoscale total bamboo leaf flavonoid dispersion. The method comprises the following steps: (1) extracting a nanoscale bamboo leaf flavonoid compound by using an integrated device for superfreezing-assisted high pressure-double vortex countercurrent back-pressure cavitation continuous dynamic cyclic nano-grinding and wall-breaking extraction and filtration; (2) subjecting same to adsorption separation and dynamic elution and desorption by means of a combination of ionic liquid functionalized vortex magnetic nano-elliptic hollow ring balls and an external rotating magnetic field; (3) performing low-temperature vacuum evaporation and concentration; and (4) freeze-drying same to prepare an ultra-high-purity nanoscale total bamboo leaf flavonoid dispersion with D50 of 0.02-0.08 μm and a purity of 99.7-99.9%. The method has overcome the limitations of an industrial technique for extracting flavonoids from bamboo leaves, achieves large-scale industrialization of an ultra-high-purity nanoscale total bamboo leaf flavonoid dispersion, and is used in the fields of active pharmaceutical ingredients, health products, food products for special needs, drink products with special functions, cosmetics, etc.

The invention belongs to the technical field of electrolyte materials, and discloses a high-purity lithium bis (fluorosulfonyl) imide solution as well as a preparation method and application thereof. The preparation method of the high-purity lithium bis (fluorosulfonyl) imide solution comprises the following steps: 1) mixing inert chloralkane and lithium carbonate to form a suspension, dropwise adding bis (fluorosulfonyl) imide into the suspension at reaction temperature and pressure for reaction, after the reaction is finished, performing filter pressing, washing, and performing filter pressing again to obtain a filter cake; and 2) crushing the filter cake, feeding the crushed filter cake into a closed-loop circulating fluidized bed, sequentially drying in a low-temperature area and a medium-temperature area, instantaneously contacting and dissolving the obtained hot powder with an atomized and sprayed carbonate solvent to form a solution, and performing microfiltration to obtain the high-purity lithium bis (fluorosulfonyl) imide solution. The lithium bis (fluorosulfonyl) imide solution has ultra-high purity and ultra-low moisture, the content of other impurities such as chloride ions, free acids and metal ions is extremely low, additional steps of dehydration, purification or acidity adjustment and the like are not needed, and the lithium bis (fluorosulfonyl) imide solution can be directly used for preparing a high-performance lithium ion battery electrolyte.

The present invention relates to the field of lactic acid technology, and specifically discloses a kind of ultra-high purity crystalline lactic acid and its preparation method and application. The present invention carries out ultra-high vacuum evaporation crystallization on polymerization-grade liquid L-lactic acid at 6 ℃ ~ 10 ℃, 0.7kPa ~ 0.9kPa, adds L-lactic acid seed crystals when the lactic acid specific gravity is 1.34 ~ 1.35, and terminates crystallization until the lactic acid specific gravity is 1.38 ~ 1.39, thereby obtaining ultra-high purity crystalline lactic acid. The present invention utilizes the limited water solubility of lactic acid at low temperatures, and only utilizes ultra-high vacuum evaporation crystallization in one step under ultra-low temperature and ultra-high vacuum to obtain ultra-high purity crystalline lactic acid, which has a purity of more than 99.95%, a granular shape, a high crystallization rate, uniform and dense, high looseness, strong anti-caking performance, and excellent quality. The ultra-high purity crystalline lactic acid can be directly polymerized for the production of polylactic acid, which improves production efficiency, greatly reduces production costs, has excellent market competitiveness, and is suitable for large-scale production.

The disclosed technology encompasses novel methods, systems, and materials for the efficient recycling and upgrading of carbon dioxide containing streams and their conversion into high purity methane and ultra-high purity methane. In various embodiments, the methods comprise utilizing a reactor equipped with both a sorbent and catalyst; supplementing the incoming stream with appropriate amounts of hydrogen to fully convert the carbon dioxide; initiating flow of the incoming stream in the sorbent-enhanced catalysis reactor; removing contaminants like nitrogen with sorption or reactors; drying the gas; and finally injecting the gas into the infrastructure of industrial process for the gas. Notably, the reaction of carbon dioxide with hydrogen gas to yield methane takes place at a temperature substantially consistent with the desorption stage on the catalytic unit. This invention represents a significant advancement in carbon upgrading processes, offering a highly efficient and reliable method for producing high purity methane and ultra-high purity methane.

This application discloses a method for preparing ultra-high purity citric acid monohydrate based on supercritical CO2, belonging to the field of citric acid preparation technology. The method includes the following steps: dissolving citric acid monohydrate in an organic solvent to prepare a citric acid solution; spraying the citric acid solution into a supercritical CO2 environment to crystallize the citric acid using the supercritical anti-solvent effect; performing dynamic washing with pure supercritical CO2; and obtaining ultra-high purity citric acid monohydrate crystals after depressurization and drying. The citric acid monohydrate product prepared by this method has high purity, high light transmittance, low total metal ion content, controllable crystal habit, and low organic solvent residue, meeting the stringent requirements of high-end applications such as electronic and pharmaceutical grades.

The present application provides a low odor / low whitening structure instant adhesive and a preparation method thereof. The low odor / low whitening structure instant adhesive comprises 70-90 wt% of cyano acrylate, 3-20 wt% of acrylic acid copolymer, 1-13 wt% of fumed silica, 0.2-2 wt% of plasticizer, 0.1-1 wt% of carbon black and 0-0.05 wt% of additive in terms of mass fraction. The present application selects ultra-high purity monomers in the environment of low polymerization inhibitor, which can significantly shorten the polymerization induction period, so that the monomer can be instantaneously initiated and completely cured after contacting the surface of the substrate, thereby minimizing the release of volatile monomers into the environment, further reducing the gaseous monomer that causes respiratory tract / mucosa irritation from the source, and inhibiting the polymerization of volatile monomers in the air to form white powder.

In semiconductor manufacture requiring ultra high purity water, particles of specified sizes are detected using acoustic particle detection capable of detecting nanoparticles. A sensor unit receives a flow of water, with the pressure and rate of flow to the sensor controlled closely. In each sensor unit is a measurement cell to receive a continuous flow of water, with a transducer module engaged with the cell to deliver an acoustic pulse at a known level of intensity as the liquid flows through the cells, the acoustic pulse acting on the liquid at a focus zone to cause cavitation in the event a particle of size detectable at that intensity is present. A waveform emitter / receiver connected to the sensor unit sends high-frequency, high-voltage signal to the transducer module to cause the acoustic pulse, and it also receives a waveform echo indicating a cavitation event. The system is controlled by a microprocessor.

The invention discloses a preparation method of tetra (dimethylamino) hafnium, and belongs to the technical field of preparation of IVB group metal organic compounds. The preparation method comprises the following steps: S1, carrying out primary rectification on a tetra (dimethylamino) hafnium crude product, and collecting a primary main fraction; s2, dissolving the primary main fraction, and recrystallizing to obtain a crystal; and S3, dissolving the crystal, carrying out secondary rectification, and collecting a secondary main fraction. The tetra (dimethylamino) hafnium crude product is derived from waste liquid in the production process of cyclopentadienyl tris (dimethylamino) hafnium, and the crude product contains less than or equal to 8.0 ppm of Fe and less than or equal to 1.0 ppm of Ti; according to the method, 6N-grade (99.9999% or above) ultra-high-purity recovery of the TDMAHf product in the CpHf synthesis waste liquid is achieved by optimizing key parameters such as rectification and recrystallization parameters, and the recovered product completely meets the strict requirements of high-end fields such as semiconductor film deposition on metal precursors; the preparation method is short in process period and high in treatment efficiency, does not introduce other impurities, and can realize industrial application.

The present invention relates to the technical field of silica sol preparation, and in particular to a method for preparing high-purity silica sol and hydrogen chloride, comprising the following steps: adding a higher alcohol to a reactor, heating to melt the higher alcohol; adding silicon tetrachloride to the reactor, fully reacting silicon tetrachloride with the molten higher alcohol to generate silicate and hydrogen chloride, during the reaction, the higher alcohol and the generated silicate are kept in a heated and melted state, and the hydrogen chloride is discharged from the reactor in the form of gas and collected; the substances in the reactor are kept in a heated and melted state, and an excess of water is added to the reactor to completely hydrolyze the silicate to generate silica hydrosol and higher alcohol; cooling the reactor until the higher alcohol is converted into a solid state and the silica hydrosol remains in a liquid state; and separating the liquid silica hydrosol from the solid higher alcohol. The method for preparing high-purity silica sol of the present application has the advantages of preparing ultra-high purity silica sol and separating hydrogen chloride at a low cost.

The invention discloses an electrochemical synthesis method of an ultra-high-purity precious metal compound, which comprises the following steps: dissolving precious metal powder in a high-purity acid solution system by adopting an electrochemical dissolution process in a clean environment to form an ionic precious metal, selectively removing impurities through acid-resistant chelating resin, and carrying out reduced pressure distillation and concentration to obtain the ultra-high-purity precious metal compound. In the process, introduction of other impurity ions is avoided, the efficiency is high, and industrial batch production is easy. The purity of the obtained precious metal compound can reach 99.999% or above, and the obtained precious metal compound can be used as a raw material in the fields of chips, electrons, catalysts and the like.

The invention relates to the technical field of inorganic salt purification, and discloses high-purity ammonium sulfate and a preparation process thereof.The preparation process includes the following steps that firstly, a magnetic response macrocyclic ether complexing agent is added into an ammonium sulfate solution to be purified, the complexing agent can specifically capture impurities such as potassium ions, and a stable complex with magnetic responsiveness is formed; then, selectively crystallizing and separating out the target product ammonium sulfate under a mild condition by a gas-phase anti-solvent crystallization method, and meanwhile, effectively repelling a large-volume impurity complex into a mother solution. The key step is that obtained solid-liquid mixed crystal mush is introduced into a gradient magnetic field for enhanced separation. Through creative integration of molecular recognition, phase equilibrium engineering and a magnetochemical separation technology, the limitation of a co-crystallization effect is fundamentally broken through, and ultra-high-purity ammonium sulfate with extremely low impurity content can be prepared in an efficient and environment-friendly manner.

The invention provides a process for extracting high-purity copper from iron, and relates to the technical field of metal material purification, and the process comprises the following steps: S1, preparing raw materials, S2, dissolving, adding concentrated sulfuric acid into a reaction container, and heating to 10-35 DEG C, S3, replacing iron powder, heating the solution to 60-80 DEG C, adding reduced iron powder with a preset proportion into the solution, and carrying out heat preservation for 2-3 hours; in the process, a catalyst, natural copper powder and hydrogen peroxide are sequentially added at the same time and stirred, then a mixed solution is formed, and the mixed solution is subjected to standing for 1-3 h at the room temperature; s4, filtering and separating, S5, medium-frequency smelting and S6, vacuum distillation, copper ingots obtained after medium-frequency smelting are put into a vacuum distillation furnace, the temperature ranges from 1600 DEG C to 1800 DEG C, the vacuum degree ranges from 10 <-3 > Pa to 10 <-5 > Pa, the distillation time ranges from 2 h to 4 h, and the ultra-high-purity copper ingots are obtained; according to the method, the ultra-high-purity copper ingot with the purity as high as 99.994824% can be obtained, and compared with a traditional copper purification process, the cost input is low, and remarkable economic benefits are brought to enterprises.

The invention relates to a metal oxide photoresist and a purification method thereof. The purification method comprises the following steps: S1, dissolving a metal oxide crude product containing metal ion impurities in a specific solvent to obtain a crude product solution; s2, applying crystallization driving force to the crude product solution to induce metal oxide crystals to separate out, so as to obtain metal oxide crystals; s3, separating the metal oxide crystal from the crude product solution to obtain a crystal wet cake; s4, washing and drying the crystal wet cake to obtain a high-purity crystal; and S5, dissolving the high-purity crystal in a photoresist solvent to obtain a purified metal oxide photoresist solution. According to the method, the metal ion impurity concentration of the metal oxide photoresist can be stably reduced, and the requirement of the EUV photoetching process on ultra-high purity is met. The purification process is simple and rapid, the purification time is greatly shortened, and the purification efficiency is improved.

The invention discloses an ultra-high-purity regular spherical silicon dioxide microsphere and a preparation method thereof, and belongs to the technical field of electronic-grade silicon micropowder functional fillers, the preparation method comprises the following steps: mixing organosilane and ultrapure water in proportion, and then carrying out hydrolysis reaction to obtain a silanol aqueous solution; adding an alkaline polycondensation catalyst into the silanol aqueous solution, controlling reaction conditions, and carrying out polycondensation reaction to obtain an organic silicon source mixed solution; centrifugally separating the organic silicon source mixed solution and washing with ultrapure water to obtain a semi-finished product polysilsesquioxane microspheres; and heating the polysilsesquioxane microspheres to 1050 DEG C at a controlled heating rate under the protection of negative pressure and clean air, and carrying out constant-temperature oxygen-enriched calcination for 1-5 hours to obtain the ultra-high-purity regular spherical silicon dioxide microspheres. The preparation method disclosed by the invention is simple to operate and low in cost, the prepared silicon dioxide microspheres are good in sphericity, uniform in particle size distribution and good in flowability, and the purity of the silicon dioxide microspheres is as high as 99.9999% and far exceeds the purity index of national standard'spherical silicon dioxide micro powder '.

The invention discloses a preparation method of a high-purity aluminum-based fine-grain cast ingot, and belongs to the technical field of target material preparation and non-ferrous metal material forming. The preparation method of the high-purity aluminum-based fine-grain cast ingot comprises the following steps: (1) raw material pretreatment and vacuum charging; (2) preheating and temperature control of a high-purity graphite mold; (3) carrying out vacuum induction melting and homogenization; (4) precise casting; (5) multidirectional composite vibration solidification in the mold; (6) in-mold heat preservation and rapid water quenching; a vertical-horizontal alternate combined vibration motor is used for achieving melt global vibration, a 99.999% high-purity graphite crucible and a mold are matched for blocking contact pollution, a refining agent is not needed, and coarse grains of several centimeters to dozens of centimeters in high-purity aluminum can be effectively refined to the average grain size of 0.90 centimeters (namely within 1 centimeter); while the ultra-high purity of 5N grade and above is ensured, the crystal grain uniformity is improved, the processing is simplified, the loss is reduced, and the method is suitable for high-end fields such as semiconductor target materials and precise components.

The invention discloses a preparation method of a three-dimensional skeleton enhanced aluminum foil of a magnetron sputtering nano-copper coating film, and belongs to the technical field of copper foil surface treatment. The preparation method of the three-dimensional skeleton enhanced aluminum foil of the magnetron sputtering nano-copper coating film comprises the following steps: putting an aluminum foil substrate into an ultrasonic cleaning machine, immersing the aluminum foil substrate in an isopropanol solution for cleaning, then putting the aluminum foil substrate into stronger ammonia water for soaking to obtain an aluminum foil substrate with a three-dimensional skeleton structure, carrying out magnetron sputtering on the aluminum foil substrate, using an ultra-high-purity copper target material, and after deposition is finished, preparing the three-dimensional skeleton enhanced aluminum foil of the magnetron sputtering nano-copper coating film. And carrying out post-treatment to finally obtain the three-dimensional skeleton reinforced aluminum foil of the magnetron sputtering nano-copper coating film. The three-dimensional skeleton enhanced aluminum foil of the magnetron sputtering nano-copper coating film has excellent bonding strength.

The invention relates to the technical field of carbon dioxide extraction and purification, in particular to a preparation process of ultra-pure carbon dioxide. A preparation process of ultra-pure carbon dioxide comprises the following steps: transferring a liquid phase III into an absorption tower filled with a carbon dioxide adsorption material which is a methyl functionalized covalent organic framework material coated with a polar polymer, so as to obtain a carbon dioxide-rich adsorption material; and transferring the carbon dioxide-rich adsorption material into a desorption tower to obtain the ultra-pure carbon dioxide. According to the preparation process of the ultra-high-purity carbon dioxide, a low-temperature rectification method is adopted, washing, flash evaporation and a carbon dioxide adsorption material are cooperatively matched, and impurity components such as SO2, H2, CO, CH4, N2 and 02 in crude carbon dioxide feed gas are removed, so that the ultra-high-purity carbon dioxide is obtained.

Processes for producing two CO2 streams having different purities, including one stream comprising ultra high purity CO2. The processes incorporate a second fractionation column in a CO2 fractionation process. The bottoms stream from the first cryogenic fractionation column is sent to the second CO2 fractionation column. The second CO2 fractionation column can produce ultra high purity CO2. The bottoms stream from the first column can be divided and a portion of the bottoms stream can be recovered as a second CO2 product stream having a lower purity than the purity of the product stream.

The invention discloses an efficient diethyl ether purification process, and belongs to the technical field of diethyl ether purification processes. Comprising the following steps: dynamically adsorbing diethyl ether through an adsorption column filled with a composite filler; adding a complexing agent into the effluent, stirring and reacting to obtain a mixed solution; performing normal-pressure separation on the mixed solution through a divided-wall rectifying tower, then performing reduced-pressure separation, collecting fractions, filtering the fractions through a polytetrafluoroethylene membrane, and packaging the fractions to obtain the high-purity diethyl ether. The composite filler is prepared from thiourea modified D101 macroporous resin and 4A molecular sieve powder through alumina sol treatment, silane coupling agent modification and programmed heating firing. The complexing agent is prepared by carrying out reaction on SAA-15 mesoporous molecular sieve loaded phosphotungstic acid and an 18-crown-6 ether derivative. According to the process, peroxide, trace moisture, alcohol and organic impurities in diethyl ether are remarkably removed, efficient separation and purification are achieved, an ultra-high-purity diethyl ether product is obtained, meanwhile, the process is stable and efficient, and the process is suitable for preparing high-purity diethyl ether.

This invention discloses a method and device for the directional formation of palladium recombination centers in a PN junction using low-temperature oxidation masking, belonging to the field of semiconductor device manufacturing. This invention employs LTO (Low Temperature Oxidation) technology, using ultra-high purity oxygen to carry silane in a low-temperature environment within an LTO oxidation furnace to form a dense oxide film on the surface of a conventional PIN diode diffuser wafer with pre-formed trenches. Following photolithography and etching processes, precise directional palladium diffusion is performed. This results in a diffuser substrate with well-concentrated parameters such as Vf (forward voltage drop) and Trr (reverse recovery time), significantly improving chip utilization on the diffuser and substantially enhancing product quality. Compared to using expensive ion implanters, this invention significantly reduces costs while achieving parameter quality comparable to ion implantation.

The invention relates to the technical field of preparation of anhydrous indium chloride, in particular to a preparation method of anhydrous indium chloride, which comprises the following steps: (a) providing an indium source and a chlorine source, the indium source being indium metal or indium compound, and the chlorine source being chlorine, hydrogen chloride or organic chloride; and (b) in an anhydrous inert atmosphere, introducing the indium source and the chlorine source into a reactor, controlling the reaction temperature in a range of 100-400, and carrying out a chlorination reaction for 1-10 hours to generate the indium chloride intermediate. According to the preparation method of anhydrous indium chloride, a product with ultra-high purity and stable chlorine content can be stably obtained by effectively inhibiting a hydrolysis reaction, meanwhile, the hygroscopicity of the product is remarkably reduced, and the product is convenient to store and transport. The technological process is mild and controllable, the safety is high, toxic corrosive gas is prevented from being used, and the method has the remarkable advantages of being easy and convenient to operate and environmentally friendly.

The invention relates to the technical field of nano materials, in particular to a process for preparing ultra-high-purity hydroxyl-free silicon dioxide, which comprises the following steps: S1, mixing a silicon source, alkali and an organic modifier, adding the mixture into a reaction medium to form a reaction liquid, and carrying out microencapsulation treatment on the reaction liquid to obtain reaction liquid microcapsules; s2, in the reaction process of synthesizing the composite frame material with the hollow structure, adding the reaction liquid microcapsules, and performing high-temperature and high-pressure reaction to obtain a precursor material; s3, depositing magnetic ferroferric oxide nanoparticles on the surface of the precursor material through a hydrothermal method to obtain a pretreated precursor material; and S4, in argon, under the action of oscillation, performing high-temperature treatment on the pretreated precursor material at 800-850 DEG C, and then performing magnetic separation screening to obtain the high-purity hydroxyl-free silicon dioxide. The synthesized silicon dioxide is small in particle size, round and regular in structure and good in dispersity, and can be applied to the industries of electronic packaging materials, mechanical lubrication, ceramics and the like.

Systems for detecting gas leaks in gas systems are provided. The systems can include: at least one gas cylinder; at least one valve assembly operatively engaged with the gas cylinder; and a purge conduit assembly operatively engaged with an interior portion of the valve assembly. Methods for detecting gas cylinder leaks in a gas system are provided. The methods can include providing purge gas through an interior portion of a valve assembly operably coupled to a gas cylinder. The system is enclosed within a cabinet; the method can include providing positive pressure within the cabinet sufficient to provide flow through the purge conduit assembly. Ultra-high purity gas cylinder valve assemblies are provided. The assemblies can include: a diaphragm separating an upper and lower portion of the valve assembly; a purge gas input conduit in fluid communication with the upper portion; and a purge gas outlet conduit in fluid communication with the upper portion.