1274 results about "Calcium hydroxide" patented technology

The invention discloses a preparation process of a fireproof lightweight thermal-insulation cement-based mortar material, which comprises the following steps: (1) placing porous lightweight aggregate in a sodium silicate solution for standing, and drying the obtained aggregate to obtain pretreated thermal-insulation aggregate; (2) uniformly mixing silica fume, calcium silicate powder, calcium hydroxide powder and water to form slurry; mixing the pretreated thermal insulation aggregate with the slurry, separating, airing the aggregate, and curing to obtain the primary thermal insulation aggregate. And (3) spraying water on the primary thermal insulation aggregate for wetting, then spraying ethanol containing a silane coupling agent, and airing to obtain the modified thermal insulation aggregate. And (4) uniformly mixing Portland cement, the modified thermal insulation aggregate, basalt fiber and a water reducing agent as raw materials, adding water, and uniformly stirring to obtain the mortar material. According to the invention, the water absorption rate of the porous lightweight aggregate is reduced, so that the adverse effect of the high water absorption characteristic of the aggregate on the mechanical properties of the mortar material is effectively reduced.

The invention belongs to the technical field of calcium hydroxide preparation, and particularly relates to a preparation method of calcium hydroxide with high specific surface area, which comprises the following steps: S1, adding triethanolamine and diethanolisopropanolamine into water, and uniformly mixing to obtain an active agent solution; s2, mixing quick lime with an active agent solution, and carrying out digestion reaction to generate a calcium hydroxide coarse material; and S3, sieving and drying the calcium hydroxide coarse material to obtain the calcium hydroxide with the high specific surface area. The specific surface area of calcium hydroxide can be remarkably increased through the active agent solution, meanwhile, the uniformity and sufficiency of the quick lime digestion reaction are optimized, the calcium hydroxide particle aggregation phenomenon is reduced, and finally the calcium hydroxide product with the high specific surface area and the high activity is prepared.

The invention discloses a high belite sulphoaluminate cement-based two-component grouting material and a preparation method thereof. The grouting material comprises a gelling component and a coagulating reinforcing component, wherein the gelling component is prepared from a high belite sulphoaluminate cement clinker and an additive A; the admixture A comprises a water reducing agent, a retarder and slow-release minerals; the coagulating and reinforcing component comprises ordinary Portland cement clinker, calcium hydroxide, gypsum and an additive B; the admixture B comprises a water reducing agent and an early strength agent. According to the high belite sulphoaluminate cement-based grouting material, the formula composition of the high belite sulphoaluminate cement-based grouting material is optimized, so that the hydration process of the high belite sulphoaluminate cement is more continuous and lasting, and the compressive strength of the obtained high belite sulphoaluminate cement-based grouting material can be continuously improved.

The invention provides a hydraulic concrete freeze-thaw damage microstructure segmentation method, electronic equipment and a medium. The method comprises the following steps: acquiring concrete two-dimensional CT images of different freeze-thaw cycle times; and taking the concrete two-dimensional CT image as the input of the U-Net network model, and training the U-Net network model to obtain a concrete microstructure segmentation model. According to the method, the problem that high-density groups of hydrated silicate, calcium hydroxide, unhydrated clinker and the like belonging to a mortar phase are misclassified into coarse aggregates is effectively avoided, and the problems that a traditional threshold method is not obvious in dividing boundary and unstable in dividing result are solved. The method provides an effective means for quantifying the influence of freeze-thaw damage on a multi-scale pore structure in the concrete and establishing damage evolution of the concrete under the action of freeze-thaw cycle.

The invention belongs to the field of hydrometallurgy, and particularly discloses a high-purity vanadium oxide electrode and a preparation method thereof. The method comprises the following steps: pre-treating the alkaline vanadium leaching solution by using an activated aluminum oxide adsorption column to obtain a pre-treated solution; adding a composite impurity removal agent taking modified lignosulfonate as a main agent into the pretreatment liquid for primary impurity removal to obtain primary impurity-removed filtrate; adding a calcium hydroxide suspension and a flocculating agent into the primary impurity-removed filtrate for secondary impurity removal to obtain secondary impurity-removed filtrate; purifying the secondary impurity-removed filtrate by using an ion exchange column to obtain a purified solution; ammonium salt is added into the purified liquid for vanadium precipitation, and ammonium metavanadate crystals are obtained; calcining the ammonium metavanadate crystal to obtain high-purity vanadium pentoxide; and preparing the high-purity vanadium oxide electrode by using the high-purity vanadium pentoxide. According to the scheme, the high-purity vanadium pentoxide is prepared by taking the alkaline vanadium leaching solution as a raw material through a multi-stage deep impurity removal process, and the high-purity vanadium oxide electrode is prepared by taking the alkaline vanadium leaching solution as the raw material.

The invention relates to the technical field of environmental protection and dust removal, and discloses a dust removal device for calcium hydroxide product production, the dust removal device comprises a box body, the lower surface of the box body is provided with two sets of dust falling hoppers, the two sides of the box body are fixedly connected with an air inlet pipe and an air outlet pipe respectively, and the inner wall of the box body is provided with a partition plate. The driving assembly drives the pulse sliding pipe and the plugging assembly to move downwards, after the pulse sliding pipe and the plugging assembly move to a certain position, the control assembly controls the plugging assembly to plug a certain section of the filter cartridge, then the pulse mechanism enables gas to pass through the pulse main pipe, the pulse fixing pipe and the pulse sliding pipe, and then the gas is blown out from the pulse head. And then the driving assembly drives the blocking assembly to continue to move downwards, pulse dust removal is carried out on the filter cartridge section by section, pulse airflow accurately covers the whole section of the filter cartridge, it is ensured that dust on all parts can be thoroughly removed, and the dust removal effect is greatly improved.

The invention discloses a method for preparing calcium hydroxide slurry with high specific surface area and high pore volume, which comprises the following steps: S1, adding an alcohol reagent into water to obtain a solution A; s2, adding an inorganic salt solution into the solution A, and uniformly mixing to obtain a solution B; s3, a reagent X is added into the solution B, ultrasonic mixing is performed to obtain a solution C, and the reagent X is a mixture of phenol or triethanolamine, ethidene diamine and ethylamine; and S4, adding calcium oxide powder into the solution C, continuously stirring, and reacting to obtain calcium hydroxide slurry. The invention provides a method for preparing calcium hydroxide slurry with high specific surface area and high pore volume, the calcium hydroxide slurry prepared by the method can form calcium hydroxide with high specific surface area and high pore volume when in use, and the method aims to solve the problems of low specific surface area and low pore volume of the existing calcium hydroxide. Therefore, the problem of desulfurization performance inactivation caused by blockage of calcium hydroxide (desulfurizer) pores by generated CaSO3 and CaSO4 in the desulfurization process is avoided.

The present invention discloses a kind of preparation method and use method of anti-abrasion concrete admixture under freeze-thaw-solution environment, the admixture includes the components of following parts by weight:50~60 parts of STG powder, 5~8 parts of polyimide fibers, 1~3 parts of hydroxypropyl methyl (HPMC) cellulose, 10~13 parts of polycarboxylate water-reducing agent, 10~15 parts of antifreeze, 10~13 parts of expansion agent, wherein STG powder includes modified silica fume-glass powder, silicon carbide titanium, graphene oxide. Anti-abrasion concrete admixture under freeze-thaw-solution environment of the present invention can effectively suppress the decomposition of calcium hydroxide, and can refine pore structure, make hydraulic concrete more compact, while improving the ability of hydraulic concrete to resist dissolution, enhance its anti-abrasion performance, the admixture has good low temperature resistance, can be applicable to cold low temperature environment, for the anti-abrasion strength under low temperature conditions there is obvious improvement.

The invention discloses a method for preparing calcium hydroxide with high specific surface area and high pore volume by a semi-dry method, which comprises the following steps: S1, adding an alcohol reagent into water, and uniformly mixing to obtain a solution A; s2, adding a composite cationic surfactant into the solution A, and dissolving to obtain a solution B; s3, adding an iron salt solution into the solution B, and uniformly mixing to obtain a solution C; s4, adding triethanolamine into the solution C, and performing ultrasonic dissolution to obtain a solution D; and S5, spraying the solution D into calcium oxide powder, continuously stirring, and reacting to prepare calcium hydroxide with high specific surface area and high pore volume. The calcium hydroxide prepared by the method has a high specific surface area and a rich pore structure, is powdery after reaction, and is relatively low in water content.

The invention provides a method for decomposing and mineralizing fluorine-containing organic matter wastewater, which is applied to the technical field of treatment of fluorine-containing organic matter wastewater generated in a perfluoroether elastomer emulsion flocculation process, and comprises the following steps: S1, carrying out adsorption and desorption treatment on the fluorine-containing organic matter wastewater to obtain a concentrated solution of the fluorine-containing organic matter wastewater; s2, hydrogen peroxide and ferrous ions are added into a container containing the concentrated solution to obtain a mixed solution, the pH of the mixed solution is adjusted to be 2-4, the concentration mass ratio of the hydrogen peroxide to organic matter contained in the fluorine-containing organic matter wastewater is 1: 1-2, the molar ratio of the hydrogen peroxide to the ferrous ions is 1-6: 1, micro-nano bubbles are introduced into the mixed solution, and ultrasonic treatment is conducted; s3, calcium hydroxide is added into the treated mixed solution, calcium fluoride precipitates are obtained through centrifugal treatment, and the fluorine-containing organic matter in the wastewater can be degraded and mineralized.

The invention discloses a modified recycled aggregate preparation method, modified recycled aggregate and concrete.The modified recycled aggregate is prepared through the following steps that waste concrete fragments are soaked in induction liquid, the induction liquid comprises water and calcium hydroxide, the pH of the induction liquid is larger than or equal to 11.5, and wet pretreated fragments are obtained after soaking treatment is finished; blowing tail gas containing CO2 into the induction liquid to reduce the pH value of the induction liquid to 8.5-9.0, standing and waiting for aging for 12 hours, fishing out the fragments, and drying; the concrete comprises water, a gel material and aggregate, the aggregate comprises the modified recycled aggregate, through the synergistic effect of chemical dissolution-carbonization filling, the core problems that the modified recycled aggregate is many in surface impurity, high in water absorption rate and low in strength are solved, and the performance of the modified recycled aggregate is close to that of natural aggregate.

The present disclosure relates to the field of the preparation of high purity sodium and the safe treatment of sodium calcium slag, and discloses a method and apparatus for sodium slag recovery by using gravity separation—controllable combustion—alkaline liquor leaching process for the preparation of high purity sodium and safe treatment of sodium calcium slag. The method comprises the following steps: (1) subjecting a liquid sodium slag to a gravity stratification to obtain pure metallic sodium and high calcium content sodium slag; (2) roasting the high calcium content sodium slag to obtain a roasting slag; and (3) leaching the roasting slag by using an alkaline liquor to obtain the sodium hydroxide solution and calcium hydroxide. The method and apparatus provided by the present disclosure have advantages including high efficiency separation of sodium and calcium, saving separation time, safe and controllable production process, and continuous production process, thereby providing a safe and efficient method for the preparation of high purity sodium and safe treatment of new sodium calcium slag generated by the method, allowing continuous production of high purity sodium and safe recycle of new sodium calcium slag.

The embodiment of the invention discloses a fluorine removal agent and a fluorine removal process for rare earth feed liquid. The fluorine removal agent comprises a first fluorine removal agent and a second fluorine removal agent, the first fluorine removal agent is polycrystal system composite calcium, the polycrystal system composite calcium is composed of calcium oxide / calcium hydroxide and calcium carbonate according to the mass ratio of (0.1-1): (0.1-1), and the second fluorine removal agent is composed of polycrystal system composite calcium and an inorganic flocculant according to the mass ratio of (0.01-1): (0.01-1). According to the method, fluorine is removed under the condition that the pH value is 4.6-5.8, fluoride composite salt precipitation is formed, fluorine in the rare earth solution can be efficiently removed, rare earth carbonate precipitated from subsequent oxalic acid or carbonate (sodium carbonate, sodium bicarbonate, ammonium bicarbonate and the like) or high-concentration rare earth feed liquid can be recycled, and the quality of the rare earth is improved. The requirements (the F content in the mixed rare earth oxide is less than 0.3%, and the F content in the high-concentration rare earth feed liquid (the concentration is greater than 100g / L) is less than 100mg / L) are met. The method is simple in process and high in operability, and has a relatively good application prospect.

The invention relates to the technical field of waterproof building materials, in particular to a waterproof building material. The waterproof building material is prepared from the following raw materials in parts by weight: 80-100 parts of cement, 8-15 parts of modified montmorillonite, 5-8 parts of modified konjac glucomannan, 3-5 parts of a fiber reinforced material, 1-3 parts of a coupling agent, 1-3 parts of a dispersing agent and 0.1-0.5 part of a defoaming agent. According to the invention, through the synergistic effect of various raw materials, after the montmorillonite is modified, the interlayer spacing is increased, the hydrophilicity is weakened, a nano-scale sheet-shaped barrier layer can be formed in a cement matrix, like countless tiny shields, and water molecule permeation is effectively blocked, and the modified konjac glucomannan has good water resistance in an alkaline cement environment. The water-proofing agent has a cross-linking reaction with hydrated calcium silicate and calcium hydroxide of cement to form a continuous gel network structure to fill pores and capillary channels in set cement and cut off water seepage channels, so that a good water-proofing effect of a building in a long-term humid environment is ensured.

The invention discloses a preparation method of high-viscosity cationic starch, which belongs to the technical field of modified starch, and comprises the following steps: crosslinking epichlorohydrin, ball-milling and cationizing; the epoxy chloropropane crosslinking comprises the following steps: mixing starch, calcium hydroxide and deionized water, stirring at 40-50 DEG C, adding sodium stearoyl lactylate, stirring at 50-55 DEG C, naturally cooling to room temperature, adding sodium chloride and epoxy chloropropane, stirring, dropwise adding a potassium hydroxide aqueous solution, stirring, adjusting the pH value to 6, filtering, taking filter residues, washing and drying to obtain crosslinked starch; in the step of ball milling, calcium hydroxide, sucrose fatty acid ester SE-11 and deionized water are mixed and then subjected to ball milling, and a ball-milled material is obtained; the prepared high-viscosity cationic starch is high in paste liquid viscosity and cationic substitution degree, good in paste liquid viscosity stability, uniform in substitution degree and paste liquid viscosity, high in reaction efficiency in cationization and low in alkali consumption.

The invention discloses a steam supply system based on calcium hydroxide thermochemical energy storage and an operation method. The system comprises a thermochemical energy storage device, a steam supply device, an electric heating device and a material circulation auxiliary device. The thermochemical energy storage device is a fluidized bed reactor and a solid material storage tank, reversible conversion between high-grade heat energy and chemical energy is achieved through hydration / dehydration reaction, then heat energy storage is achieved, and the thermochemical energy storage device is matched with the auxiliary device to form a closed material circulation loop. The steam supply device integrates multiple paths of steam through a valve and a mixer; the electric heating device serves as a supplementary heat source in the peak regulation stage of the coal-fired heat supply unit. The operation method is divided into a starting stage, a non-peak-shaving stage and a peak-shaving stage, and cooperative control over high-pressure steam extraction heat energy storage and low-temperature water supply evaporation overheating is achieved. The system aims to solve the thermoelectric decoupling problem of the coal-fired heat supply unit, and has the advantages of flexibility, high efficiency, safety, environmental protection, low application cost, high energy storage density, small occupied area and the like.

The invention relates to the technical field of lithium battery materials, in particular to a method for preparing battery-grade lithium carbonate from waste lithium batteries. The method comprises the following steps: disassembling, crushing and sieving a recycled lithium iron phosphate battery to obtain a crushed lithium battery material; a choline chloride-citric acid mixed solution is adopted to conduct leaching treatment on the crushed materials, and sulfuric acid is added to inhibit leaching of iron and phosphorus ions; filtering to obtain a first filtrate and a first filter residue; adding calcium hydroxide into the first filtrate, and filtering to obtain second filtrate and second filter residues; adsorbing the second filtrate with activated carbon to remove impurities, and filtering to obtain a third filtrate and a third filter residue; adding hydrochloric acid into the third filtrate to obtain a lithium chloride solution; carbonizing and converting the lithium chloride solution into a lithium carbonate solution; and carrying out gradient crystallization treatment on the lithium carbonate solution, pulping with pure water, and drying to obtain the high-purity lithium carbonate finished product. The method overcomes the problems of low lithium recovery rate, complex process, low lithium carbonate purity, large crystal particle size, more impurities and the like of the existing lithium iron phosphate battery.

The invention discloses a method for preparing a battery-grade lithium compound. The method comprises the following steps: S1, carrying out sulfuric acid acidification reaction on a lithium-containing raw material or roasting by adding sulfate, and carrying out water leaching to obtain leached slurry; the lithium-containing raw material is a lithium mineral or a waste lithium battery material; s2, calcium oxide or calcium hydroxide is added into the leaching slurry, filtering is performed after full reaction, filtrate A and filter residues A are obtained, the main component of the filtrate A is lithium hydroxide, and the filtrate A further comprises soluble impurities formed after water leaching; s3, adding a substance for removing calcium ions into the filtrate A, fully reacting, and filtering to obtain filtrate B and filter residues B; s4, fully contacting the filtrate B with an extracting agent for extraction, and then separating to obtain a loaded organic phase and raffinate; s5, reversely extracting the loaded organic phase to obtain a lithium solution and a blank organic phase; and S6, further treating the lithium solution to obtain the battery-grade lithium compound. Sodium ions are basically not introduced, the energy consumption is low, the process is simplified, the product quality is high, the production cost is low, the lithium yield is high, and byproducts are convenient to treat.

A method of preparation of a foamed concrete, comprising the steps of; providing a cementitious slurry, comprising in wt% relative to the wt of the slurry, 60-70% of a cementitious material, 0.5-5% in

The invention provides a treatment process of a byproduct sodium hypophosphite in a phosphorane preparation process, and aims to efficiently remove impurities and prepare a high-purity hypophosphorous acid product. The process comprises the following steps: carrying out small-volume sampling on reaction mother liquor, introducing carbon dioxide gas, and drawing an acidification curve of pH and conductivity; according to the plateau phase of an acidification curve, the CO2 flow rate and the pH value are controlled, step-by-step selective precipitation of impurities such as PO4 < 3->, HPO4 < 2->, Fe < 3 + >, AsO4 < 3-> and S < 2-> is achieved, and loss of a target component H2PO4 < 2-> is avoided; calcium hydroxide turbid liquid is introduced at a proper time to supplement Ca < 2 + > and promote efficient removal of phosphorus, arsenic and sulfur impurities; and subsequently removing excessive Na < + > and Ca < 2 + > through cation exchange, and concentrating to obtain a hypophosphorous acid product with the purity of more than or equal to 99.5%. The method is accurate in process control, thorough in impurity removal and good in repeatability and industrial adaptability, and the resource utilization efficiency of by-products and the added value of products are remarkably improved.

Processes and apparatuses for degrading PFAS into calcium fluoride, carbon dioxide, and water. PFAS are heated and introduced to a calcium base which will degrade the PFAS. The PFAS may be in a stream that is a PFAS enriched stream formed by desorbing the PFAS from an adsorbent which removed the PFAS from a contaminant stream. The PFAS may be desorbed in the presence of the calcium base. The calcium base may be calcium hydroxide, calcium oxide, calcium carbonate, or combinations thereof.

The invention relates to a starch pore-enlarging type high-chlorine-capacity long-acting high-temperature dechlorinating agent and a preparation method thereof, and belongs to the technical field of dechlorinating, the starch pore-enlarging type high-chlorine-capacity long-acting high-temperature dechlorinating agent comprises the following raw materials: complexing coating calcium hydroxide, modified hydroxyapatite, a composite inorganic adhesive, reinforcing and toughening whiskers, a composite pore-forming agent, a composite synergist, nano calcium carbonate and water; according to the starch reaming type high-chlorine-capacity long-acting high-temperature dechlorinating agent obtained by the invention, the breakthrough chlorine capacity is 40.9 to 44.9 percent, the crushing strength is 139 to 151N. Cm <-1 >, and the abrasion rate is 0.8 to 1.5 percent.

The invention discloses a method for comprehensively recycling electrolytic aluminum carbon residues, and relates to the technical field of comprehensive recycling of waste materials. The method for comprehensively recycling the electrolytic aluminum carbon residues comprises the following steps of: breaking the carbon residues into 0.1-1cm particles by a hammer, carrying out wet ball milling under the condition of adding a flotation agent, and separating carbon powder on the upper layer and gray regenerated cryolite on the bottom layer of slurry through flotation equipment, wherein the fineness is 40-100 meshes, and the carbon content is less than 1%; the preparation method comprises the following steps: adding water into cryolite to prepare slurry, adding calcium oxide or calcium hydroxide, heating, stirring and reacting for 1-3 hours, and carrying out filter pressing to obtain filtrate and filter residues which are calcium fluoride and a sodium metaaluminate solution; the purity of the calcium fluoride powder is greater than 85%; and introducing hydrochloric acid into the filtrate, stirring and adjusting the pH to 7-9 to obtain aluminum hydroxide slurry, filtering and washing to obtain aluminum hydroxide, and drying to obtain the aluminum hydroxide with the purity of more than 95%.

The present invention provides a method for producing lithium hydroxide, comprising the steps of reacting lithium carbonate and calcium hydroxide in a liquid to obtain a solution containing lithium hydroxide, and performing solid-liquid separation on the solution into a liquid component containing lithium hydroxide and a solid component containing lithium derived from the lithium carbonate, and recovering lithium hydroxide from the liquid component.

The invention discloses a method for preparing calcium hydroxide with a high specific surface area by digesting calcium oxide, and relates to the technical field of preparation of calcium hydroxide with a high specific surface area. The method is characterized in that diethylene glycol / triethanolamine / magnesium chloride is adopted as a compound digestion aid through two processes of wet digestion and dry digestion; and calcium hydroxide with high specific surface area can be controllably prepared. The specific surface area of the calcium hydroxide prepared through wet digestion can reach 70 m < 2 >. G <-1 > or above, the specific surface area of the calcium hydroxide prepared through dry digestion is 45 m < 2 >. G <-1 > or above, the reaction activity of the calcium hydroxide is effectively improved, and the novel controllable method for preparing the calcium hydroxide with the high specific surface area is provided.

A process produces high-purity vanadium chemicals from vanadium raw materials having high molybdenum contents. Molybdenum is selectively precipitated via vanadium from alkaline vanadate solutions using the following process steps: providing a molybdenum-containing alkaline vanadate solution, adding calcium hydroxide as a precipitant in portions while keeping the pH constant between 6 and 7 using acid, mixing the solution, solid-liquid separation of the resulting suspension, and further processing the low-molybdenum alkaline vanadate solution to produce a high-purity vanadium chemical having a molybdenum content of at most 500 ppm.

The invention discloses a concrete carbon sequestration parameter optimization method and a carbon sequestration pre-reaction system thereof, and relates to the technical field of concrete carbon sequestration. S2, collecting basic data in the sample brick, wherein the basic data comprises the content and density of calcium hydroxide and the maximum particle size in aggregate; s3, acquiring an initial carbon dioxide replenishment amount based on the input into the central control module in the step S2; s4, setting gradient reaction conditions for the reaction kettle based on the initial carbon dioxide supply amount as an intermediate value; s5, distributing gradient reaction conditions to the corresponding carbon sequestration reaction bins; s6, monitoring a carbon dioxide consumption rate and a sample brick carbonization strength curve in each carbon sequestration reaction bin; s7, establishing a mapping model of concentration, time and intensity; s8, industrial reaction kettle control parameters are output, and the problem that in the prior art, the carbon dioxide input amount cannot be dynamically adjusted according to different batches of concrete raw materials, and consequently the concrete forming strength does not reach the standard is solved.

The invention relates to the technical field of desulfurizing agents, and discloses a desulfurizing agent and a preparation method and application thereof, the desulfurizing agent is calcium hydroxide with a porous structure, a zinc metal organic framework grows in situ in the porous structure of the calcium hydroxide, and hydrophilic groups are grafted on the zinc metal organic framework and the calcium hydroxide. The desulfurizer disclosed by the invention is a calcium hydroxide desulfurizer, and not only has a relatively high specific surface area, but also has a relatively good desulfurization effect.

The application relates to the field of fireproof bricks, and discloses a baking-free fireproof brick and a preparation method thereof. The baking-free fireproof brick comprises iron tailings, cement, fly ash, a functional additive, fine aggregate, quartz sand, a chromium aluminum phosphate binder, a water reducing agent and water. The functional additive is prepared by using aluminum chloride hexahydrate and alkaline silica sol as raw materials, ammonium molybdate tetrahydrate as a catalyst, growing mullite whiskers on the surface of silicon carbide fibers through vacuum impregnation and heat treatment, modifying the prepared composite silicon carbide fibers through 3-(methacryloxy) propyl trimethoxysilane, and then copolymerizing the modified composite silicon carbide fibers with acrylic acid and 4-hydroxybutyl vinyl ether. The chromium aluminum phosphate binder is prepared by using aluminum hydroxide, phosphoric acid and chromium trioxide as raw materials and calcium hydroxide as a curing agent. The baking-free fireproof brick prepared through the synergistic effect of the components has high compressive strength and bending strength, small water absorption and good baking-free fireproof and heat insulation performance.

The invention discloses a phosphoric acid production process which comprises the following steps: S1, mixing phosphoric acid and phosphorite in a reactor for reaction, and filtering and washing reaction liquid to obtain monocalcium phosphate filtrate; s2, the monocalcium phosphate filtrate enters a bipolar membrane electrodialyzer, the bipolar membrane electrodialyzer is formed by sequentially arranging a cation exchange membrane, an anion exchange membrane and a bipolar membrane, and an acid chamber, a salt chamber and an alkali chamber are formed respectively; the monocalcium phosphate is converted into phosphoric acid and calcium hydroxide under the action of the electrodialyzer. According to the method, phosphoric acid with relatively high purity can be directly prepared, and phosphogypsum is not generated. Compared with the traditional wet-process phosphoric acid, the produced solid waste amount is sharply reduced and is about one tenth to one twentieth of that of the traditional wet-process phosphoric acid, and the phosphoric acid is rich in silicon, magnesium, iron and the like and can be used as a fertilizer additive.