A regeneration method for iron phosphate waste

Abstract

The present invention relates to a regeneration treatment method for iron phosphate waste. The regeneration treatment method for iron phosphate waste comprises the following steps: S1. mixing iron phosphate waste with a phosphoric acid solution with a mass concentration of 16-20%, reacting, filtering, and obtaining a filtrate; S2. mixing the filtrate with water to obtain a mixed solution, reacting the mixed solution under the condition of 70-90°C, aging, filtering, and calcining the filtered material to obtain regenerated iron phosphate; in step S1, the molar ratio of the iron element in the iron phosphate waste to the phosphorus element in the phosphoric acid solution is 1: (2.8-3.4); in step S2, the concentration of iron ions in the mixed solution is 1.35%-1.45%. The regeneration treatment method has a simple process, no other impurity ions are introduced into the system, less washing water is used, both the mother liquor and the washing water can be recycled in the system, no waste water is generated, and the cost is low and easy to operate.

Description

Technical Field

[0001] The present invention relates to the technical field of iron phosphate, and more specifically, to a method for regenerating and treating iron phosphate waste. Background Art

[0002] In the production process of iron phosphate, some iron phosphate waste that cannot be directly reused will be generated due to process errors, experimental tests, equipment failures, human errors, testing and other reasons. If these iron phosphate wastes are not utilized and treated as solid waste, it will be a waste and not environmentally friendly. Therefore, it is very necessary to regenerate and recycle the iron phosphate waste.

[0003] The Chinese patent entitled "A method for regenerating waste iron phosphate" first adds an inorganic acid to dissolve it, then adds iron salt, phosphate salt or phosphoric acid to control the iron-phosphorus ratio of the dissolved solution, adds an alkaline solution to adjust to a certain pH for reaction, and finally adds phosphoric acid for aging, separation and calcination to obtain battery-grade anhydrous iron phosphate. This method has the following disadvantages: using an inorganic strong acid to dissolve the waste iron phosphate, while adding iron salt, phosphate salt or phosphoric acid to adjust the iron-phosphorus ratio, and then adding an alkaline solution for reaction. These processes will introduce more impurity ions, and the washing process will produce more wastewater, which puts great pressure on environmental protection treatment.

[0004] A Chinese patent entitled "A method for treating waste iron phosphate" adds waste iron phosphate into a phosphoric acid solution, dissolves it by stirring and heating, then adds ammonium sulfide to remove impurities and filter it, and then adds urea to react to obtain dihydrate iron phosphate, which is then calcined and dehydrated to obtain anhydrous iron phosphate. This method involves more filtration and a long process. At the same time, ammonia nitrogen is introduced into the system, and filter residues and wastewater are generated that require environmentally friendly treatment.

[0005] Therefore, it is necessary to solve the problem that the current iron phosphate regeneration method introduces a lot of impurity ions, requires a lot of washing and filtration, and produces a lot of wastewater. Summary of the invention

[0006] The primary purpose of the present invention is to overcome the problem that the existing ferric phosphate regeneration method introduces a lot of impurity ions, washes and filters a lot and generates a lot of waste water, and provide a regeneration treatment method for ferric phosphate waste. The regeneration treatment method has the following indicators: the iron-phosphorus ratio and the ratio table of the regenerated ferric phosphate meet the requirements of the production standard. The process is simple, no other impurity ions are introduced into the system, the washing water is small, the mother liquor and the washing water can be recycled in the system, no waste water is generated, the cost is low and the operation is easy.

[0007] The above-mentioned object of the present invention is achieved by the following technical solutions:

[0008] A method for regenerating iron phosphate waste comprises the following steps:

[0009] S1. Mixing the iron phosphate waste with a phosphoric acid solution having a mass concentration of 16 to 20%, reacting, filtering, and obtaining a filtrate;

[0010] S2. The filtrate is mixed with water to obtain a mixed solution, the mixed solution is reacted at 70 to 90°C, and then aged and filtered, and the filter material obtained by filtration is calcined to obtain regenerated iron phosphate;

[0011] In step S1, the molar ratio of the iron element in the iron phosphate waste to the phosphorus element in the phosphoric acid solution is 1:(2.8-3.4); and the mass fraction of the iron element in the mixed solution in step S2 is 1.35%-1.45%.

[0012] The present invention first uses a phosphoric acid solution of a certain concentration to dissolve a certain amount of iron phosphate waste, and obtains a filtrate containing dihydrogen phosphate iron after filtering; then the filtrate is diluted so that the concentration of iron ions in the filtrate is 1.35% to 1.45%, and reacts at this concentration and a specific temperature to generate dihydrate iron phosphate, and after further aging, filtering and calcining, regenerated iron phosphate is obtained. The iron-phosphorus ratio and the ratio table of the regenerated iron phosphate meet the requirements of the production standard, the process is simple, no other impurity ions are introduced into the system, the washing water is small, the mother liquor and the washing water can be recycled in the system, no waste water is generated, the cost is low and it is easy to operate.

[0013] The concentration of phosphoric acid solution and the molar ratio of iron in iron phosphate waste to phosphorus in phosphoric acid solution are very critical. If the concentration of phosphoric acid solution is too low or too high, the iron-phosphorus ratio and the specific table of iron phosphate after regeneration do not meet the requirements of production standards; if the molar ratio of iron in iron phosphate waste to phosphorus in phosphoric acid solution is not appropriate, for example, the amount of phosphorus in phosphoric acid solution is too high, then the iron-phosphorus ratio of iron phosphate after regeneration is high, and the specific table is low. In addition, the control of the mass fraction of iron in the mixed solution and the reaction temperature in step S2 are also critical. For example, if the mass fraction of iron in the mixed solution is too high, the iron-phosphorus ratio of iron phosphate after regeneration is low, and the specific table is high, which does not meet the requirements of production standards.

[0014] Preferably, the concentration of the phosphoric acid solution in step S1 is 18-20%.

[0015] By regulating the concentration of the phosphoric acid solution within the range of 18-20%, the indicators of the regenerated iron phosphate can be made higher than the table while meeting the production standards, thereby making the rate performance of the material higher.

[0016] Preferably, in step S1, the molar ratio of the iron element in the iron phosphate waste to the phosphorus element in the phosphoric acid solution is 1:(2.8-3).

[0017] Controlling the molar ratio of iron in waste iron phosphate to phosphorus in phosphoric acid solution to 1:(2.8-3) can make the tap density of regenerated iron phosphate higher, thereby making the energy density of the material higher.

[0018] Preferably, the reaction in step S1 is carried out in a sand mill.

[0019] Carrying out the reaction in a sand mill is beneficial to accelerating the reaction rate and is more conducive to complete reaction.

[0020] More preferably, the stirring rate of the sand mill is 300-1000 rpm.

[0021] Preferably, the reaction temperature of the reaction in step S1 is 20-80° C., and the reaction time is 0.5-1.5 h.

[0022] In this temperature range, the reaction is more favorable.

[0023] Preferably, the filtering method is filter pressing.

[0024] Preferably, the pH of the mixed solution in step S2 is 1.0-1.2.

[0025] In this pH range, the formation of ferric phosphate dihydrate is more suitable, and the quality of the regenerated ferric phosphate (iron-phosphorus ratio, specific surface area, etc.) is better.

[0026] More preferably, the pH of the mixed solution in step S2 is 1.02-1.19.

[0027] Preferably, the reaction temperature of the reaction in step S2 is 70-90° C., and the reaction time is 1-2 h.

[0028] Carrying out the reaction within this temperature and time range is more conducive to the formation of ferric phosphate dihydrate.

[0029] Preferably, the mass fraction of iron in the mixed solution in step S2 is 1.40-1.45%.

[0030] By controlling the mass fraction of the iron element in the mixed solution to 1.40-1.45%, the tap density of the regenerated iron phosphate can be higher, thereby making the energy density of the material higher.

[0031] Preferably, the mixed solution in step S2 is reacted at 80-90°C.

[0032] When the temperature is controlled at 80-90°C and the indicators of the regenerated iron phosphate meet the production standards, the specific indicators are higher, thereby making the material's rate performance higher.

[0033] Preferably, the reaction and aging in step S2 are carried out under stirring.

[0034] More preferably, the stirring speed is 60-200 rpm.

[0035] Preferably, the aging temperature in step S2 is 70-90°C.

[0036] Aging at this temperature can obtain iron phosphate with better morphology and crystal form, further improving the quality of iron phosphate.

[0037] Preferably, the aging time in step S2 is 2 to 4 hours.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The iron-to-phosphorus ratio and specific surface area of ​​the ferric phosphate after regeneration by the regeneration treatment method meet the requirements of production standards. The process is simple, no other impurity ions are introduced into the system, less washing water is required, both the mother liquor and the washing water can be recycled in the system, no waste water is generated, the cost is low and the operation is easy. DETAILED DESCRIPTION

[0040] In order to more clearly and completely describe the technical solution of the present invention, the present invention is further described in detail through specific embodiments below. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention. Various changes can be made within the scope of the rights of the present invention.

[0041] Example 1

[0042] This embodiment provides a method for regenerating iron phosphate waste, comprising the following steps:

[0043] 1. Put a certain amount of iron phosphate waste into a dissolution tank, then add a certain amount of phosphoric acid solution with a mass concentration of 18%, mix well, and react at 50°C for 1 hour until the iron phosphate waste is completely dissolved. During the reaction, the slurry in the dissolution tank is circulated and sanded by a sand mill, and the stirring rate of the sand mill is 700rpm. After the reaction is completed, filter it through a plate and frame filter press to obtain a filtrate containing dihydrogen ferric phosphate.

[0044] The molar ratio of the iron element in the iron phosphate waste to the phosphorus element in the phosphoric acid solution is 1: 3. The iron phosphate waste comes from the iron phosphate waste generated due to abnormal reaction temperature. The detection values ​​of various indicators of the iron phosphate waste are shown in Table 1 below.

[0045] Table 1 Detection values ​​of various indicators of iron phosphate waste in Example 1

[0046]

[0047] 2. The mass concentration of iron in the filtrate was 3.13%. The filtrate and water were injected into the reactor at a mass ratio of 0.809:1. The mass fraction of iron in the mixed solution in the reactor was 1.40%. The pH of the mixed solution was measured to be 1.12. The reaction was carried out for 1.5 hours at a stirring speed of 120 rpm and a temperature of 80°C. After the reaction was completed, the slurry obtained after the reaction was aged at an aging temperature of 80°C, a stirring speed of 120 rpm, and an aging time of 3 hours.

[0048] 3. After aging, the slurry is subjected to solid-liquid separation to obtain filter material, which is dried at 105° C. and then calcined at 550° C. to dehydrate and obtain regenerated iron phosphate.

[0049] Example 2

[0050] This embodiment provides a method for regenerating iron phosphate waste, comprising the following steps:

[0051] 1. Put a certain amount of iron phosphate waste into a dissolution tank, then add a certain amount of phosphoric acid solution with a mass concentration of 16%, mix well, and react at 50°C for 1 hour until the iron phosphate waste is completely dissolved. During the reaction, the slurry in the dissolution tank is circulated and sanded by a sand mill, and the stirring rate of the sand mill is 700rpm. After the reaction is completed, filter it through a plate and frame filter press to obtain a filtrate containing dihydrogen ferric phosphate.

[0052] The molar ratio of the iron element in the iron phosphate waste to the phosphorus element in the phosphoric acid solution is 1:3. The iron phosphate waste comes from the same source as that in Example 1.

[0053] 2. The concentration of iron in the filtrate was found to be 2.81%. The filtrate and water were injected into the reactor at a mass ratio of 0.994:1. The mass fraction of iron in the mixed solution in the reactor was 1.40%. The pH of the mixed solution was measured to be 1.11. The mixture was stirred at a speed of 120 rpm and a temperature of 70°C for 1.5 hours. After the reaction was completed, the slurry obtained after the reaction was aged at a temperature of 80°C, a stirring speed of 120 rpm, and an aging time of 3 hours.

[0054] 3. After aging, the slurry is subjected to solid-liquid separation to obtain filter material, which is dried at 105° C. and then calcined at 550° C. to dehydrate and obtain regenerated iron phosphate.

[0055] Example 3

[0056] This embodiment provides a method for regenerating iron phosphate waste, comprising the following steps:

[0057] 1. Put a certain amount of iron phosphate waste into a dissolution tank, then add a certain amount of phosphoric acid solution with a mass concentration of 20%, mix well, and react at 50°C for 1 hour until the iron phosphate waste is completely dissolved. During the reaction, the slurry in the dissolution tank is circulated and sanded by a sand mill, and the stirring rate of the sand mill is 700rpm. After the reaction is completed, filter it through a plate and frame filter press to obtain a filtrate containing dihydrogen ferric phosphate.

[0058] The molar ratio of the iron element in the iron phosphate waste to the phosphorus element in the phosphoric acid solution is 1:3. The iron phosphate waste comes from the same source as that in Example 1.

[0059] 2. The concentration of iron in the filtrate was 3.45%. The filtrate and water were injected into the reactor at a mass ratio of 0.684:1. The mass fraction of iron in the mixed solution in the reactor was 1.40%. The pH of the mixed solution was measured to be 1.10. The reaction was carried out for 1.5 hours at a stirring speed of 120 rpm and a temperature of 90°C. After the reaction was completed, the slurry obtained after the reaction was aged at an aging temperature of 80°C, a stirring speed of 120 rpm, and an aging time of 3 hours.

[0060] 3. After aging, the slurry is subjected to solid-liquid separation to obtain filter material, which is dried at 105° C. and then calcined at 550° C. to dehydrate and obtain regenerated iron phosphate.

[0061] Example 4

[0062] This embodiment provides a method for regenerating iron phosphate waste, comprising the following steps:

[0063] 1. Put a certain amount of iron phosphate waste into a dissolution tank, then add a certain amount of phosphoric acid solution with a mass concentration of 18%, mix well, and react at 50°C for 1 hour until the iron phosphate waste is completely dissolved. During the reaction, the slurry in the dissolution tank is circulated and sanded by a sand mill, and the stirring rate of the sand mill is 700rpm. After the reaction is completed, filter it through a plate and frame filter press to obtain a filtrate containing dihydrogen ferric phosphate.

[0064] The molar ratio of the iron element in the iron phosphate waste to the phosphorus element in the phosphoric acid solution is 1:2.8. The iron phosphate waste comes from the same source as that in Example 1.

[0065] 2. The concentration of iron in the filtrate was 3.33%. The filtrate and water were injected into the reactor at a mass ratio of 0.724:1. The mass fraction of iron in the mixed solution in the reactor was 1.40%. The pH of the mixed solution was measured to be 1.11. The reaction was carried out for 1.5 hours at a stirring speed of 120 rpm and a temperature of 80°C. After the reaction was completed, the slurry obtained after the reaction was aged at an aging temperature of 80°C, a stirring speed of 120 rpm, and an aging time of 3 hours.

[0066] 3. After aging, the slurry is subjected to solid-liquid separation to obtain filter material, which is dried at 105° C. and then calcined at 550° C. to dehydrate and obtain regenerated iron phosphate.

[0067] Example 5

[0068] This embodiment provides a method for regenerating iron phosphate waste, comprising the following steps:

[0069] 1. Put a certain amount of iron phosphate waste into a dissolution tank, then add a certain amount of phosphoric acid solution with a mass concentration of 18%, mix well, and react at 50°C for 1 hour until the iron phosphate waste is completely dissolved. During the reaction, the slurry in the dissolution tank is circulated and sanded by a sand mill, and the stirring rate of the sand mill is 700rpm. After the reaction is completed, filter it through a plate and frame filter press to obtain a filtrate containing dihydrogen ferric phosphate.

[0070] The molar ratio of the iron element in the iron phosphate waste to the phosphorus element in the phosphoric acid solution is 1:3.4. The iron phosphate waste comes from the same source as that in Example 1.

[0071] 2. The concentration of iron in the filtrate was found to be 2.79%. The filtrate and water were injected into the reactor at a mass ratio of 1.007:1. The mass fraction of iron in the mixed solution in the reactor was 1.40%. The pH of the mixed solution was measured to be 1.13. The mixture was reacted for 1.5 hours at a stirring speed of 120 rpm and a temperature of 80°C. After the reaction was completed, the slurry obtained after the reaction was aged at an aging temperature of 80°C, a stirring speed of 120 rpm, and an aging time of 3 hours.

[0072] 3. After aging, the slurry is subjected to solid-liquid separation to obtain filter material, which is dried at 105° C. and then calcined at 550° C. to dehydrate and obtain regenerated iron phosphate.

[0073] Example 6

[0074] This embodiment provides a method for regenerating iron phosphate waste, comprising the following steps:

[0075] 1. Put a certain amount of iron phosphate waste into a dissolution tank, then add a certain amount of phosphoric acid solution with a mass concentration of 18%, mix well, and react at 50°C for 1 hour until the iron phosphate waste is completely dissolved. During the reaction, the slurry in the dissolution tank is circulated and sanded by a sand mill, and the stirring rate of the sand mill is 700rpm. After the reaction is completed, filter it through a plate and frame filter press to obtain a filtrate containing dihydrogen ferric phosphate.

[0076] The molar ratio of the iron element in the iron phosphate waste to the phosphorus element in the phosphoric acid solution is 1:3. The iron phosphate waste comes from the same source as that in Example 1.

[0077] 2. The concentration of iron in the filtrate was 3.13%. The filtrate and water were injected into the reactor at a mass ratio of 0.758:1. The mass fraction of iron in the mixed solution in the reactor was 1.35%. The pH of the mixed solution was measured to be 1.19. The reaction was carried out for 1 hour at a stirring speed of 120 rpm and a temperature of 80°C. After the reaction was completed, the slurry obtained after the reaction was aged at an aging temperature of 80°C, a stirring speed of 120 rpm, and an aging time of 3 hours.

[0078] 3. After aging, the slurry is subjected to solid-liquid separation to obtain filter material, which is dried at 105° C. and then calcined at 550° C. to dehydrate and obtain regenerated iron phosphate.

[0079] Example 7

[0080] This embodiment provides a method for regenerating iron phosphate waste, comprising the following steps:

[0081] 1. Put a certain amount of iron phosphate waste into a dissolution tank, then add a certain amount of phosphoric acid solution with a mass concentration of 18%, mix well, and react at 50°C for 1 hour until the iron phosphate waste is completely dissolved. During the reaction, the slurry in the dissolution tank is circulated and sanded by a sand mill, and the stirring rate of the sand mill is 700rpm. After the reaction is completed, filter it through a plate and frame filter press to obtain a filtrate containing dihydrogen ferric phosphate.

[0082] The molar ratio of the iron element in the iron phosphate waste to the phosphorus element in the phosphoric acid solution is 1:3. The iron phosphate waste comes from the same source as that in Example 1.

[0083] 2. The concentration of iron in the filtrate was 3.13%. The filtrate and water were injected into the reactor at a mass ratio of 0.863:1. The mass fraction of iron in the mixed solution in the reactor was 1.45%. The pH of the mixed solution was measured to be 1.02. The reaction was carried out for 1.5 hours at a stirring speed of 120 rpm and a temperature of 80°C. After the reaction was completed, the slurry obtained after the reaction was aged at an aging temperature of 80°C, a stirring speed of 120 rpm, and an aging time of 3 hours.

[0084] 3. After aging, the slurry is subjected to solid-liquid separation to obtain filter material, which is dried at 105° C. and then calcined at 550° C. to dehydrate and obtain regenerated iron phosphate.

[0085] Example 8

[0086] This embodiment provides a method for regenerating iron phosphate waste, comprising the following steps:

[0087] 1. Put a certain amount of iron phosphate waste into a dissolution tank, then add a certain amount of phosphoric acid solution with a mass concentration of 18%, mix well, and react at 50°C for 1 hour until the iron phosphate waste is completely dissolved. During the reaction, the slurry in the dissolution tank is circulated and sanded by a sand mill, and the stirring rate of the sand mill is 700rpm. After the reaction is completed, filter it through a plate and frame filter press to obtain a filtrate containing dihydrogen ferric phosphate.

[0088] The molar ratio of the iron element in the iron phosphate waste to the phosphorus element in the phosphoric acid solution is 1:3. The iron phosphate waste comes from the iron phosphate waste discharged when the electromagnetic magnetic separator removes magnetic foreign matter. The detection values ​​of various indicators of the iron phosphate waste are shown in Table 2 below.

[0089] Table 2 Detection values ​​of various indicators of iron phosphate waste in Example 8

[0090]

[0091] 2. The concentration of iron in the filtrate was 3.14%. The filtrate and water were injected into the reactor at a volume ratio of 0.858:1. The mass fraction of iron in the mixed solution in the reactor was 1.45%. The pH of the mixed solution was measured to be 1.03. The reaction was carried out for 1.5 hours at a stirring speed of 120 rpm and a temperature of 80°C. After the reaction was completed, the slurry obtained after the reaction was aged at an aging temperature of 80°C, a stirring speed of 120 rpm, and an aging time of 3 hours.

[0092] 3. After aging, the slurry is subjected to solid-liquid separation to obtain filter material, which is dried at 105° C. and then calcined at 550° C. to dehydrate and obtain regenerated iron phosphate.

[0093] Comparative Example 1

[0094] This comparative example provides a regeneration method for iron phosphate waste, which is different from Example 1 in that the mass concentration of the phosphoric acid solution in step 1 is 15%, and the molar ratio of the iron element in the iron phosphate waste to the phosphorus element in the phosphoric acid solution is 1:3.4.

[0095] Comparative Example 2

[0096] This comparative example provides a regeneration method for iron phosphate waste, which is different from Example 1 in that the mass concentration of the phosphoric acid solution in step 1 is 21%, and the molar ratio of the iron element in the iron phosphate waste to the phosphorus element in the phosphoric acid solution is 1:2.8.

[0097] Comparative Example 3

[0098] This comparative example provides a regeneration method for iron phosphate waste, which is different from Example 1 in that the concentration of phosphoric acid in step 1 is 16%, and the molar ratio of iron in the iron phosphate waste to phosphorus in the phosphoric acid solution is 1:3.5.

[0099] Comparative Example 4

[0100] This comparative example provides a method for regenerating iron phosphate waste, which is different from Example 1 in that: in step 2, the filtrate and water are injected into the reactor at a mass ratio of 0.920:1, and the mass fraction of iron element in the mixed liquid in the reactor is 1.5%.

[0101] Performance Testing

[0102] Table 3 shows the results of measuring the index values ​​of the regenerated iron phosphates of Examples 1 to 8 and Comparative Examples 1 to 4.

[0103] Table 3 Test index results of iron phosphate after regeneration in each embodiment and comparative example

[0104]

[0105]

[0106] It can be seen from Table 3 that various indicators of the regenerated iron phosphate of Examples 1 to 8 meet the requirements of the standard, indicating that the iron-phosphorus ratio (controlled between 0.9700 and 0.9900) and the ratio table (controlled between 3.000 and 10.000 m2 / g) of the iron phosphate after regeneration by the regeneration treatment method of the present invention meet the requirements of the production standard, the process is simple, no other impurity ions are introduced into the system, less wash water is used, the mother liquor and wash water can be recycled in the system, no waste water is generated, the cost is low and the operation is easy.

[0107] The concentration of the phosphoric acid solution in Comparative Example 1 is too low, the iron-phosphorus ratio of the regenerated iron phosphate is too high, and the specific surface is too low, which does not meet the requirements of the production standards; the concentration of the phosphoric acid solution in Comparative Example 2 is too high, the iron-phosphorus ratio of the regenerated iron phosphate is too low, and the specific surface is too high, which does not meet the requirements of the production standards; the molar amount of phosphorus element in the phosphoric acid solution of Comparative Example 3 is too high, and the mass fraction of iron element in the mixed solution of Comparative Example 4 is too high, so the iron-phosphorus ratio and specific surface of the regenerated iron phosphate do not meet the requirements of the production standards.

[0108] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for regenerating iron phosphate waste, characterized in that: The steps include: S1. mixing the iron phosphate waste with a phosphoric acid solution having a mass concentration of 16 to 20%, reacting, filtering, and obtaining a filtrate; S2. 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 filter material obtained by filtration is calcined to obtain regenerated iron phosphate; In step S1, the molar ratio of the iron element in the iron phosphate waste to the phosphorus element in the phosphoric acid solution is 1:(2.8-3); the mass fraction of the iron element in the mixed solution in step S2 is 1.40%-1.45%; The pH of the mixed solution in step S2 is 1.0-1.2; The reaction time of the reaction in step S2 is 1 to 2 hours; The aging temperature of the aging in step S2 is 70-90°C; The aging time of the aging in step S2 is 2 to 4 hours.

2. The regeneration method according to claim 1, characterized in that: The concentration of the phosphoric acid solution in step S1 is 18-20%.

3. The regeneration method according to claim 1, characterized in that: The reaction temperature of the reaction in step S1 is 20-80° C., and the reaction time is 0.5-1.5 h.

4. The regeneration method according to claim 1, characterized in that: In step S2, the mixed solution is reacted at 80-90°C.

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