138results about "Ammonium sulfates" patented technology

The invention relates to the technical field of preparation of nano aluminum oxide, in particular to a preparation method of high-purity nano aluminum oxide, which comprises the following steps: dissolving aluminum ammonium sulfate in high-temperature hot water, filtering, recrystallizing, drying the recrystallized aluminum ammonium sulfate to remove moisture to obtain dried aluminum ammonium sulfate, and roasting the dried aluminum ammonium sulfate at high temperature to obtain the high-purity nano aluminum oxide. The preparation method comprises the following steps: calcining the alumina powder, decomposing to generate alpha-Al2O3 nano-alumina, simultaneously releasing ammonia gas and sulfur dioxide gas, introducing the ammonia gas and sulfur dioxide released in the roasting process into water through a negative pressure absorption device to generate an ammonium sulfate solution, and finally obtaining the superfine alumina powder with the particle size reaching the nanoscale. According to the method, the market value of the product is improved, ammonia gas and sulfur dioxide generated in the roasting process are absorbed to successfully generate a byproduct ammonium sulfate, and the byproduct ammonium sulfate is reused in a catalyst wet vanadium precipitation process, so that the environmental pollution is reduced, the output quality of aluminum oxide is improved, and the production loss caused by impurities is reduced, thereby improving the production efficiency and economic benefits.

The invention discloses an ammonia desulfurization system and method based on zone control. The ammonia desulfurization system comprises a desulfurization tower, an absorption circulating tank, an ammonia water tank, a rinsing tank and a process water tank. The desulfurization tower is sequentially provided with a flue gas outlet, a demisting section, a second-section absorption layer, a first-section absorption layer and a concentration section from top to bottom. A partition plate is arranged in the absorption circulating tank and divides the absorption circulating tank into an upper oxidation tank and a lower absorption circulating section. An aeration pipe is arranged in the upper oxidation tank, and the upper oxidation tank is connected with a spraying liquid inlet of the second absorption layer through a pipeline; the lower concentration section of the desulfurizing tower is connected with the oxidation tank through a liquid conveying pipeline. The water washing tank supplies water to the demisting section and the absorption circulating tank; the ammonia water tank supplements ammonia water to the oxidation tank, the first-section absorption layer and the lower absorption circulation section respectively; recycled liquid of the demisting section is connected back to the rinsing bath through a pipeline. According to the invention, absorption and oxidation are partitioned in the same tank, so that coupling interference is eliminated; two-stage absorption and demisting recovery are matched, so that ammonia escape is effectively controlled while efficient removal of sulfur dioxide is guaranteed.

The present application relates to the technical field of ammonia compound preparation, in particular to a method for preparing ammonium sulfate and co-producing sodium bicarbonate by using sodium sulfate, comprising the following steps: mixing industrial-grade liquid ammonia with deionized water to prepare ammonia water with a free ammonia concentration of 60-120 ti (ti is the abbreviation of titer, which is 1 / 20 mol / L), controlling the temperature of the mixing process to be less than or equal to 40 DEG C to avoid ammonia volatilization, pre-carbonizing by passing in CO2 under the conditions of 20-70 DEG C and a carbon dioxide pressure of 0.1-0.6 MPa, and adding sodium sulfate or a mixture of sodium bicarbonate and mirabilite to obtain a pre-carbonized liquid. The present application adopts an integrated process of pre-carbonization, clarification, carbonization, ammonia separation and low-temperature crystallization, and ammonia evaporation circulation, and can be operated continuously or intermittently, has low industrial implementation difficulty, strong running stability, separates ammonium sulfate by using ammonia separation and low-temperature crystallization technology, replaces the traditional evaporation and concentration process, combines material recycling design, and reduces the energy consumption per unit product compared with the traditional process.

The invention provides a process for the preparation of sul furic acid and minerali zation of CO2 from industrial gases, comprising : CO2- absorption step, comprising continuously sparging C02- containing gas through an aqueous solution of ammonia in a first reactor, or continuously sparging C02-containing gas and ammonia gas through water, to form [ (NH4 ) 2CO3 / NH4HCO3 ] solution; continuously withdrawing [ (NH4 ) 2CO3 / NH4HCO3 ] solution from the first reactor and providing said [ (NH4 ) 2CO3 / NH4HCO3 ] solution, after it has been optionally cooled, to a second reactor, wherein NH3 and CO2-bearing gas stream discharged from the first reactor is fed to the second reactor, thereby producing (NH4 ) 2CO3 aqueous solution in the second reactor and releasing an essentially NH3 and CO2- free gas from the second reactor; CO2-minerlai ztion step, comprising reacting the (NH4 ) 2CO3 in water with calcium sul fate [ CaSO4 ], to form a solution of ammonium sul fate [ (NH4 ) 2SO4 ] and precipitate solid calcium carbonate [ CaCO3 ], separating CaCO3 from said solution and recovering ammonium sulfate crystals from the solution; and H2SO4- format ion step, comprising thermally decomposing the (NH4 ) 2SO4 to give sul furic acid and supplying a stream of ammonia released from the thermally decomposed (NH4 ) 2SO4 to the CO2-absorption step.

The application discloses a process for preparing high-molecular-ratio cryolite and ammonium sulfate by using fluorine-containing etching waste liquid, and comprises the following steps: adding sodium metaaluminate slurry and sodium sulfate solution into the fluorine-containing etching waste liquid, then adjusting pH to be acidic by using a sulfuric acid solution, carrying out heating reaction, then carrying out centrifugal separation treatment, and drying the obtained cryolite precipitate; adding sodium metaaluminate slurry into the fluorine-containing supernatant, and obtaining defluorination filtrate by treatment; adding a sulfuric acid solution into the defluorination filtrate, carrying out neutralization reaction, then carrying out vacuum evaporation on the reaction mixture containing ammonium sulfate, carrying out centrifugal separation treatment after cooling, drying the obtained ammonium sulfate precipitate, and obtaining ammonium sulfate product. The fluorine ion in the fluorine-containing etching waste liquid can be effectively utilized, the generated cryolite product can reach the national standard of high-molecular ratio, the fluorine ion content of the generated filtrate is less, so that the filtrate can enter the synthesis of ammonium sulfate, and no waste liquid is generated in the process.

The present disclosure relates to new methods and processes of byproduct conversion, wastewater remediation, byproduct upcycling / recycling, and sustainable cyclic methods thereof.

A process for the synthesis of hydrogen by catalytic cleavage of ammonia; the process comprising the step of subjecting an ammonia-containing stream (10) to a catalytic cleavage step (11) in the presence of heat to produce a combustion gas and a hot cleavage stream (14) containing nitrogen, hydrogen and potentially residual ammonia, and optionally water; the process further comprising the step of subjecting the hot cleavage stream to a hydrogen recovery step to produce a high-purity hydrogen stream (22).

The utility model discloses a chemical waste gas treatment device, belongs to the technical field of chemical waste gas treatment, and solves the problems of low efficiency and incomplete treatment of an existing waste gas treatment method. The input end of the alkaline waste gas collecting induced draft fan is communicated with the alkaline waste gas collecting pipe, and the output end is communicated with the input end of the pickling tower. The output end of the pickling tower and the output end of the alkaline washing tower are both communicated with the input end of the biological treatment unit, the output end of the biological treatment unit is communicated with the input end of the activated carbon adsorption tower, the output end of the activated carbon adsorption tower is communicated with the input end of the air exhaust induced draft fan, and the output end of the air exhaust induced draft fan is communicated with the input end of the coal-fired boiler. The output end of the coal-fired boiler is communicated with the input end of the denitration unit, the output end of the denitration unit is communicated with the input end of the bag-type dust removal unit, the output end of the bag-type dust removal unit is communicated with the input end of the desulfurization unit, and the output end of the desulfurization unit is communicated with the input end of the cyclone. The chemical waste gas treatment device can efficiently and thoroughly treat chemical waste gas.

The present application belongs to the technical field of energy saving and consumption reduction of titanium dioxide production, and particularly relates to a method for energy saving and pollution reduction in the calcination process of sulfuric acid method titanium dioxide. The present application realizes the cascade utilization of high-temperature to medium-low-temperature waste heat through the integrated scheme of "preheating and quality improvement + oxygen-rich calcination + tail gas synergistic desulfurization and denitrification + resource utilization of by-products", that is, the calcination tail gas (1000-1100℃) is first used to generate steam for production through a waste heat boiler, and then is used for preheating and drying metatitanic acid after being cooled, thereby realizing the cascade utilization of high-temperature to medium-low-temperature waste heat, and simultaneously, the oxygen-rich combustion improves the fuel efficiency, the natural gas combustion is more sufficient, the energy consumption per unit product is reduced by 30-40%, and the ammonia method is used to simultaneously remove SO2 and NO x in a single reactor, the desulfurization efficiency is greater than or equal to 95%, the denitrification efficiency is greater than or equal to 85%, the concentration of dust in the tail gas after being removed by a bag filter is less than or equal to 10 mg / Nm3 for emission, the unity of environmental benefits and economic benefits is realized, and a new path is provided for the green upgrading of the sulfuric acid method titanium dioxide industry.

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 invention relates to the technical field of ammonia compound preparation, in particular to a method for preparing ammonium sulfate and co-producing sodium bicarbonate by using sodium sulfate, which comprises the following steps: mixing industrial liquid ammonia with deionized water to prepare ammonia water with the free ammonia concentration of 60-120ti (ti titer abbreviation, namely 1 / 20mol / L), and controlling the temperature to be less than or equal to 40 DEG C in the mixing process to avoid ammonia volatilization, cO2 is introduced for pre-carbonization under the conditions that the temperature is 20-70 DEG C and the pressure of carbon dioxide is 0.1-0.6 MPa, sodium sulfate or a mixture of mirabilite and sodium bicarbonate is added, and a pre-carbonization solution is obtained; the process adopts an integrated process of pre-carbonization, clarification, carbonization, ammoniation low-temperature crystallization and ammonia distillation circulation, can be continuously or intermittently operated, is low in industrial implementation difficulty and high in operation stability, separates ammonium sulfate through an ammoniation and low-temperature crystallization synergistic technology, replaces a traditional evaporation and concentration process, is combined with a material cyclic utilization design, and has a good industrial application prospect. The unit product energy consumption is reduced compared with the traditional process.

The utility model discloses an ammonium sulfate and monoammonium phosphate mixed solution evaporative crystallization salt separation treatment system which comprises a preheating unit, an ammonium sulfate evaporation concentration unit, an ammonium sulfate evaporation crystallization unit, a recovery heat exchange unit, an ammonium sulfate post-treatment unit, a monoammonium phosphate cooling crystallization unit, a monoammonium phosphate post-treatment unit and a carnallite treatment unit. According to the technical scheme adopted by the utility model, a mixed solution containing ammonium sulfate and monoammonium phosphate is subjected to combined treatment, so that qualified ammonium sulfate crystal salt, monoammonium phosphate crystal salt and mixed salt can be obtained, and the by-product benefit of a wastewater treatment system can be effectively improved.

The invention discloses a reactor suitable for ammonium sulfate crystallization, and relates to the technical field of ammonium sulfate crystallization. The reactor suitable for ammonium sulfate crystallization comprises a crystallization tank, a heat exchange tank communicated with the crystallization tank, and a heat exchange plate installed in the heat exchange tank and communicated with a water conveying pipe, and the crystal removal assembly comprises a crystal removal plate located outside the heat exchange plate, under the driving of the driving element, crystals formed on the surface of the heat exchange plate are scraped to become seed crystals for growth of the crystallizing tank; the temperature sensor is fixed on the crystal removal plate and is used for detecting the temperature of the surface of the corresponding heat exchange plate and providing a basis for the operation of the switching assembly; and the expansion area is fixedly mounted in the crystal removal plate, deforms under the action of external force to be adaptive to the shape of the heat exchange plate and is adaptively attached to the outline of the whole heat exchange surface, so that dead-corner-free scraping is ensured, uniform pressure is kept, and a product with high quality, uniform granularity and good fluidity can still be produced after the scraped ammonium sulfate crystals continuously grow in the main body solution.

The invention belongs to the technical field of mirabilite resource utilization, and particularly relates to a mirabilite resource utilization method based on micro-nano bubble enhanced mass transfer. The method comprises the following steps: (1) dissolving mirabilite solid waste with water or carrying out concentration treatment on mirabilite waste water to enable the concentration of sodium sulfate to be close to a saturated state so as to obtain a mirabilite solution; (2) firstly introducing ammonia gas in a micro-nano bubble form into the mirabilite solution in the step (1) to form a sodium sulfate solution system rich in dissolved ammonia, and then continuously introducing carbon dioxide in the micro-nano bubble form to carry out a crystallization precipitation reaction; (3) carrying out solid-liquid separation on the reaction material in the step (2), and washing and drying the solid phase to obtain a sodium bicarbonate product; adding sulfuric acid into the liquid phase to react to convert the dissolved sodium bicarbonate into sodium sulfate, then performing concentration-crystallization treatment on the solution to obtain an ammonium sulfate crystal product, and recycling the residual mother liquor in the step (1). According to the method, a high-purity sodium bicarbonate product and a high-purity ammonium sulfate product can be simultaneously obtained through a simple process.

The invention discloses a lithium source impurity removal method, lithium phosphate and a preparation method thereof, and belongs to the technical field of battery materials. The invention solves the problem of how to provide a method for preparing high-purity lithium phosphate from a lithium source in lithium ore. The method comprises the step of removing impurities from a lithium source, and specifically comprises the following steps: roasting lithium ore, and leaching a product obtained after roasting to obtain a lithium sulfate solution; adding one or more of ammonia water, ammonia gas or liquid ammonia into the lithium sulfate solution to adjust the pH value to 8-11, and then filtering to obtain primary purified mother liquor; adding monoammonium phosphate or / and diammonium phosphate into the primary purified mother liquor, adjusting the pH value to 8-11 again, reacting under the stirring condition, and filtering to obtain secondary purified mother liquor; and adding EDTA (Ethylene Diamine Tetraacetic Acid) into the secondary purified mother liquor to obtain the lithium sulfate purified mother liquor. And adding one or more of ammonia water, ammonia gas or liquid ammonia into the monoammonium phosphate solution to adjust the pH value to 8-11, and adding the purified lithium sulfate mother liquor into the monoammonium phosphate solution to obtain the high-purity lithium phosphate.

The application discloses a kind of green treatment recycling methods of vanadium precipitation wastewater, belong to chemical industry.Green treatment recycling methods of vanadium precipitation wastewater include the following steps: removing metal impurity ions from sodium vanadium extraction vanadium precipitation wastewater, then adding calcium oxide and passing compressed air to remove ammonia, ammonia gas generated by ammonia removal is absorbed to obtain ammonium sulfate solution, calcium sulfate is calcined to generate calcium oxide and sulfur dioxide, and further prepared sulfuric acid, after ammonia removal, the wastewater is passed into carbon dioxide to generate sodium bicarbonate, evaporation concentration is obtained sodium bicarbonate solid and condensate, and the residual concentrated slurry returns evaporation concentration process.In the process flow, the generated sodium bicarbonate returns the roasting process, the condensate returns the leaching process, the ammonium sulfate solution returns the vanadium precipitation process, and the calcium oxide returns the ammonia removal process.The green treatment recycling method of vanadium precipitation wastewater has the advantages of low cost, convenient operation, resource recycling, etc., and realizes the green treatment of vanadium precipitation wastewater.

To manufacture granular ammonium sulfate with large grain diameter stably.SOLUTION: A manufacturing method of granular ammonium sulfate includes: reacting an ammonia-containing gas with a sulfuric acid aqueous solution to obtain an ammonium sulfate aqueous solution; introducing the ammonium sulfate aqueous solution to a crystal can; precipitating ammonium sulfate in the crystal can to obtain granular ammonium sulfate; and pulling a slurry containing the granular ammonium sulfate from a lower part of the crystal can. The manufacturing method of granular ammonium sulfate is characterized by that solid-liquid ratios at plural heights in the crystal can are measured and a pulling amount of the slurry is controlled based on the solid-liquid ratio.SELECTED DRAWING: Figure 1

The utility model discloses an ammonium sulfate drying, spraying and water replenishing system which comprises a belt conveyor, a drying bed main body, a heat exchanger, a cyclone dust collector, a water washing dust collector and an evaporation raw water tank, one end of the heat exchanger is connected into heat source steam, the other end of the heat exchanger is connected into a condensation bolt pipe network, the heat exchanger inputs air through the air blower for heat exchange to form hot air, and the hot air enters the drying bed main body, passes through the cyclone dust collector and then passes through the washing dust collector for secondary dust removal. The system has the beneficial effects that the problems of tail gas dust and smell in the ammonium sulfate drying process can be solved, the problems of dust particles and hot gas drifting in the tail gas are solved, crystals in the tail gas are recycled, and particulate matter pollution caused by direct exhaust of the tail gas is reduced; the problem that other water is introduced is effectively avoided, the evaporation water amount of the system is reduced, and water resource consumption of a large amount of spraying water is avoided.

The invention discloses an automatic mother liquor level detection and supplement subsystem in a coked ammonium sulfate system, which relates to the technical field of ammonium sulfate production systems and is technically characterized by comprising a radar liquid level meter mounted above a full-flow tank to measure the liquid level; the steam heater uses water vapor as a heat source to heat nitrogen or dry compressed air to 40-80 DEG C; the anti-frosting protection nozzle is of an angle-adjustable rotary type, a protection film can be formed on the surface of the radar liquid level meter probe, and the hot anti-frosting protection gas conveying pipe conveys heating gas for the radar liquid level meter probe. A saturator mother liquor operation control valve and a mother liquor circulation operation control valve control on-off of mother liquor; the anti-freezing and anti-crystallization blocking circulating pipe is prevented from being frozen and blocked by mother liquor; spraying the mother liquor to a French spray saturator by a spray absorption nozzle; the replenisher flowmeter measures the flow, and the replenisher pump provides power; the device has the functions of liquid level height automatic detection and supplement, radar liquid level frosting prevention in winter and acid gas corrosion prevention.

The present invention generally relates to a method of treating PCB wastewater. More specifically, the present invention relates to a method of ammonical copper etching of PCB wastewater and a process for treating the wastewater. The present invention also relates to the method of purifying the wastewater to reuse the same.

The utility model discloses a system for preventing a pipeline from being blocked in an ammonium sulfate crystallization process, and belongs to the technical field of ammonium sulfate devices. According to the technical scheme, the device comprises a crystallizer, a cyclone hydraulic separator, a centrifugal machine and a controller; a discharging port of the crystallizer is connected with a discharging pump through a discharging pump liquid inlet pipeline, an outlet of the discharging pump is connected with a discharging pump liquid outlet pipeline, the other end of the discharging pump liquid outlet pipeline is connected with a cyclone hydraulic separator, and a discharging port of the cyclone hydraulic separator is connected with a centrifugal machine through a pipeline. The discharging pump liquid inlet pipeline and the discharging pump liquid outlet pipeline are each provided with a flushing water branch, each flushing water branch is provided with a control valve, and the control valves are electrically connected with the controller. The crystallizer comprises a crystallizer tank body, a vapor phase outlet is formed in the top of the crystallizer tank body, a washing water inlet and an ammonium sulfate light mother liquor outlet are formed in the side wall of the crystallizer tank body, and a discharging opening is formed in the side face of the bottom of the crystallizer tank body. The cleaning cycle is prolonged, sewage discharge is reduced, and long-period stable operation is achieved.

The invention belongs to the technical field of wastewater treatment, and particularly relates to a recycling method of coal chemical industry conversion high-ammonia-nitrogen wastewater, which comprises the following steps: S1, diluting the coal chemical industry conversion high-ammonia-nitrogen wastewater by at least one time to obtain diluted wastewater, and carrying out oxidation treatment to obtain first treatment liquid; s2, performing cold treatment on the first treatment liquid to obtain ammonium carbonate and a second treatment liquid; s3, performing carbonization treatment on the second treatment solution to obtain ammonium bicarbonate and a third treatment solution; and S4, carrying out ammonium sulfate treatment on the third treatment liquid to prepare ammonium sulfate. According to the recycling method of the high-ammonia-nitrogen wastewater provided by the embodiment of the invention, effective components in the wastewater are recycled step by step through a simple hierarchical recycling process, so that the treatment problem of the high-ammonia-nitrogen wastewater is effectively solved, the treatment cost of the wastewater is reduced, and the resource utilization of the wastewater is also realized.

A dilute sulfuric acid manufacturing apparatus (40) includes: a pipe (42) or the like that supplies a raw material containing at least a sulfur component, a nitrogen component, and 40 to 80% by weight or more of moisture; a PVSA 45d or the like that generates an oxygen-containing gas having an oxygen concentration of 22 to 40% by volume; a combustion furnace (51) that combusts the raw material using the oxygen-containing gas to generate a combustion gas containing sulfur oxides (SOx: here, 1 ≤ x < 3) and 10% by volume or more of moisture; a waste heat boiler (52) that cools the combustion gas; a converter (61) that oxidizes the sulfur oxides (SOx) using a catalyst to generate a reaction gas containing sulfur trioxide (SO3); and a dilute sulfuric acid tower (71) that cools the reaction gas to generate dilute sulfuric acid, and does not add water from at least the combustion furnace (51) up to the dilute sulfuric acid tower (71), and generates dilute sulfuric acid of less than 90% by weight using only the moisture of the raw material.

The invention relates to a method for preparing light magnesium carbonate based on carbon dioxide mineralized serpentinite, which comprises the following steps: mixing serpentinite powder and ammonium sulfate for low-temperature synergistic activation to realize efficient conversion of magnesium element and produce byproduct ammonia gas at the same time; magnesium-silicon separation is achieved through water medium selective leaching, and active silicon slag is generated; accurately regulating and controlling the pH value, and selectively precipitating the iron oxide yellow byproduct to obtain pure magnesium liquid; cO2 is introduced into the pure magnesium liquid for a carbonation reaction, high-purity light magnesium carbonate is prepared, and precipitated mother liquor is obtained; and the closed-loop circulation of the ammonium sulfate reagent is realized through evaporative crystallization of the mother liquor. According to the method, all traditional waste residues are creatively converted into high-value products, the process economy is remarkably improved, meanwhile, the method has the outstanding advantages of being low in energy consumption, high in reagent recycling rate, environmentally friendly and the like, and a brand new technical path is provided for recycling of serpentinite solid waste and carbon emission reduction.

The application discloses a method for removing inhibitors in kitchen waste fermentation liquor and cooperatively recovering nitrogen and phosphorus and application thereof. The method comprises the following steps: (1) inoculating a complex bacterial liquid into pretreated kitchen waste fermentation liquor and aerating to obtain a degradation liquid; the complex bacterial liquid is a mixed liquid of Pseudomonas maltophilia and Bacillus subtilis; (2) adding MgCl2·6H2O into the degradation liquid, stirring for 20-40 min, then separating, and then blowing off ammonia nitrogen from the supernatant after separation to obtain a treated liquid; (3) adding a PEI-MNP adsorbent into the treated liquid, stirring for 15-30 min, and then performing magnetic separation to obtain treated fermentation liquor. The method can not only realize targeted removal of inhibitors in kitchen waste fermentation liquor and cooperatively recover nitrogen and phosphorus, but also can harvest high-quality carbon sources. The treated fermentation liquor can be applied to sewage treatment as a carbon source, so that the denitrification rate can be improved.

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.

The present disclosure is related to the methods and devices for the manufacture of a urea ammonium sulphate-based composition, in particular in a pipe reactor. In its broadest aspect, the present disclosure is related to a method for producing a urea ammonium sulphate-based composition in a pipe reactor comprising a first and a second mixing zone. The method comprises the steps of: a) directing a liquid stream comprising ammonium bisulphate to the first mixing zone of the pipe reactor; b) directing a first stream of ammonia to the first mixing zone of the pipe reactor for reacting with the liquid stream comprising ammonium bisulphate, provided in step a), to obtain a liquid stream comprising ammonium sulphate; c) directing the liquid stream comprising ammonium sulphate, provided in step b), to the second mixing zone of the pipe reactor; and d) directing a liquid stream of urea to the second mixing zone of the pipe reactor for mixing with the liquid stream comprising ammonium sulphate, provided in step b), to obtain a urea ammonium sulphate-based composition; wherein, in step b), the first stream of ammonia directed to the first mixing zone of the pipe reactor is pre-heated to at least 100 °C.

The invention relates to the technical field of inorganic salt purification, and discloses high-purity ammonium sulfate and a preparation process thereof.The preparation process includes the following steps that firstly, a magnetic response macrocyclic ether complexing agent is added into an ammonium sulfate solution to be purified, the complexing agent can specifically capture impurities such as potassium ions, and a stable complex with magnetic responsiveness is formed; then, selectively crystallizing and separating out the target product ammonium sulfate under a mild condition by a gas-phase anti-solvent crystallization method, and meanwhile, effectively repelling a large-volume impurity complex into a mother solution. The key step is that obtained solid-liquid mixed crystal mush is introduced into a gradient magnetic field for enhanced separation. Through creative integration of molecular recognition, phase equilibrium engineering and a magnetochemical separation technology, the limitation of a co-crystallization effect is fundamentally broken through, and ultra-high-purity ammonium sulfate with extremely low impurity content can be prepared in an efficient and environment-friendly manner.

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 invention relates to a method for selectively extracting lithium from waste lithium iron phosphate batteries and high-valued utilization of residues. According to the method disclosed by the invention, the characteristic of large solubility difference of Li2SO4 and (NH4) 2SO4 is utilized, and the acid and (NH4) 2S2O8 form a selective leaching system, so that the problem of low purity of a Li recovery product caused by similar chemical properties of Na or K and Li in a traditional process is avoided, and resource recovery of a high-purity Li product is realized. Moreover, by adopting a selective leaching system with a specific pH range, on one hand, the leaching rate and selectivity of Li can be improved, on the other hand, the method is suitable for recycling a Li-containing solution, effective enrichment of Li is realized, and meanwhile, discharge of high-salinity wastewater can be effectively reduced. Besides, the carbon content of the ferrophosphorus residues prepared by the method is relatively high, so that the activity of the ferrophosphorus residues used for a Fenton-like catalyst is favorably improved, and the degradation effect of organic pollutants in water is enhanced.