44 results about "Calcium crystals" patented technology

A method for producing calcium phosphate crystals according to the present invention comprises a step (S11) for preparing a weakly basic phosphoric acid solution containing a complex comprising a rare earth element ion and a coordination compound having a ligand coordinated to the rare earth element ion and a step (S12) for adding a calcium-containing compound to the weakly basic phosphoric acid solution and hydrolyzing. Some of the plurality of calcium ions contained in the structure of the calcium phosphate crystals are substituted by the rare earth element ion.

The application discloses a kind of based on hydration calcium silicate and polycrystalline fiber composite board and preparation method, belong to inorganic fireproof heat insulation board technical field. Including board body, the board body is by following component weight parts constitutes: calcium source 25-45 parts, silicon source 30-55 parts, polycrystalline fiber 5-25 parts, interface modifier 0.5-3 parts, dispersing agent 0.1-1 part, foam stabilizer 0.1-0.5 parts, water 150-300 parts;The calcium source and silicon source hydrothermal reaction generate hydration calcium silicate crystal, the hydration calcium silicate crystal is mutually interwoven and forms porous matrix skeleton, the polycrystalline fiber disperses in the porous matrix skeleton, the hydration calcium silicate crystal in-situ growth on polycrystalline fiber surface, and forms chemical combination layer with polycrystalline fiber.The based on hydration calcium silicate and polycrystalline fiber composite board and preparation method of the application, the prepared board has excellent fireproof heat insulation performance, while having good mechanical toughness, impact resistance and high temperature long-term stability.

The application discloses an open set recognition method for urine red blood cells, white blood cells and calcium oxalate crystals. The method comprises the following steps: collecting images of urine red blood cells, white blood cells, calcium oxalate crystals and similar impurities under a microscope, and constituting a data set after professional physician labeling; performing a combined data enhancement operation on the data set, and completing data normalization; secondly, constructing a urine sediment open set recognition network based on a conditional variational autoencoder; setting a multi-constraint optimization objective function and network training parameters; then, obtaining a pre-training model, and further migrating the pre-training model to the urine sediment data set for training; finally, testing the model classification performance, and calculating the recognition accuracy. The application is mainly applied to the field of medical images and urine formed element testing scenes, and has high accuracy and good applicability.

The invention relates to the technical field of building material admixtures, and particularly discloses nano calcium carbonate, an alkaline residue-based solid waste cementing material early strength agent, a preparation method and application. The preparation method of the nano calcium carbonate comprises the following steps: carrying out reaction on alkaline residues and a chlorine-containing solution, and carrying out solid-liquid separation to obtain filtrate; and adding an alcohol solvent into the filtrate, introducing carbon dioxide and nitrogen to carry out carbonization reaction, and crystallizing to obtain the nano calcium carbonate. The growth process of the nano calcium carbonate crystals is controlled by controlling the carbonization reaction conditions and the flow of nitrogen and carbon dioxide, the method has the advantage of being easy to operate, and the prepared nano calcium carbonate is applied to the alkaline residue-based solid waste cementing material early strength agent; the strength, the initial setting time and the final setting time of the solid waste cementing material at each age can be improved, and a new idea is provided for preparation of the alkaline residue-based solid waste cementing material early strength agent.

The invention discloses a solid waste filling method based on cooperation of an MICP technology and carbon dioxide mineralization. Gangue aggregate is treated through microbial infiltration; cO2 is introduced into the alkaline solid waste for carbonation treatment, so that the alkalinity of the alkaline solid waste is reduced, and CO2 is absorbed and cured; the microbe modified aggregate and the mineralized solid waste slurry are fully mixed according to a reasonable ratio to form the filling slurry with stable performance. After the slurry is injected into the goaf, calcium carbonate is formed through induction of the MICP technology, calcium carbonate crystals are further generated, internal pores of the material are effectively filled, and the compactness and certain mechanical performance of the grouting body are enhanced. The method can synchronously and efficiently solve the problem of treatment of solid wastes such as coal gangue and fly ash, realizes large-scale storage of CO2, provides a filling body with excellent mechanical properties for a goaf, enhances the surface corrosion resistance and improves the bonding property with surrounding rock.

The invention relates to the technical field of calcium aspartate preparation, in particular to a high-purity and high-bulk-density calcium aspartate crystal and a preparation method and application thereof.The preparation method specifically comprises the steps that asparaginic acid and a calcium oxide solution are mixed according to the molar ratio of 2: 1, the pH value is adjusted to 6.5-7.0, after kieselguhr is added and filtered, the calcium aspartate crystal is obtained; adding calcium aspartate seed crystal liquid at 85-95 DEG C to induce crystallization, and cooling, centrifuging and drying to obtain the finished product. According to the method, the purity, bulk density and fluidity of the product are effectively improved and the moisture content is reduced through key technologies such as accurate pH control, induced crystallization by using activated seed crystal liquid and mother liquor regeneration and recycling; the obtained calcium aspartate crystal has bimodal particle size distribution, the loose bulk density reaches 0.5-0.65 g / mL, the tight bulk density reaches 0.75-1.05 g / mL, the water content is lower than 1.5%, the calcium aspartate crystal is suitable for various calcium fortified food and health care products such as tablets, capsules and solid beverages, and the method is simple in process, low in energy consumption and excellent in product performance and has good industrial application prospects.

The present disclosure relates to a calcium phosphate coating that includes a plurality of nanometer sized calcium phosphate crystals that form a single layer. The coating is on a surface of a conductive substrate and is about 1 to 1000 nanometers thick, and greater than 25 percent of the coated surface area comprises the single layer of the crystals.

The invention belongs to the technical field of batteries, and discloses a preparation method of a zinc-nickel secondary battery negative electrode active material. The preparation method comprises the following steps: adding ZnO into a KOH solution of saturated ZnO, uniformly mixing, adding Ca (OH) 2, reacting, and aging to obtain the negative active material of the zinc-nickel secondary battery. A hydrothermal coprecipitation method is adopted, used raw materials comprise calcium hydroxide, zinc oxide, potassium hydroxide and the like, and a calcium zincate crystal generated in the preparation process has a quadrilateral crystal form. The crystal form of calcium zincate can be effectively stabilized by controlling hydrothermal coprecipitation conditions. The solubility of the zinc oxide in an alkaline solution is low and is far lower than that of zinc oxide. And due to the characteristic, the concentration of zincate radicals in the electrolyte is remarkably reduced, so that the growth of negative electrode dendritic crystals is effectively inhibited, and the cycling stability and the service life of the zinc-nickel battery are further improved.

The invention relates to an earthen archaeological site loose soil body disease strengthening method, and relates to the field of archaeological site soil body protection and restoration. An earthen archaeological site loose soil body disease strengthening method comprises the following steps that a calcium hydroxide solution is injected into a loose soil body, and preliminary cohesive soil is obtained after standing; uniformly spraying a silicate solution on the surface of the primary binding soil, repeatedly spraying for three times, and standing to obtain binding soil; in-situ silty soil of loose soil is evenly sprayed on the surface of the binding soil, the binding soil is covered and then stricken off, and solidified soil is obtained after drying. A calcium hydroxide solution reacts with carbon dioxide to generate a calcium carbonate crystal'cementation bridge ', insoluble calcium salt is formed through ion exchange, a stable framework is built from the inside, and migration of soluble salt is inhibited; the silicate solution forms a silicon-oxygen network reinforcing film with stable chemical properties through a sol-gel reaction, external erosion is prevented, and meanwhile, the silicate solution and calcium carbonate crystals are interwoven to reinforce a structure; therefore, long-term influence of natural environment is effectively resisted, and soil strength is maintained.

The invention discloses an engineered exosome of LTH peptide modified miR-146a-5p and application, the core component of the medicine is the engineered exosome, and the engineered exosome is constructed by the following method: miR-146a-5p mimic infected human renal tubular epithelium HK2 cells with nucleotide sequences shown as SEQ ID NO.1-SEQ ID NO.2 are cultured and screened, the exosome rich in miR-146a-5p is separated from the culture supernatant of the cells, and the exosome rich in miR-146a-5p is obtained. Then, the kidney targeting peptide LTH is modified on the surface of the exosome. The invention reveals that HNRNP M protein is a key molecule for regulating and controlling miR-146a-5p to be sorted and enter the exosome for the first time, and verifies that the engineered exosome can be efficiently enriched in kidney, and by delivering miR-146a-5p to target IRAK1 gene in macrophage and inhibiting TRAF6 / IKK / NF-kappa B inflammation signal pathway, the macrophage is promoted to be polarized to a repairable M2 phenotype, so as to realize the purpose of improving the activity of the miR-146a-5p. And finally, the kidney injury induced by the calcium oxalate crystal is effectively relieved. The medicine has the advantages of clear mechanism, strong targeting property, good biocompatibility and the like, provides a brand new immunoregulation treatment strategy for renal injury, and has a wide clinical application prospect.

The invention discloses a method for preparing high-quality light calcium carbonate based on green liquid separation and impurity removal-crystal nucleus induction causticization granulation, and relates to the technical field of pulping and papermaking waste liquid treatment. According to the method, pulping black liquor is used as a raw material, calcium silicate is separated through fractional precipitation, granular calcium carbonate crystals are generated through crystal nucleus induction causticization reaction, and high-quality light calcium carbonate is prepared through multi-stage purification. The content of calcium carbonate prepared by the method can reach 98-99.5% of the purity of industrial calcium carbonate, the purity of calcium silicate byproducts is greater than or equal to 90%, the calcium silicate byproducts can be directly used for roadbed materials or cement retarders, the recovery rate of sodium hydroxide in the black liquor is greater than or equal to 92%, and resource utilization is realized.

The application discloses a method for testing anti-radiation damage performance of calcium fluoride crystal. The method adopts X-ray radiation to irradiate calcium fluoride crystal, and judges the anti-radiation damage performance of the crystal according to an X-ray radiation dose for inducing color center absorption peak of the calcium fluoride crystal and a color center absorption coefficient of a characteristic absorption peak induced by radiation.

This invention provides a method for microbial soil nailing slope reinforcement based on microbial-induced calcium carbonate precipitation, belonging to the field of geotechnical engineering technology. The invention involves drilling holes in the slope surface and filling these holes with calcareous sand. A slurry containing urease-producing bacteria is injected into the calcareous sand-filled holes, and the mixture is allowed to stand. Then, a cementing liquid is injected to induce microbial calcium carbonate precipitation, resulting in a microbial soil nailed slope reinforcement. This invention creatively combines MICP technology with soil nail structure, using MICP technology to replace traditional cement grouting. This generates calcium carbonate crystals that cement the calcareous sand and surrounding soil, reducing the swelling and shrinkage of expansive soil under rainwater conditions. It inhibits slope surface collapse under alternating wet and dry conditions and reduces the possibility of shallow landslides during these processes. Simultaneously, it improves the shear strength and pull-out resistance of the nail-soil interface, reducing environmental pollution.

The present application relates to a method for regulating the growth of calcium carbonate crystals into calcite by glucose uronic acid, so as to improve the mechanical strength of the solidified body. The specific steps of the method are as follows: (1) screening and identification of acetate mineralization bacteria with calcium acetate as substrate; (2) culture of carbonate mineralization strain; (3) growth and regulation of calcium carbonate crystals induced by microorganisms; (4) characterization of calcium carbonate crystals. The microbial solidification of the uranium tailings beach is a green solidification method with great application prospect. The carbonate mineralization strain provided by the present application has no secondary pollution in the process of microbial induction of calcium carbonate precipitation, has strong environmental friendliness, and can regulate the growth of calcium carbonate crystals into calcite by glucose uronic acid, so as to improve the mechanical strength of the calcium carbonate crystals, and has potential application prospect.

The application provides a landslide rock mass crack repair device and method based on calcium carbonate precipitation, and belongs to the technical field of geotechnical engineering geological disaster prevention and control. The device integrates precise grouting, precipitation regulation, mechanical monitoring, dry-wet cycle simulation module and intelligent control terminal, adopts a degradable multi-stage telescopic grouting pipe, combines electric field, pH and temperature for precise regulation to realize directional precipitation of calcium carbonate crystals, and is matched with multiple types of sensors to complete real-time monitoring of all parameters in the repair process. The method configures MICP / EICP precursor liquid according to the rock mass lithology, and completes the repair through the steps of crack survey, environment calibration, precursor liquid mixing, precise grouting regulation, simulation maintenance and effect evaluation, and is suitable for different scenes such as reservoir area, mountain area, mining area and high altitude. The application realizes intelligent and quantitative evaluation of the repair process, can improve the compressive strength and shear strength of the rock mass, is convenient to construct and has little disturbance to the original rock mass, the long-term mechanical stability of the repaired rock mass is excellent, and is suitable for various landslide rock mass crack repair projects.

The invention discloses a calcium-based microporous carbon fiber carton board, a formula and a preparation method. The calcium-based microporous carbon fiber carton board is prepared from macromolecular calcium crystal master batches and carbon fiber powder in a mass ratio of (10: 1)-(3: 1), wherein the high-molecular calcium crystal master batch comprises calcite as a base material; adding a base material and an auxiliary agent; the mass ratio of the calcite to the base material to the auxiliary agent is (67%-84%): (15%-30%): (1%-3%). The preparation method comprises the following steps: pretreating each raw material; weighing the raw materials according to a preset proportion; putting the raw materials into a high-speed hot mixing machine to form a first pretreated material; putting the first pretreated material into a low-speed cold mixer to form a second pretreated material; and carrying out extrusion molding, cutting and packaging on the basis of the second pretreated material. The composite material is excellent in mechanical property, good in forming stability and wide in application prospect.

The invention discloses a stable preparation method of an unsteady vaterite calcium carbonate crystal, and belongs to the technical field of inorganic material preparation. According to the method, gamma-dicalcium silicate (gamma-C2S) is taken as a slow-release calcium source, amino acid is taken as a crystal form regulating agent, CO2 is introduced into a system at normal temperature and normal pressure for a carbonization reaction, and an unstable state reaction environment of instantaneous supersaturation-dynamic passivation-heterogeneous adsorption is constructed, so that controllable nucleation of vaterite is realized, and transformation of vaterite to calcite is remarkably inhibited. Optionally, gypsum powder can be added as a crystal form stabilizer, and the stability of vaterite is further enhanced through heterogeneous adsorption. The process is simple, green and energy-saving, and the obtained vaterite calcium carbonate crystal is high in purity, regular in morphology and excellent in long-term stability in water, and is suitable for the fields of carbon mineralization carbon sequestration, functional fillers, low-carbon building materials and the like.

The application relates to the field of self-repairing concrete, in particular to high-strength self-repairing concrete and a preparation method thereof. The high-strength self-repairing concrete comprises the following substances in parts by weight: cement 45-60 parts; recycled coarse aggregate 100-120 parts; fine aggregate 65-80 parts; water 10-20 parts; water reducing agent 0.1-0.3 parts; the recycled coarse aggregate is a recycled coarse aggregate with immobilized self-repairing microorganisms, and the self-repairing microorganisms comprise at least one of bacillus subtilis, bacillus megaterium and bacillus pasteurii. The application endows the concrete with crack self-repairing capability by immobilizing the self-repairing microorganisms. The microorganisms form dormant spores in the concrete, when cracks are generated and infiltrate water, the microorganisms are activated and metabolize calcium sources and urea in the surrounding environment, calcium carbonate crystals are generated through a microbial-induced carbonate precipitation mechanism, cracks are filled and structural integrity is restored. The process does not require external intervention and can significantly prolong the mechanical structure and mechanical properties of the concrete structure.

The application discloses a method for efficiently preparing beta-amino propionic acid calcium from beta-amino propionitrile, and comprises the following steps: beta-amino propionitrile and a calcium salt solution are reacted in the presence of a catalyst and an additive, and microwave radiation is used to promote the reaction; after the reaction solution is filtered and deaminated, the solution is concentrated, cooled and alcohol crystallized to obtain beta-amino propionic acid calcium crystals which can be used for the production of calcium pantothenate; wherein the catalyst is a transition metal complex, and the additive is a phase transfer catalyst or a buffer metal salt. The application has the advantages of simple process, high yield and high reaction efficiency.

The invention relates to the technical field of cutting equipment, and discloses a calcium fluoride crystal processing efficiency and damage depth coordinating device which comprises a workbench and further comprises a U-shaped frame, and the two vertical edges of the U-shaped frame are fixedly installed at the top of the workbench; the transverse plate is horizontally arranged between the upper part of the workbench and the transverse edge of the U-shaped frame; the cutting assembly is arranged on the transverse plate, and the cutting assembly is used for cutting the calcium fluoride crystals; and the control assembly is arranged on the transverse plate, and the control assembly is used for controlling the cutting assembly, so that the calcium fluoride crystals cannot be overheated and damaged when the cutting assembly cuts the calcium fluoride crystals. According to the calcium fluoride crystal cutting device, the cutting disc moves up and down in a reciprocating mode to cut calcium fluoride crystals, namely, high-speed airflow is automatically formed to cool and clean kerfs of the calcium fluoride crystals and the cutting disc while the cutting disc moves upwards, the cutting smoothness and stability are guaranteed, and then the using effect of the device is improved.

This invention relates to the field of road engineering, specifically to a process for constructing a road without a subbase using refined slag and converter slag. The process involves crushing converter slag as the skeleton aggregate and mixing it with refined slag as the fine aggregate. Pasteurella multocida inoculum solution and a cementing solution containing soluble calcium salts and urea are alternately sprayed into the mixture in stages and mixed. After paving, compaction, and curing, the mixture is covered and left to stand. Microbial metabolism generates calcium carbonate crystals in situ at the contact points between steel slag particles, forming a microscopic cementing network. This process, through in-situ mineralization and physical coating, blocks the contact between free calcium oxide and moisture inside the converter slag, eliminating local expansion stress caused by delayed hydration of free calcium oxide in the subbase structure, preventing the expansion and fracture of microcracks within the base layer, and cementing the steel slag mixture into a monolithic load-bearing slab.

This invention discloses a stable preparation method for unsteady aragonite calcium carbonate crystals, belonging to the field of inorganic material preparation technology. The method uses γ-type dicalcium silicate (γ-C2S) as a slow-release calcium source and amino acids as crystal form regulators. CO2 is introduced into the system at room temperature and pressure to initiate a carbonization reaction. By constructing an unsteady reaction environment of "instantaneous supersaturation-kinetic passivation-heterogeneous adsorption," controllable nucleation of aragonite is achieved, and its transformation to calcite is significantly inhibited. Optionally, gypsum powder can be added as a crystal form stabilizer to further enhance the stability of aragonite through heterogeneous adsorption. This invention features a simple, green, and energy-saving process, yielding aragonite calcium carbonate crystals with high purity, regular morphology, and excellent long-term stability in water. It is suitable for applications such as carbon mineralization and carbon fixation, functional fillers, and low-carbon building materials.

The application discloses a method for synchronously removing calcium and phosphorus in industrial circulating cooling water, which comprises the following steps: adding sodium bicarbonate into a solution containing calcium ions to which a scale inhibitor is added; passing oxygen into the solution so that the solution is in an oxygen saturation state; taking a carbon-based TiO2 electrode as a working electrode, a graphite electrode as a counter electrode, and a silver chloride standard electrode as a reference electrode, applying a voltage through an electrochemical workstation to electrochemically treat the solution, continuously passing oxygen in the whole process, and generating white precipitates in the solution after the reaction is completed; and realizing the synchronous removal of calcium and phosphorus by filtering and drying the white precipitates. The method can induce the release of calcium and phosphorus in the industrial circulating cooling water and induce the generation of calcium phosphate crystals, so that the synchronous Ca removal and P recovery are realized, and phosphorus fertilizer is provided for agricultural production. The method provides an environment-friendly and potentially economically valuable new idea for the repair of the industrial circulating cooling water.

The invention discloses a step-by-step recovery treatment method and system for mixed wastewater of sulfuric acid and fluosilicic acid, which comprises the following steps: adding a lime solution into a desulfurization induced crystallization reactor to adjust the pH value of the wastewater to 1.5-3, combining sulfate radicals in the wastewater with calcium to form calcium sulfate crystals, and carrying out filter pressing to obtain a calcium sulfate product with higher purity; the effluent of the desulfurization induced crystallization reactor enters a defluorination induced crystallization reactor, a lime solution is added to adjust the pH value of the wastewater to 4-5, calcium ions and fluorine ions in the wastewater are combined to form calcium fluoride crystals, the calcium fluoride crystals are subjected to multi-stage cleaning and filter pressing to obtain a calcium fluoride product with high purity, and the effluent of the defluorination induced crystallization reactor is subjected to up-to-standard treatment. According to the method, the pH value of a reaction system is precisely regulated and controlled in stages, so that more than 98% of fluorine ions are deeply removed, meanwhile, a high-purity calcium sulfate product and a high-quality calcium fluoride product are produced, and resource recycling of core resources of sulfur and fluorine in the wastewater is really achieved.

The invention relates to the technical field of civil engineering concrete materials, in particular to a self-healing microcapsule reinforced concrete anti-corrosion structure and a crack repairing method. According to the structure, repair triggering microcapsules (type A) and mineralization guiding microcapsules (type B) are uniformly dispersed in a concrete matrix; the A-type capsule is provided with a chloride ion responsive shell layer, and a core contains epoxy resin, a vapor phase corrosion inhibitor and a crystal nucleus guiding agent; the B-type capsule has a pH responsive shell layer, and the core is a calcium source. The method comprises the steps that crack generation triggers release of the A-type capsule, and crack filling and immediate reinforcement protection are completed; the formed restoration body causes reduction of the pH value of the internal microenvironment, and further triggers the B-type capsule to release calcium ions, and calcium carbonate crystals are generated under the guidance of crystal nucleuses, so that secondary restoration and long-acting corrosion prevention are realized; accurate triggering of repairing and repairing corrosion prevention are achieved, and the durability of the concrete structure is remarkably improved.

The invention discloses a calcium fluoride crystallization process for glass thinning wastewater and treatment equipment used in the process, and the treatment equipment comprises an acid water adjusting tank, a lime dispensing tank, a fluorine recovery reactor, a first-stage filter pressing device, a second-stage filter pressing device, a cleaning device, a fluorine-containing wastewater adjusting tank and a two-stage fluorine removal system, the glass thinning concentrated acid wastewater homogenized by the acid water adjusting tank and a lime solution prepared by the lime dispensing tank are crystallized in the fluorine recovery reactor to form large-particle calcium fluoride crystals; large-particle calcium fluoride crystals are subjected to filter pressing by the first-stage filter pressing device, washed by the washing device and subjected to filter pressing by the second-stage filter pressing device to obtain a high-purity large-particle calcium fluoride crystal product, and effluent of the fluorine recovery reactor, filtrate generated by dehydration and washing water generated by washing are homogenized by the fluorine-containing wastewater adjusting tank and then enter the two-stage fluorine removal system; according to the method, the high-purity calcium fluoride product can be obtained, resource circulation is achieved, and the disposal cost of an enterprise is reduced.

The invention relates to the field of building coatings, and discloses an interior and exterior wall calcium crystal porcelain pure inorganic coating and a preparation method thereof. The formula of the coating comprises the following components by weight: nano calcium hydroxide, active magnesium oxide, a magnesium source compound, magnesium nitrate, modified magnesium-aluminum layered double hydroxide, nano titanium dioxide, nano silicon dioxide, monocalcium phosphate, nano calcium carbonate, ammonium bicarbonate, citric acid and deionized water. The innovation of the method is that an endogenous carbonization and dynamic pH buffer synergistic system is constructed: ammonium bicarbonate provides endogenous carbonate and accelerates the generation of calcium-magnesium multiphase crystals; the layered double hydroxide regulates the pH value of a system through ion exchange, so that the pH value of the coating is rapidly stabilized in a weak base range. The interior and exterior wall calcium crystal porcelain pure inorganic coating is a single component, and has the comprehensive performance of zero VOC, A1-level fire prevention, alkalescence, salt mist resistance, high hardness, antibacterial property and mildew resistance. The invention solves the technical problems of high alkali, alkali efflorescence, slow curing and poor water resistance of the traditional inorganic coating.

The invention relates to a jet fluidized bed fluorine recovery device system for fluorine-containing wastewater and a fluorine recovery method. The jet fluidized bed fluorine recovery device system comprises a fluidized bed crystallization system, a chemical mixing system, a circulating system, a water outlet system, a crystallization separation system and an air supply system. The jet fluidized bed fluorine recovery device system provided by the invention has good mixing effect and treatment efficiency, can recover calcium fluoride crystals, and is stable in operation and good in effluent quality.

The invention discloses a calcium fluoride crystallization method based on graded dosing in a single reaction tank, which comprises the following steps: S1, introducing high-fluorine wastewater into a first-stage reaction zone of the reaction tank, and adding a precipitator to be mixed with the high-fluorine wastewater to form first slurry containing calcium fluoride coarse crystal nucleuses; s2, introducing the first slurry into a second-stage reaction zone of the reaction tank, and adding a calcium salt agent into the second-stage reaction zone to mix the calcium salt agent with the first slurry to form second slurry containing calcium fluoride crystals; and S3, introducing the second slurry into a separation area, carrying out solid-liquid separation on the second slurry, and recovering calcium fluoride crystals. The reaction area in the reaction tank is divided into the first-stage reaction area and the second-stage reaction area, and the three chemical adding units of the chemical adding device mounted at the top of the reaction tank are combined, so that the occupied area of the reaction area is reduced, the equipment structure is simplified, and meanwhile, two chemicals can be prevented from mutually competing and interfering; the fractional crystallization process is accurately controlled while the dosage of the medicament is reduced.

The application discloses a kind of powder 3D printing high-toughness fast-hardening sulphoaluminate cement-based materials, surface modification is carried out to fast-hardening sulphoaluminate cement using nano-oxide, for powder 3D printing fast-hardening sulphoaluminate cement material, using water solution post-treatment maintenance, after printing forming, immerse saturated calcium chloride aqueous solution, make unhydrated sulphoaluminate cement further reaction hardening, immerse in water glass solution again, make the calcium chloride in the inside of printing model pore and the sodium silicate in water glass solution react to generate calcium silicate, fill the inside of printing model pore, simultaneously, the hydration sulphoaluminate calcium crystal and ettringite are tightly bonded, form dense mesh structure, improve the density and mechanical properties of material.