Treatment method for recycling iron phosphate and iron phosphate

Abstract

The invention relates to the technical field of iron phosphate waste regeneration, in particular to a treatment method for iron phosphate recycling and iron phosphate. The treatment method comprises the following steps: step 1, mixing a phosphoric acid solution and a hydrochloric acid solution to obtain a mixed acid solution, putting iron phosphate waste into the mixed acid solution to obtain a first mixed solution, and removing impurities from the first mixed solution to obtain a first filtrate; step 2, adding iron oxyhydroxide slurry into the first filtrate, mixing, pulping and reacting to obtain a second mixed solution with the pH value of 1-2, and filtering the second mixed solution to obtain second filtrate; and 3, stirring the second filtrate, heating to 75-90 DEG C, separating out a solid-liquid mixture containing an iron phosphate dehydrate solid, filtering the solid-liquid mixture, separating out the iron phosphate dehydrate solid and a third filtrate, washing and drying the iron phosphate dehydrate solid to obtain battery-grade iron phosphate, and recycling the third filtrate to obtain the battery-grade iron phosphate. According to the treatment method for recycling the iron phosphate, the iron phosphate waste can be efficiently regenerated at low cost, and the obtained battery-grade iron phosphate has the advantage of high purity.

Description

Technical Field

[0001] The invention relates to the technical field of iron phosphate waste regeneration, and in particular to an iron phosphate regeneration treatment method and the iron phosphate. Background Art

[0002] As an important precursor of lithium iron phosphate cathode material, iron phosphate has important influence on the physical and chemical properties and electrochemical properties of lithium iron phosphate battery, such as iron-phosphorus ratio, particle size, specific surface area and structural morphology. In particular, the battery-grade iron phosphate can be prepared by recycling iron phosphate waste.

[0003] In the process of preparing iron phosphate, due to the influence of factors such as people, machines, materials, methods, environment, and measurement, unqualified iron phosphate is produced, which is iron phosphate waste. Its main performance is abnormal indicators such as impurity content, iron-phosphorus ratio, magnetic substances, morphology, purity, etc., and it cannot be used in the production of lithium iron phosphate. If these wastes are discarded, solid waste or landfilled,

[0004] This causes waste and loss of resources. Therefore, the resource recycling and utilization of iron phosphate waste is of great significance to the healthy development of the industry and the improvement of ecological and economic benefits.

[0005] Chinese patent CN116002643 A discloses a method for regenerating and treating waste iron phosphate, wherein the waste iron phosphate is mixed with a phosphoric acid solution having a mass concentration of 16-20%, reacted, filtered, and a filtrate is obtained; the filtrate is mixed with water to obtain a mixed solution, the mixed solution is reacted at 70-90°C, and then aged and filtered, and the filtered material is calcined to obtain regenerated iron phosphate. This method uses phosphoric acid with a relatively low concentration to dissolve the waste iron phosphate, and then dilutes the solution with water to a pH of 1.0-1.2 and an iron content of 1.35-1.45%. A large amount of water is required for dilution, and a large amount of dilute acid water is produced, which is not easy to handle; in addition, the use of phosphoric acid to dissolve the waste iron phosphate needs to be carried out in a sand mill, which has high requirements for equipment.

[0006] Chinese patent CN118702080 A discloses a method for preparing battery-grade iron phosphate by recycling iron phosphate waste, including phosphoric acid leaching of iron phosphate waste, pH adjustment of mixed powder of iron powder and iron-containing compound, sodium fluoride aluminum removal, oxidation precipitation and other processes. The obtained iron phosphate dihydrate precipitate is battery-grade iron phosphate after calcination, and the obtained mother liquor can be reused as a leaching agent after supplementing phosphoric acid. This method has the disadvantages of long process flow and the introduction of many impurity ions, which makes it difficult to post-process the washing water.

[0007] Therefore, a treatment method for recycling waste iron phosphate is developed, which has the advantages of simple process, low cost, high production capacity, high purity of regenerated iron phosphate and good performance. Summary of the invention

[0008] The purpose of the present invention is to avoid the shortcomings of the prior art and provide a treatment method for the regeneration of iron phosphate, which can regenerate iron phosphate waste at low cost and high efficiency, and the resulting battery-grade iron phosphate has the advantage of high purity.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] A treatment method for regenerating and utilizing iron phosphate is provided, comprising the following steps:

[0011] Step 1, mixing a phosphoric acid solution and a hydrochloric acid solution to obtain a mixed acid solution, adding iron phosphate waste to the mixed acid solution to obtain a first mixed solution, and removing impurities from the first mixed solution to obtain a first filtrate;

[0012] Step 2: adding ferric oxyhydroxide slurry to the first filtrate, mixing and beating to react, to obtain a second mixed solution, wherein the pH of the second mixed solution is 1 to 2, and filtering the second mixed solution to obtain a second filtrate;

[0013] Step three, stirring the second filtrate and heating it to 75-90° C. to precipitate a solid-liquid mixture containing dihydrate ferric phosphate solid, filtering the solid-liquid mixture to separate the dihydrate ferric phosphate solid and the third filtrate, washing and drying the dihydrate ferric phosphate solid to obtain battery-grade iron phosphate, and recycling the third filtrate.

[0014] In some embodiments, in the mixed acid, the concentration of the phosphoric acid solution is 60% to 85%, the concentration of the hydrochloric acid solution is 5% to 15%, and the mass ratio of the phosphoric acid solution to the hydrochloric acid solution is 2 to 5:1.

[0015] In some embodiments, the mixing and stirring speed of the waste iron phosphate and the mixed acid solution is 50 r / min to 300 r / min.

[0016] In some embodiments, the mixing reaction time of the waste iron phosphate and the mixed acid solution is 1 to 2 hours, and the reaction temperature is 70 to 90°C.

[0017] In some embodiments, the mass ratio of the mixed acid solution to the iron phosphate waste is 3 to 5:1.

[0018] In some embodiments, the iron oxyhydroxide slurry is obtained by mixing iron oxyhydroxide with water or diluted acid water, and the solid content of the iron oxyhydroxide slurry is 10% to 15%.

[0019] In some embodiments, the molar ratio of the amount of the ferric oxyhydroxide slurry added to the ferrophosphorus in the first filtrate is 1.2 to 1.4:1.

[0020] In some embodiments, the reaction temperature of the iron oxyhydroxide slurry and the first filtrate is 50-70° C., the reaction stirring time is 0.5-2 h, and the Fe mass fraction of the second mixed solution is 4.5%-6.5%;

[0021] The time for the second filtrate to precipitate solid ferric phosphate dihydrate is 1 to 3 hours.

[0022] In some embodiments, the third filtrate is returned to the iron oxyhydroxide slurry of step two for slurrying reaction or returned to the iron phosphate waste dissolution reaction of step one.

[0023] Beneficial effects of the treatment method for regenerating and utilizing iron phosphate of the present invention:

[0024] (1) The treatment method for regenerating and utilizing iron phosphate of the present invention first uses a mixed acid solution obtained by mixing phosphoric acid and hydrochloric acid to dissolve iron phosphate, wherein the phosphoric acid in the mixed acid solution helps to improve the dissolution efficiency of iron phosphate. Since the dissolution rate of iron phosphate in hydrochloric acid is higher than that of phosphoric acid, hydrochloric acid is added to phosphoric acid to dissolve iron phosphate, which effectively improves the dissolution efficiency and overcomes the problem of low efficiency of using phosphoric acid alone. When the hydrochloric acid in the mixed acid can be recycled subsequently, there is no need to replenish the hydrochloric acid solution, and high cost is not required and the mixed acid solution can be recycled. After the mixed acid solution fully dissolves the iron phosphate waste, a phosphoferric salt solution is obtained, which is filtered to remove the insoluble impurities and avoid reintroduction into the regeneration process.

[0025] (2) The treatment method for regenerating and utilizing iron phosphate of the present invention uses a mixed acid solution to dissolve waste iron phosphate to obtain a first filtrate that is a phosphophosphate solution with a relatively high acidity. The present invention uses ferric hydroxide to carry out a neutralization reaction, thereby avoiding the problem of using clean water to adjust the pH value and requiring a large amount of water, and also avoiding the problem of using alkaline solution or ammonia water to neutralize the acidity and introducing a large amount of salt, thereby effectively avoiding the introduction of other impurity ions, and effectively controlling the impurities in the raw materials used; and, by using ferric hydroxide for neutralization, the pH can be quickly adjusted by only adjusting the molar ratio of the raw materials, thereby improving production efficiency; in addition, by using ferric hydroxide for neutralization, less salt substances and lower impurity ions are generated, thereby less washing water is generated, reducing the wastewater treatment load, saving energy consumption and costs, and having better environmental benefits.

[0026] (3) The treatment method for recycling iron phosphate of the present invention gradually precipitates solid iron phosphate dihydrate by temperature control, which can better control the morphology and obtain a product with stable morphology, controllable particles and high tap density. The solid iron phosphate obtained after washing and drying is suitable for preparing high-voltage lithium iron phosphate batteries and has good electrical properties.

[0027] (4) Compared with the conventional method for preparing ferric phosphate, the processing method for regenerating and utilizing ferric phosphate of the present invention does not require the steps of removing aluminum with sodium fluoride, oxidative precipitation or aging, thereby effectively shortening the production process, being highly efficient, and being suitable for large-scale production and application.

[0028] (5) The processing method for regenerating and utilizing iron phosphate of the present invention is to reuse the mother liquor generated by the recycling of waste iron phosphate and return it to the recycling production line for slurrying of hydroxyl iron oxide; or to use it in the iron phosphate synthesis production line, without the need for separate processing steps and equipment, and has the advantages of environmental protection and low cost.

[0029] (6) The processing method for recycling iron phosphate of the present invention can be operated without expensive equipment, has low energy consumption cost, and is easy to realize industrial production. The recycling and utilization of iron phosphate meets battery-grade requirements and has good performance.

[0030] Also provided is iron phosphate, which is obtained by the above-mentioned treatment method for regenerating and utilizing iron phosphate.

[0031] Figure 1 This is the XRD pattern of the regenerated anhydrous iron phosphate obtained in Experimental Example 3.

[0032] Figure 2 This is a SEM image of the regenerated anhydrous iron phosphate obtained in Experimental Example 3. DETAILED DESCRIPTION

[0033] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0034] Example

[0035] The treatment method for regenerating and utilizing iron phosphate disclosed in this embodiment comprises the following steps:

[0036] Step 1, mixing phosphoric acid and hydrochloric acid to obtain a mixed acid solution, adding iron phosphate waste to the mixed acid solution to obtain a first mixed solution, and removing impurities from the first mixed solution to obtain a first filtrate;

[0037] Step 2: adding ferric oxyhydroxide slurry to the first filtrate, mixing and beating to react, to obtain a second mixed solution, wherein the pH of the second mixed solution is 1 to 2, and filtering the second mixed solution to obtain a second filtrate;

[0038] Step three, stirring the second filtrate and heating it to 75-90° C. to precipitate a solid-liquid mixture containing dihydrate ferric phosphate solid, filtering the solid-liquid mixture to separate the dihydrate ferric phosphate solid and the third filtrate, washing and drying the dihydrate ferric phosphate solid to obtain battery-grade iron phosphate, and recycling the third filtrate.

[0039] The above-mentioned treatment method for recycling iron phosphate uses a mixed acid solution of phosphoric acid and hydrochloric acid to dissolve iron phosphate. High-concentration phosphoric acid helps to improve the dissolution efficiency of iron phosphate, and the dissolution efficiency of mixed acid is faster than that of phosphoric acid alone. The dissolution rate of iron phosphate in hydrochloric acid is higher than that of phosphoric acid. That is, mixed acid is used to dissolve the iron phosphate waste for the first time, and a small amount of hydrochloric acid is added. When it is subsequently recycled, there is no need to supplement the hydrochloric acid solution.

[0040] After the mixed acid solution fully dissolves the iron phosphate waste, a phospho-ferric salt solution is obtained, which is filtered to remove insoluble impurities to avoid reintroduction into the regeneration process.

[0041] The obtained ferrophosphite solution has a high acidity. If clean water is used to adjust the pH in this process, a large amount of water is needed to reduce its acidity. If alkali solution or ammonia water is used, a large amount of salt is introduced to neutralize the acidity. The use of ferric hydroxide can avoid the introduction of other impurity ions. Metal impurities have been controlled in ferric hydroxide during the production process, and the impurities in the raw materials used in the process are effectively controlled.

[0042] The ferric hydroxide oxide is first pulped to disperse the lumps of material coming out of the filter press, and then neutralized with a high-acid ferric phosphide solution to generate ferric phosphate. The ferric hydroxide oxide in a dispersed state is easier to react with the high-acid ferric phosphide solution, thereby increasing the reaction rate. Moreover, under the process conditions, the ferric phosphate is first formed in a solution state, and the mass fraction of iron in the solution is relatively high (4.5%-6.5%).

[0043] For the solution state iron phosphate, under the above conditions, dihydrate iron phosphate solid is gradually precipitated, the morphology can be well controlled, and a product with stable morphology, controllable particles and high tap density is obtained. After washing and drying, the obtained iron phosphate solid is suitable for preparing high-voltage lithium iron phosphate batteries and has good electrical properties. This step is different from the conventional process, and no aging process is required, which improves efficiency.

[0044] The method uses ferric hydroxide to participate in the neutralization reaction, and does not use alkaline materials to adjust the pH. It produces less salt substances and low impurity ions, that is, less washing water is produced, reducing the treatment load of wastewater, saving energy consumption and cost, and having good environmental benefits.

[0045] The mother liquor generated from the recycling of waste iron phosphate is returned to the recovery production line for slurrying of iron oxyhydroxide; or used in the iron phosphate synthesis production line without the need for separate processes and equipment.

[0046] The process equipment is simple, the energy consumption cost is low, and it is easy to realize industrial production. The recycled iron phosphate prepared meets battery-grade requirements and has good performance.

[0047] In this embodiment, in the mixed acid, the concentration of the phosphoric acid solution is 60% to 85%, preferably 70%, the concentration of the hydrochloric acid solution is 5% to 15%, preferably 10%, and the mass ratio of the phosphoric acid solution to the hydrochloric acid solution is 2 to 5:1, preferably 4:1.

[0048] The amount of hydrochloric acid used should not be too large to avoid introducing too much chloride ions.

[0049] In this embodiment, the mixing and stirring speed of the waste iron phosphate and the mixed acid solution is 50 r / min to 300 r / min, preferably 200 r / min.

[0050] In this embodiment, the mixing reaction time of the waste iron phosphate and the mixed acid solution is 1 to 2 hours, preferably 1.5 hours, and the reaction temperature is 70 to 90°C, preferably 80°C.

[0051] In this embodiment, the mass ratio of the mixed acid solution to the iron phosphate waste is 3-5:1, preferably 4:1.

[0052] In this embodiment, the ferric oxyhydroxide slurry is obtained by mixing ferric oxyhydroxide with water or diluted acid water, and the solid content of the ferric oxyhydroxide slurry is 10% to 15%, preferably 12%.

[0053] The solid content ratio has good mixing effect. If it is too high, the material will be viscous, with poor fluidity and difficulty in material transfer. If the solid content ratio is too low, the production capacity will be reduced and the efficiency will be low.

[0054] In this embodiment, the molar ratio of the amount of the ferric oxyhydroxide slurry added to the ferrophosphorus in the first filtrate is 1.2-1.4:1, preferably 1.3:1.

[0055] In this embodiment, the reaction temperature of the iron oxyhydroxide slurry and the first filtrate is 50-70°C, preferably 60°C, the reaction stirring time is 1h, and the Fe mass fraction of the second mixed solution is 4.5%-6.5%, preferably 5%;

[0056] The time for precipitating solid ferric phosphate dihydrate from the second filtrate is 1 to 3 hours, preferably 2 hours.

[0057] In this embodiment, the third filtrate is returned to the iron oxyhydroxide slurry of step two for slurrying reaction or returned to the iron phosphate waste of step one.

[0058] Test Example 1

[0059] 200kg of iron phosphate waste and 730kg of phosphoric acid (600kg, 85%) & hydrochloric acid (130kg, 5%) mixed acid solution were dissolved in a stirring tank. The reaction conditions were: stirring speed 50r / min, reaction temperature 70℃, reaction time 1h. After the iron phosphate waste was completely dissolved, a filter press was used to filter and remove insoluble impurities to obtain a filtrate. 480kg of hydroxyl iron was mixed with 2800kg of clean water (the slurry solid content was 14.63%) and mixed with the filtrate of the iron phosphate waste. The amount of hydroxyl iron slurry added was 1.37:1 according to the phosphorus-iron ratio (molar ratio) in the solution. The reaction temperature was 50℃, the stirring time was 0.5h, and the Fe mass fraction in the solution after the reaction was 6.27%. The temperature was raised to 83℃, the stirring time was 1h, and 710kg of anhydrous iron phosphate solid was obtained by filtration, washing, and drying. The mother liquor obtained by filtration was returned for hydroxyl iron slurrying.

[0060] Test Example 2

[0061] 150kg of iron phosphate waste and 740kg of phosphoric acid (500kg, 60%) & hydrochloric acid (240kg, 15%) mixed acid solution were dissolved in a stirring tank. The reaction conditions were: stirring speed 300r / min, reaction temperature 90℃, reaction time 1.5h. After the iron phosphate waste was completely dissolved, a filter press was used to filter and remove insoluble impurities to obtain a filtrate. 330kg of hydroxyl iron was mixed with 2800kg of clean water (the slurry solid content was 10.54%) and mixed with the filtrate of the iron phosphate waste. The amount of hydroxyl iron slurry added was 1.21:1 according to the phosphorus-iron ratio (molar ratio) in the solution. The reaction temperature was 60℃, the stirring time was 1h, and the Fe mass fraction in the solution after the reaction was 4.63%. The temperature was raised to 90℃, the stirring time was 2h, and 498kg of anhydrous iron phosphate solid was obtained by filtration, washing and drying. The mother liquor obtained by filtration was returned for hydroxyl iron slurrying.

[0062] Test Example 3

[0063] 170kg of iron phosphate waste and 667kg of phosphoric acid (520kg, 70%) & hydrochloric acid (147kg, 10%) mixed acid solution were dissolved in a stirring tank. The reaction conditions were: stirring speed 200r / min, reaction temperature 80℃, reaction time 2h. After the iron phosphate waste was completely dissolved, a filter press was used to filter and remove insoluble impurities to obtain a filtrate. 355kg of hydroxyl iron oxide was mixed with 2650kg of dilute acid recycled water (the slurry solid content was 11.81%), and mixed with the iron phosphate waste filtrate for reaction. The amount of hydroxyl iron oxide slurry added was 1.32:1 according to the phosphorus-iron ratio (molar ratio) in the solution. The reaction temperature was 70℃, the stirring time was 2h, and the Fe mass fraction in the solution after the reaction was 5.29%. The temperature was raised to 75℃, the stirring time was 3h, and 532kg of anhydrous iron phosphate solid was obtained by filtration, washing and drying. The mother liquor obtained by filtration was returned to the iron phosphate synthesis production line.

[0064] The test results of regenerated anhydrous ferric phosphate are:

[0065] project Manufacturer's required value Test Example 1 Test Example 2 Test Example 3 Fe / % 35.7-36.7 36.33 36.41 36.28 P / ％ 20.0-21.1 20.90 20.89 20.85 Fe / P 0.96-0.97 0.964 0.966 0.965 Ca / ppm ≤50 10.2 18.1 20.5 Mg / ppm ≤50 8.7 9.3 7.2 Na / ppm ≤50 29.1 20.8 24.3 K / ppm ≤50 1.7 2.3 3.2 Cu / ppm ≤1 0.1 0.2 0.1 Zn / ppm ≤30 2.3 5.2 3.9 Mn / ppm ≤100 2.9 3.8 4.8 Al / ppm ≤80 3.5 8.1 6.9 Ti / ppm ≤100 8.8 7.9 9.1 Co / ppm ≤20 2.3 3.1 4.2 Pb / ppm ≤20 4.6 2.5 5.3 Cr / ppm ≤30 10.2 9.8 7.1 S / ppm ≤100 20.1 23.5 30.5 Magnetic substances / ppm ≤0.5 0.15 0.12 0.18 Moisture / % ≤0.5 0.20 0.33 0.25 <![CDATA[Tap density g / cm 3 > ≥0.6 0.91 0.93 0.90 Particle size D50 / um ≤6 2.7 2.4 3.1 <![CDATA[Specific surface area m 2 / g]]> 7-10 9.3 9.1 8.7

[0066] Parameters for preparing lithium iron phosphate by regenerating iron phosphate in the embodiment:

[0067] project Compaction 0.1C charging 0.1C discharge 1C charging 1C discharge Test Example 1 Lithium Iron Phosphate 2.59 157.5 157.2 153.1 130.4 Test Example 2 Lithium Iron Phosphate 2.57 159.1 158.6 155.5 131.9 Test Example 3: Lithium Iron Phosphate 2.63 156.4 156.1 151.6 128.9

[0068] according to Figures 1-2 It can be seen that the present invention can produce high-purity iron phosphate.

[0069] It can be seen from the test results of regenerated anhydrous iron phosphate in the above table that all indicators of the prepared regenerated iron phosphate meet the iron phosphate battery grade standards, with high purity and good crystallinity; it is suitable for preparing high-density iron phosphate; and it has good performance in preparing lithium iron phosphate.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A treatment method for regenerating and utilizing iron phosphate, characterized in that: The following steps are involved: Step 1, mixing a phosphoric acid solution and a hydrochloric acid solution to obtain a mixed acid solution, adding iron phosphate waste to the mixed acid solution to obtain a first mixed solution, and removing impurities from the first mixed solution to obtain a first filtrate; Step 2: adding ferric oxyhydroxide slurry to the first filtrate, mixing and beating to react, to obtain a second mixed solution, wherein the pH of the second mixed solution is 1-2, and filtering the second mixed solution to obtain a second filtrate; Step 3: Stir the second filtrate and heat it to 75-90° C. to precipitate a solid-liquid mixture containing dihydrate iron phosphate solid, filter the solid-liquid mixture to separate the dihydrate iron phosphate solid and the third filtrate, wash and dry the dihydrate iron phosphate solid to obtain battery-grade iron phosphate, and recycle the third filtrate.

2. The method for regenerating and utilizing iron phosphate according to claim 1, characterized in that: In the mixed acid, the concentration of the phosphoric acid solution is 60%-85%, the concentration of the hydrochloric acid solution is 5%-15%, and the mass ratio of the phosphoric acid solution to the hydrochloric acid solution is 2-5:

1.

3. The method for regenerating and utilizing iron phosphate according to claim 2, characterized in that: The mixing and stirring speed of the iron phosphate waste and the mixed acid solution is 50 r / min~300 r / min.

4. The method for regenerating and utilizing iron phosphate according to claim 3, characterized in that: The mixing reaction time of the waste iron phosphate and the mixed acid solution is 1-2 hours, and the reaction temperature is 70-90°C.

5. The method for regenerating and utilizing iron phosphate according to claim 1, characterized in that: The mass ratio of the mixed acid solution to the iron phosphate waste is 3-5:

1.

6. The method for regenerating and utilizing iron phosphate according to claim 1, characterized in that: The ferric oxyhydroxide slurry is obtained by mixing ferric oxyhydroxide with water or dilute acid water, and the solid content of the ferric oxyhydroxide slurry is 10% to 15%.

7. The method for regenerating and utilizing iron phosphate according to claim 1, characterized in that: The molar ratio of the amount of the ferric oxyhydroxide slurry added to the ferrophosphorus in the first filtrate is 1.2-1.4:

1.

8. The method for regenerating and utilizing iron phosphate according to claim 1, characterized in that: The reaction temperature of the iron oxyhydroxide slurry and the first filtrate is 50-70° C., the reaction stirring time is 0.5-2 h, and the Fe mass fraction of the second mixed solution is 4.5%-6.5%; The time for the second filtrate to precipitate solid ferric phosphate dihydrate is 1 to 3 hours.

9. The method for regenerating and utilizing iron phosphate according to claim 1, characterized in that: The third filtrate is returned to the iron oxyhydroxide slurry of step two for slurrying reaction or returned to the iron phosphate waste dissolution reaction of step one.

10. An iron phosphate, characterized in that: It is obtained by the treatment method for regenerating and utilizing iron phosphate according to any one of claims 1 to 9.

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