548 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 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 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 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 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 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.

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.

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 discloses a method for measuring the content of calcium fluoride in dolomite-containing fluorite mine. The method comprises an acetic acid solution, a hydrochloric acid solution, a triethanolamine solution, a potassium hydroxide solution and boric acid. The method for measuring the content of calcium fluoride in the dolomite-containing fluorite mine comprises the following steps: S1, reagent proportioning; s2, preparing a calcium standard solution; s3, preparing an EDTA standard titration solution; s4, selecting an instrument; s5, preparing a sample; s6, step analysis; s7, content correction and determination; and S8, calculating a result. The invention belongs to the technical field of calcium fluoride content determination, and particularly relates to a method for measuring the content of calcium fluoride in dolomite-containing fluorite mine, compared with the prior art, the method solves the problem of dolomite dissolution when calcium carbonate is leached by acetic acid, and the content of calcium fluoride in the fluorite mine can be measured by accurately calculating the dissolution amount of dolomite. The measured calcium fluoride content is clearer, more reasonable and more reliable and approaches to a true value, and the process operation is simple and rapid, and is suitable for the requirements in the fields of mine production, assay detection and the like.

The invention discloses a fluorine-containing wastewater advanced treatment system and a fluorine-containing wastewater advanced treatment method based on cooperation of chemical precipitation and a membrane method. Comprising a sedimentation tank, a dynamic filter and a double-membrane system which are arranged in sequence, wherein in the sedimentation tank, a modified calcium salt precipitator and CaF2 seed crystals are added into the fluorine-containing wastewater for reflux, and large calcium fluoride particle precipitates are formed through an induced crystallization adsorption-sedimentation mechanism; the dynamic filter is used for intercepting sediments from effluent of the sedimentation tank through a gradient aperture structure to realize solid-liquid separation and preliminary fluorine removal; and the double-membrane system is used for removing residual fluorine-containing particles, colloids and ions in the wastewater treated by the dynamic filter by utilizing an ultrafiltration membrane and a reverse osmosis membrane. Through cooperation of a modified calcium salt adsorption-precipitation mechanism and a membrane gradient interception method, efficient trapping and solid-liquid separation of fluorine ions are achieved, the fluorine removal precipitation reaction is enhanced, the medicine consumption is reduced, and near-zero external water consumption is achieved.

The utility model provides a multistage deep defluorination device for fluorine-containing wastewater. The multistage deep defluorination device comprises a crystallization tank, a coagulation tank, a coagulation aid tank, a flocculation tank, a precipitation water distribution tank and an efficient precipitation tank which are connected in sequence, a calcium chloride solution adding pipe is arranged in the crystallization tank; a first stirrer, a coagulant feeding pipe and an alkali liquor feeding pipe are arranged in the coagulation tank; a second stirrer and a particle medium adding mechanism are arranged in the coagulation aid tank; a flow guide cylinder is arranged in the flocculation tank, and a flocculant feeding pipe is arranged at the upper part of the flocculation tank; an inclined pipe and a water outlet collecting tank are arranged in the sedimentation water distribution tank; and a mud bucket and a mud scraper are arranged at the bottom of the efficient sedimentation tank. According to the technical scheme, the crystallization-adsorption-coordination-co-precipitation principle is utilized, fluorine is removed step by step, fluoride is efficiently and stably removed, meanwhile, the sludge yield is reduced, and calcium fluoride crystals can be recycled.

The invention discloses a molybdenum-vanadium-aluminum intermediate alloy and a low-cost preparation method thereof. The molybdenum-vanadium-aluminum intermediate alloy comprises the following chemical components in percentage by mass: 39-41% of Mo, 39-41% of V and the balance of Al. The method comprises the following steps: uniformly mixing vanadium oxide (tablets replace powder), molybdenum trioxide, metal aluminum, calcium fluoride, calcium oxide and a cold material according to a mass ratio of (28-32): (24-26): (32-35): (10-13): (1.5-4): (5-10); then putting the mixture into a graphite crucible for tamping treatment; and finally, the metal powder is directly ignited for a reduction reaction, and the molybdenum-vanadium-aluminum intermediate alloy can be obtained. According to the method, the recovery rates of the molybdenum and the vanadium are increased by adjusting the components and the ratio of the raw materials and the auxiliary materials and adopting a one-step aluminothermic reduction method, and the recovery rates of the molybdenum and the vanadium can reach 95 wt% or above and 96 wt% or above respectively.

A coated optical component includes an optical component and a conformal coating. The optical component is crystalline calcium fluoride and the conformal coating is an atomic layer deposition (ALD) coating in contact with a surface of the optical component. The ALD coating includes a metal fluoride ALD coating having a metal different from calcium. The ALD coating can include other metal oxide or metalloid oxide ALD coating layers. The method for making the coated optical component includes depositing an atomic layer deposition (ALD) coating on a surface of the optical component, where the ALD coating can be a metalloid oxide, a metal oxide, a metal fluoride having a metal that is different from calcium, or combinations of these. Sulfur hexafluoride is used as a fluorine source in the ALD process.

The application relates to the technical field of ceramic materials, and discloses a low-dielectric-loss aluminum nitride ceramic substrate and a preparation method thereof. The low-dielectric-loss aluminum nitride ceramic substrate comprises the following components by weight: 80-90 parts of aluminum nitride, 6-8 parts of a sintering aid, 3-5 parts of a toughening agent, 3-4 parts of a composite aid, 6-10 parts of a binder, 6-8 parts of a dispersing agent and 60-70 parts of a solvent; the composite aid comprises boron trioxide, calcium fluoride and lithium carbonate. The technical scheme solves the problem of high dielectric loss of the aluminum nitride ceramic substrate in the related art.

The embodiment of the invention provides a friction material composition, a brake lining, a preparation method of the brake lining, a brake and a vehicle. The friction material composition comprises the following raw materials in parts by weight: 2-10 parts of a fluoride mixture, 8-15 parts of graphite, 8-12 parts of phenolic resin, 4-12 parts of a metal oxide, 15-40 parts of a fiber material and 20-40 parts of other fillers, wherein the fluoride mixture comprises at least two of calcium fluoride, barium fluoride, cerium fluoride, aluminum fluoride, magnesium fluoride, potassium fluoride, sodium fluoride, beryllium fluoride and manganese fluoride. The brake lining prepared from the friction material composition can solve the problems of high wear rate and heat fading at the same time, the service life of the brake lining is prolonged, and the braking effect is improved.

The invention belongs to the technical field of photoelectric ceramic material manufacturing, and relates to high-density calcium fluoride photoelectric ceramic and an ultralow-temperature preparation method thereof. The method comprises the following steps: S1, wet mixing: weighing calcium hydroxide (Ca (OH) 2) powder and ammonium fluoride (NH4F) powder according to a molar ratio of 1: (1.5-2), and mixing by taking an organic solvent as a medium to form slurry; s2, rapid drying: rapidly drying the slurry obtained in the step (1) to obtain mixed precursor powder; and S3, reaction cold sintering: putting the mixed precursor powder into a mold, and carrying out reaction cold sintering. The sintering temperature used in the method is not higher than 350 DEG C, and the sintering temperature can be changed according to actual needs so as to improve the mechanical property of the ceramic, and the mechanical property is improved by 2-4 times compared with that of a conventional hot pressed sintering sample.

The present invention provides an efficient fluorine crystal wastewater defluorination device, relating to the field of wastewater treatment. The efficient fluorine crystal wastewater defluorination device comprises a crystallization reaction tank, a seed crystal stirring tank, and a seed crystal silo, which are connected in sequence. The seed crystal stirring tank is provided with two water inlets. A tank cover is fixedly mounted on the upper end of the crystallization reaction tank. A drainage channel for drainage is provided inside the tank cover. The drainage end of the drainage channel is connected to a tee pipe A. One end of the tee pipe A is connected to one of the water inlets of the seed crystal stirring tank, and the other end is used for drainage. The efficient fluorine crystal wastewater defluorination device forms larger calcium fluoride crystals by adding fluorine crystals and precipitant calcium ions into the crystallization reaction tank. The calcium fluoride crystals are screened layer by layer to recover large calcium fluoride crystals. Small calcium fluoride crystals are returned to the crystallization reaction tank to continue to produce large calcium fluoride crystals. Sludge in the crystallization reaction tank is recovered, generating certain economic benefits and reducing operating costs.

The invention relates to the technical field of cement, and particularly discloses Portland cement and a preparation method thereof.The preparation method comprises the following steps that S1, 70-85 parts by mass of limestone, 10-20 parts by mass of clay, 3-5 parts by mass of iron ore, 3-6 parts by mass of silica fume, 0.8-2 parts by mass of calcium fluoride and 2-4 parts by mass of activated aluminum oxide are smashed and mixed to be uniform, 8-12 parts by mass of pulverized coal and 0.15-0.85 part by mass of a combustion improver are added, and a mixture is obtained; uniformly mixing to obtain a mixed raw material; s2, the mixed raw material is preheated and then calcined, the calcination temperature ranges from 1200 DEG C to 1400 DEG C, the calcination pressure ranges from 800 Pa to 1200 Pa, the calcination time ranges from 30 min to 60 min, cooling is conducted, and the Portland cement is obtained. According to the invention, by optimizing the raw material ratio and calcining in sections, the stability, compressive strength and breaking strength of the cement are effectively improved.

The invention discloses a refining impurity cleaning and removing process for secondary copper, which comprises the following steps: (a) pretreatment melting: melting a secondary copper raw material to form copper liquid, and controlling the temperature to be 1150-1250 DEG C; (b) oxidizing and slagging: introducing oxygen-containing gas into the copper liquid for 20-40 minutes to oxidize impurity elements to form scum; according to the refining impurity cleaning and removing process for the secondary copper, As and Sn are converted into high-valence oxides through oxidation, then a low-melting-point borate slag system is formed through borax in the composite flux, and efficient trapping of impurities is achieved. The mass transfer process is enhanced, flux agglomeration is avoided, and the impurity removal rate is increased by 30% or above. The borax / calcium fluoride combination significantly reduces the melting point of the slag system (actually measured lt; and the lead and tin removal efficiency is improved.

The invention belongs to the technical field of crystals, and particularly relates to a calcium fluoride crystal doped with metal ions, a preparation method of the calcium fluoride crystal and application of the calcium fluoride crystal in optical elements. The crystal is a calcium fluoride crystal doped with magnesium ions and barium ions, and in the preparation method of the crystal, the magnesium ions and the barium ions for doping are pretreated and coated with a calcium fluoride precursor, and the calcium fluoride crystal which is uniform in doping and excellent in performance is prepared by combining a traditional Bridgman-Stockbarger method with a gradient doping process. The crystal is applied to an excimer laser lighting system, and after an optical element manufactured by the crystal is exposed to gamma radiation larger than 2.8 Mrads, the 515 / 380 nm transmittance loss ratio of the optical element is lower than 0.4.

The invention discloses a topcon battery fluorine-containing wastewater calcium fluoride sludge treatment process based on a double-layer printing process, and relates to the technical field of solar cell production, the topcon battery fluorine-containing wastewater calcium fluoride sludge treatment process comprises the steps of wastewater pretreatment, accurate pH value regulation and control, efficient precipitation generation, fine sludge separation and drying, an online fluorine ion concentration detector and an automatic control program are combined to precisely add a calcium chloride solution to form precipitation particles easy to settle, a sludge treatment device adopts a double-layer filter pressing structure to improve the sludge dewatering effect, and meanwhile, a filter pressing belt cleaning and monitoring system is arranged to prevent filter holes from being blocked and monitor the state of a filter pressing belt in real time, so that the sludge dewatering effect is improved. According to the method, the fluorine-containing wastewater can be efficiently converted into the high-quality calcium fluoride sludge, the wastewater treatment cost is reduced, and the resource utilization rate is increased.