718 results about "Fluoride calcium" patented technology

The invention relates to a modified chrome corundum ramming material and a preparation and construction process thereof, and belongs to the technical field of chrome corundum ramming materials. The ramming material comprises a material A, a material B and a material C, wherein the material A comprises chrome corundum aggregate, titanium dioxide coated aluminum oxide microspheres, calcium sulfide dehydrate and silicon carbide porous microspheres; the material B comprises chromium oxide-zirconium oxide composite nano powder, sodium thiosulfate pentahydrate, tricalcium phosphate and hexagonal boron nitride flaky crystals; and the material C comprises an aluminum dihydrogen phosphate-magnesium hydroxide compound, a calcium fluoride-aluminum oxide co-melt and a silane coupling agent. The preparation process comprises the steps of pretreatment of all the components, preparation of composite powder and layered preparation. The construction process comprises the steps of pretreatment, wet-process mixing, layered ramming, negative-pressure permeation, medium-temperature reaction, spraying curing, integral firing and the like. Generation of hexavalent chromium can be effectively inhibited, the thermal shock resistance, the mechanical strength and the heat-conducting property of the material are remarkably improved, and the material has the advantages of being good in environment friendliness, long in service life, excellent in construction performance and the like.

The utility model belongs to the field of chemical raw material recovery, and discloses a continuous resourceful treatment system for photovoltaic fluorine-containing wastewater. The system comprises a first-stage fluorine removal unit, a second-stage fluorine removal unit and a silicon removal unit. According to the utility model, the fluorine element is subjected to resource recovery in the form of high-purity calcium fluoride with the purity of more than 95%, meanwhile, the consumption of a fresh sodium hydroxide solution is avoided, the purpose of treating waste with waste is realized, and the residual fluorine quantity in the effluent of the system is reduced to be less than 5mg / L.

The invention discloses a composite clarifying agent for alkali-free glass and a manufacturing method of an alkali-free glass substrate, and relates to the technical field of glass manufacturing, the composite clarifying agent for alkali-free glass comprises the following components by mass: 12-30% of ammonium chloride, 48-73% of sulfate, and 11-25% of calcium fluoride; the preparation method comprises the following steps: adding a composite clarifying agent accounting for 0.2-1.2% of the total weight of the glass raw material into the glass raw material, uniformly mixing to form a batch, and carrying out melting, molding, spraying, annealing, cutting, alkali cleaning and other processes on the batch to finally prepare the glass substrate. The prepared composite clarifying agent does not contain toxic substances such as arsenic oxide and antimony oxide, the glass substrate produced by using the clarifying agent not only has an excellent clarifying effect, but also can recycle SO2 and NH3 gas generated in the melting process, can effectively solve the quality problems such as micro-flaws on the surface of the glass substrate in the production process, and has a good application prospect. And the production cost can be reduced and the product quality can be improved.

The invention discloses a rapid tubular induced crystallization reaction process and device for fluorine-containing wastewater, the device comprises a tubular reactor, a crystal sedimentation tank and crystal dehydration equipment, the fluorine-containing wastewater is pumped from a water inlet at one end of the tubular reactor, calcium liquid is pumped from dosing ports at intervals on the tubular reactor along the flowing direction of the wastewater at a set flow rate, and the calcium liquid is pumped from the dosing ports at intervals along the flowing direction of the wastewater; the fluorine-containing wastewater reacts with a calcium agent in the tubular reactor to generate calcium fluoride crystals with the particle size range of 10-80 microns, a mixture is discharged into a crystal sedimentation tank through a water outlet in the other end of the tubular reactor, clear water is discharged from a water outlet in the upper portion of the crystal sedimentation tank, and crystal slurry sinking to the bottom of the crystal sedimentation tank is pumped into a cyclone separator through a crystal discharging pump; large-particle crystals discharged from an outlet in the lower end of the cyclone separator are collected by a crystal collection pool and are regularly discharged into crystal dehydration equipment for dehydration, small-particle crystals discharged from an outlet in the upper end of the cyclone separator flow back to the water inlet end of the tubular reactor, the reactor is small in size and low in investment, and the stability of the calcium fluoride crystal product quality is guaranteed.

The invention discloses a far-infrared high-transmittance composite material, a preparation method thereof and an optical device, and the far-infrared high-transmittance composite material comprises the following components in parts by weight: 70-99 parts of a polymer matrix; 1-30 parts of an anti-reflection auxiliary agent; the polymer matrix is a sulfur-containing polymer prepared by polymerization reaction of a polymeric monomer and sulfur, and the proportion of carbon-carbon unsaturated bonds is less than 3%; the polymeric monomer is selected from at least one of a vinyl monomer, a propenyl monomer, an acrylic acid monomer, a methacrylic acid monomer, an epoxide monomer, a thiopropyl ring monomer, an alkynyl monomer, a butadiene monomer, an isoprene monomer and a norbornene monomer; the anti-reflection auxiliary agent comprises at least one of nano zinc sulfide, nano zinc selenide, nano calcium fluoride, nano magnesium fluoride and nano magnesium oxide. The composite material and the optical device thereof have high far infrared transmittance and good mechanical properties and processability, and can meet the requirements of various far infrared optical fields.

The invention relates to the technical field of environmental science and engineering, and discloses a method for removing and recycling fluorine ions by promoting calcium fluoride precipitation through sulfate doping, and the method comprises the following steps: S1, preparing sodium fluoride solutions of sulfate with different concentrations, and analyzing the influence of different sulfate concentrations on calcium fluoride precipitation; s2, respectively adding calcium chloride solutions into the prepared sodium fluoride solutions of the sulfates with different concentrations; s3, the two solutions are subjected to a reaction within a set time, filtering is conducted after the reaction is conducted for a period of time, and the fluorine ion removal reaction is completed. By changing the concentration of sulfate in the sodium fluoride solution, the effect of the sulfate in calcium fluoride precipitation and the influence of the sulfate on the fluorine ion removal efficiency are researched; the positive effect and the action mechanism of the low-concentration sulfate in the calcium fluoride precipitation process are defined, and the problems that the influence of the sulfate in the high-fluoride wastewater on calcium fluoride precipitation is ignored, the calcium fluoride purity is low and the recovery difficulty is large are finally solved.

The invention relates to a quartz crucible coating and a preparation method thereof.The coating is of a double-layer composite structure and comprises a substrate layer and a functional layer, the substrate layer is composed of 40-65 vol% of polycrystalline silicon powder (the particle size D50 ranges from 1 micrometer to 5 micrometers) and 35-60 vol% of nanometer silica sol, and the functional layer covers the surface of the substrate layer and is composed of 50-70 vol% of polycrystalline silicon powder, 20-35 vol% of nanometer silica sol and 5-15 vol% of calcium fluoride powder (the particle size D90 is smaller than 0.5 micrometer). The preparation method comprises the following steps: preparing a substrate layer slurry and a functional layer slurry, sequentially coating the inner wall of a crucible with the slurry, drying, and sintering in an inert atmosphere according to a three-step temperature control program to finally form a coating with the thickness of 180-300 microns and the porosity of 8-15 vol%; the coating structure can avoid pollution of silicon nitride or silicon carbide particles, has excellent demolding performance, thermal stability and adhesive force, further improves the service life of a crucible and the purity of a silicon ingot, and meets the requirements of an advanced semiconductor process for cleanliness and reliability.

The invention relates to the field of nylon materials, provides a high-performance, scratch-resistant, wear-resistant and corrosion-resistant nylon material replacing steel with plastic, and solves the problem that an existing nylon material is insufficient in scratch resistance, wear resistance and corrosion resistance. The material is prepared from a surface modified calcium fluoride and aluminum oxide whisker filler, polytetrafluoroethylene coated boron nitride particles, nylon matrix resin, a compatilizer, an antioxidant and a lubricant. The dispersibility and the interface compatibility of the key components are improved by adopting a special preparation process, so that the mechanical property, the wear resistance and the chemical stability of the composite material are remarkably enhanced. The material is suitable for metal replacement application in the fields of automobiles, machinery and the like, realizes excellent scratch resistance and wear resistance, solves the problem of poor corrosion resistance of nylon materials, and has wide application value.

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 provides a method and system for recovering phosphate radicals, fluorine ions and sulfate radicals from phosphogypsum washing water step by step, and belongs to the technical field of industrial wastewater resourceful treatment. The method comprises the following steps: (1) adjusting the pH value of the wastewater to 3.0 + / -0.5, adding ferric sulfate according to the molar ratio of Fe to PO4 < 3-> of (1.0-1.5): 1, and selectively precipitating phosphate radicals to generate iron phosphate with the purity of more than or equal to 97%; (2) adjusting the pH value of the first filtrate to 4.7 + / -0.5, adding calcium fluoride seed crystals with the particle size of 50-200mm and CaCl2 (the molar ratio of Ca to F <-> is 0.5: 1-0.6: 1), and carrying out induced crystallization to recover calcium fluoride with the purity of more than or equal to 96%; and (3) adding Ca (OH) 2 (Ca: SO4 < 2-> molar ratio of 1.0: 1-1.2: 1) into the second filtrate, and directionally precipitating sulfate radicals to generate calcium sulfate dihydrate with the purity of more than or equal to 98%. According to the method, the pH and the precipitation sequence are controlled step by step, so that the problem of polyanion competition is solved, the recovery rates of phosphate radical, fluorine ion and sulfate radical respectively reach 98.8%, 96.3% and 97.5%, the content of PO4 < 3-> in purified water is less than or equal to 10 mg.L <-1 >, the content of F <-1 > is less than or equal to 5 mg.L <-1 >, and the content of SO4 < 2-> in purified water is less than or equal to 100 mg.L <-1 >, and the purified water can be directly recycled.

The invention relates to the technical field of concrete crack repairing agents, in particular to a triggered precipitation type concrete crack repairing agent as well as a preparation method and application thereof. The repairing agent is prepared from the following raw materials: sulphoaluminate cement, nano anhydrite with a core-shell structure, fluorine-phosphorus composite seed crystal, magnesium oxide, metakaolin and a water reducing agent, wherein the core-shell structure nano anhydrite is prepared by coating mesoporous silica with nano anhydrite, and the fluorine-phosphorus composite seed crystal is prepared from calcium fluoride and monocalcium phosphate through a hydrothermal reaction. According to the trigger precipitation type concrete crack repairing agent prepared by the invention, sulfate ions are slowly released through the core-shell structure nano anhydrite, the crystal form of ettringite is regulated and controlled through the fluorine-phosphorus composite seed crystal, the problems that a traditional repairing agent shrinks and falls off in the later period, the high-temperature strength is suddenly reduced, and the binding power is insufficient are solved, and the trigger precipitation type concrete crack repairing agent is suitable for concrete structure crack repairing and high-temperature environment engineering.

The invention discloses a grading reaction crystallization recovery process and system for semiconductor fluorine-containing and phosphorus-containing waste liquid, the fluorine-containing and phosphorus-containing waste liquid and a lime solution react in a fluorine recovery crystallization reactor under the condition that the pH is 3-4 to form calcium fluoride crystals, and the calcium fluoride crystals are dehydrated to obtain calcium fluoride particle crystal products; the effluent of the fluorine recovery crystallization reactor, the calcium fluoride crystal dehydration filtrate, the lime solution and the calcium chloride solution react in a secondary reaction tank under the condition that the pH is 5-6, and calcium fluoride, fluorapatite, silicon dioxide and silicon-aluminum precipitates are removed through coagulation, flocculation and precipitation; effluent of the second-stage reaction tank, the lime solution and the calcium chloride solution react in the phosphorus recovery crystallization reactor under the condition that the pH is 7-8 to generate hydroxyapatite crystals, and the hydroxyapatite crystals are dehydrated to obtain hydroxyl calcium phosphate particle crystal products. Meanwhile, a high-purity calcium fluoride crystal product and a hydroxyl calcium phosphate crystal product are produced, and fluorine and phosphorus are recycled.

The invention relates to the technical field of metal material surface strengthening and modification, in particular to a preparation method and process of a titanium alloy laser cladding cobalt-based wear-resistant coating. The invention provides a titanium alloy surface laser cladding cobalt-based wear-resistant coating which takes titanium or a titanium alloy as a base material, comprises the following components in percentage by weight: 40-50% of cobalt (Co), 30-40% of tungsten carbide (WC), 10-15% of chromium (Cr), 1-5% of lanthanum hexaboride (LaB6), 2-5% of silicon (Si) and 0.5-3% of calcium fluoride (CaF2), and has the beneficial effects of improving wear resistance, high-temperature stability, corrosion resistance, high hardness, high bonding strength, difficulty in cracking and the like.

The invention belongs to the technical field of industrial wastewater treatment and resource recovery, and particularly relates to an enhanced treatment method for recovering fluorine resources in semiconductor processing fluorine-containing wastewater. And step-by-step efficient recovery of sodium fluosilicate and calcium fluoride is realized through cooperation of precipitant compounding and pH regulation. The method comprises the following steps: firstly, adding a NaCl-NaHCO3 composite precipitator and sodium fluosilicate seed crystals to induce crystallization and recover hexagonal prism-shaped sodium fluosilicate single crystals; and after filtering, adding a CaCl2-Ca (OH) 2 composite precipitator and calcium fluoride seed crystals into the filtrate to generate large-particle calcium fluoride. And the impurity content in the recovered product respectively reaches the industrial sodium fluosilicate superior product standard and the metallurgical grade calcium fluoride secondary product standard. And the treated wastewater is neutral or weakly alkaline, so that the subsequent mixed treatment with other wastewater is facilitated.

A method for preparing monodisperse nanoscale calcium fluoride, comprising the following steps: (S1) dispersing calcium long-chain alkylbenzenesulfonate and an acrylate copolymer in a mixed solution of water, n-hexane, and an alcohol to form a stable emulsion A, wherein monomers of the acrylate copolymer comprise (meth)acrylic acid, a polyether macromonomer, and a C1-4 alkyl (meth)acrylate; (S2) dissolving a fluoride salt in water, adding polyvinyl alcohol, and uniformly mixing these materials to obtain a solution B; and (S3) slowly dropwise adding the solution B to the emulsion A under stirring and ultrasonic conditions, and carrying out standing for aging, centrifugal separation, washing, and drying to obtain monodisperse nanoscale calcium fluoride. By using the calcium long-chain alkylbenzenesulfonate with surface activity as a calcium source in combination with homemade acrylate as a dispersing agent, an emulsion is formed in a specific combined solvent, and by dropwise adding a fluorine salt aqueous solution to the emulsion under an ultrasonic condition, nanoscale calcium fluoride with a uniform and controllable particle size can be prepared under the action of a microemulsion.

The invention relates to a large-size glass product with a natural ice crystal imitating effect and an industrial casting method of the large-size glass product. The product is a lead-free glass casting with the weight larger than or equal to 100 kg, dendritic crystal-shaped or snowflake-shaped devitrified phases which are formed by growing calcium fluoride as crystal nucleuses and are distributed randomly are arranged in the product, and the three-dimensional aesthetic effect imitating natural ice crystals is achieved. The method comprises the following steps: mixing lead-free glass particles with a calcium fluoride nucleating agent with a specific particle size, and filling a mixture into a special mold with a three-layer composite structure and a temperature monitoring function; and executing a four-stage programmed thermal regulation including melting homogenization, nucleation cooling, isothermal crystallization and super-slow multi-step annealing, wherein the melting and heat preservation time and the maximum thickness of the product meet the quantitative relation of t = k.H. Through systematic collaboration of materials, molds and processes, the technical problems that crystallization in large-size glass is not uniform and cracking is easily caused by thermal stress are solved, high yield and stable mass production of products of 500 kg or above are achieved, and the method is suitable for the fields of high-end buildings, art devices and decoration.

The invention provides a zinc-copper-nickel-copper smelting deslagging agent and a preparation method and a use method thereof. The zinc-copper-nickel-copper smelting deslagging agent comprises the following raw materials in percentage by mass: 5-15% of calcium fluoride, 20-30% of sodium carbonate, 5-15% of sodium fluoride, 10-20% of sodium hexafluoroaluminate and the balance of borax. Compared with the prior art, the zinc-copper-nickel-copper slag remover prepared by mixing the raw materials can effectively reduce impurities to be less than 0.14% of Fe, less than 0.005% of Pb and less than 0.003% of Si in the smelting process, the impurity components are obviously reduced, the number of times of component adjustment and unqualified sampling is reduced, impurities mixed in a casting blank are reduced, and finally the metal purity and the casting quality are improved. Meanwhile, loss of zinc and nickel is reduced to the maximum extent; and adverse effects on the zinc-copper-nickel alloy are avoided.

The application discloses a device for reducing fluorine-containing gas pollutant emission in electroslag remelting and a use method, which comprises a flue gas recovery cover (1), a flue gas discharge pipeline (7) and a purification tank (10). The flue gas recovery cover (1) is respectively provided with a remelted slag discharging hole (2), a self-consuming mother electrode (6) passing hole and a flue gas discharge pipeline (7) mounting hole. The flue gas discharge pipeline (7) is arranged through the flue gas discharge pipeline (7) mounting hole, one end of the flue gas discharge pipeline (7) is located in a closed space formed by the flue gas recovery cover (1) and a crystallizer (5), and the other end is inserted into the purification tank (10). A fan (8) is arranged on the flue gas discharge pipeline (7). Through the device, the fluorine-containing flue gas is recovered, and the fluorine-containing flue gas is converted into calcium fluoride by using an alkali solution. The device can realize the cyclic and repeated use of part of the calcium fluoride, greatly reduces the concentration of fluorine-containing harmful gas in the air environment of an electroslag remelting operation site, and makes the concentration of the fluorine-containing harmful gas reduce from the original 5.6 mg / m 3 to 0.02 mg / m 3 .

The invention provides a preparation method of a surface layer shell for precise casting production of a thick-wall titanium alloy. The preparation method comprises the following steps: S1, preparing a surface layer binder, wherein the surface layer binder comprises modified silica sol, a stabilizer, a reinforcing agent, a wetting agent and an acid-base regulator; the modified silica sol is diluted sodium-stabilized alkaline colloidal silicon dioxide; s2, preparing surface layer refractory powder, wherein the surface layer refractory powder comprises yttrium oxide powder, zirconium oxide powder and calcium fluoride powder; s3, preparing a surface layer coating; adding the surface layer refractory powder in the step S2 into the surface material binder in the step S1; s4, preparation of a surface layer shell, specifically, a module for preparing the surface layer shell enters the surface layer coating in the S3 to be subjected to slurry hanging, sand spraying and drying, and the step is repeated 1-2 times; and S5, the surface layer shell in the step S4 is subjected to firing forming, and the surface layer shell for precise casting production of the thick-wall titanium alloy is obtained. The surface layer shell obtained through the preparation method can be used for producing titanium alloy castings with the wall thickness ranging from 25 mm to 50 mm.

The invention discloses a toughened glass ceramic and a preparation method thereof, and relates to the technical field of glass ceramics, and the toughened glass ceramic comprises the following components in percentage by weight: 64 to 68 weight percent of silicon dioxide, 22.67 to 26.5 weight percent of lithium oxide, 0.9 to 1.2 weight percent of antibacterial agent, 0.8 to 1.1 weight percent of modified mica powder, 1.98 to 2 weight percent of aluminum oxide, 1.78 to 1.8 weight percent of potassium oxide, 1.68 to 1.7 weight percent of zirconium dioxide, 1.19 to 1.2 weight percent of phosphorus pentoxide and 1 to 3 weight percent of calcium fluoride. According to the toughened glass ceramic and the preparation method thereof, a multi-scale anti-cracking network is formed through macroscopic crack deflection of mica and nanoscale phase change toughening of zirconium oxide, the fracture toughness is remarkably improved, zirconium oxide agglomeration can be reduced through interface optimization of modified mica powder, zirconium oxide is dispersed more uniformly, and the phase change potential is further exerted; due to high-temperature stability of aluminum oxide, antibacterial agent particles can be wrapped, and excessive volatilization or aggregation of the antibacterial agent particles in the sintering process is prevented; aluminum oxide is used as a'protective shell 'to delay the Cu < 2 + > release rate and realize long-acting antibiosis.

The invention relates to a method for recovering lithium and fluorine from aluminum electrolysis hazardous waste, which comprises the following steps: firstly, mixing organic polyol and alkaline hydroxide according to a molar ratio of 1: (0.5-2) to obtain a eutectic solvent; heating the eutectic solvent to 80-150 DEG C, and adding a proper amount of raw material fine powder and calcium oxide for reaction leaching; carbonating and filtering the leachate to obtain lithium carbonate; washing the leaching residues with an acetic acid solution to obtain a calcium fluoride product; the concentration of fluorine ions in the leachate is smaller than or equal to 200 ppm, and the purity of calcium fluoride is larger than or equal to 90%; the leaching rate of lithium in the method is greater than 85%; the slag feeding rate of fluorine is greater than 95%; and no hydrogen fluoride gas is generated in the method. According to the method, a non-toxic and biodegradable eutectic solvent is adopted as a leaching agent, and efficient leaching of lithium and fluorine in the aluminum electrolysis dangerous waste materials is achieved; calcium oxide is used as a precipitating agent, free fluorine is promoted to be precipitated and recycled as calcium fluoride, the whole process meets the requirement of green metallurgy, and the win-win situation of resources and the environment is achieved.

The invention discloses a method for recovering high-purity fluorine and silicon from fluorine-silicon slag and co-producing a low-alkali fluorine-free accelerator, which comprises the following steps: S1, dissolving the fluorine-silicon slag in a sodium hydroxide solution to obtain a solution A; s2, adding dilute sulphuric acid into the solution A, reacting until gel is obtained, and filtering to obtain filtrate A and high-purity silicon dioxide gel; s3, adding calcium sulfate and EDTA (Ethylene Diamine Tetraacetic Acid) into the filtrate A, stirring and reacting, and filtering after the reaction is finished to obtain calcium fluoride and filtrate B; and S4, taking clear water, heating, carrying out heat preservation, then adding aluminum sulfate, lithium sulfate, diethanol amine and the filtrate B obtained in S3, continuously stirring until the aluminum sulfate is completely dissolved, then adding hydrated magnesium silicate, continuously carrying out heat preservation stirring, and obtaining the low-alkali fluorine-free accelerator after stirring is finished. The method is simple in process and easy to implement industrially, and fluoride and silicon oxide obtained through separation are high in purity and beneficial to follow-up extension application; more importantly, high-value recycling of the fluorosilicon slag is achieved, and the problems of stockpiling waste and environmental pollution of the fluorosilicon slag are solved.

The invention belongs to the technical field of sodium-ion battery positive electrode material preparation, and particularly discloses a double-modified sodium-ion battery layered oxide positive electrode material and a preparation method thereof, and the preparation method comprises the following steps: S1, synthesizing a P2-type sodium-ion battery nickel-manganese-based layered oxide by using a high-temperature solid-phase method; s2, uniformly mixing two or more of lithium fluoride, sodium fluoride, calcium fluoride or magnesium fluoride in proportion to prepare a multi-element fluoride coating material; and S3, uniformly mixing the P2-type sodium-ion battery nickel-manganese-based layered oxide and the multi-fluoride coating material according to a ratio, and then carrying out high-temperature quenching treatment to obtain the surface fluoride-coated and near-bulk-phase-doped dual-modified sodium-ion battery layered oxide positive electrode material. According to the dual-modified layered oxide positive electrode material for the sodium-ion battery and the preparation method, surface fluoride coating and near bulk phase doping are cooperatively utilized, so that the high-voltage cycle performance of the layered oxide positive electrode material for the sodium-ion battery is 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 provides a high-concentration fluorine-containing wastewater treatment process based on in-situ calcium ion generation, and belongs to the technical field of wastewater treatment. Aiming at the problems of low mass transfer efficiency of traditional calcium-series fluorine removal and high cost of aluminum-series fluorine removal, fluorine removal is realized through a synergistic effect of step-by-step pH regulation and calcium ion in-situ release, and the method specifically comprises the following steps: under an acidic condition, carrying out acidolysis on lime milk turbid liquid to generate excessive calcium ions in situ, breaking through the mass transfer limitation of dependence on external calcium salt in a traditional method, and carrying out in-situ release on the calcium ions; unreacted lime milk is promoted to be dissolved, and calcium ions are released; and under a neutral condition, residual calcium ions and residual fluorine ions are subjected to a secondary reaction, and the electrical neutralization of PAC and the adsorption bridging effect of PAM are combined, so that calcium fluoride particle sedimentation is enhanced.

The invention provides a method for synergistically preparing calcium fluoride and a molecular sieve based on multi-element industrial waste, and belongs to the technical field of industrial waste recycling. The method comprises the following steps: respectively taking an electrolytic aluminum industry byproduct fluorine-containing waste electrolyte cryolite and lithium slag after lithium extraction of lithium ore as raw materials, performing acid leaching on the electrolyte cryolite, adding a calcium compound, separating to obtain calcium fluoride solid and a mixed solution containing aluminum chloride and sodium chloride, and adding an alkaline solution into the mixed solution to obtain an aluminum hydroxide product. And carrying out alkaline leaching on the lithium slag to obtain a mixed solution containing sodium silicate and sodium metaaluminate, and proportionally synthesizing the mixed solution with the obtained aluminum hydroxide and sodium hydroxide solution to obtain the 4A zeolite molecular sieve product. The calcium fluoride and the zeolite molecular sieve are cooperatively prepared by adopting multi-element industrial waste, and the problems that electrolyte cryolite cannot be completely applied to the aluminum electrolysis process, the lithium slag treatment cost is high and the like in the prior art are solved.

The invention relates to the technical field of cement preparation, and particularly discloses dry-process clinker cement and a preparation process thereof. The dry-process clinker cement comprises the following raw materials in parts by weight: 180-200 parts of limestone; 30-50 parts of iron tailing powder; 20 to 30 parts of coal gangue; 10 to 20 parts of fly ash; 5-8 parts of calcium fluoride; 5-8 parts of nano silicon dioxide; 1-5 parts of nano calcium carbonate; 1-5 parts of sodium sulfide; 1-5 parts of a charcoal-ferrous sulfate loading material; 100 to 200 parts of water; 5-20 parts of a sintering aid; the biochar-ferrous sulfate loading material is obtained by loading ferrous sulfate on biochar particles. According to the dry-process clinker cement disclosed by the invention, the reduction activity and chromium removal efficiency of the ferrous sulfate can be effectively enhanced through the charcoal-ferrous sulfate loading material, so that hexavalent chromium in the cement can be efficiently removed by using a relatively small amount of ferrous sulfate, and the cement can keep relatively good compressive strength while the cost is reduced.

A hydrocarbon gas detection system including a longwave infrared camera, a spectral filter, and a computation unit. The spectral filter is disposed in the light path of the camera sensor. The spectral filter is made of a material selected from the group consisting of calcium fluoride, zinc sulfide, magnesium fluoride, and silicon. The computation unit is arranged to process image data of the longwave infrared camera for the hydrocarbon gas detection.

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 invention provides a calcium fluoride crystal defect detection system and method, and relates to the technical field of detection, and the method comprises the following steps: preprocessing a crystal to determine a reference position and environmental parameters, and then respectively carrying out optical uniformity detection and stress birefringence detection to obtain an interference fringe pattern and polarization state change data; and optical path difference data and stress field data are generated. And through spatial registration and data association analysis, extracting areas with both refractive index anomaly and stress anomaly as candidate defect areas, quantifying defect strength and stress influence range, and finally outputting a quality judgment result of the crystal defect. The method improves the defect detection precision and reliability, and is especially suitable for high-precision calcium fluoride crystal quality control.