109results about "Ammonium chloride" patented technology

The invention relates to the technical field of wastewater treatment, and provides a treatment method of glycine production wastewater. The treatment method of glycine production wastewater comprises the following steps: (1) rectifying glycine wastewater to recover methanol, adding dilute sulphuric acid to adjust the pH value to 2.5-3.0, stirring, and standing; (2) transferring the supernate into another container, adding a ZIF-8 modified material, stirring, standing, filtering, collecting filter residues and filtrate, washing the filter residues with diethyl ether, and recovering urotropine; and (3) evaporating and concentrating the filtrate under the vacuum condition of-0.08 MPa and the temperature of 50-60 DEG C, and separating out high-purity ammonium chloride crystals. According to the treatment method for the glycine production wastewater, the problem that an existing treatment method is poor in removal effect on urotropin in the glycine production wastewater is solved; and the treated glycine production wastewater reaches the discharge standard.

The invention belongs to the technical field of acyclic compounds, and particularly relates to a method for preparing glycine by an aqueous phase method. Mixing the ammonium salt aqueous solution, chloroacetic acid and a catalyst, adding ammonia gas, and carrying out ammonification reaction to obtain a reaction solution; cooling and crystallizing the reaction liquid, performing primary centrifugal separation to obtain a glycine crude product and a primary separation liquid, and drying the glycine crude product to obtain a glycine product; adding an ammonium source into the primary separation liquid for dissolving to obtain an ammonium dissolving liquid; cooling the ammonium dissolving solution, and performing secondary centrifugal separation to obtain an ammonium chloride crude product and a secondary separation solution; the ammonium chloride crude product is dried to obtain an ammonium chloride byproduct, and the secondary separation liquid continues to participate in the ammoniation reaction. According to the invention, steam consumption is reduced, the catalyst utilization rate is improved, and the product yield is high.

The invention discloses a method for sequestration of carbon by using strong brine wastewater of a steel plant and a used device, and belongs to the technical field of tempering co-production process production. The method comprises a sodium carbonate production process I and an ammonium chloride production process II which form a cycle; raw materials NH3, salt NaCl and gas carbon dioxide are continuously added into the circulating system, and meanwhile sodium carbonate and ammonium chloride products are continuously produced; the raw material carbon dioxide comes from steel mill blast furnace top gas, steel rolling heating furnace tail gas or lime kiln tail gas; the raw material salt NaCl comes from concentrated salt wastewater of a steel mill; the raw material NH3 is from a byproduct coke oven gas generated in the production process of a steel enterprise and a coking plant. According to the method, sodium carbonate is prepared by fully utilizing three wastes, the situation that soxhlet and Hou's alkali production is adopted in the traditional alkali production industry to damage natural ecology and generate a large amount of waste gas, waste water and waste residues is broken, and double protection of resource recycling and environment is realized.

The invention provides a system and a method for concentrating an ammonium chloride solution and co-producing fresh water. The system comprises a fresh water system, a concentrated water system and a water storage system, the fresh water system comprises a sea fresh water system and a brackish water system which are arranged in sequence, the concentrated water system comprises a primary concentration system and a secondary concentration system which are arranged in sequence, and the concentrated water system is connected with the fresh water system. The water storage system comprises a raw water tank, a fresh water tank and a concentrated water tank, the raw water tank is connected with the fresh water system or the concentrated water system, the fresh water tank is connected with the brackish water system, and the concentrated water tank is connected with the concentrated water system. The system and the method disclosed by the invention have the advantages of low energy consumption, no wastewater discharge and the like, and the ammonium chloride concentrated solution of which the TDS is greater than or equal to 170000 mg / L and the fresh water of which the TDS is less than or equal to 300 mg / L can be obtained.

The invention discloses a method for recycling process water in an APT (ammonium paratungstate) production process, and relates to the field of water recovery in an APT production process, and the method comprises the following steps: S1, recycling wastewater of an alkali extraction system; s2, evaporating strip liquor and recovering ammonia water; s3, chemical treatment of pure ammonium tungstate evaporation ammonia water; s4, ammonium molybdate evaporation ammonia water closed-loop utilization; and S5, recycling ammonia gas in a crystallization section. According to the method, the recovery rate of tungsten and molybdenum in the tail liquid is remarkably increased by optimizing the processes of wastewater reuse of the alkali extraction system, strip liquor evaporation, ammonia water recovery and the like; one part of the tail liquid is recycled in the pulping process, the other part of the tail liquid is subjected to evaporation treatment, zero emission of wastewater is achieved, evaporated condensate water can be recycled to be used for preparing a stripping agent, the utilization rate of water resources is further increased, the production cost is reduced, and meanwhile the environment-friendly requirement is met.

The invention discloses a process for recovering zinc, nickel, cadmium, copper and chlorine in high-chlorine zinc slag. The process comprises the following steps: S1, four-stage reverse water washing; s2, removing impurities from water washing liquid; s3, concentrating and crystallizing the impurity-removed liquid; s4, leaching the washed mixed slag; s5, neutralizing the leachate to remove arsenic and iron; s6, replacing to remove copper, cadmium and nickel; and S7, concentrating and crystallizing the copper-cadmium-nickel-removed solution. According to the method, the technical bottleneck problem that the high-chlorine zinc slag is used for recovering zinc and discarding chlorine resources by applying a traditional zinc hydrometallurgy process technology is solved, and the environment-friendly process technology for recovering zinc and chlorine at low cost, producing ammonium chloride and zinc sulfate products and realizing zero emission of three wastes is realized. And meanwhile, valuable metals such as lead, cadmium and copper in the high-chlorine zinc slag are enriched and recycled.

The present invention provides a method and device system for preparing sodium carbonate and / or sodium bicarbonate and co-producing ammonium sulfate from sodium-based wastewater. According to the phase equilibrium law of a multi-component water-salt system, through the regulation of crystallization kinetics and supersaturation, the sodium-based wastewater does not need to be evaporated and crystallized to produce sodium sulfate solid. Instead, the wastewater after simple pretreatment is directly treated to achieve gradient crystallization separation of sodium sulfate, ammonium sulfate and sodium bicarbonate, thereby obtaining high-quality sodium bicarbonate, sodium carbonate and ammonium sulfate products.

The invention discloses a low-cost method for preparing high-purity potassium sulfate and co-producing calcium carbonate and ammonium chloride from gypsum, and belongs to the technical field of resource utilization of gypsum solid waste. The method comprises the following steps: (1) dissolving excessive gypsum in a first mixed solution, and filtering to obtain a first filtrate; (2) adding a carbon source into the first filtrate, filtering to obtain a first filter cake and a second filtrate, and separating and purifying the first filter cake to obtain CaCO3; (3) adding KCl into the second filtrate, filtering to obtain a second filter cake and a third filtrate, and separating and purifying the second filter cake to obtain K2SO4 and NH4Cl; the first mixed solution comprises an aqueous solution of ammonia water and a phase transfer reagent, the concentration of the ammonia water is 2-3 mol / L, and the concentration of the phase transfer reagent is not less than 1 mol / L. On one hand, high-purity potassium sulfate and co-production of calcium carbonate and ammonium chloride are obtained, generation of impurities is avoided, and the product value and the economic value are high; the method is simple, saves energy, reduces consumption, reduces cost and is beneficial to large-scale utilization of gypsum solid waste.

Provided herein is a process comprising: a) calcining limestone at a cement plant to form carbon dioxide and a calcium compound selected from calcium oxide, calcium hydroxide, or a combination thereof; b) treating the calcium compound with an N-containing salt in water to produce an aqueous solution comprising the calcium salt and the N-containing salt; and c) contacting the aqueous solution with carbon dioxide under one or more precipitation conditions to produce a precipitation material comprising calcium carbonate, including vaterite, and an aqueous supernatant solution.

The invention discloses an ionic rare earth separation high ammonium salt wastewater treatment method, which comprises: adding ammonia water and xanthate to wastewater, carrying out solid-liquid separation, continuously adding phosphate to the liquid, and carrying out solid-liquid separation to obtain impurity-removed wastewater; carrying out evaporative crystallization on the waste water after impurity removal until the volume is reduced to 10-30%, and then carrying out solid-liquid separation to obtain an ammonium chloride product and crystallization mother liquor; and combining the crystallization mother liquor with the high ammonium salt wastewater, and repeating the steps. The invention aims to provide the method for recycling the southern ionic rare earth separation high ammonium salt wastewater, which is simple in process, low in operation cost and good in product quality.

A system for recovering ammonia from an endothermic reaction in a subsurface formation may comprise a subsurface formation; a wellbore fluidly connected to the subsurface formation; a tubing string positioned within the wellbore, wherein the wellbore and an exterior of the tubing string together define a wellbore annulus; a wellhead comprising one or more injection lines and one or more return lines fluidly connected to the wellbore; one or more fluid injection pumps configured to supply an endothermic fluid composition to the subsurface formation through the one or more injection lines and the tubing string, the endothermic fluid composition operable to form ammonia when reacted; and one or more ammonia retention vessels fluidly connected to the return lines for receiving the ammonia through the wellbore annulus.

The invention provides an integrated preparation method of lithium iron phosphate, and belongs to the technical field of preparation of lithium iron phosphate materials. The method comprises the following steps: adding a proper amount of FeCl2 solid into FeCl2 waste liquid, mixing, and concentrating; introducing Cl2, oxidizing the FeCl2, and filtering to remove impurities, so as to obtain a high-purity FeCl3 solution; the filter residues are transferred to a building material factory to be manufactured into building materials; the method comprises the following steps: pumping a high-purity FeCl3 solution, a NH4H2PO4 solution and NH3.H2O into an overflow crystallization reaction kettle for reaction, and filtering and countercurrent washing after reaction slurry overflows to obtain a FePO4. 2H2O solution; performing triple-effect evaporative crystallization on the wastewater to obtain an NH4Cl by-product, and transferring the NH4Cl by-product to a chemical fertilizer plant to prepare a fertilizer; transferring the FePO4. 2H2O solution into a turnover tank, and carrying out concentration treatment on the FePO4. 2H2O solution; transferring into a stirring kettle, and adding lithium carbonate and glucose; and carrying out continuous drying, sintering and grading treatment.

This invention relates to a method for the resource utilization of ammonia-containing waste generated during beryllium smelting, belonging to the technical field of wastewater and waste residue treatment and resource utilization. The method includes: mixing aluminum ammonium vanadium slag with beryllium washing wastewater; mixing the resulting aluminum ammonium vanadium beryllium solution with a calcium-containing transforming agent to obtain aluminum-calcium slag and aluminum ammonium vanadium purified solution; mixing solution A with beryllium precipitation wastewater and adding a calcium-containing alkaline substance to obtain a conditioning solution and gypsum slag; adding a decalcifying agent to the conditioning solution for precipitation and decalcification to obtain decalcified slag and decalcified solution; stripping the decalcified solution to obtain ammonia water and ammonia stripping mother liquor; solution A is an aluminum ammonium vanadium beryllium solution and / or aluminum ammonium vanadium purified solution; or, mixing the aluminum ammonium vanadium purified solution with beryllium precipitation wastewater and evaporating and crystallizing to obtain ammonium salts. This method fully utilizes the ammonia resources in the ammonia-containing waste generated during beryllium smelting, preparing ammonium salts or ammonia water, achieving full recycling of ammonia nitrogen in the production process.

The present application belongs to the technical field of inorganic salt separation and purification, and discloses a method for purifying ammonium chloride solution, aiming to solve the technical problem that the prior art cannot effectively separate ammonium ions and sodium ions. The method comprises: S1, purifying agricultural-grade ammonium chloride solution containing sodium ions through a first membrane system to obtain a first permeate and a first retentate, wherein the separation layer surface of the first special membrane is electronegative; S2, secondly purifying the first permeate through a second membrane system; and S3, obtaining product ammonium chloride solution and reusable fresh water through a product recovery system from the second permeate. The present application utilizes the electronegativity of the membrane surface and the differential interface interaction of different monovalent cations to realize the preferential permeation of ammonium ions and the effective retention of sodium ions. The method does not need to adjust the pH value or heat the raw material solution, has a simple process, low energy consumption, and can obtain ammonium chloride products with a purity of more than 99.5%.

The invention relates to a production method and device for preparing ammonium / alkali through a microreactor, and belongs to the technical field of safety, environmental protection, energy conservation and water conservation. The method comprises the following steps: simultaneously feeding a saturated aqueous solution of sodium chloride and a sodium bicarbonate solution into a mixing zone for premixing, and feeding into a reaction zone for reaction through shunting to obtain a reaction mixed solution; crystallizing, filtering, washing and drying the reaction mixed solution to obtain sodium bicarbonate; performing crystallization, chemical sublimation, precipitation and recrystallization on the mother liquor obtained by filtering to obtain ammonium chloride, and recovering ammonia gas generated in the crystallization, chemical sublimation, precipitation and recrystallization processes of the mother liquor; calcining the sodium bicarbonate to obtain sodium carbonate, and recovering carbon dioxide released in the calcining process; the recovered ammonia gas, carbon dioxide and water are prepared into a sodium bicarbonate solution to be used as a reaction base solution. According to the invention, liquid-gas reaction is improved into liquid-liquid reaction, and the microreactors connected in series and in parallel are improved, so that the yield and purity of the product are improved.

The present application relates to the harmless treatment field of chemical waste liquid, and particularly discloses a device and method for solving the problem of excessive production of hydrochloric acid in the treatment process of trichloro-sucrose waste liquid, wherein the hydrogen chloride and ammonia gas in the flue gas after denitration are reacted in a gas-gas reactor to generate ammonium chloride, and the by-product of ammonium chloride is separated through heat exchange, trapping and other steps, and the considerable reaction heat is ingeniously used to generate steam for use in the workshop, so that the problems of excessive production of hydrochloric acid and corrosion of the device are solved, the water is used instead of liquid caustic soda in the flue gas purification step, the pollution treatment cost and difficulty are further reduced, and important economic benefits and environmental protection benefits are achieved.

A process and a chemical production unit for producing crystalline ammonium chloride in the presence of a crystallization additive are provided, wherein the process comprises the steps a) reacting NH3 and HCl by feeding NH3 and HCl to an aqueous solution of ammonium chloride; b) crystallizing ammonium chloride from the aqueous ammonium solution obtained in step a), and c) separating the crystalline ammonium chloride, wherein energy required in step b) is generated in step a). The crystalline ammonium chloride, obtainable by said process, is suitable as a flavoring agent, as an animal feed additive, as an additive for a cosmetic composition or as an additive for a pharmaceutical composition.

The invention provides a carbon dioxide energy storage system combined with a magnesium oxide and ammonium chloride co-production system and a control method thereof, and belongs to the technical field of energy storage. The carbon dioxide energy storage system comprises a compression energy storage module, a liquid storage container, an expansion power generation module and a gas storage which are sequentially connected in a closed loop mode, and further comprises a waste heat utilization module. The waste heat utilization module is configured to be capable of absorbing waste heat in flue gas generated by the magnesium oxide production subsystem and waste heat of carbon dioxide separated by the flue gas treatment subsystem, and is configured to be capable of supplying heat to the expansion power generation module in an energy release stage; the gas storage is configured to be capable of temporarily storing gaseous carbon dioxide separated from the flue gas generated by the flue gas treatment subsystem from the magnesium oxide production subsystem; the carbon dioxide energy storage system is configured to be capable of compressing and condensing gaseous carbon dioxide in the gas storage in the energy storage stage, and liquid carbon dioxide is stored in the liquid storage container. The carbon dioxide energy storage system can improve the waste heat utilization rate and reduce the overall cost.

The invention discloses a method for efficiently extracting and recycling chloride ions in desulfurization wastewater, and belongs to the technical field of industrial wastewater treatment and recycling. The method comprises the following steps: firstly, constructing a composite extraction system which takes tertiary amine N235 as a main extraction agent, n-decanol as a modifier and a mixed solution of kerosene and benzene as a diluent; then, the desulfurization wastewater is subjected to multi-stage extraction, and the chloride ion removal rate is stabilized at 68.9%-69.4%; after extraction, ammonia water is used as a back-extraction agent to carry out back extraction on an organic phase loaded with chloride ions, the back-extraction rate can reach 90% or above, and the organic phase can be recycled. The extraction system disclosed by the invention has strong anti-interference capability on common cations such as Ca < 2 + >, Mg < 2 + > and Na < + > in wastewater, solves the problems of low extraction efficiency, poor stability and high cost in the prior art, and is simple in process flow and suitable for industrial application.

A system for recovering ammonia from an endothermic reaction in a subsurface formation may comprise a subsurface formation; a wellbore fluidly connected to the subsurface formation; a tubing string positioned within the wellbore, wherein the wellbore and an exterior of the tubing string together define a wellbore annulus; a wellhead comprising one or more injection lines and one or more return lines fluidly connected to the wellbore; one or more fluid injection pumps configured to supply an endothermic fluid composition to the subsurface formation through the one or more injection lines and the tubing string, the endothermic fluid composition operable to form ammonia when reacted; and one or more ammonia retention vessels fluidly connected to the return lines for receiving the ammonia through the wellbore annulus.

The invention belongs to the technical field of industrial solid waste recycling and environmental protection, discloses a red mud total recycling and innocent treatment method based on material internal circulation, and solves the problem of high dependence degree on external materials in the current red mud treatment process. The method comprises the following steps: calcining red mud and then performing acid leaching; adding sodium carbonate while heating the pickle liquor to co-precipitate iron and aluminum in one step, and collecting CO2; washing the precipitate to obtain iron-aluminum concentrate and a sodium chloride solution; cO2 is introduced into a NaOH solution to prepare sodium carbonate; the sodium chloride solution is converted into NaHCO3 and NH4Cl through a Hou's alkali preparation method, and NaHCO3 is calcined to obtain Na2CO3 and CO2; regenerating NaOH from the Na2CO3 solution through a causticization method; and extracting silicon from acid leaching residues by using regenerated NaOH to produce white carbon black. The method disclosed by the invention fundamentally avoids the generation of high-salinity wastewater, synchronously and efficiently recovers iron, aluminum, silicon and sodium resources, and has remarkable economic and environmental benefits.

The invention relates to a preparation method of bis [3-(triethoxysilyl) propyl] amine, and belongs to the technical field of chemical synthesis. According to the preparation method of the bis [3-(triethoxysilyl) propyl] amine, 3-chloropropyltriethoxysilane and 3-aminopropyltriethoxysilane are subjected to a substitution reaction, liquid ammonia is introduced for a reaction, the 3-aminopropyltriethoxysilane is replaced out for recycling, generated ammonium chloride salt can be filtered and removed, and the bis [3-(triethoxysilyl) propyl] amine is obtained. The filtrate is subjected to reduced pressure distillation to obtain a high-quality bis [3-(triethoxysilyl) propyl] amine product, the chromatographic content is as high as 99%, and the product quality can be effectively improved. Wherein the 3-aminopropyltriethoxysilane can be recycled and reused, and the production requirements of green, economic and environment-friendly effects are met. The raw materials are wide in source and convenient to obtain, the conversion rate is high, the reaction is simple, and the productivity can be effectively improved.

The invention discloses a salt lake brine comprehensive recovery method and system, and belongs to the technical field of salt lake resource utilization. The method comprises the following steps: performing ammonia precipitation reaction on salt lake brine and an ammonia precipitator, and then filtering and washing to obtain Mg (OH) 2 and ammonia precipitation filtrate; carrying out dehydration and roasting treatment on Mg (OH) 2 to obtain an active MgO product; introducing carrier gas into the ammonia precipitation filtrate under a negative pressure condition to perform deamination treatment, and crystallizing and drying the deaminated filtrate to obtain an ammonium chloride product; and returning ammonia gas recovered by deamination treatment to an ammonia precipitation reaction section for cyclic utilization, and recycling water obtained by crystallization and drying to a filtering and washing section for cyclic utilization. The method provided by the invention has the advantages of short process flow, low energy consumption, continuous production, increased yield, no generation of waste liquid and waste residue, and no environmental pollution, realizes efficient preparation and recovery of active magnesium oxide and ammonium chloride, and realizes efficient utilization and zero emission of salt lake brine.

The present disclosure relates to a method of carbon dioxide mineralisation, the method comprising: treating a material, such as a mineral, with carbon dioxide and a base, wherein the treatment occurs in solution phase, the material comprising: a first cation that is Ca or Mg; a second cation which is not Ca and or Mg; and one or more anions which are not carbonate; such that a product solution comprising an acid or a salt of the base and one of the one or more anions and a salt of the second cation and one of the one or more anions is formed, and a carbonate salt of the first cation is caused to precipitate.

The application discloses a kind of based on ammonium salt leaching agent cycle's smelting slag efficient low-consumption leaching method, belong to metallurgical solid waste resource utilization technical field.Water leaching is carried out to smelting slag, and the obtained water leaching residue is subjected to multistage countercurrent leaching using ammonium salt solution to obtain calcium-rich leaching solution, and the calcium-rich leaching solution is subjected to carbon fixation reaction with excess carbon dioxide gas to generate calcium bicarbonate solution;The calcium bicarbonate solution is subjected to neutralization precipitation with the obtained water leaching solution, liquid-solid separation, to obtain light calcium carbonate and ammonium salt solution, and the obtained ammonium salt solution is recycled for multistage countercurrent leaching.The method designs an ammonium salt solution closed-loop process and a calcium carbonate open-loop process, which not only reduces the acid and alkali consumption cost in the smelting slag leaching process, but also produces high-value light calcium carbonate products, realizes the resource utilization of all components of smelting slag, reduces the processing cost of smelting slag, and provides a new way for harmless, efficient and high-value utilization of steel smelting slag.

The application relates to a method for preparing super-pure silicon nitride powder by a silicon amine group exchange method, belonging to the field of materials. In the method, hexamethyldisilazane (HMDZ) and SiCl4 are reacted in an organic solvent, the Cl atoms in the SiCl4 are removed from the reaction system in the form of a by-product (CH3)3SiCl, HMDZ and SiCl4 form [Si(NH)2] in the organic solvent, and the [Si(NH)2] is converted into [Si(CH3)3] under the action of NH3 and heating m [Si(CH3)3] n polymer; the latter forms a Si(NH)2(s) silicon amine precursor precipitate under the action of NH3 and heating, and finally, the silicon amine precursor precipitate is heated and decomposed to form super-pure Si3N4 powder. The synthesis process condition is mild, and high-pressure synthesis conditions are avoided. By adjusting the concentration of HMDZ in the organic solvent and the gas feeding rate of SiCl4, the particle size of the final silicon nitride powder can be directly controlled, and the adjustment is convenient. The cost is low, and the product purity is high.

The invention belongs to the technical field of organic fertilizers, discloses a composition for preparing matured compost and application thereof, and solves the technical problems of high nitrogen loss and poor nitrogen immobilization effect of a compost finished product in the prior art. The composition for preparing the matured compost comprises a high-carbon-nitrogen-ratio biomass raw material, a low-carbon-nitrogen-ratio biomass raw material, exogenous nitrogen, citric acid-ferrous modified biochar and a complex microbial inoculant, the C / N ratio of the high-carbon-nitrogen-ratio biomass raw material is 60-80; the C / N ratio of the low-carbon-nitrogen-ratio biomass raw material is 15-20; the complex microbial inoculant A comprises organic nitrogen mineralization promoting bacteria, TNRA functional bacteria and nitrification-denitrification inhibiting bacteria.

The application discloses a method for preparing sodium bicarbonate, co-producing potassium sulfate and ammonium chloride from sodium sulfate waste salt, which comprises the following steps: dissolving; purifying and carbonizing; separating and drying; secondary treatment; double decomposition and hydrolysis; and freezing and crystallizing. The process is short, the reaction condition is mild, no organic chemical raw material is selected, no high-temperature and high-pressure reaction is selected, the operation is easy to control, no flammable and explosive safety risk exists, all intermediate products are recycled, no sewage is generated, waste gas is discharged after being absorbed, a small amount of solid waste is from the purified sodium sulfate waste salt, no environmental protection pressure exists, no evaporation crystallization process is selected in the whole chemical reaction, energy consumption is low, secondary dissolution, low-temperature centrifugal separation and ammonium chloride hydrolysis technology are adopted, product conversion rate is high, equipment investment is small, economic benefits are good, and the method is suitable for industrialized production; the obtained product is stable in quality, the sodium sulfate waste salt is purified by using a chemical method, and the toxicity is removed, and the utilization problem of the by-produced industrial salt is effectively solved.

The preparation method comprises the following steps: firstly, adding PEG (Polyethylene Glycol) which accounts for 3% of the mass of an industrial byproduct magnesium chloride solution as a dispersing agent into the industrial byproduct magnesium chloride solution, stirring and dissolving under the ultrasonic action to obtain a mixed solution, then carrying out ultrasonic precipitation reaction, and carrying out ultrasonic precipitation reaction on the mixed solution at constant temperature to obtain the flame-retardant grade magnesium hydroxide. The preparation method comprises the following steps: under the combined action of stirring and ultrasound, dropwise adding ammonia water to carry out a precipitation reaction, then standing and curing the reacted slurry at a constant temperature, and finally carrying out solid-liquid separation, washing, drying and grinding to obtain a flame-retardant grade magnesium hydroxide product, the XRD pattern of the product is consistent with the characteristic diffraction peak of a standard magnesium hydroxide diffraction pattern, the diffraction peak is sharp and has no impurity peak, and the flame-retardant grade magnesium hydroxide product is obtained. The particle size D90 is less than or equal to 1.5 mu m, and the morphology is an irregular sheet structure which is uniformly dispersed. According to the invention, the industrial byproduct magnesium chloride is used as a raw material to prepare the flame-retardant grade magnesium hydroxide with high purity, superfine particle size and good dispersity, and high-valued utilization of the byproduct magnesium chloride is realized.

The present invention discloses a method and application of titanium extraction tailings dechlorination coupled with mineralization and CO2 sequestration to produce NH4Cl. The titanium extraction tailings and hydrochloric acid are mixed and stirred to carry out a leaching reaction to obtain a first reactant; the first reactant is separated into solid and liquid to obtain a leachate and a leach residue, which can be used as a building material. After adding ammonia water to the leachate to adjust it to a predetermined pH value, carbon dioxide is introduced to carry out a mineralization reaction to obtain a second reactant; the second reactant is subjected to solid-liquid separation to obtain a separated liquid containing NH4Cl and solid residue (CaCO3 and MgCO3); the separated liquid is evaporated, concentrated, cooled and crystallized to obtain an NH4Cl product. The present invention can not only realize the recycling of valuable elements in titanium extraction tailings, but also reduce CO2 emissions to a certain extent, while co-producing building materials, CaCO3, MgCO3 and NH4Cl and other by-products, which is of great significance to promoting the green, low-carbon and sustainable development of the steel industry.