71 results about "Silenes" patented technology

The invention discloses a clean preparation method of a rare earth ferrosilicon alloy based on cooperative control of carbon addition and silicon supplement, and belongs to the technical field of thermometallurgy. In order to solve the problems that according to an existing carbon thermal reduction method, the furnace bottom is prone to nodulation, the recovery rate is low, and energy consumption is high, the'carbon addition-silicon supplementation-carbon depletion 'ternary cooperative regulation and control method is provided. Comprising the following steps: taking a rare earth-containing material, a siliceous raw material and a carbonaceous reducing agent as raw materials, burdening, pelletizing, and adding into a submerged arc furnace for reduction smelting; the core technology is that the weight ratio of oxide to reducing agent carbon in the rare earth pellets is controlled to be 1: (1.20-1.30), meanwhile, a silicon element accounting for 2.0-10.0% of the weight of the oxide is added, and parameters meet the coupling relational expression S = k * (1.30-R) * 100% + S0; and the smelting adopts carbon deficit operation, and the carbon addition amount is 0.90-0.95 times of the theoretical amount. The method inhibits the generation of the rare earth carbide nodule at the furnace bottom from the aspects of thermodynamics and dynamics, and realizes continuous and stable production. The rare earth recovery rate reaches 96% or above, the comprehensive power consumption is reduced to 8600-9000 kWh / t, the furnace life is prolonged to 25 months or above, and remarkable economic and environmental benefits are achieved.

The present invention concerns an industrial chemical process (400f) and an apparatus for carrying out that process. The chemical process integrates into a single, combined method: (i) a method (303, 304) of producing iron and / or manganese from their ores, and (ii) a method (205a, 205b, 207, 208, 209) of producing an oxide or hydroxide of at least one of calcium, magnesium and iron from another ore respectively comprising a carbonate mineral of at least one of calcium, magnesium and iron. This combined method has the iron and / or manganese ore and the other ore comprising the carbonate mineral as its only essential ingredients, with common salt and / or water as optional extra ingredients. The combined method produces iron and / or manganese in elemental form, an oxide or hydroxide derived from the carbonate mineral, and oxygen as its corresponding products. If the iron and / or manganese ore also comprises a siliceous mineral, the method may also produce an alkaline mixture comprising sodium silicate as a co-product. Salt and water act as intermediaries to produce these end-products, but are only consumed if supplied in excess. An amount of sodium oxide, hydroxide and / or carbonate determined by the amount of salt consumed may be produced as a co-product, along with a corresponding amount of at least one of chlorine and hydrochloric acid. An amount of hydrogen determined by the amount of water consumed may also be produced as a co-product, along with an increased amount of oxygen. The iron, manganese and oxygen produced may all be used in steelmaking. Any excess oxygen may be safely vented to atmosphere. The oxide or hydroxide derived from the carbonate mineral may be used in cement manufacture, as a flux in steelmaking and / or as an ingredient in the manufacture of soda-lime glass. The alkaline mixture comprising sodium silicate may be used as an alkaline activator for an alkaline activated or geopolymer cement. The sodium carbonate may be used in the manufacture of soda-lime and / or borosilicate glass, for example. The chlorine and / or hydrochloric acid may be used in the manufacture of chlorinated organic compounds, for example. The hydrogen may be used as a fuel in a hydrogen economy. The method of the invention requires no nett input of heat because the chemical reactions it involves are exothermic overall. It also consumes no fossil fuels and has electricity as its only energy requirement. Thus if the electricity is produced from a source of renewable energy, this method produces no greenhouse gas emissions. In some embodiments, the method can even have a negative carbon footprint overall. The invention is intended to replace existing techniques for producing iron and / or manganese from their ores, including hydrogen-DRI, the calcination of limestone and other carbonate minerals, both in cement manufacture and in the production of lime for other purposes, and the ammonia-soda, or Solvay, process for the production of sodium carbonate. The invention therefore has the potential to eliminate up to about 20% of anthropogenic carbon dioxide emissions. [Fig. 9B]

The application relates to a preparation method of a beta-C2S crystal structure, and the specific steps are as follows: S1, calcium raw materials, silicon raw materials and a crystal structure regulator are mixed according to a calcium-silicon molar ratio of 2:1 to obtain sintered raw materials; S2, the sintered raw materials obtained in the step S1 are mixed with anhydrous ethanol, are pressed into a green body, are dried, are sintered, are naturally cooled, and beta-C2S is obtained. Compared with the prior art, trace heavy metals Cr2O3 and ZnO are used as the crystal structure regulator to regulate the beta-C2S crystal structure, so that sintering at a lower temperature, higher reactivity, reduced calcination energy consumption, reduced beta-C2S cost and the cooling mode of relatively rapid cooling in the furnace are realized, the method is safer, has very important practical significance for industrial production and application of the beta-C2S, and provides technical support for low-carbon development of the silicate cement.

The present invention provides a method (600a) and apparatus for producing an alkaline mixture comprising sodium silicate, which mixture is suitable for use as an alkaline activator for alkaline activated and geopolymer cements, but which may also be used, for example, to mineralize captured carbon dioxide. The method comprises comminuting (301) an ore of a target metal into fines, wherein the ore comprises a siliceous mineral and at least one of iron and manganese as the target metal. The siliceous mineral may comprise the target metal itself and / or it may be silica and / or another silicate mineral present as gangue. The ore is dehydrated and hydroxylated compounds contained therein are dehydroxylated (302). The ore thus treated is then reacted (601) in an inert atmosphere with an amount of liquid sodium in excess of the stoichiometric amount thereof required for a redox reaction between the liquid sodium and an oxide of the target metal from the ore, to precipitate out from the liquid sodium a solid phase comprising both the target metal in elemental form and other insoluble products comprising sodium oxide. The redox reaction is conducted at a temperature of at least 320 °Celsius to induce a reaction between the sodium oxide and silica derived from the siliceous mineral to produce sodium silicate, but also below a temperature at which the liquid sodium can react with the oxide of the target metal to produce a ternary oxide thereof. At least some of the liquid sodium having sodium silicate dissolved therein is then separated (305) from the solid phase and is reacted (602) with at least one of oxygen and water to produce a mixture comprising sodium silicate and at least one of sodium oxide and sodium hydroxide. The corresponding apparatus comprises a comminution device (such as a rock crusher or grinder), means for dehydrating and dehydroxylating the ore (such as a dryer), a gas-tight first reaction vessel for reacting the ore thus treated with the liquid sodium, a solid-liquid sodium phase separator, and a second reaction vessel for reacting the liquid sodium having sodium silicate dissolved therein with at least one of oxygen and water. The resulting alkaline mixture is therefore produced whilst extracting the target metal in elemental form from its ore. Thus the energy consumed is split between the production of these two co-products, making the method of the invention a low-energy method of producing an alkaline activator for alkaline activated and geopolymer cements. Both reactions (601, 602) are also significantly exothermic and at least some of the thermal energy from them may be recycled. The invention does not consume any carbon and is therefore at least carbon-neutral. On the other hand, it consumes the silica content of gangue mineral species and / or of siliceous minerals of the target metal in its ore, which have previously been treated as waste products. The amount of waste material produced when extracting the target metal from its ore is thereby reduced as well.

The invention discloses a gypsum composition as well as a preparation method and application thereof, and relates to the technical field of inorganic materials. The gypsum composition comprises gypsum, a filler, silicon-containing industrial solid waste, a nano siliceous material and an auxiliary agent, the nano siliceous material comprises nano silicon dioxide and modified nano silicon dioxide; the modified nano silicon dioxide is obtained by modifying nano silicon dioxide through a silane coupling agent. As gypsum putty, the gypsum composition has good coating matching performance, overcomes the defect that physical bonding between traditional gypsum putty and a coating is easy to peel off, can ensure that the coating is stable for a long time and does not fall off, improves the humidity resistance, and can keep stable performance and keep the beauty of wall decoration in the environments of plum rain seasons, coastal damp and the like. The service cycle is prolonged.

The invention discloses a low-creep siliceous prefabricated material and a preparation method thereof, and relates to the technical field of unshaped refractory materials, and the low-creep siliceous prefabricated material comprises the following components by weight: 40-50 parts of silica brick sand, 10-20 parts of calcined silica sand, 15-25 parts of silica brick powder, 1-5 parts of silica micropowder, 1-5 parts of calcium silicate cement clinker, 5-10 parts of silica sol, 1-5 parts of silicon nitride, and 0-0.5 part of a rare earth silicate solid solution. The composite water reducing agent is a mixture of sodium tripolyphosphate and a polycarboxylic acid water reducing agent, and the weight ratio of the sodium tripolyphosphate to the polycarboxylic acid water reducing agent is 2: 1. By optimizing the process ratio, the residual quartz amount and the creep rate of the siliceous prefabricated material are reduced, the long-term creep resistance of the siliceous prefabricated material under low stress is remarkably improved, and the siliceous prefabricated material with a more stable structure is provided for the high-temperature industry.

The invention discloses an experimental material for simulating gradual damage of a moraine structure, a preparation method and an experimental system. The preparation method comprises the following steps: preparing gravels, coarse sand and powder particles into a dry mixture; adding low-temperature molten soda-lime glass powder, and heating to form a siliceous cementation prototype; the preparation method comprises the following steps: adding pretreated calcium type clay and ice crystals into a material in a negative temperature environment, stirring, filling a mold and preliminarily fixing, feeding a carbonate solution into a fixed framework in batches through a liquid supply system at the bottom of the mold to realize mud-salt integrated synergistic cementation, and finally, compacting and carrying out negative temperature maintenance to obtain the experimental material. The experimental system integrates a temperature control unit, a pressurization and force measurement integrated module, an in-mold directional constant-flow liquid supply module and a control unit, and the whole process from material preparation to progressive failure test is integrated and automatically controlled. Compared with the prior art, the method has the advantages that an ice, mud-salt and siliceous triple cementation structure is successfully constructed in the material, and the problem of temperature and pressure disturbance caused by sample transfer is thoroughly solved.

Concrete materials and thermal energy storage devices employing such concrete materials are disclosed herein. The concrete material may include fibers in an amount ranging from about 1 to about 2 vol. %; an aggregate in an amount ranging from about 50 to about 80 vol. %, wherein the aggregates comprises siliceous aggregate and optionally carbonate aggregate; and a cementitious material in an amount from about 12 to about 20 vol. %, wherein the cementitious material comprises a combination of about 70 to about 85 vol. % of Portland cement and about 15 to about vol. % of silica fume, wherein all volume percentages unless otherwise indicated are based on the total volume of the concrete material.

The invention provides a hydration heat in-situ self-foaming light composite board and a preparation method thereof. The light composite board is prepared from the following raw materials: an inorganic cementing material, expanded polystyrene particles and an active siliceous material, wherein the inorganic cementing material comprises quick lime. According to the preparation method, hydration heat released in the hydration process of quick lime is used as an endogenous heat source to induce expanded polystyrene particles to generate in-situ expansion foaming in a system, and meanwhile, a high-alkalinity environment is formed to promote cementitious materials such as silicon hydrochloric acid cement and active siliceous materials to generate inorganic gel on the surfaces of the expanded polystyrene particles; and a composite interface structure wrapped by inorganic gel is formed, so that the light weight of the board is reduced, the synergism and unification of the light structure, the mechanical property and the fireproof property are realized, and the organic-inorganic interface stability and the structural integrity are improved.

The application relates to a preparation method of silica gel, which extracts siliceous elements from waste concrete rich in SiO2, Al2O3 and other components to prepare inorganic silica gel, and comprises the following steps: crushing, calcining, peeling, ball milling, preparation of a silicon-containing mixture, sol-gel, centrifugation, drying and the like; the application rationally utilizes the component characteristics of the waste concrete block, and prepares inorganic silica gel by taking the separated old hardened cement stone as a silicon source, has the advantages of simple process, low synthesis temperature, low energy consumption, green environmental protection, and the prepared inorganic silica gel has the advantages of large specific surface area and uniform pore structure; the method saves the production cost, effectively improves the economic added value and utilization rate of the waste concrete and the old hardened cement stone, avoids land resource occupation and environmental pollution, and has important environmental protection significance and application value.

The invention provides an insulation board and a raw material composition, a preparation method and application thereof. The insulation board raw material composition comprises a first component and a second component, the first component comprises polyol and isocyanate, and the second component comprises siliceous hollow microspheres, a siliceous substance and a calcareous substance; the calcium substance comprises calcium oxide and / or calcium hydroxide; the content of the siliceous hollow microbeads is 30%-90%; the particle size of the siliceous hollow microbeads is 10 to 150 meshes; the mass ratio of the first component to the second component is (2-18): (82-98). The insulation board prepared from the insulation board raw material composition meets the requirement of light weight, has excellent thermal insulation performance, fireproof performance and physical strength (compression strength and tensile strength), and has excellent comprehensive performance; in addition, the durability of the obtained insulation board is good.

This invention belongs to the field of coatings and coating systems, and discloses a two-component coating: Component A comprises 5-20 parts of organosilicon-modified diol oligomer, 10-30 parts of polyester diol, 0.1-1 parts of catalyst, 5-15 parts of boron-containing flame-retardant filler, 5-10 parts of ceramic filler, and 20-60 parts of solvent; the boron flame retardant in the boron-containing flame retardant filler is one or more of zinc borate, borax, sodium borate, calcium borate, triphenyl borate, and tributyl borate; the ceramic filler is aluminum dihydrogen phosphate and silica powder; Component B comprises 50-90 parts of diisocyanate and 10-40 parts of polyisocyanate. By mixing Component A and Component B in a weight ratio of 100:5-15 and spraying multiple times onto the substrate surface according to a spray-drying process, a flexible ablation-type thermal protective coating can be obtained. This thermal protective coating can form a coating ablation product containing a borosilicate glass phase within 2 minutes under high-temperature ablation at temperatures above 1000°C. Such a flexible ablation-type thermal protective coating combines the normal flexibility and toughness of the coating with the strong mechanical properties of the coating ablation products.

The invention discloses a preparation method of a chromium melt adhesive multifunctional adhesive, relates to the field of adhesives, and aims to solve the problems that in the prior art, an organic adhesive is poor in environmental protection performance, and an inorganic adhesive is poor in viscosity, flowability and permeability. The soaking speed can be increased by heating and adding the penetrating agent, and the bonding strength of the adhesive can be improved by adding the coupling agent. According to the method, the raw material cost is reduced, meanwhile, sufficient dissolution and uniform reaction of effective substances are ensured, and the prepared adhesive has high bonding strength, has the advantages of being low in raw material cost, sufficient in reaction and good in environmental protection property due to the fact that the adhesive does not contain organic volatile substances, and is low in viscosity and good in fluidity and permeability.

The invention discloses a preparation method of a high-strength heavy metal cured geopolymer based on lead-zinc tailings, and belongs to the technical field of solid waste resource utilization and heavy metal pollution treatment. The lead-zinc tailings, the fly ash, the diatomite and the alkali activator are used as raw materials, and the three action mechanisms of mesoporous adsorption-chemical bonding-structure enhancement of the diatomite are utilized, so that the curing efficiency and stability of heavy metal residues contained in the lead-zinc tailings are improved, and the risk to the ecological environment is greatly reduced; the fly ash is used as a core aluminum-silicon raw material, is rich in active SiO2 and Al2O3, is dissolved under the action of alkali to generate a geopolymer gel skeleton, and is a main source of strength; the lead-zinc tailings serve as an auxiliary silicon-aluminum source and aggregate, part of active ingredients of the lead-zinc tailings participate in the reaction, meanwhile, unreacted particles play a role in filling micro aggregate, and particle composition is optimized; and the alkali activator provides a high-alkalinity environment, aluminosilicate active components in other raw materials are dissolved, and finally the high-strength geopolymer is generated through an alkali excitation reaction.

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.

Disclosed herein are methods and kits for purifying therapeutic-grade plasmid DNA using magnetic particles. In particular, the technology of the present disclosure relates to methods and kits for purifying therapeutic-grade plasmid DNA at a high degree of purity using magnetic particles with a siliceous oxide surface layer and a superparamagnetic core.

The invention provides a method for preparing iron and a cementing material through electrolysis of molten steel slag, and belongs to the technical field of solid waste resource utilization. The method comprises the following steps: mixing molten steel slag and a siliceous modifier to obtain mixed molten slag; the mixed slag is subjected to electrolytic reduction, and modified slag with reconstructed components and metal iron are obtained; and mixing the modified slag with the reconstructed components with calcium oxide to obtain silicate slag, then cooling to room temperature, and recycling cooling heat for preheating the siliceous modifier and calcium oxide to obtain the silicate cementing material. According to the method, the iron element is directly recovered from the molten steel slag through an electrochemical reduction method, so that the reduction efficiency is high, the addition of other reagents can be reduced, and the carbon emission of iron and steel enterprises is reduced; the modified slag obtained after component reconstruction and calcium oxide are mixed and cooled to the room temperature, the silicate cementing material is directly prepared, recycled heat is used for preheating raw materials, carbon emission reduction in the ferrous metallurgy industry is achieved, and energy consumption of iron and steel enterprises is reduced.

This invention discloses a high-density, high-thermal-conductivity silica refractory slurry and its preparation method. The refractory slurry consists of dry-based powder and additives. The dry-based powder includes: 65-75% silica, 15-20% micron-sized silica clay, 10-15% amorphous fused silica powder (containing micron-sized and nano-sized powders in a 2:1 mass ratio), and 2-3% borosilicate glass powder. The additives include silica sol and a high molecular weight block copolymer dispersant. The silica sol is added at 20-30% of the total mass of the dry-based powder, and the high molecular weight block copolymer dispersant is added at 2.5% of the silica sol mass. During preparation, the silica is first calcined at 600℃, then the silica sol and high molecular weight block copolymer dispersant are mixed, and the micron-sized powder and calcined silica are added sequentially and mixed thoroughly. The refractory mortar of this invention has a porosity of ≤25% after drying, a thermal conductivity of 2.2-2.6 W / (m·K), and a refractoriness of ≥1620℃. It has high density, high thermal conductivity, excellent high-temperature performance, and wide temperature range adaptability (from room temperature to 1750℃). It is suitable for the construction and repair of siliceous refractory materials and high-density siliceous ceramics.

To provide a polysiloxane composition capable of suppressing the generation of voids when forming a siliceous film. A polysiloxane composition comprising a polysiloxane; a dicarboxylic acid having the first acid dissociation constant pKa1 of 4.0 or less and represented by the following formula (II): HOOC-L-COOH (II) (wherein, L is a single bond, a hydroxy-substituted or amino-substituted alkylene having 1 to 6 carbon atoms, a substituted or unsubstituted alkenylene having 2 to 4 carbon atoms, a substituted or unsubstituted alkynylene having 2 to 4 carbon atoms, or a substituted or unsubstituted arylene having 6 to 10 carbon atoms); and a solvent.

The application discloses a wet siliceous mud, a preparation method and application thereof, and belongs to the technical field of mud. The wet siliceous mud comprises the following components in mass fraction: 30-52% of silica sand, 7-16% of calcined quartz, 6-7% of silica brick fine powder, 4-6% of silica micro powder, 1-2% of dextrin, 1-2% of sodium dihydrogen phosphate, 0.5% of quaternary ammonium salt preservative, 0.5-1% of BIT and 25-30% of water, and the sum of the mass of the components is 100%. The siliceous mud has excellent performance and long holding time.

The present invention relates to a method for manufacturing a siliceous mixed material, the method comprising the steps of: preparing a residue of an ore from which lithium has been extracted and calcium sulfate has been removed; and drying the residue of the ore from which lithium has been extracted and calcium sulfate has been removed.

The invention relates to the technical field of aluminum composite plates, in particular to an A1-grade fireproof and decorative aluminum composite plate and a manufacturing process thereof, and the A1-grade fireproof and decorative aluminum composite plate sequentially comprises the following raw materials from inside to outside: an inner-layer aluminum plate, a first polymeric membrane, a calcium silicate plate, a second polymeric membrane and an outer-layer aluminum plate. According to the invention, the polymer film is subjected to blending modification through the ethylene-butyl acrylate copolymer and the low-density polyethylene, and is matched with the halogen-free flame retardant coated with the silane coupling agent, so that efficient bonding and flame-retardant synergy among the layers are realized, and the interface bonding strength of the composite board is enhanced; the calcium silicate board is based on siliceous and calcareous raw materials, and silane modified glass fibers and nano magnesium hydroxide are introduced, so that excellent fire resistance is provided, and the composite board structure is endowed with supporting force; the modified outer-layer aluminum plate is subjected to micro-arc oxidation and graphene modified PVDF coating composite treatment, on one hand, the bonding stability of the modified outer-layer aluminum plate and a polymeric membrane is improved, and on the other hand, the decoration performance, the weather resistance and the corrosion resistance are remarkably improved.

The invention discloses chromite fluxed sintered ore and a preparation method thereof. The preparation method comprises the steps that chromite powder, chromium-containing slag, a calcium flux, a magnesium flux, a siliceous flux and fuel serve as raw materials to be subjected to burdening, even mixing and granulation, and a sintered mixture is obtained; and distributing, igniting, sintering, crushing, cooling and screening the sintered mixture to obtain the chromite fluxed sinter. According to the method, the fluxing agent adopted in the sintering process is based on the fluxing agent used for electric furnace smelting slagging, the calcium fluxing agent is added, the binary alkalinity is improved, the sintering mineralization consolidation process of chromite powder can be completed at the low sintering temperature by adjusting the composition and addition amount of the fluxing agent, developing a low-melting-point phase and reducing the sintering liquid phase generation temperature, and the high-purity chromite powder can be obtained. And meanwhile, the produced chromite fluxed sintered ore has the advantages of being high in strength, high in yield and the like.

This invention belongs to the technical field of solid waste treatment and hazardous waste harmless treatment, specifically disclosing a method and application for siliceous-steam synergistic dechlorination of waste incineration fly ash. Waste incineration fly ash is mixed with siliceous materials at a mass ratio of 1:0.2–1.2, and heat-treated at 750–950℃ for 60–70 min in an atmosphere with a steam volume fraction of 5%–30%. After treatment, the total chlorine removal rate reaches over 99.6%, the residual chlorine content is as low as 0.052 mass, the chloride peak disappears, and it is mainly converted into silicate phases such as CaSiO3. This method operates at medium temperatures, causes no secondary pollution, requires no water immersion washing, no evaporation crystallization for salt production, and generates no saline wastewater. The residue has cementing activity and can be used for co-processing in cement kilns or for preparing auxiliary cementing materials, achieving efficient, harmless, and resource-based treatment of fly ash. Ultimately, it achieves the goal of treating waste with waste.

The invention provides a high-purity quartz product prepared from waste quartz glass and a preparation method of the high-purity quartz product, and the preparation method comprises the following steps: pretreating the waste quartz glass to obtain refined quartz glass powder; proportioning the refined quartz glass powder and a sodium hydroxide solution, putting the mixture into a high-pressure reaction kettle with a stirring and heating device, carrying out hydrothermal reaction, and after the reaction is finished, carrying out solid-liquid separation on a product to obtain crude alpha-quartz and sodium silicate filtrate; and respectively carrying out post-treatment on the crude alpha-quartz and the filtrate to obtain high-purity alpha-quartz and high-purity SiO2 micro powder. The content of SiO2 in the prepared high-purity alpha-quartz ranges from 99.99% to 99.9999%, and the content of SiO2 in the high-purity SiO2 micro powder ranges from 99.99% to 99.999%. According to the method, two high-purity siliceous products can be obtained at the same time, all-component utilization of the raw materials is achieved in the whole process, secondary pollution is avoided, meanwhile, reaction conditions are mild, and harm to the environment is small.

This invention provides a low-halogen alkaline oxide composite additive for industrial silicon submerged arc furnaces and its application method. The additive contains at least magnesium and calcium source components, respectively, based on MgO and CaO equivalents. The fluxing and reinforcing component is selected from alkali metal oxides or alkaline earth metal oxides. The additive is added at a rate of 0.03-1% based on silica mass, and the halide content, based on Cl, is ≤0.5%. Using this additive can effectively reduce the softening temperature of siliceous raw materials and the reaction resistance in the furnace, reducing unit power consumption by 2-20% and increasing the daily output of the submerged arc furnace. Simultaneously, under the constraint of low halogen content, the chloride content of the microsilica powder does not increase. The calcium source component can be provided by industrial solid waste such as calcium carbide dust / calcium carbide slag and is compatible with the magnesium source, achieving stable smelting results under the condition of meeting the equivalent ratio. This invention is also applicable to the smelting of silicon-based ferroalloys such as ferrosilicon in submerged arc furnaces, helping to improve furnace stability and iron tapping smoothness.

A repair composition has at least a first part and a second part. The first part includes an aqueous silicate, which may be an alkali silicate, ammonium silicate, or a combination of an alkali silicate and ammonium silicate. The second part includes a chemical curing agent and a liquid carrier. At least one of the first part or the second part includes particulate filler. At least one of the first part or the second part includes a humectant, and the humectant may or may not be the liquid carrier. Methods of using the repair composition and use of a cementitious repair composition for a non-cementitious damaged surface are also described.

The invention relates to a slagging method for producing high-carbon ferrochrome through high-temperature smelting of chromite. Calcium, magnesium and siliceous fluxes are adopted as slagging fluxes, the adding amount of a reducing agent is determined according to the theoretical carbon addition amount of ferrochrome oxide reduction, and the adding amount of each slagging flux is determined on the basis, so that the mass ratio of SiO2 to Al2O3 in the final smelting slag composition is (1.0-2.0): 1, the mass ratio of (CaO + MgO) to Al2O3 is (1.0-1.5): 1, and the mass ratio of CaO to MgO is (0.2-0.5): 1. Smelting is conducted in high-temperature smelting equipment according to the slagging method, the smelting temperature ranges from 1600 DEG C to 1700 DEG C, and after slag and alloy are separated, the high-carbon ferrochrome alloy is obtained. The slagging method is used for high-carbon ferrochrome smelting, the smelting temperature is reduced, the slag amount and carbon emission are reduced, the recovery rate of the chromium element is increased, the production cost is reduced, and obvious economic benefits and environmental benefits are achieved.

The invention relates to a siliceous refractory material based on silica tailings and a preparation method thereof, and the preparation method comprises the following steps: cleaning original silica tailings to obtain cleaned tailings; and the washed tailings are subjected to size grading screening, the screened washed tailings are sorted, and tailings particles with the Fe2O3 content not exceeding 0.3% are obtained. And the tailing particles are crushed and ground according to the particle size, and the crushed and ground tailing particles are subjected to quality detection to obtain the silica tailing raw material meeting the set standard. The preparation method comprises the following steps: putting 70-80% of a silica tailing raw material and 20-30% of an additive into a mixing mill, and fully premixing to obtain a premixed sample, wherein the mass of the silica tailing raw material accounts for 70-80% of the total mass of the premixed sample; feeding silica tailing raw materials with different particle size grades and the premixed sample into a mixer according to a set proportion, and fully mixing to obtain a first mixture; and selecting a sample from the first mixture according to a preset proportion, and carrying out quality detection on the sample to obtain the siliceous refractory material with a quality detection result meeting a set index.

This application provides a silica-based taphole clay for submerged arc furnaces and its preparation method, belonging to the field of refractory materials technology. The silica-based taphole clay for submerged arc furnaces, by weight, comprises the following components: 40-60 parts silica aggregate, 8-20 parts silica fine powder, 6-12 parts binder, 3-8 parts toughening agent, 1-5 parts antioxidant, 2-6 parts pore-forming agent, and 3-8 parts regulator. The silica-based taphole clay of this invention exhibits excellent comprehensive performance, adaptability to acidic slag environments, good opening properties, and a simple and controllable preparation process. It also possesses good environmental protection characteristics and practical value, meeting the needs of intensified smelting in large-scale submerged arc furnaces.