37 results about "Double salt" patented technology

The invention discloses a method for preparing large-particle sodium bicarbonate from sodium sulfate. The method comprises the following steps: pretreating raw materials; dynamically adjusting reaction conditions; establishing a raw material database; carrying out multistage continuous crystallization reaction; heat integration and waste heat recovery; the alkali medium is recycled; the temperature gradient design is simplified; double salt crystal separation and resource utilization, and bicarbonate radical concentration control; strengthening double salt separation by a membrane separation technology; and carrying out solid-liquid separation and product collection. In a sodium sulfate raw material dissolving stage, sodium carbonate or sodium bicarbonate is added to adjust the concentration of carbonate in a solution, so that the concentration is stabilized in a target range, ATR FT-IR is used for carrying out in-situ real-time quantitative analysis on carbonate ions in an aqueous solution, carbonate is automatically supplemented through feedback control, and the content of carbonate ions in the aqueous solution is determined. A plate heat exchanger is installed in a multi-stage reaction device, waste heat of previous-stage reaction liquid is utilized to preheat next-stage reaction liquid, and heat in mother liquor is recovered by adopting a vacuum evaporation technology in salting-out crystallization.

The present disclosure provides a method for extracting rare earth elements from industrial waste and other materials. The method includes pre-treating a starting material including but not limited to materials containing coal, coal ash, and mined aggregates, combining the pre-treated starting material with a first aqueous solution comprising one or more ionic salts in a first stage reactor to form a first slurry containing double-salt crystals, separating the first slurry in a first stage separator to obtain a double salt solution and separated impurities, combining the double salt solution with a second aqueous solution in a second stage reactor to form a second slurry, and separating the second slurry in a second stage separator to obtain a purified product and a remaining aqueous solution. The method enables efficient extraction of rare earth elements from industrial waste materials while producing a purified product.

This invention discloses a system for producing ammonium sulfite using electrolytic manganese ammonium sulfate double salt. The system includes a drum high-temperature drying device. The electrolytic manganese ammonium sulfate mixture output from the drum high-temperature drying device is fed into a crushing device via an elevator. The electrolytic manganese ammonium sulfate mixture output from the crushing device is fed into an anaerobic calcining furnace. A three-stage electrostatic precipitator is connected to the rear end of the anaerobic calcining furnace. The exhaust gas, after dust removal by the three-stage electrostatic precipitator, is sent to a multi-stage absorption and conversion tower via an exhaust gas pipeline. The conversion liquid and the completed absorption liquid after passing through the multi-stage absorption and conversion tower are sent to an evaporation device. This system and method for producing ammonium sulfite using electrolytic manganese ammonium sulfate double salt improves the calcination effect through pretreatment such as drying and crushing, and ultimately converts the ammonium sulfate into sulfur dioxide through anaerobic calcination to prepare ammonium sulfite. The difference lies in the direct blending and calcination method used in domestic and international processes.

The invention provides a preparation method of ammonium ferrous sulfate, and relates to the technical field of inorganic salt preparation.The preparation method of the ammonium ferrous sulfate comprises the following steps that raw materials of iron and a sulfuric acid solution are taken and mixed for a reaction, and a ferrous sulfate solution is obtained; adding solid ammonium sulfate into the ferrous sulfate solution to obtain an ammonium ferrous sulfate solution; and taking the ammonium ferrous sulfate solution, filtering impurities, taking filtrate, and performing evaporative crystallization to obtain ammonium ferrous sulfate. Ferrous sulfate reacts with ammonium sulfate to form double salt ammonium ferrous sulfate, and since the electron configuration is affected by a ligand field, the electron configuration of ferrous iron in the double salt is not easy to oxidize due to the influence of the ligand field, and the ferrous iron is not easy to oxidize even if the ferrous iron is fully contacted with air in the filtering process; the method has the advantages that oxidation of ferrous ions is reduced, the impurity content is reduced, the product purity and the batch stability are improved, additional secondary purification treatment is not needed, and the technological process is simplified.

This invention relates to a method for recovering ammonium components during the production of sodium bicarbonate from sodium sulfate, belonging to the field of chemical production technology. The recovery method includes: pretreating a crystallization mother liquor containing sodium sulfate, ammonium sulfate, ammonium bicarbonate, and diammonium carbonate, then mixing it with sodium sulfate and crystallizing to obtain a liquid-solid mixture; separating fine particles from coarse crystals in the liquid-solid mixture to obtain a coarse crystal slurry and a slurry containing fine particles, respectively; performing solid-liquid separation on the obtained coarse crystal slurry to obtain a double salt and a filtrate; and mixing the obtained double salt with a solution for washing to obtain solid sodium sulfate and a solution of ammonium sulfate. The recovery method provided by this invention has advantages such as a short process flow, simple operation, and no environmental pollution risk. This method not only avoids high-temperature ammonia stripping and low-temperature freezing processes, reducing investment and operating costs and energy consumption, but also improves the ammonia recovery rate and enhances raw material utilization efficiency.

The application provides a low-grade high-silicon type niobium concentrate sulfuric acid smelting method and belongs to the field of niobium metallurgy. The application uses an activator, concentrated sulfuric acid and low-temperature roasting to convert niobium minerals into water-soluble salts and convert rare earth minerals into water-insoluble double salts. After roasting, the minerals are water-immersed to separate niobium from rare earth, silicates and other insoluble impurities. The niobium leaching solution is treated by a small amount of HF to remove impurities, and then is treated by TBP extraction, back extraction and heat treatment to obtain a niobium oxide product with a purity of more than 99%. The rare earth-containing filter residue can be treated by an alkali solution to obtain a rare earth hydroxide, and then is treated by hydrochloric acid leaching, extraction and carbon precipitation process to obtain a rare earth carbonate product. The application solves the problems of low niobium leaching rate of Baotou low-grade high-silicon type niobium concentrate and industrialization of sulfuric acid smelting, and has the advantages of simple process, high element yield, low production cost, energy saving and emission reduction.

The invention provides a particle size control method of perchlorate-based energetic double salt. The particle size control method comprises the following steps: step 1, preparing a solution; step 2, granularity control crystallization: directly pumping the perchlorate-based energy-containing double salt solution into a sample collection bottle according to a set feeding rate through a feeding pump, and meanwhile, introducing inert gas into the sample collection bottle according to a set gas flow rate through a pipeline gas flow regulator to carry out gas flow disturbance on the perchlorate-based energy-containing double salt solution, and stirring and dispersing the perchlorate-based energetic double salt in the solvent in the sample collection bottle, crystallizing, aging, filtering, washing and drying, and collecting to obtain the perchlorate-based energetic double salt with controlled particle size. According to the granularity control method, reaction parameters and conditions are easy to control stably, and the method is particularly suitable for preparing the ultrafine DAP-4 energetic material through crystallization.

A simple and efficient method for preparing high-purity rubidium chloride includes the following steps: Adding crude rubidium salt to glacial acetic acid, heating and stirring to dissolve, filtering to remove insoluble impurities, yielding a crude rubidium salt solution in glacial acetic acid; adding a certain amount of antimony trichloride solution to the crude rubidium salt solution in glacial acetic acid, stirring the reaction to obtain a small amount of pale yellow precipitate and solution until the reaction reaches equilibrium, yielding a clear liquid and precipitate, the precipitate being used to prepare high-purity cesium salt; secondary precipitation: adding a certain amount of tin tetrachloride solution in glacial acetic acid to the clear liquid, stirring the reaction to obtain a white precipitate and solution; standing, filtering, and washing: cooling and standing the solution until the reaction reaches equilibrium, filtering, washing the precipitate with glacial acetic acid, yielding a precipitate and washing liquid; double salt decomposition: adding high-purity water to the precipitate to form a slurry, then adding ammonia to adjust the pH value, filtering to obtain tin hydroxide precipitate and rubidium chloride solution; sending the filtrate for testing: evaporating the qualified rubidium chloride solution to dryness, calcining to obtain rubidium chloride; recrystallization: obtaining the high-purity rubidium chloride product. It has the advantages of effectively removing cesium ions from crude rubidium salt and avoiding the influence of alkali metal ions on the purity of the final product, without loss, and with high product purity.

The invention belongs to the technical field of industrial solid waste treatment, and particularly relates to a harmless conversion treatment method of ardealite, which comprises the following steps of: preparing potassium ammonium gypsum solid solution double salt from ardealite, K2SO4 and (NH4) 2SO4 through a one-step synthesis process, and mutually replacing K < + > and NH4 < + > in any proportion to form a continuous solid solution in a crystallization process by utilizing the characteristics that the K < + > and the NH4 < + > are similar in ion radius and coordination; and constructing a stable double salt structure together with Ca < 2 + >, SO4 < 2-> and crystal water. The solid solution double salt can slowly release K < + > and NH4 < + > in soil, the potassium-ammonium ratio of the product is regulated and controlled by adjusting the ratio of K2SO4 to (NH4) 2SO4, the differentiated requirements of different crops on nutrients are met, a solid-liquid quantitative model is established based on a quaternary system phase diagram, a mother liquor circulation production process is performed, it is ensured that the system is stably located in a solid solution double salt crystalline region, the purity and consistency of the product are guaranteed, and the quality of the product is improved. And high-valued conversion and large-scale consumption of the phosphogypsum are realized.

The application discloses a method for preparing two-dimensional metal nitride by using bulk metal oxide powder, which comprises the following steps: 1) uniformly mixing and grinding metal oxide powder with alkali metal carbonate or alkali metal hydroxide; adding neutral alkali metal or alkali earth metal halide salt, and uniformly mixing and grinding again; 2) performing heat preservation reaction on the mixture obtained in the step 1) under ammonia atmosphere, and cooling; 3) performing acid washing on the reaction product obtained in the step 2), washing to neutral, performing suction filtration and centrifugation, and drying, so as to obtain two-dimensional metal nitride in nanosheet shape. The application firstly proposes a method for preparing two-dimensional metal nitride nanosheet by using alkaline-neutral mixed double salt as an auxiliary, and the alkali metal carbonate or alkali metal hydroxide is used as a reactant to synthesize an intermediate of alkali metal oxide with two-dimensional layer-like structure, and the neutral alkali metal or alkali earth metal halide salt is used as a molten salt auxiliary agent to promote the nitridation conversion of the alkali metal oxide. The method is suitable for preparing two-dimensional niobium nitride by using bulk niobium oxide, two-dimensional tungsten nitride by using bulk tungsten oxide, and two-dimensional molybdenum nitride by using bulk molybdenum oxide, and is related to a simple process and low cost.

The invention discloses a system and a method for prolonging operation of a carnallite crystallization device. The system comprises a carnallite crystallization device, a water inlet of the carnallite crystallization device is connected with a high-salinity water pipeline, and the carnallite crystallization device is configured to separate a saturated salt solution and secondary steam from the high-salinity water; the vacuum crystallization device is connected with an outlet of the carnallite crystallization device, the vacuum crystallization device is configured to pump out secondary steam, the vacuum device comprises a gas return pipeline, and the gas return pipeline is connected with a connecting pipeline between the carnallite crystallization device and the vacuum crystallization device; and the rotary drum drying device is connected with the carnallite crystallization device, and the rotary drum drying device is configured to pump out the saturated salt solution and separate salt in the saturated salt solution. Through cooperation of the vacuum crystallization device and the rotary drum drying device, the operation time of the carnallite crystallization device can be effectively prolonged, the maintenance and shutdown cost of the carnallite crystallization device can be reduced, and the environmental protection property of heavy salt water treatment can be improved.

The invention discloses a room-temperature curing water-based ceramic-based heavy-duty coating, and belongs to the field of anticorrosive coatings. The coating is composed of a component A and a component B, and is characterized in that the component A is composed of an isocyanate group-containing oligomer, dihydric phosphate, phosphate, phosphoric acid, a pigment filler, water and an auxiliary agent; and the component B is composed of an amino-containing oligomer, an oxide, a hydroxide, a pigment filler, water, a pH value regulator and an auxiliary agent. According to the component A and the component B, dihydric phosphate, phosphoric acid and metal hydroxides or oxides are subjected to an acid-base reaction to form amorphous phosphate double salt which serves as a main film forming substance of a coating, the metal hydroxides and oxides are excessive, and the residual metal hydroxides or metal oxides and pigments and fillers form pigments and fillers of the coating. And a heavy anti-corrosion coating system is jointly constructed. The prepared coating has excellent salt mist resistance, water resistance, brine resistance, condensation resistance and the like, and has an excellent protection function on a metal base material.

The invention relates to a double salt separation device and method, in particular to a sodium ammonium sulfate double salt separation device and method. In order to overcome the defects that in the prior art, energy consumption for separating sodium sulfate and ammonium sulfate from sodium ammonium sulfate double salt is too high, the separation cost is high, and industrial production is not facilitated, the sodium ammonium sulfate double salt separation device comprises a sodium sulfate crystallization system, a cooling crystallization system, an ammonium sulfate crystallization system and a heat pump system; a refrigerant is arranged in the heat pump system and used for coupling heat generated by cooling of the cooling crystallization system with heat needed by the sodium sulfate crystallization system and the ammonium sulfate crystallization system, and meanwhile a large amount of heat generated by state changes of the refrigerant is used for reducing energy consumption of the system. Meanwhile, the invention also provides a sodium ammonium sulfate double salt separation method based on the device.

The invention belongs to the field of rare earth metallurgical metals, and provides a rare earth scandium recovery treatment process which comprises the following steps: carrying out acid leaching on scandium-containing waste residues to obtain acid leaching mother liquor; mixing ammonium sulfate, an acid solution and the acid leaching mother liquor to obtain ammonium scandium sulfate double salt coarse precipitate; and the ammonium scandium sulfate double salt coarse precipitate is subjected to acid pickling, metal impurities are removed, and a rare earth scandium product is obtained. Aiming at the problem that ammonium scandium sulfate as a soluble precipitate is not beneficial to high-efficiency recovery of scandium, the recovery treatment process provided by the invention uses ammonium sulfate and an acid solution for precipitation, can control the acidity in a reaction system and the corresponding relationship between ammonium ion concentration and ammonium scandium sulfate solubility, and can effectively improve the ammonium scandium sulfate precipitation rate to 99% or above; and impurities such as U, Th, Fe, Na and Cu can be effectively washed away, so that a rare earth scandium intermediate product with relatively high purity is prepared, and efficient recovery of scandium resources is realized.

The present disclosure relates to a double salt, a preparation method therefor, and a pharmaceutical composition containing same. More specifically, the present disclosure relates to a double salt consisting of magnesium ions, monovalent metal cations, phosphate ions, optional hydrogen phosphate ions, and optional hydroxide ions. The present disclosure further relates to a method for preparing the double salt, a pharmaceutical composition containing the double salt, a kit containing the pharmaceutical composition, the use of the double salt in the preparation of a drug for reducing the level of ammonia and / or ammonium ions and / or urea in the blood and / or digestive tract of a subject and preventing and / or treating a disease or condition associated therewith, and a method for preventing and / or treating a related disease or condition.

The invention discloses a method for preparing a hydrotalcite-like adsorbent from electrolytic manganese crystal double salt, and relates to the field of solid waste resource utilization. The method comprises the following steps: firstly, crushing the electrolytic manganese crystal double salt, dissolving the crushed electrolytic manganese crystal double salt in a reactor under set conditions, and adding aluminum salt and magnesium salt into a reaction system according to a set proportion to obtain a mixed solution; secondly, adding a set amount of water into a reactor, simultaneously adding alkali liquor and the mixed solution obtained in the first step into the reactor through a pump, controlling the pH value of the solution in the adding process, aging under set reaction conditions after the addition is finished, and carrying out solid-liquid separation after the aging is finished; and drying the obtained precipitate to obtain the magnesium-aluminum-manganese-based hydrotalcite-like adsorbent. The adsorbent can efficiently adsorb and remove low-concentration pollutants such as fluorine, phosphorus, cobalt and nickel in water. And finally, the filtrate obtained by solid-liquid separation can be separated to obtain an ammonium sulfate product after being evaporated and concentrated, and the evaporated liquor can be used for dissolving the next batch of electrolytic manganese crystal double salt. Compared with other electrolytic manganese crystal double salt recycling methods, the method has the advantages that the hydrotalcite-like adsorbing material is prepared through a directional regulation and control layered structure assembly process, high-value conversion of waste is achieved, the technical limitation that only element separation and low-added-value conversion are focused in traditional double salt recycling is broken through, and the method has the advantages of being low in cost, easy to operate and the like; and meanwhile, high-quality utilization of metals such as magnesium and manganese in the electrolytic manganese crystallization double salt can be realized, and the ammonium salt in the electrolytic manganese crystallization double salt can be prepared into a qualified ammonium sulfate product.

The invention relates to the technical field of metallurgy, in particular to a method for improving the leaching rate of clinker lithium. According to the leaching method, water washing is adopted in the immersion cleaning stage, acid washing is adopted in the leaching stage, under the condition that most lithium sulfate in the clinker can be leached out by water, insoluble lithium potassium sulfate double salt in the clinker is further dissolved through sulfuric acid leaching, and therefore the leaching rate of clinker lithium is increased. Wherein the dosage of the sulfuric acid can be determined according to an experimental formula, namely the total molar dosage of the sulfuric acid is 0.2 * molar weight of lithium in the clinker + 0.2 * molar weight of potassium in the clinker + 0.03 molar weight of sodium in the clinker. 10% dilute sulfuric acid is prepared according to the total molar weight of sulfuric acid to serve as leaching acid liquor, experiments confirm that the filtering performance of a filter cake is not obviously influenced when 10% acid is adopted as washing liquor, a good washing effect can be guaranteed, leaching liquor and the washing liquor are separated and purified respectively, and the treatment cost and loss of lithium in the solution can be reduced.

The invention discloses a reversible aqueous zinc-based electrolyte and a preparation method and application thereof, and belongs to the technical field of aqueous electrolytes. The invention discloses a preparation method of a reversible aqueous zinc-based electrolyte, which comprises the following steps: adding double salts into a mixed solvent, and uniformly stirring to obtain the reversible aqueous zinc-based electrolyte, wherein the double salt is a mixed salt of zinc trifluoromethanesulfonate and zinc acetate; the mixed solvent is a mixed solution of water and polyethylene glycol. When the reversible aqueous zinc-based electrolyte prepared by the method is applied to a zinc-copper battery, the technical problem that the stability and high discharge depth reversibility of a zinc metal anode are difficult to realize by the existing electrolyte is solved.

The invention relates to a method for preparing aluminum sulfate from an iron-containing aluminum sulfate solution, and belongs to the technical field of inorganic chemical processes and industrial waste recycling. The method comprises the following steps: carrying out double salt reaction on an iron-containing aluminum sulfate solution and an ammonium source, crystallizing, and separating out aluminum ammonium sulfate double salt crystals and crystallization mother liquor; when the concentration of Fe < 3 + > in the iron-containing aluminum sulfate solution is greater than 0, firstly carrying out ferric iron reduction by adopting a reducing agent and then carrying out double salt reaction; at the starting moment of the double salt reaction, the molar ratio of total NH4 < + > in the solution to Al < 3 + > in the solution is (0.8-2): 1; and roasting the aluminum ammonium sulfate double salt crystal to remove ammonium to obtain aluminum sulfate and roasting gas. According to the method, an iron removal and crystallization separation process including reduction of ferric iron, addition of an ammonium source, double salt crystallization and roasting for ammonium removal is adopted, so that the content of key iron impurities in formed anhydrous aluminum sulfate crystals is lower than 0.01%.

The invention discloses a preparation method of modified ammonium perchlorate triethylene diamine perchloric acid double salt. According to the disclosed scheme, K < + > or NO3 <-> is doped in DAP-4, so that the sensitivity of DAP-4 is reduced, and the modified ammonium perchlorate triethylene diamine perchloric acid double salt is prepared. The doped perovskite energetic compound DAP-4 belongs to a heat-resistant explosive, and plays an important role in the fields of oil exploration and civil industry.

The application provides a high-impurity salt mine sediment void oil storage injection and production operation parameter optimization device and method, the device comprises a transparent heat-insulating pressure-resistant safety box, an acrylic salt cavity, an oil injection and production assembly, a brine injection and production assembly, an air compression assembly, a temperature regulation assembly and a sealing assembly, can simulate the whole process of sediment void oil storage injection and production of a salt cavity and a double salt cavity (U-shaped cavity) of a salt mine, can realize the whole process of injection and production of different sediment gradations, different oil injection / brine injection rates and pressures, and different ground temperature conditions, can obtain the oil injection and production rates and brine injection and production rates under different injection and production conditions and the sediment void oil storage recovery rate, can obtain the oil / brine / gas displacement micro-flowing conditions in the sediment void, so as to determine the sediment void oil storage volume and oil storage capacity of the salt mine, and establish the sediment oil storage injection and production operation adjustment parameters. The application can simulate the injection and production working conditions in the real underground salt cavity, realize the whole process control of the sediment void oil storage, and explore the feasibility of the oil production by gas injection.

The invention discloses a garden clearing rapid solidification primer and a preparation method thereof, and relates to the technical field of fireworks and firecrackers. A halogen powder-composite coagulant ion acceleration system and a magnesium-based composite active powder hydration catalysis system cooperate, magnesium chloride and calcium-magnesium double salt provide a sufficient ion source, and the rapid solidification primer is prepared; nano calcium carbonate is used as a nucleating agent to induce rapid growth of crystals, high activity of light calcined magnesia accelerates a hydration reaction, sodium borate catalyzes the reaction and forms a stable complex with a hydration product, the mechanism radically solves the problem of single curing mechanism in the prior art, and ion acceleration and hydration catalysis are realized. Insufficient strength caused by pure dependence on magnesium chloride is avoided, and magnesium-based component halogenation is inhibited through complex reaction, so that a cured product is compact in structure, and the moisture regaining and caking phenomena are completely eradicated.

The application discloses a method for removing impurities and recycling potassium resources from an alumina production system, and belongs to the technical field of non-ferrous metallurgy and resource comprehensive utilization. In view of the problem that potassium impurities in the circulating lye in the Bayer alumina production process continuously accumulate, and affect the production stability and alkali consumption, the application introduces sodium sulfate into the alkaline solution of the system, and through accurate control of the reaction temperature, alkali concentration and crystallization time, the potassium, sodium and sulfate ions in the solution are selectively combined, and the potassium sodium sulfate double salt solid is crystallized and separated out, so that the product is obtained after solid-liquid separation. The liquid is returned to the main process of the alumina after being purified by evaporation, the separated impurity salt is treated by causticization, and a reaction system is formed with the circulating mother liquor. The application has the advantages of simple process, effective connection with the existing alumina production line, impurity purification and valuable element extraction of the alumina system, and environmental and economic benefits.

This invention provides a film-forming material, a film-forming slurry, a spray coating, and a spraying component. A coating is formed using a film-forming material containing particles of a crystalline phase comprising rare earth element fluorides, particles of a crystalline phase comprising rare earth element oxides, and particles of a crystalline phase comprising rare earth element ammonium fluoride double salts; or, the film-forming material contains particles of a crystalline phase comprising rare earth element fluorides and particles of a crystalline phase comprising rare earth element oxides and a crystalline phase comprising rare earth element ammonium fluoride double salts. If a spray coating is formed using the film-forming material or the film-forming slurry, a rare earth element oxyfluoride spray coating can be formed without excessive heat. Therefore, even under atmospheric conditions, oxidation reactions caused by spraying heat are suppressed, resulting in a rare earth element oxyfluoride spray coating with low levels of rare earth element fluorides and rare earth element oxides. Furthermore, coating peeling caused by excessive heat can be suppressed.

The invention discloses fluoro aromatic hydrocarbon and a preparation method thereof, and belongs to the technical field of organic synthesis. The preparation method of the fluoro-aromatic hydrocarbon comprises the following steps: S1, mixing and grinding potassium fluoride and part of anhydrous dipotassium phosphate to obtain powder A; continuously adding part of anhydrous dipotassium phosphate, mixing with the powder A, and grinding to obtain powder B; continuously adding the residual anhydrous dipotassium phosphate and the powder B, mixing and grinding to obtain double salt; and S2, adding the double salt obtained in the step S1 and a nitro-aromatic hydrocarbon substrate into a third solvent, and reacting to obtain a fluoro-aromatic hydrocarbon product. According to the preparation method provided by the invention, the yield of fluorobenzonitrile is increased, and cyclic utilization of phosphorus chemical fluorine resources is realized.

The invention discloses a method for producing baking soda and ammonium sulfate by utilizing solid treatment hazardous waste salt sodium sulfate, and belongs to the technical field of chemical engineering. The method comprises the following steps: performing high-temperature refining on the waste salt sodium sulfate, mixing the refined waste salt sodium sulfate with ammoniated mother liquor, adding mixed salt for reaction, performing salting-out crystallization, and performing cold-out crystallization; cO2 is introduced into the cold separation mother liquor, ammonium bicarbonate solids and CO2 are added into the carbonized solution, sodium bicarbonate solids and mother liquor are formed through separation, ammonia gas is introduced into the mother liquor to enter an ammoniation process, the ammoniated mother liquor is subjected to salting-out crystallization, and circulation is formed; refining the double salt I to obtain mixed salt and mixed salt mother liquor, cooling the mixed salt mother liquor to obtain double salt II and an ammonium sulfate solution, evaporating the ammonium sulfate solution to obtain ammonium sulfate, and enabling the double salt II to enter a double salt refining process for recycling. Efficient treatment and resource utilization of the industrial waste salt are achieved, the process is environmentally friendly, secondary pollution is low, and the quality of the product baking soda and ammonium sulfate is stable.

The invention relates to a preparation method and application of hypophosphorous acid double salt, and the preparation method comprises the following steps: I, adding water and various metal salts into an ultrasonic grinding reactor, and starting the ultrasonic grinding reactor to obtain metal salt slurry; iI, adding sodium hypophosphite and water into a reaction kettle for dissolving and clarifying, heating to 70-90 DEG C, adding the first batch of metal salt slurry, uniformly stirring, adding the sol, and continuously stirring and reacting for 1-2 hours; and III, after the reaction is completed, heating to 90-110 DEG C, adding a second batch of metal salt slurry, regulating the pH value of the system by using a pH buffer reagent, controlling the pH value to be 4.0-8.0, and stirring to react for 1-3 hours. According to the invention, the problems in the prior art that particles formed by agglomeration of hypophosphite crystals produced by an inorganic double decomposition synthesis method are irregular and large in particle size, so that the product is large in particle size and wide in distribution, and the flame retardance, the mechanical property and the like of the product are unfavorably influenced are solved.

The invention relates to an efficient iron removal method for a coal gangue acid process aluminum extraction solution, and belongs to the technical field of wet metallurgy purification and impurity removal. The method comprises the following steps: in the presence of an oxidizing agent, carrying out neutralization and iron precipitation on the coal gangue acid-process aluminum extraction solution, and carrying out solid-liquid separation to obtain a precipitate and a filtrate; carrying out double salt reaction on the filtrate, a reducing agent and an ammonium source, crystallizing, and separating out aluminum ammonium sulfate double salt crystals and crystallization mother liquor; at the starting moment of the double salt reaction, the molar ratio of total NH4 < + > in the solution to Al < 3 + > in the solution is (0.8-2): 1. The invention provides an iron-aluminum separation process of oxidation iron precipitation-ferric iron reduction-solution ammonium salt induced crystallization-precipitation hydrothermal transformation aiming at the problem of deep purification of iron impurities in the leaching solution for extracting aluminum from coal gangue by an acid method, so that the content of the iron impurities in the formed anhydrous aluminum ammonium sulfate double salt crystal is lower than 0.01%, and the anhydrous aluminum ammonium sulfate double salt crystal is used for subsequent production of electrolytic aluminum; and hematite with high iron content can also be obtained to be recycled as an ironmaking raw material.

The utility model provides a kind of double salt crystallization device of production sodium sulfate and ammonium sulfate, including reactor, upper cover, salt adding mechanism, cooling mechanism, reactor is sequentially divided into clear liquid section, transition section, reaction section from top to bottom, center tube is equipped in reactor, clear liquid section side is equipped with reaction liquid collection tank, reaction liquid collection tank is connected with the upper portion of center tube by pipeline, overflow pipe is equipped with in clear liquid section top side, reaction section is equipped with crystal taking port, salt adding mechanism includes salt adding circulating pump, salt adding pipe, salt adding circulating pump is arranged in upper cover center, outlet is connected with the upper end of center tube, upper cover salt adding mouth is communicated with the lower portion of center tube by salt adding pipe, cooling mechanism includes cooling circulating pump, external cooler, cooling circulating pump is arranged in upper cover, cooling circulating pump inlet passes through upper cover and extends into reactor clear liquid section, cooling circulating pump outlet is connected with the lower end of external cooler by pipeline, external cooler upper end is connected with liquid collection tank by pipeline.The utility model integrates reaction equipment, compact structure, comprehensive function.