29 results about "Cristobalite" patented technology

The invention relates to the technical field of metallurgical coking, and provides a devitrification and CO erosion resistant zero-expansion silica brick and a preparation method thereof.The devitrification and CO erosion resistant zero-expansion silica brick is prepared from, by weight, 3-10 parts of nanoscale alpha-Al2O3, 15-35 parts of andalusite, 30-40 parts of high-purity fused mullite, 10-20 parts of superfine silica powder, 2-5 parts of silica sol binding agent and 3-5 parts of composite mineralizer. Through the synergistic effect of the design of the composite mineralizer and the stepped heat treatment process, the technical problems that the existing zero-expansion silica brick is easy to devitrify and crystallize fused quartz, poor in CO erosion resistance and lack of crystallization degree during long-term use at high temperature are solved; the thermal shock cycle index and the high-temperature breaking strength of the material can be improved, the formation of alpha-cristobalite crystallization peak is effectively inhibited, and the mass loss is reduced in a reducing atmosphere, so that the structural stability of the material is enhanced, and the service life of the material is prolonged.

The application relates to a method for preparing high-purity cristobalite sand and / or high-purity fused quartz glass sand by using waste quartz crucible, which comprises the following steps: 1) crushing and first screening the waste quartz crucible; 2) high-temperature roasting the first screening residue to obtain a mixture material in which a surface crystallization layer containing cristobalite sand is separated from fused quartz glass sand; 3) self-grinding and second screening the mixture material; 4) scrubbing the first crude cristobalite sand, removing the third screening residue by wet screening, taking the third screening residue to obtain high-purity cristobalite sand after treatment, and scrubbing the first fused quartz glass sand, removing the fourth screening residue by wet screening, and taking the fourth screening residue to obtain high-purity fused quartz glass sand after treatment. The application also relates to high-purity cristobalite sand and / or high-purity fused quartz glass sand prepared by using the above method.

A negative electrode active material for a nonaqueous electrolyte secondary battery has composite particles that include a lithium silicate phase, a silicon phase dispersed within the lithium silicate phase, and a crystalline phase of silicon dioxide dispersed within the lithium silicate phase. The crystalline phase of silicon dioxide includes β-cristobalite and quartz.

The application belongs to the field of new materials, and discloses an alumina ceramic with low thermal expansion coefficient, which is formed by sintering raw materials, the raw materials comprising: alumina: 98.5-99.1 wt%; silicon powder: 0.15-0.25 wt%; magnesium oxide: 0.15-0.25 wt%; yttrium fluoride: 0.15-0.25 wt%; and fused crystal beta-cristobalite: 0.25-0.75 wt%. The product is composed of four-element ceramic formula of Al, Si, Mg and Y, which meets the demand of the market for 99 alumina ceramic products with low thermal expansion coefficient, and greatly improves the application value of 99 alumina ceramic in ceramic substrates and electrostatic chucks. Meanwhile, the application also discloses a preparation method of the alumina ceramic.

The invention relates to a siliceous furnace lining material for a smelting environment with a high scrap ratio and a preparation method of the siliceous furnace lining material. The siliceous furnace lining material comprises the following components in parts by mass: 30-40 parts of selected microcrystalline silica tailings, 30-40 parts of fused quartz, 20-35 parts of spherical zirconium composite silica powder and 1-2 parts of a sintering aid. Wherein the SiO2 content of the selected microcrystalline silica tailings is greater than or equal to 99.5%. According to the present invention, the 99.5% selected microcrystalline silica tailings are adopted as the aggregate, such that the impurity reaction sites can be effectively reduced, the refractoriness can be increased to more than or equal to 1720 DEG C, and the spherical zirconium composite silica micro-powder is adopted as the matrix so as to effectively inhibit the cracking of the furnace lining and improve the fluidity of the slurry; boric acid in the sintering aid can promote low-temperature sintering to form a glass-phase combined phase. According to the siliceous furnace lining material for the smelting environment with the high scrap ratio, the sintering layer is specifically composed of the cristobalite phase and the silicon zirconium glass phase, and the siliceous furnace lining of an intermediate frequency furnace can be better protected.

A cristobalite includes: a d50 particle size selected within a range of from 1 μm to 15 μm; an L color coordinate of greater than 96; a color coordinate of less than 1; and a b color coordinate of 1 or less, in which the cristobalite is a powder. Also provided are compositions containing the cristobalite, coatings formed with compositions, and methods of preparing cristobalite.

The application relates to a doped optical fiber preparation process and discloses a high-uniformity and high-concentration Pr 3+ The application discloses a preparation method of a doped quartz-based glass optical fiber. Rare earth oxide Pr2O3, silica powder SiO2 and aluminum oxide Al2O3 are weighed, mechanically mixed, ball milled, dried, sieved, pre-sintered to be transformed into cristobalite, drawn into a glass rod containing a core by using a tube melting method, and processed to remove the outer cladding of the glass rod to obtain a core rod with adjustable diameter. The tube rod method is combined with a high-purity quartz tube to form an optical fiber preform rod. Finally, the optical fiber preform rod has high uniformity, low loss and high concentration of Pr 3+ The application discloses a drawing method of a doped quartz optical fiber. The aluminum oxide Al2O3 is introduced to improve the solubility of the rare earth ion Pr 3+ in the quartz glass and reduce the melting point of the quartz raw material. The rare earth doping concentration is adjustable. The raw material is transformed into cristobalite by pre-sintering, and the effect of reducing the bubbles of the core glass and improving the uniformity of the core glass is remarkable by combining the vacuum tube melting method.

The invention provides a high-strength cement-based grouting material and a preparation method thereof. The high-strength cement-based grouting material comprises the following components: Portland cement, fly ash, an expanding agent, quartz sand, a water reducing agent, a powder defoaming agent, a plastic expanding agent and a strength enhancer. Wherein the strength enhancer is prepared by taking rice hulls as a raw material, carrying out constant-temperature calcination to obtain rice hull ash, modifying one part of the rice hull ash with KH560, carrying out heating calcination on the other part of the rice hull ash, carrying out hydroxylation treatment on the other part of the rice hull ash, then carrying out KH550 modification, and finally carrying out blending reaction on the two parts of products. In the strength enhancer disclosed by the invention, products obtained by calcining rice hulls in two stages are respectively amorphous silicon dioxide and cristobalite, and after the rice hulls are modified by KH560 and KH550, an epoxy group is grafted on the surface of the amorphous silicon dioxide, and an amino group is grafted on the surface of the cristobalite. The early strength and the later strength of the cement-based grouting material can be remarkably improved through the interaction of the amorphous silicon dioxide, the cristobalite and the cement matrix.

The invention discloses a method for converting 6N-grade quartz sand into high-purity alpha-cristobalite by doping and coating, and belongs to the technical field of inorganic non-metallic material preparation. The method comprises the following steps: with 6N-grade quartz sand as a raw material, coating the surface of the 6N-grade quartz sand with a silicic acid precursor containing alkali metal elements to form a coating layer; after drying, carrying out temperature-controlled crystallization at a relatively low temperature, inducing the quartz sand to generate lattice reconstruction from outside to inside by utilizing alkali metal in a coating layer, and converting the quartz sand into alpha-cristobalite; after crystallization, a surface coating layer and residual impurities are removed through an acid pickling process, the high-purity characteristic is recovered, and a high-purity alpha-cristobalite product is obtained. According to the method, efficient crystallization of the 6N-grade quartz sand at the relatively low temperature is achieved, the purity of the obtained product can reach the 6N grade, the crystal phase is pure, the light transmittance is excellent, the method can be widely applied to the fields of optical lenses, electronic packaging, aerospace high-temperature-resistant parts and the like, and the method has the advantages of being simple in process, low in energy consumption and suitable for large-scale production.

The application relates to a preparation method of a photocured 3D printing silicon-based ceramic core with controllable cristobalite content, which comprises the following steps: preparing a pre-curing agent by mixing a silicon-based ceramic solid-phase powder and a liquid-phase solvent. The silicon-based ceramic solid-phase powder comprises a skeleton support agent, an auxiliary sintering agent and a cristobalite content regulating agent; the liquid-phase solvent comprises a viscosity regulator, an auxiliary curing agent, a powder aggregation inhibitor and a cross-linking auxiliary agent. The pre-curing agent is subjected to a photocured 3D printing process to obtain a ceramic core green body; the ceramic core green body is subjected to a debinding treatment and a sintering treatment to obtain the photocured 3D printing silicon-based ceramic core. The application can accurately regulate the content of cristobalite, reduce the use of the auxiliary sintering agent, simplify the composition of the ceramic core, reduce the number of micro-crack-containing particles in the microstructure of the silicon-based ceramic core material, weaken the stress concentration phenomenon caused by the micro-cracks, improve the high-temperature strength of the ceramic core and better be used for high-temperature alloy casting.

The utility model discloses energy-saving and environment-friendly quartz sand refining and drying equipment, which relates to the technical field of quartz sand preparation, and comprises a drying equipment shell, the surface of the drying equipment shell is fixedly connected with a feed hopper, the surface of the drying equipment shell is provided with a discharge hopper, and the discharge hopper is fixedly connected with the feed hopper. The energy-saving and environment-friendly quartz sand refining and drying equipment comprises a drying equipment shell, a driving rod is rotatably connected to the interior of the drying equipment shell, a fixing pipe is fixedly connected to the surface of the drying equipment shell, and the two connecting positions of the fixing pipe and the drying equipment shell are obliquely arranged. Therefore, exchange of the upper quartz sand and the lower quartz sand in the drying equipment shell is completed, the situation that the lower quartz sand is always in contact with hot air to be dried, but the upper quartz sand is not dried is avoided, the drying speed is increased, electric energy is reduced, energy is saved, and the using effect of the device is improved.

Provided is a grain oriented electrical steel sheet including a base metal steel sheet, an intermediate layer and an insulation coating, wherein: the intermediate layer is an oxide film; an average thickness of the oxide film is 2-500 nm; the insulation coating is a phosphate coating; an average thickness of the insulation coating is 0.1-10 μm. When grazing incidence X-ray diffraction is performed on the phosphate coating using a Co-Kα excitation source, the X-ray diffraction pattern has a diffraction peak originating from cristobalite-type aluminum phosphate at a diffraction angle of 2θ=24.8°; a half value width FWHM0.5 of the diffraction peak under a diffraction condition with an X-ray incident angle ω=0.5° and a half value width FWHM1.0 of the diffraction peak under a diffraction condition with an X-ray incident angle ω=1.0° satisfy 0.20°≤FWHM0.5≤2.00°, 0.20°≤FWHM1.0≤2.00°, and 0°≤|FWHM0.5−FWHM1.0|≤1.00°.

The invention belongs to the technical field of drilling compositions, and particularly relates to a high-temperature-resistant material for well cementation cement slurry, the well cementation cement slurry and application of the high-temperature-resistant material in thermal oil recovery. The high-temperature-resistant material for the well cementation cement slurry, provided by the invention, is prepared from the following components in percentage by mass: 50 to 70 percent of cristobalite and 30 to 50 percent of metakaolin. The cristobalite and the metakaolin are adopted to form the high-temperature-resistant material, the high-temperature-resistant material can react with a hydration product calcium hydroxide of the cement paste at the temperature of 150 DEG C when being used in cooperation with the cement paste, a scolecite product with stable strength at the high temperature is generated, and set cement can have high strength at the high temperature; and the strength is kept not attenuated in the ultrahigh-temperature and normal-temperature alternate curing period of 300-350 DEG C, and the adverse effect that the water content is increased sharply due to the fact that the cement sheath is prone to thermal damage in the thermal recovery process of the thermal recovery well is prevented, so that the service life of the thermal recovery well is prolonged.

Provided is a glass containing a crystalline phase, the glass including at least one crystalline phase selected from the group consisting of cristobalite, lithium disilicate, and petalite, in which a value of E / ρ, which is a ratio of Young's modulus E to specific gravity ρ, is 35 or more, and a glass transition point is 680° C. or higher.

Silicon is widely used as a bond coat in environmental barrier coatings (EBCs). However, due to its reversible phase change and cracking behavior caused during thermal cycling, the formation of cristobalite thermal growth oxide (TGO) is the major lifetime limiting factor of EBC exposed to high temperature steam environments. Thus, it would be desirable for highly durable EBC systems by designing coating chemistry and architecture to control or avoid cristobalite TGO formation. To address this problem, a coating system is described that includes an Al-Si-N layer and an oxide top layer to reduce oxygen diffusion. A steam test at 1316 DEG C for 510 hours shows that the Al-Si-N layer successfully prevents the oxidation of the lower silicon bonding layer and avoids the formation of a harmful cristobalite phase. A method of preparing the coating system by a composite vapor deposition process is described.

The present invention relates to process for producing a hot blended material of amorphous silicon dioxide—crystalline silicon dioxide (Hot Blending silica—PheniSilic™) from materials containing silicon dioxide such as sand, cristobalite, crushed glass, waste rock powder / burrs from process of producing artificial stone, waste products and by-products from the exploitation and processing of natural quartz stone. The present invention also relates to artificial stone product produced by using base resins such as unsaturated polyester, epoxy, acrylic or combination thereof and reinforcement is the hot blended material of amorphous silicon dioxide—crystalline silicon dioxide wherein the artificial stone has a flexural strength≥40N / mm2, a water absorption≤0.05%, an impact resistance≥3J, as well as process for producing this artificial stone.

The application relates to the technical field of special ceramics and daily-use ceramics, in particular to high-strength lightweight daily-use ceramics and a preparation method thereof, and the raw material composition and weight percentage of the body of the high-strength lightweight daily-use ceramics are as follows: talc 35-60%; calcite 5-15%; feldspar 5-18%; quartz 8-25%; bentonite 3-8%; washed mud 5-15%; the total content of alumina in the raw material composition is not more than 8%; the main crystal phase of the high-strength lightweight daily-use ceramics is original enstatite and alpha-cristobalite, and the original enstatite is generated by the reaction of talc, calcite and quartz at high temperature; through unique crystal phase structure design, the key indexes such as the Vickers hardness, bending strength and light transmittance of the prepared ceramic product have reached the performance level of lightweight light-transmitting special ceramics, but the raw material cost and sintering energy consumption are only one sixth of those of traditional special ceramics, so that the high-strength lightweight daily-use ceramics can also be applied to the field of daily-use ceramics with higher cost requirements.

A Si-based composite bond coat for environmental barrier coating on Si-based ceramic matrix composites protects the CMC from oxidizing environments by in-situ modifying the thermally grown oxide (TGO) using a TGO modifier to suppress cristobalite TGO cracking during thermal cycling in gas turbine engines.

An inorganic composition article obtained by strengthening a crystallized glass, wherein the crystallized glass comprises one or more kinds selected from α-cristobalite and α-cristobalite solid solution as a main crystal phase, the crystallized glass comprises, by mass % in terms of oxide, a content of a SiO2 component of 50.0% to 75.0%, a content of a Li2O component of 3.0% to 10.0%, a content of an Al2O3 component of 5.0% or more and less than 15.0%, a content of a B2O3 component of more than 0% and 10.0% or less, a content of a P2O5 component of more than 0% and 10.0% or less, and a mass proportion SiO2 / (B2O3+Li2O) of 3.0 to 10.0, and the inorganic composition article has a compressive stress layer on the surface, and has a central tensile stress (CT) of 80 MPa to 160 MPa.

The application belongs to the field of inorganic nonmetallic materials, and particularly relates to a preparation method of a low-expansion silicon-based ceramic core, which comprises the following steps: carrying out surface modification on quartz glass micropowder by using a gamma-methacryloxypropyltrimethoxysilane coupling agent; introducing 3-8% zirconium oxide nanofibers as a stress relaxation phase; realizing more than 95% dispersion uniformity through high-energy ball milling mixing; precisely controlling the heating rate of each temperature interval by adopting gradient heating sintering to realize uniform conversion of cristobalite crystal phase; and finally removing the stress relaxation phase through alkali corrosion treatment to form a connected pore network with a porosity of 15%-30%. The application utilizes the stress-induced phase change characteristics and crack deflection toughening mechanism of zirconium oxide to make the core fracture toughness reach 5-8 MPa.m^(1 / 2), the thermal expansion coefficient is controlled within 6-10*10^(-6) / DEG C, the removal efficiency is improved by 50%-70%, and the dispersion uniformity reaches more than 95%.

This invention discloses a multiphase ceramic for sealing with adjustable thermal expansion coefficient and its preparation method. The multiphase ceramic comprises an expanding phase and a matrix phase. The matrix phase is mainly composed of Li₂O and SiO₂, with at least one of B₂O₃, Al₂O₃, MgO, Na₂O, ZrO₂, and La₂O₃ as a modifier. The thermal expansion coefficient of the multiphase ceramic is controlled by adjusting the ratio of the high thermal expansion phase to the matrix phase. In this preparation method, the quartz raw material is introduced into the matrix phase in a single step, eliminating the need for a long and complex heat treatment process to induce cristobalite growth, thus improving the production efficiency in the sealing process of electronic devices.

The invention discloses a method for preparing high-grade calcium fluoride from photovoltaic sludge, which comprises the following steps: (1) drying and grinding the photovoltaic sludge to obtain a powdery dried product for later use; (2) roasting the powdery dried product at 800-1000 DEG C, and grinding again after roasting to obtain a to-be-floated product; and (3) adding the product to be floated into a flotation machine, adding a regulator, an inhibitor and a collecting agent into the flotation machine for flotation, and filtering and drying to obtain a high-grade calcium fluoride product. The crystallinity of calcium fluoride is promoted to be increased to 80% or above through high-temperature roasting, and the effect of the calcium fluoride and the collecting agent is enhanced; high-temperature roasting induces silicon dioxide to be converted into cristobalite phase from amorphous state, and impurity ore phase transformation is promoted. By means of high-temperature roasting, the grade of calcium fluoride in flotation concentrate is increased to 77.36% from 64.11%, and the recovery rate is increased to 74.58% from 11.81%. In addition, the method is simple in process, environment-friendly and suitable for industrial popularization.

The invention discloses a recovery method of a quartz crucible after application of a Czochralski single crystal, and relates to the technical field of waste recovery. The method comprises the steps of sorting, grading and screening, preliminary cleaning, high-temperature treatment (500-1000 DEG C, heat preservation for 4-8 hours), water quenching and cooling, secondary screening, high-purity fused quartz treatment and cristobalite treatment. The core is that the fused quartz and the cristobalite are efficiently separated by utilizing the thermophysical property difference between the fused quartz (the thermal expansion coefficient is 0.5 * 10 <-6 > / DEG C) and the cristobalite (the thermal expansion coefficient is 11 * 10 <-6 > / DEG C) and the stress generated by crystal form transformation (beta-alpha, and the volume expansion is 2.8%) of the cristobalite. The fused quartz silica powder (used for ceramic crucible coatings, PCBs and the like) and the high-purity cristobalite silica powder (used for high-end ceramics, coatings and the like) with the purity larger than or equal to 99.995% can be obtained, the fused quartz recovery rate reaches 74% or above, the whole process is environmentally friendly and free of pollution, the problems that an existing recovery method is low in additional value and poor in product quality are solved, and the method is suitable for industrial production. And high value-added utilization of the scrapped quartz crucible is realized.

The preparation method of the cadmium telluride polycrystal comprises the following steps: weighing a 5N tellurium block and a cadmium block according to a molar ratio of 1: (1.021-1.043); s2, loading the tellurium block into the bottom of a quartz tube, loading the cadmium block into a quartz boat with a tapered side wall, then loading the quartz boat into the quartz tube and placing the quartz boat above the tellurium block, keeping the quartz tube to be vertically placed after the quartz boat is loaded, and forming a gap between the radial direction of the quartz boat and the inner wall of the quartz tube; vacuumizing, and vertically sealing the pipe; vertically loading the quartz tube into a heating furnace, and placing the quartz tube in a constant-temperature area; heating from room temperature to 460 DEG C at the speed of 50-100 DEG C / h, and keeping for 1-2 hours; heating from 460 DEG C to 760-800 DEG C at the speed of 10-20 DEG C / h, and keeping for 8-12 hours; heating to 1100-1150 DEG C at the speed of 50-100 DEG C / h, and keeping for 3-5 hours; naturally cooling the quartz tube to room temperature; and taking out the quartz tube from the heating furnace, crushing, and carefully taking down the quartz boat to obtain the cadmium telluride polycrystalline ingot.

The present application relates to the field of doped optical fiber preparation, and particularly relates to a method for preparing a rare earth doped quartz-based optical fiber by using an in-tube melting method after pretreating raw materials, the method introduces an inorganic compound containing rare earth elements, performs a high-temperature pre-sintering treatment on the mechanically ground raw material, then performs a ball milling process, the raw material is dried and sieved after ball milling, then is converted into a cristobalite block by a second pre-sintering, and is then transferred into a high-melting-point quartz tube to be melted at a temperature above the melting point of cristobalite for a period of time, so that a transparent bubble-free optical fiber is drawn. In the above process, the inorganic compound containing rare earth elements improves the solubility of rare earth ions in quartz glass and reduces the melting point of the quartz raw material; the ball milling process improves the uniformity of the raw material, which is beneficial to improving the uniformity of the later molten glass; the two pre-sintering processes convert the raw material into a cristobalite phase, which significantly reduces the bubbles in the core glass in combination with the vacuum in-tube melting method.

The utility model provides a formation tank aluminum foil extension cooling device and a formation device, and belongs to the technical field of electrode foil formation equipment, the formation tank aluminum foil extension cooling device comprises a formation tank as well as a first driving roller, a second driving roller and an extension cooling assembly which are positioned in the formation tank, the extension cooling assembly comprises a quartz tube, and the first driving roller and the second driving roller are positioned on the same horizontal plane; the quartz tube is located between the first transmission roller and the second transmission roller, the first transmission roller, the second transmission roller and the quartz tube are parallel to one another, and the two ends of the first transmission roller, the second transmission roller and the quartz tube are connected with the groove walls on the two sides of the formation groove respectively; the quartz tube is arranged between the first transmission roller and the second transmission roller, the aluminum foil sequentially penetrates through the upper portion of the first transmission roller, the lower portion of the quartz tube and the upper portion of the second transmission roller, the surface stress of the aluminum foil is reduced, the ductility of the aluminum foil is improved by means of the high-temperature-resistant characteristic of the quartz tube, the bending frequency is increased, and the fixing frequency in the using process is reduced; and the abrasion of the aluminum foil is reduced.

The invention discloses a high-strength reinforcing agent for direct-current electric porcelain glaze, and the high-strength reinforcing agent for direct-current electric porcelain glaze is prepared from the following raw materials in parts by mass: 100 parts of quartz sand and 7-8 parts of silane coupling agent. The quartz sand is subjected to high-temperature calcination at 850-900 DEG C, the quartz sand crystal conversion rate reaches 70% or above, the quartz sand can form a cristobalite crystal phase with higher stability through high-temperature calcination, then the quartz sand crystal is subjected to ball-milling treatment through a ball mill, the material dispersion uniformity is improved to a certain degree, and the material dispersion uniformity is improved to a certain degree. A mixture of gamma-aminopropyl triethoxy silane and gamma-glycidyl ether oxypropyl trimethoxy silane is used in the silane coupling agent, and a nano zinc oxide dispersing agent is added in the silane coupling agent, so that chemical bonding with the quartz sand is enhanced through the arrangement; the interface bonding strength is optimized; and due to the introduction of the composite rare earth oxide, glaze grains can be more refined.

The utility model is suitable for the technical field of monocrystalline silicon preparation, and provides a quartz ceramic crucible and a single crystal furnace. The quartz ceramic crucible comprises an outer layer and a ceramic layer arranged on the inner wall of the outer layer. The outer layer comprises a non-transparent layer and a vacuum transparent layer, and the vacuum transparent layer is arranged on the inner wall of the non-transparent layer; and the ceramic layer is arranged on the inner wall of the vacuum transparent layer. According to the utility model, the reaction between the quartz crucible and molten silicon is prevented, and the generation of SiO is eliminated, so that the oxygen content is reduced; a layer of compact and tiny cristobalite crystals are formed on the inner side of the crucible, so that the service life of the crucible can be greatly prolonged.

Provided is a glass containing a crystalline phase, the glass including at least one crystalline phase selected from the group consisting of cristobalite, lithium disilicate, and petalite, in which an average linear expansion coefficient at 100° C. to 300° C. is 85×10−7 / ° C. or more, and a glass transition point is 680° C. or higher.