50 results about "Cristobalite" patented technology

This application relates to a method for preparing cristobalite sand and fused silica glass sand using waste quartz crucibles, wherein the method includes the following steps: 1) crushing and first screening the waste quartz crucibles, collecting the first undersize and the first oversize respectively; 2) subjecting the first oversize obtained in step 1) to high-temperature calcination to obtain a mixture containing a surface crystallized layer of cristobalite sand and fused silica glass sand separated; 3) subjecting the mixture obtained in step 2) to auto-grinding and second screening, taking the second undersize to obtain the first cristobalite sand, and taking the second oversize to obtain the first fused silica glass sand; 4) washing the first cristobalite sand in step 3), and performing wet screening to collect the third oversize for processing to obtain the first high-purity cristobalite sand, and collecting the third undersize for processing to obtain the second high-purity cristobalite sand.

The invention relates to an inorganic composition product which is formed by strengthening crystallized glass. The crystallized glass contains, as a main crystal phase, one or more substances selected from the group consisting of alpha-cristobalite and alpha-cristobalite solid solutions. The content of the SiO2 component is 50.0% to 75.0%, the content of the Li2O component is 3.0% to 10.0%, the content of the Al2O3 component is 5.0% to less than 15.0%, the content of the B2O3 component is more than 0% to 10.0% (inclusive), and the content of the P2O5 component is more than 0% to 10.0% (inclusive) in terms of mass% of oxides; the mass ratio of SiO2 / (B2O3 + Li2O) is from 3.0 to 10.0; the inorganic composition product has a compressive stress layer on the surface and has a four-point bending strength of 760 MPa or more.

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 discloses a quartz crucible for single crystal silicon production and a preparation method thereof, relates to the technical field of crucibles, and contains a glass phase and a cristobalite phase, and the cristobalite phase is uniformly dispersed in the glass phase; the application adopts a mixture of amorphous synthetic quartz sand and cristobalite as a crucible preparation raw material, uniformly nucleates to form consistent phases inside and outside, significantly improves the stability of the crucible, effectively solves the problems of deformation such as bulging and wrinkling of the quartz crucible prepared from natural quartz sand in a high-temperature environment, and prolongs the service life of the crucible.

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 present disclosure relates to a reflective granular composition comprising a reflective pigment material including cristobalite, kaolin clay, and ATH; and at least 5 wt. % of a hardener, based on the total solids weight of the composition. The present disclosure also relates to a building material containing the reflective granular composition. The present disclosure also relates to a method for making the reflective granular composition.

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 present invention provides cristobalite and a method for preparing the same. The method comprises the steps of: pre-treating waste quartz glass to obtain 80-200 mesh coarse quartz glass sand; alkali-leaching the coarse quartz glass sand to obtain refined quartz glass sand; subjecting the refined quartz glass sand to a high-temperature crystallization treatment to completely convert the amorphous fused quartz into a crystalline phase to obtain coarse cristobalite sand; and acid-leaching the coarse cristobalite sand to obtain refined cristobalite. The method has the advantages of high crystallization conversion, low environmental pollution, and high-quality finished products. Furthermore, by utilizing waste quartz glass as raw material, it alleviates the environmental pollution and space pressure of waste quartz glass, thereby conserving resources.

To provide a system for producing a silicon ingot by the horizontal magnetic field Czochralski method.SOLUTION: A system for producing a silicon ingot includes: a natural sand crucible containing a silicon melt in which a cristobalite layer having a thickness between 0.25 mm and 1.25 mm is formed on an inner wall of the crucible; magnetic poles for generating a horizontal magnetic field; and a controller programed to produce a silicon ingot according to the following steps: rotating the natural sand crucible containing a silicon melt at two to five revolutions per minute; applying a horizontal magnetic field to the crucible using the magnetic poles; contacting the silicon melt with a seed crystal; and withdrawing the seed crystal from the silicon melt while rotating the natural sand crucible at two to five revolutions per minute to form a silicon ingot.SELECTED DRAWING: Figure 4

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 present invention discloses a method for designing particle size gradation for low-shrinkage ceramic green bodies and its application in the preparation of quartz ceramics, belonging to the field of ceramic materials technology. By optimizing the particle size gradation of quartz, the present invention promotes cristobalite crystallization during the preparation process of the quartz ceramics, improves sintering densification, and significantly enhances the mechanical properties and dimensional stability of the quartz ceramics, particularly their flexural strength under high-temperature conditions.

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.

The invention provides a synthetic quartz glass ingot manufacturing method and a synthetic quartz glass ingot, and belongs to the technical field of quartz glass. The preparation method comprises the following steps: mixing synthetic silicon dioxide powder with an alkali metal aqueous solution serving as a crystallization accelerant, controlling the concentration of mixed sodium to be 50-1000ppm, converting the synthetic silicon dioxide into beta-cristobalite in a heating process of a vacuum furnace, heating to 1800 DEG C or above while keeping open pores, and cooling to room temperature to obtain the beta-cristobalite. Therefore, the large synthetic quartz glass ingot with few bubbles and low price can be manufactured and can be applied to many fields such as semiconductors and the like.

The invention discloses a quartz crucible for semiconductor monocrystalline silicon growth and a preparation method thereof, and relates to the technical field of crucibles, the quartz crucible does not contain bubbles and is composed of a supporting layer and a transparent layer, the supporting layer contains a glass phase and a cristobalite phase, and the cristobalite phase is uniformly dispersed in the glass phase; and the thickness of the transparent layer is smaller than 1 / 4 of the wall thickness of the crucible. According to the quartz crucible prepared by the invention, the proportion of the transparent layer is small, and the transparent layer can be mechanically removed and re-deposited to generate the transparent layer, so that the regeneration of the crucible is realized.

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.

The invention provides a method for deeply removing cristobalite in bentonite by using a nanoscale filtering membrane, and belongs to the technical field of bentonite purification. The preparation method comprises the following steps: performing preliminary wet purification on calcium bentonite to remove large-particle impurities in the calcium bentonite, performing ion exchange modification and pre-hydration treatment, introducing sodium ions with excellent hydration capability between layers of the bentonite to increase the hydration expansion performance of the bentonite, and then stripping to easily strip a single layer or a few layers of nanosheets, and the submicron cristobalite and the nano montmorillonite are completely separated by utilizing a two-layer filtering device. The process provided by the invention is simple, the production cost is low, no by-product is generated in the whole process, and the obtained high-purity montmorillonite can be directly applied to the fields of production of medicines, cosmetics and the like.

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 invention belongs to the field of new materials, and discloses an aluminum oxide ceramic with a low thermal expansion coefficient, which is prepared by sintering the following raw materials: 98.5-99.1 wt% of aluminum oxide; 0.15 to 0.25 wt% of silicon powder; 0.15 to 0.25 wt% of magnesium oxide; 0.15 to 0.25 wt% of yttrium fluoride; and 0.25 to 0.75 wt% of fused crystal beta-cristobalite. According to the product, the four elements of Al, Si, Mg and Y form a quaternary system ceramic formula, the requirement of the market for the low thermal expansion coefficient of the 99 aluminum oxide ceramic product is met, and the application value of the 99 aluminum oxide ceramic in a ceramic substrate and an electrostatic chuck is greatly improved. Meanwhile, the invention further discloses a preparation method of the aluminum oxide ceramic.

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.

The invention relates to microwave plasma enhanced atomic layer deposition or microwave plasma enhanced chemical vapor deposition equipment and process for realizing a large-size uniformly deposited film, the equipment comprises a resonant guided wave cavity, a reaction cavity, a gas dispersion ring, a quartz isolation plate and an antenna network ring, and the upper cavity of the resonant guided wave cavity is uniquely designed; the gas dispersion ring is arranged on the peripheral surface of the resonant wave guide cavity and is used for spraying uniform annular gas flow into the resonant wave guide cavity; the quartz isolation plate is located in the resonance wave guide cavity and located above the gas dispersion ring, and the quartz isolation plate is used for enabling the microwaves penetrating through the quartz isolation plate to excite the gas sprayed out of the gas dispersion ring to generate uniformly distributed plasmas; according to the scheme, efficient coupling and transmission of microwave energy can be achieved, so that the density uniformity of plasma is improved, and the requirement for high-quality uniform thin film deposition of large-area substrates with the sizes of 8 inches or above is met.