44 results about "Ferrous salts" patented technology

This invention discloses an in-situ removal process for total inorganic iodide in water based on oxidation-adsorption, belonging to the field of water treatment technology. The process includes: first, taking raw water containing inorganic iodide, adding bicarbonate and adjusting the pH of the solution to 7-7.5; then, adding ferrous salt to the raw water; finally, adding KMnO4 to the raw water with added ferrous salt under stirring conditions, reacting to prepare a MnO2-nascent iron particle complex; on the one hand, promoting the removal of total inorganic iodide from water through mild oxidation-adsorption. ‑ Oxidation transformation occurs to generate HOI / I2; on the other hand, the in-situ products HOI / I2 are adsorbed and fixed through adsorption / co-precipitation methods, and nascent iron is captured through surface coordination or electrostatic adsorption. This invention achieves the capture of I2 under neutral / weakly alkaline drinking water conditions through a mild and controllable oxidation-adsorption synergistic mechanism. ‑ Simultaneous adsorption and removal of its conversion products are achieved to ensure that total iodine is removed to the required standard.

The application discloses a method for synthesizing tervalent tetraaryl iron porphyrin from pyrrole, aromatic aldehyde and ferrous salt, which comprises the following steps: adding anhydrous aluminum chloride, aromatic aldehyde, pyrrole and ferrous salt into DMF under stirring, and then heating and refluxing the reaction mixture for 0.5 hours under nitrogen; removing the nitrogen and continuing to heat the reaction mixture for a certain time; stopping the reaction; cooling the reaction mixture; and placing the reaction mixture at 273K overnight; and finally filtering the reaction mixture to obtain the iron porphyrin.

This invention provides a lithium iron phosphate cathode material, its preparation method, and its application. The preparation method includes the following steps: (1) mixing ferrous salt and phosphorus source with an alcohol solvent, heating and stirring, and adding a first lithium source solution to obtain a mixed solution; adjusting the pH of the mixed solution to obtain a mixed precursor; (2) mixing a complexing agent, ferric salt, a second lithium source, phosphorus source, and surfactant with water, stirring to form a sol solution; mixing the mixed precursor obtained in step (1) with the sol solution, heating and stirring to obtain a gel precursor; (3) sintering the gel precursor to obtain the lithium iron phosphate cathode material; wherein the mixed precursor includes lithium phosphate and ferrous phosphate. This invention can achieve lithium iron phosphate gradation of different particle sizes through a single production line, improving the uniformity and compaction density of the material, and avoiding performance differences and poor stability between different batches.

This application provides a method for preparing nano-sized orthogonal iron phosphate and a method for preparing lithium iron phosphate cathode materials, relating to the field of electrode materials. The method for preparing nano-sized orthogonal iron phosphate includes: mixing a first ferrous salt solution with a first phosphorus source solution and an oxidant to perform a co-precipitation reaction to obtain amorphous iron phosphate; mixing the amorphous iron phosphate with water to form a slurry, controlling the slurry particle size, and then adding a crystal transformation aid to the slurry, followed by aging under stirring conditions at a pH of 0.8–1.5 to obtain nano-sized orthogonal iron phosphate; wherein the crystal transformation aid includes a second ferrous salt and a second phosphorus source. The iron phosphate prepared in this application is single-crystal nano-sized orthogonal iron phosphate, reducing the grinding pressure at the lithium iron phosphate end. Simultaneously, its unique octahedral structure is more stable than monoclinic iron phosphate produced by conventional processes, with fewer crystal defects and higher lattice integrity, effectively avoiding the generation of magnetic foreign matter during sintering and contributing to the performance of lithium iron phosphate materials.

The application provides a low-cost lithium iron phosphate and a preparation method and application thereof, and belongs to the field of lithium battery materials, wherein an intermediate is obtained by mixing a ferrous salt solution with a lithium source, a phosphorus source, a reducing agent and a homogeneous precipitant; the intermediate is mixed with a carbon source to obtain a mixed slurry; and the mixed slurry is subjected to spray drying, calcination and crushing treatment to obtain lithium iron phosphate. The intermediate is prepared by directly reacting the ferrous salt solution with the lithium source, the phosphorus source, the reducing agent and the homogeneous precipitant, the synthesis of an expensive iron source precursor and the complicated nanometer grinding process in the traditional process are omitted, the process flow is greatly shortened, and the raw material cost and energy consumption are significantly reduced; in combination with the spray drying and calcination process, the introduction of impurities is effectively avoided, the prepared lithium iron phosphate has the characteristics of low cost, good consistency and excellent electrochemical performance, and effectively promotes the cost reduction and efficiency increase of new energy automobile power batteries.

This invention relates to an iron-polyphenol-coated composite aerogel, its preparation method, and its application, belonging to the field of adsorbent preparation and application technology. The invention involves first immersing a porous aerogel in a polyphenol aqueous solution, then adding ferrous salt to the solution for liquid-phase deposition, washing with ultrapure water, crosslinking with glutaraldehyde aqueous solution, thoroughly washing with ethanol and ultrapure water, and finally drying to obtain an iron-polyphenol-coated composite aerogel. The raw materials used in this method are green and safe, the preparation process is simple, and it can be produced on a large scale. The resulting iron-polyphenol-coated composite aerogel exhibits high adsorption capacity, high selectivity, and high reduction rate for gold ions in aqueous solution, and also possesses excellent adsorption-desorption cycle stability, making it suitable for the efficient separation and recovery of gold from electronic wastewater.

This application provides a gradient particle size iron phosphate, lithium iron phosphate, their preparation methods, and lithium-ion batteries, relating to the field of lithium-ion batteries. The preparation method of iron phosphate includes: mixing a ferrous salt solution, a phosphate salt solution, and an oxidant, co-precipitating them, and separating the solid and liquid phases to obtain amorphous iron phosphate; slurrying the amorphous iron phosphate to obtain a slurry; mixing the slurry and a phosphorus source to obtain mixture A; aging and calcining the mixture to obtain type A iron phosphate; mixing the slurry, phosphorus source, and type A iron phosphate to obtain mixture B; aging and calcining mixture B to obtain type B iron phosphate; and mixing the slurry, phosphorus source, and type B iron phosphate to obtain mixture C; aging and calcining mixture C to obtain type C iron phosphate. During the synthesis process, by introducing seed crystals from the previous tank, the produced iron phosphate can grow based on the seed crystal size, thereby producing iron phosphate with increasing grain / particle size.

This invention discloses a method for the simultaneous remediation of pesticide and arsenic pollution in acidic soil, belonging to the field of soil remediation technology. *Pseudomonas arsenicoxydans* Y24-2 is used as the remediation microbial agent, and calcium peroxide is used as remediation agent A. Sodium acetate, urea, potassium dihydrogen phosphate, manganese salt, and ferrous salt are mixed to obtain remediation agent B. Remediation agents A and B must be stored separately and mixed immediately before remediation. Remediation agents A and B are dispersed in water, and the remediation microbial agent is added to obtain a remediation agent suspension. The remediation agent suspension is immediately applied to the acidic soil to be remediated for simultaneous remediation of pesticide and arsenic pollution. According to experiments, after remediation using the method provided by this invention, glyphosate in the soil is effectively degraded, arsenic is effectively oxidized and passivated, and the soil pH value is raised to neutral, achieving the goal of pollutant removal and soil restoration to health.

The application discloses a kind of chlorine dioxide generator by-product online processing method, it is related to chlorine dioxide preparation technical field, comprising: chlorine dioxide generator by-product solution and ferrous salt solution are added in by-product online processing device, in by-product online processing device, water jetor extracts mixed reactor into negative pressure, chlorine dioxide generator by-product solution is sucked into mixed reactor, and ferrous salt solution is reacted under negative pressure for 20-40 minutes to generate iron salt solution, after reaction is completed, iron salt solution is added to flocculation reaction tank for raw water purification after being sucked by water jetor;Wherein, 1.0-3.0L of 5-15% ferrous salt solution is added in every 1L chlorine dioxide generator by-product solution;The by-product after processing is used as flocculating agent, to achieve the purpose of resource utilization, processing method does not need heating, the volume of equipment used is small, investment is small, reaction speed is fast, processing efficiency is high, and operation is simple.

The application discloses a sucrose complex zinc-iron-copper-manganese composite premix feed additive and a preparation method thereof, and belongs to the technical field of feed additives. The product is prepared by using sucrose as an organic ligand, and then performing step-by-step complexing reaction on zinc, iron, copper and manganese to form active complex components, and then mixing the active complex components with a carrier and / or an auxiliary material for feed additives to form the composite premix feed additive. A 1 wt% aqueous solution of the product is clear or substantially clear, and the proportion of ferrous iron in total iron is not less than 0.75. The preparation method is performed in the order of preferential addition of ferrous salt and last addition of copper salt, and an antioxidant is used to inhibit oxidation of ferrous iron, and the pH of the system is monitored and controlled in real time. The raw materials of the application have a wide source and low cost, and are suitable for comprehensive utilization of molasses resources in sugarcane production areas. The product has good stability and is not easy to absorb moisture and form lumps, and can be directly applied to feed production to provide various organic state trace element nutrients for livestock and poultry.

This invention relates to the field of lithium-ion battery materials technology, and in particular to a method for multi-level doping of a manganese iron phosphate precursor, comprising the following steps: S1, preparing a ferrous salt solution, a manganese salt solution, and a copper salt solution; S2, adding the ferrous salt solution and the manganese salt solution to a first reaction vessel, adding a precipitant and a buffer, mixing and reacting, and introducing gas 1 to obtain an MFC precursor; S3, overflowing the MFC precursor from the first reaction vessel to a second reaction vessel, adding the ferrous salt solution, manganese salt solution, buffer, precipitant, and copper salt solution to the second reaction vessel, and introducing gas 1 to obtain an MFCC slurry; S4, purging the slurry washing vessel, introducing gas 2, adding a phosphoric acid solution to obtain an MFCP slurry; S5, after aging, washing, drying, and packaging, obtaining the finished MFCP precursor. This invention allows for multi-level doping and coating to improve the cycle stability and battery capacity of the material, and this process offers high production line flexibility and low cost.

This invention relates to a carboxymethyl cellulose-modified nanomaterial of zero-valent iron, its preparation method, and its application in the remediation of trichloroethylene-contaminated water or groundwater. The material is prepared by mixing sodium carboxymethyl cellulose with a water-soluble ferrous salt in a deoxygenated aqueous phase, followed by reduction with an oxygen-free sodium borohydride aqueous solution under nitrogen protection. The sodium carboxymethyl cellulose forms a coating layer on the surface of the zero-valent iron through carboxylate groups, distributing the zero-valent iron particles on the carboxymethyl cellulose framework or the coating layer surface. Scanning electron microscopy analysis shows that the zero-valent iron particles are mainly distributed in the range of 80-150 nm; the zeta potential measured in anhydrous ethanol dispersion is -47 mV. The material is added at 0.5-5.0 g / L to trichloroethylene-contaminated water or groundwater and reacted under sealed, light-protected conditions at pH 6.0-8.0 and a temperature of 20-35°C for the reduction and dechlorination treatment of trichloroethylene.

The present invention relates to a composition for dyeing hair. The composition for dyeing hair of the present invention can be used as a single formulation or applied as a two-formulation system comprising a dyeing part and a base part, and comprises tannic acid, gallic acid, and a ferrous salt in an optimal ratio, thereby realizing excellent dyeability compared to conventional chemical hair dyes. In addition, the particle size distribution of a mixture in the dyeing part of the composition for dyeing hair of the present invention enables uniform dispersion on the surface of hair and provides effective penetration into the hair in an aqueous environment, and the composition provides a stable dyeing effect under various conditions including high-temperature storage.

This invention relates to the field of graphene and discloses a method for preparing highly dispersible graphene oxide with a high monolayer ratio at low temperatures. The method includes: S1: ball milling a mixture of graphite and activated carbon; S2: immersing the graphite / activated carbon mixture in an acidic solution containing hypochlorous acid and / or hypochlorite under light irradiation for a pre-oxidation reaction to exfoliate the graphite into a monodisperse state; S3: oxidizing the product of reaction S2 in a concentrated sulfuric acid / perchloric acid mixed acid system; S4: diluting the product of reaction S3 with water and then introducing a ferrous salt for a reduction reaction; and finally, separating and washing to obtain a graphene oxide dispersion. This invention can prepare highly dispersible graphene oxide with a high monolayer ratio under low temperature and mild conditions. Furthermore, during the preparation process, this invention utilizes the synergistic effect of activated carbon and chloride ions to fully disrupt the large π bonds of the conjugated aromatic domains in graphite, thereby increasing the flexibility of the graphene sheets and reducing viscosity.

This invention relates to a method for producing hydrogen and magnetite from water and iron in the presence of an iron(II) salt catalyst. The invention also relates to the use of the resulting iron in indirect hydrogen storage.

This invention relates to the field of soil remediation technology, specifically disclosing a method for promoting iron cycling and degrading soil organic matter based on the electron shuttle effect of natural humic acid. The humic acid extraction method includes mixing natural soil material with an alkaline solution, stirring, and centrifuging to obtain a supernatant; acidifying the supernatant to obtain a humic acid precipitate; redissolving the precipitate in KOH solution, followed by acidification and centrifugation for purification; and finally freeze-drying and grinding to obtain humic acid powder. The application method involves premixing contaminated soil with a solution prepared from the humic acid powder, a ferrous salt solution, and deionized water, then adding a persulfate oxidant to react and degrade organic pollutants in the soil. This invention utilizes naturally extracted humic acid, effectively overcoming the limitations of slow iron cycling and high oxidant consumption in traditional iron-based oxidation systems, resulting in high remediation efficiency and environmental friendliness.

The application relates to the field of postharvest preservation of flowers and cut flower vase planting and maintenance technology, in particular to a composite preservative liquid for prolonging the preservation period of cut rhododendron flowers and a preparation method thereof. The method comprises the following steps: taking part of deionized water, sequentially adding trehalose, sucrose and potassium nitrate, stirring and dissolving to obtain a sugar salt water phase; taking part of deionized water, adding citric acid and stirring and dissolving, then adding ferrous sulfate, stirring in the dark to obtain a ferrous salt acidification pre-solution; slowly adding the ferrous salt acidification pre-solution into the sugar salt water phase, mixing under stirring to obtain a composite water phase; dissolving gibberellin in ethanol to prepare a gibberellin mother liquor, and adding the gibberellin mother liquor into the composite water phase; adding diluted sec-butylamine into the obtained solution, stirring and mixing; adding the remaining deionized water to constant volume; filtering and sterilizing the adjusted solution, filling and sealing to obtain the composite preservative liquid. The application can inhibit the reproduction of botrytis cinerea and maintain the good state of cut flowers.

This invention proposes a Fenton reagent, a polishing slurry, a polishing method for diamond substrates, and a diamond polishing sheet. The invention provides a Fenton reagent comprising a hydrogen peroxide solution and a ferrous salt-containing composition; the ferrous salt-containing composition comprises: a ferrous salt, a host molecule, and a guest molecule; the host molecule has a hydrophobic cavity structure, capable of encapsulating the guest molecule through non-covalent interactions, and exhibits chemical stability in the Fenton reaction system; the guest molecule has a conjugated π system and can coordinate with Fe. Using the Fenton reagent and abrasive particles of this invention as a polishing slurry, diamond is polished under visible light irradiation, ensuring that the Fe content in the polishing slurry is maintained. 2+ A stable concentration ensures a stable supply of hydroxyl radicals, resulting in a high-quality diamond surface.

The application discloses an inorganic shielding agent for eliminating the influence of residual flocculants in machine-made sand on the workability of concrete and an application method thereof. The inorganic shielding agent is composed of hydrogen peroxide and ferrous salt. In the mixing process of concrete or mortar, the shielding agent is added into mixing water, polycarboxylic acid water reducing agent and other raw materials, and hydroxyl radicals generated by Fenton reagent are used to rapidly degrade residual polyacrylamide (PAM) in machine-made sand by using the mixing and time provided by the mixing process, so that the competitive adsorption and tackifying effect of the residual PAM on the polycarboxylic acid water reducing agent are eliminated, and the workability of the concrete is restored. The application has the advantages of high efficiency, rapidness, low cost and simple operation, and the reaction product is harmless to the environment, and is suitable for large-scale industrial application.

The application discloses a preparation method of battery-grade iron phosphate, which comprises the following steps: adding a mixed aqueous solution of monomers and an initiator into a ferrous salt solution, uniformly mixing to obtain a mixed bottom solution; respectively introducing a phosphate solution and hydrogen peroxide into the mixed bottom solution to generate an oxidation precipitation reaction; after the oxidation precipitation reaction is completed, the system starts to be heated to generate an aging reaction; after the aging is completed, the product is filtered, washed and dried to obtain iron phosphate dihydrate; and high-performance battery-grade iron phosphate can be obtained after calcination. The application constructs a "synthesis-polymerization-aging" synergistic reaction system, the precursor iron phosphate obtained after the synthesis reaction is uniformly distributed with polymerized monomers on the surface, the high molecular chains or networks generated in real time during the in-situ polymerization reaction are used as dynamic control agents, the morphology and particle size of the iron phosphate in the subsequent aging process are accurately controlled, and thus the high-performance battery-grade iron phosphate material with clear structure, moderate specific surface area and high tap density is obtained.

This application provides a method for producing xylan preparations, comprising the following steps: S1, mixing xylanase, a composite carrier, and a buffer solution to obtain a first mixture; S2, mixing the first mixture, a polypeptide, and an organosilane to obtain a xylanase preparation; the method for preparing the composite carrier comprises the following steps: S01, mixing polyurethane, carbon fiber oxide, and a solvent, collecting the solid phase to obtain a first precursor; mixing chitosan solution and copper salt, then adding a pore-forming agent, an emulsifier, and a crosslinking agent for crosslinking to obtain a second precursor; mixing the second precursor, ferrous salt, ferric salt, and water to obtain a third precursor; mixing the third precursor and EDTA salt solution, eluting, and freeze-drying to obtain a fourth precursor; S02, mixing the first precursor, the fourth precursor, dopamine hydrochloride, and an ethanol solution, collecting the solid phase, drying, and obtaining the composite carrier. The xylan preparation obtained by this application has good stability.

Provided is a method for preparing anhydrous ferric phosphate, comprising: adding an oxidant and phosphoric acid to a first solution containing ferrous salt to obtain a first mixture containing ferric salt, wherein the oxidant is at least one of air or oxygen, and the oxidant is added at a pressure of 0.6 to 1.2 MPa and an oxygen flow rate of 350 to 1350 ml / min per liter of a reaction system; adding monoammonium phosphate to the first mixture to obtain a second mixture containing a first precipitate; slurrying the first precipitate to obtain a slurry; acidizing the slurry by phosphoric acid; ageing the acidized slurry to obtain a second precipitate containing ferric phosphate dehydrate; and calcinating the second precipitate, to obtain the anhydrous ferric phosphate.

This invention relates to the preparation of a Cu / Ti-Fe3O4@FeOOH magnetic heterogeneous Fenton catalyst and its application in treating cyanide-containing wastewater. Ferrous salt, copper salt, and titanium salt are added to a hydrochloric acid solution and stirred until homogeneous to obtain a metal mixture. An alkali source is poured into a container, nitrogen gas is introduced, and the mixture is heated. The resulting mixture is added to the alkali source and stirred until homogeneous to obtain a precipitation reaction solution. A nitrate solution is added to the precipitation reaction solution and stirred until homogeneous to obtain an oxidation reaction solution. The oxidation reaction solution is heated and reacted, then cooled. The resulting solid particles are collected by magnetic separation, centrifugation, washing, drying, and grinding to obtain the copper-titanium doped iron-based magnetic heterogeneous Fenton catalyst Cu / Ti-Fe3O4@FeOOH. This catalyst exhibits excellent cyanide removal efficiency for cyanide-containing wastewater under pH conditions ranging from 6.5 to 12.5. Compared to existing Fenton processes, it eliminates the need to adjust the wastewater pH and can be directly applied to the treatment of cyanide-containing wastewater in various scenarios.

This invention discloses an apparatus and method for electrochemical oxidation-reduction synergistic treatment of chlorine-containing complex organic wastewater. The apparatus includes a reaction vessel (1), a chlorine-evolving anode (2) disposed therein, a reduction cathode (3) capable of generating atomic hydrogen in situ, a DC power supply (4), and a stirrer (5). The method includes: introducing wastewater containing chloride ions, ammonia nitrogen, and organic pollutants into the reaction vessel, adjusting the pH value, and adding ferrous salt; during the electrochemical reaction, the active chlorine generated at the anode activates ferrous ions to generate high-valence iron, selectively oxidizing the pollutants; the atomic hydrogen generated at the cathode reduces and dechlorinates the chlorine-containing intermediates, and removes Fe... 3+ The reduction and regeneration process achieves a closed-loop cycle of iron species, while the reduction of nitrates achieves a nitrogen cycle. This invention deeply couples anodic oxidation and cathodic reduction, achieving efficient mineralization of complex pollutants and effectively preventing the accumulation of toxic chlorination byproducts.

This invention discloses a magnetic adsorbent for separating proteins and pigments, its preparation method, and its application. First, ferrous and ferric salts are dissolved in a mixed solvent of water and alcohol, heated to 60–80°C, and an alkaline precipitant is added while stirring until a black precipitate is completely formed, yielding ferric oxide (Fe3O4). Next, the obtained ferric oxide is dispersed in an alcohol-water mixture, and ammonia and tetraethyl silicate are added. The mixture is stirred at room temperature for 2–5 hours to obtain silica-coated ferric oxide. Finally, ε-polylysine is dissolved in water, and the silica-coated ferric oxide is added. After ultrasonic dispersion, the mixture is stirred at 20–30°C for 10–24 hours. After washing and drying, an ε-polylysine-modified magnetic adsorbent is obtained. This invention is used for the purification of lentinan extract, specifically adsorbing proteins and pigments, and can be rapidly separated by an external magnetic field. It has the advantages of simple operation and high adsorption efficiency.

The application belongs to the technical field of environmental functional materials, and particularly relates to a sulfidized nano zero-valent iron composite material, a preparation method and application thereof. The sulfidized nano zero-valent iron composite material comprises biochar and sulfidized nano zero-valent iron loaded thereon. The application provides a preparation method of the sulfidized nano zero-valent iron composite material, which comprises the following steps: dispersing biochar in a ferrous salt solution to form a mixed solution under the protection of an inert atmosphere; dissolving a reducing agent and a sulfidizing agent in an alkaline solution to obtain a mixed reaction solution; and adding the mixed reaction solution into the mixed solution to obtain the sulfidized nano zero-valent iron composite material through reduction and sulfidization reaction. The sulfidization modification technology is combined with biochar loading, the biochar effectively prevents nano particle agglomeration, improves material stability and dispersity, the adsorption function and the catalytic degradation function of the sulfidized zero-valent iron are synergistic, and the removal efficiency of the composite material on persistent organic pollutants such as perfluorinated compounds is significantly improved.

The application discloses a fluid solidified soil for reinforcing coastal soft soil and a preparation method thereof, and belongs to the technical field of soft soil treatment, and comprises coastal soft soil, cement, slag, fly ash, a composite functional microbial agent, a composite functional stabilizer, an auxiliary microbial agent, a biological carrier and water; the composite functional microbial agent is one or more of sulfate-reducing bacteria and extracellular polymeric substance-producing bacteria; the composite functional stabilizer is one or more of iron source minerals or ferrous salts and layered double hydroxides; and the auxiliary microbial agent is an electron donor bacteria and an anaerobic alkali-tolerant bacteria. The preparation method comprises the following steps: dry mixing dry components in the solidified material, adding the coastal soft soil, water and the biological agent into the dry mixture to form the fluid solidified soil, pumping, self-flowing or pouring construction, and curing under the conditions of a temperature of 10-40 DEG C and a water content of not less than 25% for 7-28 days. The sulfate ion and the chloride ion in the coastal soft soil are converted into stable components by the biological agent.

This invention discloses a method for preparing low-viscosity basic ferric phosphate slurry and its product. The preparation method is as follows: ferrous salt solution and phosphate salt solution are prepared and simultaneously added to a reaction vessel to obtain basic ferrous phosphate slurry; an oxidant and a viscosity reducer are added for an oxidation reaction to obtain low-viscosity basic ferric phosphate slurry; the viscosity reducer is 5027W dispersant, anionic surfactant, sodium pyrophosphate, sodium hexametaphosphate, or chromium-free lignin sulfonate. This invention controls the crystal nucleation and growth rate through stepwise feeding, combined with the electrostatic and steric effects of the viscosity reducer, inducing primary particles to form a spherical structure and inhibiting agglomeration. The resulting slurry has a primary particle size of 55-80 nm, a secondary particle size of 7-10 μm, a viscosity ≤15.0 mPa·s, and a sedimentation efficiency P of 1.00-2.00. This slurry has good fluidity, and the anhydrous ferric phosphate prepared by subsequent crystal transformation has high purity, which is beneficial for improving ferric phosphate production efficiency and equipment lifespan.