35 results about "Iron sulphate" patented technology

The invention provides a preparation method of an iron phosphate material uniformly doped with a titanium element. The preparation method comprises the following steps: S1, respectively preparing a phosphoric acid solution, a phosphorus-oxygen mixed solution, a ferrous sulfate salt solution and a titanium salt solution; s2, adjusting the pH value of the ferrous sulfate salt solution to 1.0-2.5, adding the titanium salt solution and the phosphorus-oxygen mixed solution in a two-strand simultaneous adding manner, uniformly stirring, and reacting for 25-35 minutes at the temperature of 30-60 DEG C to obtain slurry A; s3, filtering and washing the slurry A to obtain a filter cake B; s4, adding water into the filter cake B, pulping, adding a phosphoric acid solution, heating, and preserving heat to obtain white slurry B; s5, filtering, washing and drying the white slurry B to obtain titanium-doped iron phosphate dihydrate, and calcining the iron phosphate dihydrate to obtain anhydrous iron phosphate; according to the invention, the crystal structure of the iron phosphate is improved by doping the titanium element, short-range preparation of the iron phosphate is realized, uniform doping of the element is ensured, the production period is shortened, and the complexity of the process is obviously reduced.

The invention provides an iron-based sulfate composite material as well as a preparation method and application thereof, and the method comprises the following steps: modifying aluminum-doped sodium ferrous sulfate Na < 2 + 2x > Fe < 2-x-1.5 y > Al < y > (SO4) 3 with few-walled carbon nanotubes subjected to surface acid treatment, and carrying out thermal shock reaction to obtain the iron-based sulfate composite material. The iron-based sulfate composite material provided by the invention can be used as a sodium ion battery positive electrode material with excellent rate capability and cycle performance.

The invention discloses a lithium ferric fluorosulfate positive electrode material as well as a preparation method and application thereof. The positive electrode material comprises lithium ferric fluorosulfate and a carbon nanotube coated on the lithium ferric fluorosulfate, the positive electrode material is a secondary particle, and the particle size of the secondary particle is 2-10 [mu] m; the secondary particles are composed of nanoscale primary particles; and the particle size of the primary particles is 20-200 nm. The preparation method comprises the following steps: 1) grinding lithium fluoride until the particle size is below 10 microns; 2) carrying out ball-milling mixing on the ground lithium fluoride, ferrous sulfate and carbon nanotubes to obtain a mixture; and 3) roasting the mixture to obtain the lithium ferric fluorosulfate positive electrode material. The positive electrode material has better electronic conductivity and ionic conductivity, higher specific capacity and more excellent cycle performance, and is excellent in high-temperature performance and low-temperature performance.

The invention provides a method for increasing the iron-phosphorus ratio of an iron phosphate material. The method comprises the steps that S1, raw materials are prepared, wherein an ammonium phosphate solution, a phosphoric acid solution, a titanium dioxide ferrous solution and 30% hydrogen peroxide are prepared; s2, synthesis: adding an ammonium phosphate solution, a titanium dioxide ferrous solution and hydrogen peroxide into a reaction container, preserving heat, and performing suction filtration and washing until the conductivity of washing water is lower than 4000 [mu] S / cm to obtain a yellow primary washing filter cake; s3, conversion: weighing 5-15 kg of pure water, adding 200-400 g of ferrous sulfate and 200-600 g of a phosphoric acid solution, adding 2.5-3.5 kg of the yellow first-washing filter cake, and after pulpifying completely, heating, preserving heat, carrying out suction filtration and washing to obtain a pink second-washing filter cake; s4, calcining: drying, calcining and crushing to obtain a finished product iron phosphate; according to the method, ferrous sulfate is introduced as a catalyst in the process of converting ammonium ferric phosphate into ferric phosphate crystals, so that a material with a high iron-phosphorus ratio is obtained under the condition of low phosphoric acid dosage.

The invention provides a barium slag harmless treatment method which comprises the following steps: mixing barium slag and desulfurized waste gypsum, adding water, beating into slurry, adding diluted industrial acid, stirring, acidifying, and heating, so that most of barium in the slurry forms BaSO4; adding a coupling agent, stirring, and carrying out coupling and competitive coordination reaction with free barium ions and barium salt in the product; adding a sulfate solution, and carrying out double decomposition reaction with the chelate barium to generate a non-toxic BaSO4 precipitate; and adding a ferrous sulfate solution to combine the rest of ferrous ions and sulfur ions in the product to form an iron sulfide precipitate, carrying out filter pressing to obtain filter residues with the water content of 20-30%, and drying. According to the method, toxic metal barium in the barium slag can be converted into nontoxic barium sulfate, and sulfur ions are converted into stable ferric sulfate, so that the barium ions, sulfide and corrosive pH value in the treated product all reach the national general solid waste first-class slag standard. The invention also provides an application of the barium slag treated by the method in building and building material industries.

The present invention discloses a method for producing lithium iron phosphate by recycling water resources, which belongs to the field of new energy material technology, including: using filtered wash water to dissolve ferrous sulfate and monoammonium phosphate, which undergo synthesis and aging reactions to obtain an iron phosphate reaction liquid, which undergoes solid-liquid separation, washing, etc. to obtain dihydrated iron phosphate; the dihydrated iron phosphate reacts with a lithium source and a carbon source, and is then dried and calcined to obtain lithium iron phosphate. During the entire process, the production wastewater is recycled after simple treatment, achieving zero discharge of wastewater and effective recovery of lithium ions, greatly reducing production costs. According to statistics, the present invention actually saves 0.15-0.58 kg of lithium and 24.3-29.3 m3 of pure water per ton of lithium iron phosphate. 3 , reduce the amount of washing water and iron-lithium wastewater treatment to 28.6~29.8m 3 and 1.6~2.2m 3 .

The present invention relates to the technical field of wastewater treatment, and in particular, to a method and application for recovering phosphorus in phosphorus-containing wastewater containing iron phosphate. The method for recovering phosphorus in phosphorus-containing wastewater containing iron phosphate comprises the following steps: (a) mixing salt-containing wastewater and filtrate to obtain a mixed water sample A; (b) adding an oxidant to the mixed water sample A to obtain a mixed solution B; (c) adding ferrous sulfate to the mixed solution B to obtain a reaction slurry C; (d) performing a first solid-liquid separation on the reaction slurry C to obtain a filter cake D; (e) adjusting the pH of the slurry containing the filter cake D to 1.4 to 1.8, and then performing a stirring reaction, a second solid-liquid separation, drying and calcining to obtain iron phosphate. The method for recovering phosphorus in phosphorus-containing wastewater containing iron phosphate has a high phosphorus recovery rate, and the obtained iron phosphate is of good quality and high purity, and can be used as a precursor of lithium battery positive electrode materials.

The present application belongs to the field of sodium batteries, and provides a composite sodium iron sulfate positive electrode material, and a preparation method therefor and the use thereof. The composite sodium iron sulfate positive electrode material comprises a core, the chemical formula of which is NaxMyFez(PO4)k(SO4)(0.4-0.6)xOt, wherein M comprises at least one of manganese, vanadium and titanium, 16≤x≤17, y=1, 4≤z≤5, 2≤k≤2.6, and y+z-0.1x-1.5k≤t≤y+z+0.1x-1.5k. In the present application, the decomposition of sulfate radicals is reduced, the material performance of the composite sodium iron sulfate positive electrode material is improved, and the performance aspects, such as the cycle performance, of a secondary battery in which the composite sodium iron sulfate positive electrode material is used are improved.

The application discloses a kind of iron wurtzite and sulphide iron ore mineral asynchronous flotation separation method, belong to nonferrous metal sulphide mineral flotation technical field;The application promotes the flotation of iron wurtzite by slurry aeration, realizes the asynchronous flotation of iron wurtzite, pyrite and pyrrhotite by means of high selectivity collector CTB-2 and oxidant calcium hypochlorite, solves the problem of difficult separation of iron wurtzite and pyrrhotite, and uses high concentration copper sulfate as depressor to rapidly improve the grade of zinc concentrate, uses ferrous sulfate to realize the sulfur-free flotation of sulfur concentrate, and finally obtains high-quality zinc concentrate, first sulfur concentrate (pyrite) and second sulfur concentrate (pyrrhotite) products.The application optimizes and simplifies the beneficiation process, cancels the magnetic separation step in the traditional process, and realizes efficient separation of zinc and sulfur through single flotation method.

This invention discloses a method for preparing battery-grade iron phosphate using iron-phosphorus titanium removal slag. The method includes: first, mixing the iron-phosphorus titanium removal slag with a titanium complex depolymerization aid, and then pretreating it to obtain an aid pretreatment slurry; next, drying the slurry and reacting it at 300-500℃ to obtain a first-stage high-temperature reaction product; then mixing it with an oxidant and reacting it at 800-900℃ to obtain a second-stage high-temperature reaction product; finally, obtaining the final product after acid leaching, aging, and drying. The battery-grade anhydrous iron phosphate prepared using this method has a specific surface area greater than 10 m². 2 The titanium residue is ≤50 ppm and the sulfur residue is ≤0.05%, and the relevant impurity indicators are better than industry requirements, which helps to reduce the charge transfer resistance of ferric phosphate. In addition, the method of this invention can be adapted to various ferric phosphate systems such as ferrous sulfate, ferrous chloride, and lithium-ion ferric phosphate slag acid solution, and has a wide range of application value.

The invention relates to the technical field of iron phosphate preparation, and discloses a method and device for continuously synthesizing iron phosphate, and the method comprises the following steps: 1) respectively adding iron powder and dilute sulphuric acid into a first continuous tubular reactor; 2) respectively pumping the ferrous sulfate solution and the phosphate solution into a second continuous tubular reactor; 3) continuously feeding the slurry into a crystal transformation aging kettle; 4) continuously conveying the aged slurry into a horizontal screw centrifuge for solid-liquid separation; 5) continuously conveying solids obtained by solid-liquid separation in the step 4) to a re-pulping tank, adding pure water, re-pulping and washing; 6) continuously conveying a filter cake to flash evaporation drying and high-temperature calcination, and then crushing, packaging and demagnetizing to obtain an iron phosphate product; according to the invention, the quality stability is ensured, the product production cycle is shortened, and the product quality stability is improved; the problem that a large amount of hydrogen escapes from a traditional kettle type reaction kettle to cause safety risks is solved.

The invention relates to the technical field of lithium ion battery materials, and discloses a low-cost method for preparing a battery-grade iron phosphate material, which comprises the following steps: mixing a phosphorus-containing ammonium sulfate solution recovered from iron phosphate production wastewater as a core phosphorus source with a ferrous sulfate solution; by accurately controlling the adding proportion of hydrogen peroxide and ammonia water and the pH value and ammonia nitrogen content of a reaction system, carrying out a synthetic reaction to generate an iron phosphate precursor; and carrying out phosphoric acid conversion, washing, flash drying and calcining on the precursor to obtain a final product. The iron phosphate material prepared by the invention has an iron-phosphorus ratio close to 1: 1 and an orthogonal and monoclinic phase coexisting double-phase structure, the sintering compaction density is high (greater than or equal to 2.47 g / cm < 2 >), the 1C specific discharge capacity is not less than 139mAh / g, and the battery grade application requirement is completely met.

This invention relates to the field of biomedical technology, and in particular to a method for preparing and applying a nanomedicine for treating deep endometriosis. The method involves mixing ferrous ammonium sulfate, trisodium citrate, and polyethyleneimine, then adding thioacetamide and triethanolamine via a solvothermal reaction to obtain two-dimensional iron sulfide nanosheets. Dopamine hydrochloride is then added and stirred at room temperature in anhydrous ethanol to obtain polydopamine-coated iron sulfide (FP). FP is then mixed with larotrectinib and anhydrous ethanol to obtain the nanomedicine FPL for treating deep endometriosis. The synthesis method of this invention is simple and highly operable; the product is stable and reproducible; FPL exhibits good biocompatibility and biodegradability. After entering the microenvironment of deep endometriosis lesions, it can responsively release larotrectinib, effectively inhibiting the Trk signaling pathway and significantly reducing the degree of nerve infiltration; simultaneously, the anti-inflammatory effect of the FP carrier alleviates the local inflammatory response, jointly inhibiting lesion progression.

The invention provides a method for preparing a sodium ferrous sulfate cathode material, and the preparation method is as follows: calcining ferrous sulfate heptahydrate for 5-6 hours under a certain temperature and vacuum conditions to obtain anhydrous ferrous sulfate; uniformly mixing anhydrous ferrous sulfate and anhydrous sodium sulfate with a molar ratio of 1:1 and pouring them into a grinding jar; sealing the grinding jar and putting it into a magnetic grinder for grinding for 2-6 hours; the ground material is heated to 300-400°C at a heating rate of 0.5-5°C / min in an argon atmosphere, and the temperature is kept constant for 10-36 hours to obtain the target material sodium ferrous sulfate. The sodium ion battery ternary cathode material provided by the invention is applied in the preparation of sodium ion batteries, has high capacity, excellent charge and discharge cycle stability and good rate performance, and the synthesis method is low in cost, convenient for industrial control, and has broad market application prospects.

The present invention relates to a preparation method of a lithium iron manganese phosphate precursor and lithium iron manganese phosphate, and the preparation method of the lithium iron manganese phosphate precursor comprises the following steps: 1) preparing ferrous phosphate from ferrous sulfate produced as a byproduct of titanium dioxide in a sulfuric acid process, separating a mother liquor, and obtaining a first solution after the mother liquor is subjected to membrane treatment and MVR concentration treatment; 2) removing impurities from ferrous sulfate produced as a byproduct of titanium dioxide in a sulfuric acid process, obtaining a second solution; 3) mixing the first solution and the second solution to obtain a mixed salt solution; 4) simultaneously dropping the mixed salt solution and the ammonium phosphate salt solution into a reactor under an inert atmosphere to react, controlling the pH value of the solution in the reactor to 5-6, and controlling the reaction temperature to 50-80°C, performing solid-liquid separation after the reaction, and obtaining ammonium iron manganese phosphate. The present invention combines the ferrous mother liquor of titanium dioxide in a sulfuric acid process to prepare an iron phosphate process, and utilizes the comprehensive utilization of the iron phosphate reaction mother liquor to prepare ammonium iron manganese phosphate, with a high degree of resource utilization, and realizes the utilization of a large amount of Mn elements in the iron phosphate reaction mother liquor.

The present invention provides a high-entropy sodium iron sulfate positive electrode material, a preparation method thereof, and a sodium-ion battery. The high-entropy sodium iron sulfate positive electrode material includes a doped sodium iron sulfate material and a carbon coating layer. The molecular formula of the doped sodium iron sulfate material is Na 2.5 Fe 1.75‑ x A y B z C m D n (SO4)3, where 0 < x ≤ 0.5, 0 ≤ y ≤ 0.06, 0 ≤ z ≤ 0.06, 0 ≤ m ≤ 0.06, 0 ≤ n ≤ 0.06, 2x = 2y + 3z + 4m + 5n, and at least two of y, z, m, and n are not 0; A is selected from at least one of Mn 2+ , Mg 2+ , Zn 2+ , Ni 2+ , Cu 2+ , Sn 2+ , Ca 2+ , Co 2+ ; B is selected from Al 3+ and / or Cr 3+ ; C is selected from Zr 4+ and / or Ti 4+ ; D is selected from Nb 5+ and / or Ta 5+ , and at least contains four doping elements, and the contained doping elements satisfy equimolar or near-equimolar doping. The present invention conducts high-entropy doping on sodium iron sulfate to improve the low-temperature performance and cycling performance of the battery.

The present invention relates to the technical field of sodium-battery materials, and discloses a positive electrode material of composite sodium ferric sulfate and a preparation method therefor, a positive electrode and a sodium-ion battery. For the positive electrode material of composite sodium ferric sulfate, particles of the positive electrode material include a sodium ferric sulfate matrix, a three-dimensional conductive network embedded into the sodium ferric sulfate matrix and a conductive coating layer coated outside the sodium ferric sulfate matrix; and the three-dimensional conductive network and the conductive coating layer are both formed from PEDOT. The preparation method includes: mixing PSS, EDOT, sodium sulfate, ferrous sulfate and an oxidant as an initiator in an aqueous solution and making the same fully react to render a precursor solution; drying the precursor solution; and then carrying out heat treatment to render the positive electrode material of composite sodium ferric sulfate. The positive electrode is prepared by the above positive electrode material. The sodium-ion battery includes the above positive electrode. The positive electrode material has good conductivity, capacity, rate and interface stability.

The invention provides a composite carbon-coated sodium ferrous sulfate positive electrode material and a preparation method and application thereof, and belongs to the technical field of sodium ion batteries, the composite carbon-coated sodium ferrous sulfate positive electrode material comprises sodium ferrous sulfate and a composite carbon coating layer coating at least part of the surface of the sodium ferrous sulfate; materials for forming the composite carbon coating layer comprise a biomass porous carbon material and an inorganic carbon source. The biomass porous carbon material and the inorganic carbon source are used at the same time to form the composite carbon coating layer, and the composite carbon coating layer is used for coating the sodium ferrous sulfate, so that the compaction density and the cycle performance of the sodium ferrous sulfate positive electrode material are effectively improved, and the resistivity of the sodium ferrous sulfate positive electrode material is reduced.

The invention discloses a dry and wet membrane tank cleaning agent as well as a preparation method and application thereof. The dry and wet membrane tank cleaning agent comprises the following components: sulfuric acid, ferrous sulfate, phenolsulfonic acid, citric acid, sodium dodecyl benzene sulfonate, hydrogen peroxide and water. According to the invention, an advanced oxidation method is adopted to replace acid washing or alkali washing in the traditional technology for the first time, and the produced tank cleaning agent has extremely strong oxidation capacity, can effectively oxidize organic matters, and is suitable for dry film and green paint development processes in the PCB processing process; precipitated solids can be effectively removed, oily substances and intractable high polymer residues in dry films and green paint tanks can be removed, and the cleaning effect is very ideal. And regular tank cleaning can effectively ensure production quality and prolong the service life of instruments and equipment.

The present invention belongs to the field of environmental protection, and in particular to a formaldehyde wastewater treatment parameter allocation system based on Fenton catalytic oxidation method and its application. The system provided by the present invention includes: a hydrogen peroxide agent tank, a ferrous sulfate solution agent tank, a formaldehyde wastewater tank, a first temperature-controlled liquid material tank, a second temperature-controlled liquid material tank, a Fenton reactor, a temperature control device, a flow control device, a formaldehyde concentration online monitoring device, and a pH value online monitoring device. In the present invention, by adjusting the parameter conditions when the system is running, the real-time influence of parameter conditions such as hydrogen peroxide concentration, ferrous sulfate solution concentration, reaction pH value, reaction time, reaction temperature, etc. on the formaldehyde removal efficiency during the dynamic reaction process of Fenton catalytic oxidation method for treating formaldehyde wastewater can be studied, so as to quickly and accurately know the most suitable parameter conditions for Fenton catalytic oxidation method for treating formaldehyde wastewater, and provide technical guidance for the practical engineering application of Fenton catalytic oxidation technology.

The utility model discloses a photo-Fenton sewage treatment system, which comprises a sewage regulating tank, which is connected with a sulfuric acid charging bucket and a ferrous sulfate charging bucket through pipelines; the pipeline mixer is connected to the sewage adjusting tank through a pipeline; the pipeline mixer is also connected with a hydrogen peroxide barrel through a pipeline; the photocatalytic equipment is connected to the pipeline mixer through a pipeline, the photocatalytic equipment comprises a plurality of photo-Fenton reaction cavities which are connected in parallel, and the photocatalytic equipment is connected to the sewage regulating tank through a T-shaped pipeline. The sewage treatment system at least has the following beneficial effects that the sewage regulating tank is connected with the pipeline mixer, the pipeline mixer is connected with the photocatalysis equipment, and the photocatalysis equipment is connected with the sewage regulating tank through the T-shaped pipeline to form a circulating structure, so that sewage which does not reach the standard can be circulated back to the treatment system, and the sewage treatment efficiency of the whole system is effectively improved.

The invention relates to the technical field of flower planting, and specifically discloses a flower planting device, comprising an irrigation module, wherein the irrigation module comprises a hollow semi-ring, a through hole, a liquid inlet pipe and a solenoid valve, wherein two groups of hollow semi-rings are symmetrically arranged on the left and right, and the through holes are equidistantly arranged at the bottom of the hollow semi-rings. When flowers are irrigated with a ferrous sulfate solution, the device is used to realize the automatic setting of a soil pH analyzer, so that the soil pH analyzer monitors the soil acidity during irrigation in real time, and prevents the pH value from being lowered due to irrigation with more ferrous sulfate solution, thereby ensuring the effect of pH value regulation. After the irrigation is completed, the soil pH analyzer is made to perform circular motion on the two groups of hollow semi-rings by setting multiple groups of primary contact switches and cooperating with a secondary driving module, so as to perform multiple pH value detections on the soil near the flowers, and prevents uneven irrigation with the ferrous sulfate solution, which causes different pH values ​​of the soil near the flowers, and facilitates personnel to remedy in time.

Iron(II) sulfate is a byproduct of the chemical industry and is inexpensive. Its addition to pig and cattle farming improves the barn climate and contributes to healthy husbandry conditions for pigs. The additional costs are offset by the benefits of deodorization and its use as a fertilizer. This also allows for improved barn climate control, even on slatted floors. Furthermore, it eliminates odor emissions.

In a method for producing iron(II) sulfate heptahydrate, materials containing iron(II) chloride are purified, followed by reaction of the iron(II) chloride with sulfuric acid to yield iron(II) sulfate monohydrate. The iron(II) sulfate monohydrate is then converted into iron(II) sulfate heptahydrate.

The invention provides a method and device for determining the content of sodium chlorate in an industrial sodium hypochlorite solution, and the method comprises the following steps: a, eliminating the interference of sodium hypochlorite: adding hydrogen peroxide into a to-be-detected industrial sodium hypochlorite solution to enable the hydrogen peroxide to be excessive so as to destroy sodium hypochlorite; b, neutralizing sodium hydroxide: neutralizing the sodium hydroxide by using a sulfuric acid solution; c, reducing sodium chlorate: adding ferrous sulfate as a reducing agent into the treated solution in an acidic environment, and reducing sodium chlorate into chloride ions; d, titrating residual ferrous ions: taking sodium diphenylaminesulfonate as an indicator, titrating the excessive ferrous ions by using 0.1 mol / L of potassium dichromate standard titration solution until the color of the solution is suddenly changed to purple, and reaching a titration end point; and e, calculating the content of sodium chlorate: calculating the mass concentration of sodium chlorate according to the volume and concentration of the potassium dichromate standard solution consumed by titration. The method and the device for determining the content of sodium chlorate in the industrial sodium hypochlorite solution have the advantage that the determination result is more accurate and reliable.

The invention belongs to the technical field of biological medicines, and discloses an iron sulfide coated polydopamine nano material for toxicity reduction and efficacy enhancement of cervical cancer radiotherapy, and a preparation method and application of the iron sulfide coated polydopamine nano material. The method comprises the following steps: dissolving ammonium ferrous sulfate and trisodium citrate in ethylene glycol to obtain a solution A, dissolving polyethyleneimine in ethylene glycol to obtain a solution B, adding the solution B into the solution A, and stirring and reacting at normal temperature to obtain a mixed solution; adding a thioacetamide solution into the mixed solution, then dropwise adding triethanolamine, carrying out stirring reaction at normal temperature, carrying out solvothermal reaction after stirring is ended, and centrifuging and washing a product after the reaction is ended, so as to obtain a two-dimensional iron sulfide nanosheet; and adding dopamine hydrochloride, and stirring in absolute ethyl alcohol at room temperature to obtain the iron sulfide coated polydopamine nano material. The synthesis method is simple, convenient and high in operability; the synthesized product is stable and has repeatability; the traditional Chinese medicine composition can be used for sensitizing radiation therapy of cervical cancer, can relieve radiation colitis and reduce side effects of radiation therapy, and is beneficial to clinical application.

In a method for producing iron(II) sulfate heptahydrate, materials containing iron(II) chloride are purified, followed by reaction of the iron(II) chloride with sulfuric acid to yield iron(II) sulfate monohydrate. The iron(II) sulfate monohydrate is then converted into iron(II) sulfate heptahydrate

The invention provides a method for preparing iron phosphate and nickel sulfate from a ferrous sulfate solution containing nickel and chromium, and belongs to the technical field of valuable metal recovery. The method comprises the following steps: S1, carrying out purification treatment on a ferrous sulfate solution containing nickel and chromium so as to deeply remove chromium; s2, introducing a phosphorus source and a composite structure directing agent into the purified solution to form a mixed system; s3, step-by-step oxidation is conducted on the mixed system, then aging treatment is conducted, and an iron phosphate suspension and a nickel sulfate solution are obtained; s4, carrying out solid-liquid separation on the iron phosphate suspension, and washing, drying and calcining the obtained solid to obtain an anhydrous iron phosphate product; and S5, purifying the nickel sulfate solution to obtain a nickel sulfate product. The iron phosphate product prepared by using the proper composite structure guiding agent and the processes of step-by-step oxidation, aging and the like has good performances in the aspects of particle size, tap density, Fe / P molar ratio and the like, and the requirements of practical application are met.

The invention relates to the field of hydrometallurgy, in particular to a short-process purification preparation method of high-purity iron phosphate, which comprises the following steps: (1) performing solid-phase extraction on ferrous sulfate feed liquid containing impurity metal elements by using a solid-phase extraction agent A, and selectively adsorbing and removing the impurity metal elements in the solution to obtain a purified ferrous sulfate solution; (2) mixing the purified ferrous sulfate solution obtained in the step (1) with a phosphate solution, and carrying out oxidation precipitation reaction to generate an iron phosphate precursor; and (3) the iron phosphate precursor obtained in the step (2) is filtered, washed, dried and roasted, an iron phosphate product is obtained, and the solid-phase extraction agent A comprises resin of a formula (I) and / or resin of a formula (II). The final product is low in impurity content and high in tap density, the industrial problem that multiple impurities are difficult to synchronously and deeply remove under the acidic and high-iron background is solved, and the requirements of the high-end lithium ion battery positive electrode material precursor are completely met. (I) and (II).

A method for producing lithium iron phosphate from waste lithium iron phosphate material is provided. [Solution] The method includes the steps of: crushing the positive electrode sheet of a waste lithium iron phosphate battery, sieving it to obtain lithium iron phosphate raw material, dissolving it in an acidic solution, and collecting the first filtrate after filtration; adding ferrous sulfate solution to the first filtrate to obtain a mixed solution; adding hydrogen peroxide solution and ammonia aqueous solution to the mixed solution, filtering and washing after the reaction to obtain a second filtrate and a filtration cake; washing and drying the filtration cake to obtain iron hydroxyphosphate; adding barium hydroxide aqueous solution to the second filtrate, allowing it to react completely and then filtering to obtain a third filtrate; adding phosphoric acid solution to the third filtrate to obtain a fourth filtrate; mixing iron hydroxyphosphate, the fourth filtrate and a carbon source, sanding the slurry, drying and obtaining a powder; and sintering and pulverizing the powder in an inert atmosphere to obtain a carbon-coated lithium iron phosphate material.