122results about "Phosphates" patented technology

The utility model relates to an ammonium phosphate evaporation and concentration system and belongs to the field of chemical engineering. The system comprises a concentrated ammonium phosphate pump, a concentrated ammonium phosphate storage tank, an I-effect evaporation chamber, an I-effect heater, an I-effect circulating pump, an I-effect charging pump, an II-effect evaporation chamber, an II-effect heater, an II-effect circulating pump, an II-effect charging pump, an III-effect evaporation chamber, an III-effect heater and an III-effect circulating pump. By adopting the system and the method, low-pressure saturated live steam is utilized to indirectly heat dilute ammonium phosphate to generate secondary steam and tertiary steam to continuously heat the dilute ammonium phosphate to produce concentrated ammonium phosphate. Compared with a two-effect evaporation concentration process flow which is widely used at present, the three-effect countercurrent evaporation concentration process flow saves energy by 47%. The utility model aims at saving energy, reducing consumption, reducing carbon emission of a production device and protecting the environment.

The invention discloses an organophosphorus degradation and synchronous recovery system based on a double-cathode induced electro-Fenton reaction. An induced iron electrode plate and an electrochemical assembly with double cathode plates are arranged in an electrolytic tank; the double cathode plates are a gas diffusion cathode plate and an iron reduction cathode plate; the gas diffusion cathode is used for reducing oxygen to generate hydrogen peroxide, the induction iron electrode releases ferrous ions under the action of an electric field, the ferrous ions and the hydrogen peroxide are subjected to a Fenton reaction, organic phosphorus is degraded into PO4 < 3->, Fenton reaction by-products Fe < 3 + > and PO4 < 3-> form iron phosphorus precipitates, and degradation of the organic phosphorus and synchronous recovery of orthophosphate are realized; excessive Fe < 3 + > is adsorbed by the iron reduction cathode and is further reduced into Fe < 2 + > which enters the solution again to participate in the Fenton reaction, so that the reaction efficiency is improved, and Fe < 3 + > / Fe < 2 + > circulation is promoted while slow release of iron is realized. The device is simple in structure, low in maintenance cost and high in operability, and the purpose of efficiently recycling phosphorus resources is achieved.

The invention relates to the technical field of ammonium dihydrogen phosphate preparation, and discloses a high-purity ammonium dihydrogen phosphate crystallization device and a method thereof.The high-purity ammonium dihydrogen phosphate crystallization device comprises a first-stage crystallization system, a first-stage centrifugal separation system, a second-stage crystallization system and a second-stage centrifugal separation system which are connected in series. The primary crystallization system comprises a crystal elimination heater, a crystal elimination mixer, a bag filter and a DTB flash cooling crystallizer which are connected in sequence, and is used for primarily purifying a concentrated solution; the primary centrifugal separation system is used for separating primary crystals; the second-stage crystallization system comprises a crystal dissolving tank, an OSLO cooling crystallizer and the like, and deep crystallization is carried out after the first-stage crystal is dissolved; the secondary centrifugal separation system is used for separating secondary crystals; through two-stage crystallization coupling, mother liquor graded circulation, a unique gradient washing process and active impurity control, efficient and continuous production of battery-grade ammonium dihydrogen phosphate with wet-process phosphoric acid as a raw material is realized, the product purity is high, the process flow is simplified, the cost is low, and the system operation is stable.

A method for production of pure phosphates comprises providing (S10) of a strip solution being an aqueous solution of one of monoammonium phosphate and monopotassium phosphate, loaded with stripped phosphate from a feed liquid comprising phosphoric acid contaminated by heavy metals and iron A base is added (S20) into the separated strip solution raising the pH to 2 – 5.5, forming of a heated solution and causing compounds comprising iron and phosphate to precipitate. A precipitant, precipitating heavy metals, is added (S30). Precipitated compounds comprising iron and phosphate and precipitated heavy metal compounds are separated (S40). The heated filtered solution is thereafter cooled off (S50) into a cooled solution, causing precipitation of phosphate compounds. The precipitated phosphate compounds are removed (S60) from the cooled solution. The cooled solution is recirculated (S70) for use as input strip solution in the stripping operation. A system for production of pure phosphates is also disclosed.

A method of recovery of ammonium phosphate comprises providing a start material (100) comprising struvite into a first aqueous process liquid (101) comprising monoammonium phosphate. The first aqueous process liquid (101) is mixed. Thereby the start material (100) comprising struvite is converted into monoammonium phosphate and / or diammonium phosphate in solution and a residue (103) comprising newberyite as a precipitate. The residue (103) is separated from the first aqueous process liquid (101), thereby giving a second aqueous process liquid (104) comprising monoammonium phosphate and / or diammonium phosphate. At least a part of said second aqueous process liquid (104) or a part of an aqueous process liquid (107, 112) emanating therefrom is returned into the first aqueous process liquid. Phosphoric acid (110) is added. A method for extracting nitrogen from reject water, an arrangement (1) for recovery of monoammonium phosphate and a system for extracting nitrogen from reject water is also disclosed.

The present invention relates to a method for producing liquid NPK fertilizer, characterized in that the reactants K2CO3 or KHCO3, NH4HCO3, and H3PO4 are reacted in an aqueous solution to produce potassium and ammonium phosphate salts, particularly K3PO4 and (NH4)3PO4; the reaction is carried out in multiple steps and includes at least one exothermic reaction and at least one endothermic reaction; and the temperature of the reaction is controlled by adjusting the amount and rate of addition of each reactant in the various steps so as to maintain the reaction mixture within a desired temperature range, preferably between 5°C and 50°C, throughout the reaction, without the need for external cooling or heating devices to control the temperature of the reaction. In a more specific embodiment, the method according to the invention is characterized in that at least one exothermic reaction comprises the reaction of K2CO3 with HO to produce KHCO3 and KOH and / or the reaction of KHCO3 with H3PO4 to produce K3PO4, CO2, and HO, and at least one endothermic reaction comprises the reaction of NH4HCO3 with H3PO4 to produce (NH4)3PO4, CO2, and HO.

The invention discloses a method for producing 55% powdery monoammonium phosphate by using filter-press white fertilizer and phosphoric acid sludge acid, and belongs to the technical field of production of powdery monoammonium phosphate. According to the method for producing novel 55% powdery monoammonium phosphate in a tubular reactor by using waste white fertilizer and phosphoric acid sludge acid which cannot be treated in the filter-press production process, the production process flow is greatly shortened, the production cost is reduced, and the production efficiency is improved. The number of process pipelines and production equipment is reduced, the length of the process pipelines is shortened, the energy consumption and the equipment maintenance cost are greatly reduced, and the effects of saving energy, reducing consumption and improving quality and efficiency are achieved; meanwhile, the waste white fertilizer which cannot be treated in the filter pressing production process and the waste phosphoric acid slag slurry generated in phosphoric acid production are treated, and the production cost is reduced.

The invention relates to the field of wastewater treatment, in particular to a method for treating wastewater containing phosphorus, aluminum, silicon and organic amine generated in a molecular sieve preparation process, which comprises the following steps: 1) adding a pH regulator and an optional silicon-aluminum component regulator into the wastewater to enable the pH of the wastewater to be 10-14 and the molar ratio of silicon to aluminum in the wastewater to be (1.0-1.8): 1, obtaining a first mixture containing an oil phase; 2) distilling the first mixture obtained in the step 1) to obtain a gas phase and a second mixture; 3) performing solid-liquid separation on the second mixture obtained in the step 2) to obtain a first solid phase and a third mixture; and 4) crystallizing the third mixture obtained in the step 3) to obtain a second solid phase. According to the method, harmless treatment can be conducted on the wastewater, organic amine, phosphorus, aluminum, silicon and the like in the wastewater can be efficiently recovered, and the recovery rate and the purity of the recovered product are high.

The invention discloses a process for reducing rare earth loss in value adjustment of phosphorus-containing rare earth feed liquid by using an iron phosphorus removal and segmented value adjustment method, and belongs to the field of rare earth hydrometallurgy. The process comprises the following steps: preparing iron, heating, adding carbon for material settling, controlling REO concentration, performing primary value adjustment, performing solid-liquid separation, performing secondary value adjustment and performing solid-liquid separation again. The method comprises the following steps: adding an iron material of which the stoichiometric ratio is 1-2 times that of a phosphorus-containing rare earth feed liquid into the phosphorus-containing rare earth feed liquid, raising the temperature to 50 DEG C or above, adding a carbon precipitation material to regulate the acidity to 0.1-0.6 mol / L, controlling REO to be less than or equal to 200g / L, regulating the pH to 0.5-2, carrying out primary phosphorus removal, separating to obtain iron phosphate slag with low rare earth content, and regulating the pH of clear liquid to 4-5 to further remove impurities; according to the method, the rare earth content in the value-adjusted slag is remarkably reduced, the dry basis CeO content of the primary value-adjusted slag can be as low as 1.61%, the rare earth yield is increased, the occupied area of a slag warehouse is reduced, recycling of phosphorus resources is achieved, and the production cost is reduced.

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 relates to the technical field of wet-process phosphoric acid purification, in particular to a strong phosphoric acid purification device for high-quality ammonium dihydrogen phosphate production and a method thereof.The strong phosphoric acid purification device comprises a settling tank, the settling tank is connected with a desulfurization reaction tank, the desulfurization reaction tank is connected with a de-heavy component, the de-heavy component is connected with the settling tank through a return pipe, and the settling tank is further connected with a flocculant compounding tank; the settling tank is connected with the filter, a liquid outlet end of the filter and the hydrogen peroxide storage tank are respectively connected with two inlets of the static mixer, and an outlet of the static mixer is connected with the filler reaction tower; the heavy component is further connected with a tail gas washing assembly through a tail gas pipe, the tail gas washing assembly is further connected with a lye tank, the tail gas washing assembly is connected with a sodium sulfide storage tank through a liquid outlet pipe, and the sodium sulfide storage tank is connected with the heavy component; alkali liquor used by the tail gas washing assembly absorbs hydrogen sulfide gas to generate a sodium sulfide solution which is used as a heavy component removal agent for heavy component removal reaction, so that efficient coordination of tail gas washing and heavy component removal reaction is realized, and consumption of the alkali liquor and the sodium sulfide solution is reduced.

The invention discloses an anti-blocking screening material passing pipe of an ammonium phosphate external loop reactor, and relates to the field of ammonium phosphate crystal screening, the anti-blocking screening material passing pipe comprises a circulating screening box and a circulating pipeline, the circulating pipeline comprises a pressurizing pipe, a circulating pipe, a feeding pipe and a circulating pump, one end of the pressurizing pipe is connected with the circulating screening box, and a screening plate is arranged in the circulating screening box; a circulating pipe is connected to the circulating screening box and used for being connected with a reaction kettle, the side wall of the pressurizing pipe is connected with a circulating pump through a feeding pipe, the circulating pump is connected with the reaction kettle through a pipeline, a material crushing mechanism is arranged at one end of the pressurizing pipe and comprises a movable column, a locking pipe and a hollow material crushing pipe, and one end of the movable column penetrates into the pressurizing pipe in a sliding mode. The hollow material crushing pipe rotatably penetrates through the movable column body, the hollow material crushing pipe is fixedly sleeved with a material crushing frustum, one end of the locking pipe penetrates through the hollow material crushing pipe to be connected with a material crushing cone, and a plurality of material locking nails slidably penetrate through the side wall of the material crushing cone, so that the precipitation content of ammonium phosphate crystals is higher, and the recovery rate of ammonium phosphate materials is improved.

Provided are electrolytes suitable for use in secondary cells, optionally lithium-ion secondary cells wherein the electrolytes provide excellent cycle life optionally in NMC based lithium-ion cells that are initially formed with a charge cutoff voltage of >4.3 V and subsequently cycled with a charge cutoff of ≤4.65 V during cell operation. The electrolyte optionally excludes ethylene carbonate and / or additives toxic to humans at the concentration used in the electrolyte.

The invention discloses a process method for producing battery-grade ammonium dihydrogen phosphate by using a solvent extraction method, which comprises the following steps: 1) respectively introducing industrial-grade refined phosphoric acid and liquid ammonia into a tubular reactor for primary reaction to obtain primary reaction slurry, introducing the primary reaction slurry into a neutralization reactor, and carrying out secondary reaction to obtain secondary reaction slurry; carrying out secondary reaction with circulating liquid ammonia in the neutralization reactor to obtain secondary reaction slurry; (2) the crystallizer is communicated with a thickener through a pipeline, a slurry outlet of the thickener is communicated with a first centrifugal machine and a second centrifugal machine through pipelines, discharging is conducted when the solid content of slurry in the thickener is 25-40%, and the first centrifugal machine and the second centrifugal machine are communicated with a drying fluidized bed conveying belt; and (3) the dried materials enter a plate cooler to be cooled for 20-40 minutes and then are cooled to 35 DEG C or below, a dehumidifier is arranged in the environment where the plate cooler is located, the dew point temperature of the dehumidifier is controlled within 15 DEG C, and the air pressure of the dehumidifier is larger than 7 KPa. The indexes of the battery grade ammonium dihydrogen phosphate product obtained by the method meet the requirements of the main quality index (GB / T 5742-2020) of ammonium dihydrogen phosphate for batteries.

This application relates to an organic compound, a perovskite precursor solution, a perovskite film, a perovskite cell, and an electric apparatus. The organic compound includes: a cation M; and an anion Q bonded to the cation M; where M includes one or more of CH3NH3+, CH5N2+, Cs+, and C2H5NH3+; and Q includes one or more of H2POx− and H2NOy−, where x and y are each independently an integer from 2 to 4.

The present invention relates to a method for combined recovery of phosphate and nitrogen from sewage sludge. The core objective of the present invention is to recover phosphorus from sewage sludge ash and convert phosphorus into NP fertilizer diammonium phosphate using steam from sewage sludge drying and nitrogen from liquid manure.

The present invention relates to a phosphorus-rich nano sponge comprising a porous matrix having an average size of less than 1000 nm and stabilized with a surface-active agent wherein the porous matrix is held together by ionic linkages of one or more of transition metals selected from iron, copper, titanium, vanadium, nickel, cobalt, post transition metals selected from zinc, cadmium, aluminum, tin, lead, bismuth, alkaline earth metals selected from calcium, magnesium, barium and strontium, metalloids selected from silicon, boron and tellurium, alkali metals selected from potassium, sodium and lithium, lanthanides selected from cerium, gadolinium, europium, or mixed metals. The phosphorus-rich nano sponge is selectively enriched for sustained and targeted delivery of molecular payloads.

The invention discloses a filtering and recycling method and system for concentrated slurry of uranyl carbonate and ammonium diuranate in crystallization mother liquor, and relates to the technical field of uranium purification, the recycling method comprises the following steps: S1, adopting at least two solid-liquid separation devices which are arranged in parallel to carry out alternate circulating filtering treatment on tower bottoms of crystallization mother liquor containing uranyl carbonate and / or ammonium diuranate, filtering to obtain filtered clear liquid and an ammonia-containing filter cake; s2, carrying out air stripping treatment on the ammonia-containing filter cake obtained in S1 to separate ammonia-containing gas and obtain a solid material with low ammonia content; s3, carrying out absorption treatment on the ammonia-containing gas separated in S2 to obtain an ammonium-containing product; and S4, carrying out pyrolysis treatment on the solid material with low ammonia content obtained in S2 to obtain a uranium-containing product. Through cooperation of double-machine alternate circulating filtration, air stripping separation, absorption recovery and pyrolysis conversion, the technical problems of ammonia nitrogen pollution transfer, dependence on manual operation, long flow and high water content of a filter cake are solved.

To provide: a novel organic ammonium salt which has excellent freezing point lowering function; and a composition which is capable of forming the salt.SOLUTION: An organic ammonium salt according to the present invention contains a cation and an anion; the cation is an ammonium cation that is represented by a formula (I) (wherein each R1 independently represents an organic group having 1 to 22 carbon atoms; each R2 independently represents a hydroxy hydrocarbon group that has one or more hydroxyl groups and a hydrocarbon moiety having 1 to 22 carbon atoms and optionally having an oxygen atom, or the like; and each of l, m and n represents an integer of 0 to 4, with the total of l, m and n being 4); and the anion is a phosphonate ion or a phosphinate ion.SELECTED DRAWING: None

The utility model relates to the technical field of ammonium phosphate production, in particular to a dust remover for ammonium phosphate production, which increases the connection strength, ensures the stability during rotation and improves the practicability. Comprising a U-shaped bottom frame, discharging boxes, a connecting pipe, an air blower, a driving motor, two U-shaped frames, a rotating component, a supporting component, a collecting component and a covering component, the middle portions of the two oppositely-arranged discharging boxes are connected with the connecting pipe and located in the U-shaped bottom frame, one side of the connecting pipe is connected with the output end of the air blower, and the other end of the air blower is connected with the collecting component; u-shaped frames are fixedly connected to the right side walls of the upper discharging box and the lower discharging box, the middles of the U-shaped frames are connected with the output end of a driving motor through rotating parts, the driving motor is installed on the outer wall of the right side of the U-shaped bottom frame, covering parts are installed on the top faces of the discharging boxes, and supporting parts are installed on the left side of the discharging boxes and installed on the inner wall of the left side of the U-shaped bottom frame.

This application discloses a method for producing industrial-grade ammonium dihydrogen phosphate, comprising: a desulfurization reaction tank, a heavy metal removal reaction tank, a multi-stage aeration tank, a settling tank, a primary membrane filter, an acid mixer, a neutralization reaction tank, and a multi-stage plate and frame membrane filter assembly; the desulfurization reaction tank and the heavy metal removal reaction tank are connected by pipelines; the outlet of the heavy metal removal reaction tank is connected by pipeline to the inlet of the first-stage aeration tank of the multi-stage aeration tank; the outlet of the last-stage aeration tank of the multi-stage aeration tank is connected by pipeline to the inlet of the settling tank. This method, by adding a primary membrane filter assembly before acid conditioning, reduces the impurity and solid content of the pretreated acid, increases phosphorus yield, reduces the amount of ammonium slag in the pretreated acid, and reduces filtration intensity, which is beneficial for improving product quality and the system's capacity after maintenance. The equipment used is reliable, requires low investment, has low labor intensity, and can achieve continuous and stable operation.

A method for recovery of rare earth elements from apatite mineral comprises dissolving (S10) of apatite mineral of magmatic origin in an acid comprising hydrochloric acid. The dissolving results in a first liquid solution comprising phosphate, calcium and chloride ions, rare earth elements, arsenic and iron. The arsenic and any ferric iron are removed. The first liquid solution is treated (S20) into a second liquid solution by extracting (S22) of a major part of the phosphate ions with an organic solvent. The treating of the first liquid solution into the second liquid solution further comprises partially neutralizing (S75) a raffinate resulting from the extracting of a major part of the phosphate to a pH > 1.5, causing precipitation of phosphates of rare earth elements, and filtering (S76) the precipitated phosphates of rare earth elements from the raffinate.

The invention discloses a production method and a co-production method of a monoammonium phosphate production device, the production device comprises a first device and a second device, and the co-production method is characterized in that the first device and the second device are partially connected, so that the effect that the two devices are simultaneously matched for production is achieved. The method provided by the invention can break through the limitation of the processing capacity of the existing production equipment. The first device and the second device can separately produce monoammonium phosphate, after the first device and the second device are linked for production, part of slurry can be introduced into the second device for drying and other links, and the pressure of the first device is relieved, so that the production load is increased, and the yield is increased. Meanwhile, indexes such as the moisture content of the monoammonium phosphate can be optimized, the moisture of the monoammonium phosphate product is further reduced and is more stable through reasonable treatment of a drying link of the second device, and the stability and consistency of the quality of the monoammonium phosphate are improved.

The method for producing powdery high-concentration monoammonium phosphate by two-stage neutralization of high-impurity raffinate acid is as follows: the by-product raffinate acid generated in the production process of wet purified phosphoric acid is preheated to 65-75 DEG C, ammonia gas is first introduced to perform a first-stage neutralization reaction, the pre-stable impurity neutralization slurry is obtained after constant temperature ripening, ammonia gas is introduced to perform a second-stage neutralization reaction on the pre-stable impurity neutralization slurry, the qualified monoammonium phosphate slurry is obtained after constant temperature ripening, the qualified monoammonium phosphate slurry is continuously subjected to grading concentration, drying is performed after the slurry solid content is concentrated to 70-75%, and the powdery high-concentration monoammonium phosphate product is prepared. The present application takes the by-product high-impurity raffinate acid generated in the production process of wet purified phosphoric acid as the only phosphorus source, realizes full-value utilization of the raffinate acid, the process is green and environmentally friendly, and is suitable for industrialized continuous production.

This invention relates to a system and method for preparing low-polymers and co-producing ammonium phosphate from nitrogen-containing oligomers in acrylonitrile wastewater. The invention aims to address the technical problems of high cost and environmental pollution associated with treating nitrogen-containing organic wastewater generated in acrylonitrile production through combustion. The system comprises a premixing tank, a raw material preheater, a reaction vessel, a neutralization tank, an oil-water separator, an extraction tower, an alcohol recovery tower, and a water recovery tower. This invention provides a method for converting wastewater containing nitrogen-containing oligomers generated in acrylonitrile plants into low-polymers, which can be used as a green fuel, by fully utilizing the oligomeric carbon chains. Simultaneously, nitrogen is removed, and ammonium salts are co-produced, which can be sold as fertilizer raw materials, thereby reducing costs. This invention provides a novel process for utilizing nitrogen-containing organic wastewater, improving the utilization rate of carbon and nitrogen resources.

The utility model relates to the technical field of chemical engineering, and particularly discloses a DAP production device. The DAP production device comprises a pre-neutralization tank, a granulator, a reactor and an ammonia feeder, an outlet of the pre-neutralization tank is communicated with the granulator, and the pre-neutralization tank is used for carrying out ammonia-acid reaction on first phosphoric acid and ammonia gas to generate first slurry; an outlet of the reactor is communicated with the granulator, and the reactor is used for carrying out amino-acid reaction on second phosphoric acid and ammonia gas to generate second slurry; the ammonia adder is communicated with the granulator, and ammonia gas, the first slurry and the second slurry in the ammonia adder all enter a material bed of the granulator to react so as to form DAP; and the slurry reacts with ammonia gas in an ammonia adder in the granulator so as to further adjust the ammonia-acid reaction, so that the ammonia-acid reaction is more sufficient, and the yield of DAP produced by the granulator is improved.

The application discloses a wet-process phosphoric acid production process for comprehensive utilization of full-element resources of phosphate rock, and belongs to the field of phosphorus chemical production. The process comprises the following steps: decomposing phosphate rock, a decomposing solution and a bottom solution to obtain a primary decomposing solution and primary decomposing residue; crystallizing the primary decomposing solution to obtain ammonium biphosphate crystals and a crystallization mother liquor of the ammonium biphosphate crystals; directly selling the ammonium biphosphate as a product or transforming the ammonium biphosphate to produce high-quality phosphoric acid, and returning the obtained crystallization mother liquor to preparation of the decomposing solution or the decomposing bottom solution; transforming the primary decomposing residue through ammonium carbonate to obtain an ammonium sulfate solution and a calcium carbonate filter cake; returning the ammonium sulfate solution to preparation of the decomposing solution or comprehensive utilization; transforming the calcium carbonate filter cake through ammonium chloride to obtain a mixed gas containing CO2 and NH3, a calcium chloride solution and an insoluble residue; and further producing calcium-containing compounds from the calcium chloride solution. The process provided by the application can absorb phosphate gypsum from the source, has low sulfuric acid consumption, high fluorine leaching rate, high comprehensive utilization rate of calcium resources, and good quality of the phosphoric acid obtained through transformation.

The invention provides a preparation method and application of ammonium ferric citrate. The preparation method of the ferric ammonium citrate comprises the following steps: carrying out a first reaction on an iron compound and first ammonia water, introducing air in the process of the first reaction, and preparing a first slurry, and carrying out solid-liquid separation on the first slurry, taking a solid, carrying out second reaction on the solid, second ammonia water and citric acid in a solvent, and concentrating to prepare the ferric ammonium citrate. According to the preparation process of the ferric ammonium citrate, the generation of hydrogen and the use of a strong oxidant in the traditional process are avoided, the safety of the production process is improved, the ferric ammonium citrate with few impurities and high purity is obtained, qualified diammonium hydrogen phosphate is co-produced, and the preparation process has a great application prospect.

A preparation method of a manganese iron phosphate precursor, a cathode sheet, and a lithium battery comprising: preparing the precursor based on a high-temperature calcination device. The high-temperature roasting furnace comprises a sprayer, a heater, and a particle size regulator. The method comprises: generating a manganese-containing solution from a manganese source and hydrochloric acid; generating an iron phosphate solution from an iron source, a phosphorus source, and hydrochloric acid; mixing the manganese-containing solution, iron phosphate solution, and dispersant to obtain a mixed solution; preheating the mixed solution; and transporting the mixed solution to the high-temperature roasting furnace; spraying and roasting the mixed solution in the high-temperature calcination furnace in the atmosphere of carrier gas, forming a powdered manganese iron phosphate precursor with at least two preset particle sizes; water washing and grinding, demagnetizing, and drying the manganese iron phosphate precursor to obtain the manganese iron phosphate precursor.