A method for preparing high-density titanium-doped iron phosphate
By controlling the molar ratio of iron to total phosphorus, ammonium phosphate, and phosphoric acid in the reaction system through a one-step pre-oxidation process, the problems of long, complex, and large wastewater treatment processes in existing iron phosphate doping processes have been solved. This has enabled uniform doping of Ti and efficient production, producing high-pressure, high-capacity iron phosphate that meets market specifications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XINYANGFENG AGRI TECH CO LTD
- Filing Date
- 2025-09-26
- Publication Date
- 2026-05-19
AI Technical Summary
Existing titanium doping processes for iron phosphate are lengthy, complex, involve large amounts of wastewater, and are costly, making it difficult to achieve uniform doping.
A one-step oxidation process is adopted, which achieves uniform Ti doping by controlling the molar ratio of iron to total phosphorus, ammonium phosphate, and phosphate in the reaction system. This avoids the need to use alkaline substances to adjust pH and add other additives, simplifies the process, and reduces wastewater generation.
The preparation cycle was shortened, the cost was reduced, the amount of wastewater treated was reduced, uniform Ti doping was achieved, and the prepared iron phosphate product met market specifications and had the characteristics of high compaction and high capacity.
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Figure CN120864463B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of battery technology, specifically relating to a high-pressure titanium-doped iron phosphate preparation method. Background Technology
[0002] As a crucial precursor in the synthesis of lithium iron phosphate (LFP), the purity and quality of iron phosphate have a significant impact on the electrochemical performance of LFP batteries. Currently, industrial LFP manufacturers primarily employ metal doping to enhance battery performance. Existing research reports indicate that LFP is doped with metals such as Cu, Mg, Cr, V, Ti, Mo, Ni, and Mn, with Ti doping being the most common. Experiments have shown that metal ion doping improves both high-rate discharge and cycle performance. Simultaneously, some manufacturers address doping uniformity issues by incorporating the doping metal into the iron phosphate synthesis stage.
[0003] To achieve Ti doping with iron phosphate, existing technologies mainly focus on the following directions: 1. Mixing the doping titanium source with phosphate and iron salts and adjusting the pH to retain Ti; 2. Adding complexing agents or doping aids to the reaction system to help retain Ti. Specific technical solutions are briefly described below:
[0004] The preparation process of iron phosphate in the three patents, namely "A method for preparing battery-grade titanium-doped iron phosphate, CN118495949A", "A method for preparing titanium and vanadium co-doped iron phosphate, positive electrode material, positive electrode sheet, lithium-ion battery and electrical equipment thereof, CN118851127A", and "A method for preparing doped iron phosphate, CN118183661A", involves mixing the dopant source with an iron salt solution, adjusting the pH of the phosphate solution with an alkaline substance, placing the mixed iron source in a reaction vessel, adding an oxidant to the reaction vessel to react with the high-pH phosphate to obtain an amorphous hydrated iron phosphate slurry, filtering and washing the amorphous slurry, re-slurrying it, adding a certain amount of phosphoric acid, and aging it at a high temperature to obtain iron phosphate dihydrate, and then drying and calcining it to obtain doped anhydrous iron phosphate.
[0005] Patent CN111908441A, entitled "A Wet Method for Preparing Titanium-Doped Ferric Phosphate," describes a process where iron and phosphate salts are dissolved in an acidic solution to obtain an acidic ferric phosphate solution. A doping solution is then added to the acidic ferric phosphate solution and stirred until homogeneous. An oxidant is added to obtain a yellow slurry. An alkaline solution is then added to the yellow slurry to adjust the pH value, followed by heating and aging to obtain a dihydrate ferric phosphate slurry. The slurry is then filtered, washed, dried, and calcined to obtain doped anhydrous ferric phosphate. Patent CN113460987A describes a process where iron salts are directly dissolved in phosphoric acid to obtain an acidic ferric phosphate solution. Subsequent steps are essentially the same as those described in the aforementioned patent.
[0006] The patent "Preparation Method and Application of Doped Iron Phosphate and Doped Lithium Iron Phosphate, CN118811781A" describes reacting a doped metal salt with a complexing agent to obtain a metal ion solution, then mixing the metal ion solution with ferrous salt, phosphate salt, oxidant, and alkali for reaction, followed by aging and calcination. The patent "A Heterogeneous Doped Iron Phosphate, Its Preparation Method and Heterogeneous Doped Lithium Iron Phosphate, CN119637825A" describes adding titanium-containing iron salt, phosphate salt, and oxidant to a reactor for rapid reaction, followed by washing and filtration to obtain an amorphous iron phosphate filter cake. The amorphous filter cake is then mixed with water and phosphoric acid to form a slurry, which is then aged at a higher temperature to obtain a dihydrate iron phosphate slurry. A secondary doping agent is then added to the slurry, followed by drying and calcination to obtain heterogeneous doped iron phosphate.
[0007] While existing doping methods can achieve Ti doping, they suffer from problems such as long processes, complex operations, large wastewater treatment volumes, and the need for external additives.
[0008] For example, the doping methods proposed in patents such as "A method for preparing battery-grade titanium-doped iron phosphate, CN118495949A", "A method for preparing titanium and vanadium co-doped iron phosphate, positive electrode material, positive electrode sheet, lithium-ion battery and electrical equipment thereof, CN118851127A", and "A method for preparing doped iron phosphate thereof, CN118183661A" although doping is completed, require two-step reactions, and the overall process is relatively long; the materials are washed twice, doubling the amount of wastewater to be treated; the first step of the reaction requires the addition of an alkaline solution to adjust the pH, increasing the complexity of the operation and raising the cost.
[0009] In the paper "A Wet Method for Preparing Titanium-Doped Iron Phosphate, CN111908441A", an acidic solution is used as the base reaction, and the amount of alkaline material required for pH adjustment increases significantly. In the paper "A Doped Iron Phosphate and Its Preparation Method and Application", pure phosphoric acid is used as the phosphate salt, which is costly, and the amount of alkaline material required for subsequent pH adjustment is still relatively large.
[0010] The method and application of doped iron phosphate and doped lithium iron phosphate, CN118811781A, requires the addition of a complexing agent, which increases the cost and requires high wastewater treatment capacity. The overall process of the method of heterogeneous doped iron phosphate, its preparation method and heterogeneous doped lithium iron phosphate, CN119637825A, is relatively long and has a large amount of wastewater to be treated; moreover, the secondary doping agent is only coated on the surface of iron phosphate dihydrate. Summary of the Invention
[0011] To address the shortcomings of existing technologies, this invention aims to provide a method with a short production process, simple operation, small wastewater treatment volume, and low cost to achieve uniform doping of metallic Ti.
[0012] A method for preparing high-pressure titanium-doped iron phosphate includes the following steps:
[0013] S1. Prepare 40-85 wt% phosphoric acid solution, 2-28 wt% hydrogen peroxide solution, Ti salt, phosphate salt solution and ferrous salt solution for later use.
[0014] S2. Mix Ti salt and ferrous salt solution evenly to obtain titanium-containing ferric salt solution; mix phosphoric acid solution and phosphate salt solution evenly to obtain phosphorus source solution;
[0015] S3. Add the titanium-iron salt solution to the reactor and add the hydrogen peroxide solution to the reactor within 30 to 120 minutes while stirring at 100 to 450 rpm.
[0016] S4. After the hydrogen peroxide feeding is completed, add the phosphorus source solution into the reactor within 30~120 minutes to obtain a yellow slurry;
[0017] S5. Heat to 80~98℃. After the slurry turns white, keep it at that temperature for 30~180 min to obtain a white slurry.
[0018] S6. The above white slurry is subjected to solid-liquid separation, the slurry liquid is removed, and then hot pure water is added to wash the filter cake until the conductivity of the wash water is reduced to below 2000 μS / cm to obtain ferric phosphate dihydrate filter cake.
[0019] S7, the iron phosphate dihydrate filter cake is dried at 80~150℃ for 6~24h, and then calcined at 500~580℃ for 2~5h to obtain Ti-doped battery-grade anhydrous iron phosphate.
[0020] Preferably, the concentration of phosphorus in the phosphate salt solution in S1 is 0.5~2 mol / L; the phosphate salt solution is any one or a mixture of ammonium hydrogen phosphate, ammonium dihydrogen phosphate, sodium monohydrogen phosphate, sodium dihydrogen phosphate, and sodium phosphate.
[0021] Preferably, the concentration of iron in the ferrous salt solution in S1 is 0.5~1.8 mol / L, and the ferrous salt solution is any one or a mixture of ferrous sulfate, ferrous nitrate, and ferrous chloride.
[0022] Preferably, the titanium salt in S1 is any one or a mixture of titanium sulfate, titanium oxysulfate, and titanium chloride, wherein the Ti doping amount is 0.01~0.8wt%.
[0023] Preferably, the molar ratio of iron to phosphorus in the yellow slurry in S4 is controlled at 1:1 to 1:1.4; wherein the molar ratio of phosphorus in the phosphoric acid solution to the phosphate salt solution is controlled at 1:2.4 to 1:3.6.
[0024] Preferably, the reaction temperature in S3 is 25~65℃.
[0025] Preferably, the solid-liquid separation method in S6 is any one of centrifugation, pressure filtration, or filtration.
[0026] Preferably, the mass ratio of the filter cake to hot pure water in S6 is 0.3:1 to 1:1.
[0027] Preferably, the temperature of the hot pure water in S6 is 40~90°C.
[0028] The principle behind the technical solution provided by this invention for wet-process doping of Ti is as follows: This invention utilizes a one-step oxidation process to prepare titanium-doped iron phosphate. By controlling the molar ratio of iron to total phosphorus, ammonium phosphate, and phosphoric acid in the reaction system, the pH of the reaction system is controlled, ensuring that the retention of Ti and the iron-phosphorus ratio in the finished product are regulated within a specified range.
[0029] During the phosphate salt feeding stage, Ti and Fe react with phosphorus simultaneously to form precipitates. By raising the temperature for conversion, doping and iron phosphate growth are carried out simultaneously, achieving uniform doping of Ti.
[0030] This invention modifies the existing titanium-doped iron phosphate process by using a one-step oxidation process to prepare iron phosphate. The process does not require the addition of alkaline substances to adjust the pH or the introduction of other doping agents. The steps are simple and the process flow is short. Compared with the existing titanium-doped iron phosphate process, it effectively shortens the preparation cycle, avoids the generation of large amounts of wastewater and waste residue, greatly reduces environmental pressure, lowers costs, and can be applied on a large scale in industrial applications.
[0031] The key to this invention lies in changing the existing titanium-doped iron phosphate process and using a one-step oxidation process to prepare iron phosphate. The product specifications are controlled by adjusting the molar ratio of iron to total phosphorus, ammonium phosphate, and phosphoric acid in the reaction system.
[0032] This process is simple and short, does not introduce other additives, produces little wastewater, and reduces preparation costs. The resulting ferric phosphate meets mainstream market standards and maintains high competitiveness. Attached Figure Description
[0033] Figure 1 This is a SEM image of the dihydrate filter cake prepared in Example 1.
[0034] Figure 2 This is a SEM image of the finished ferrophosphorus product prepared in Example 1.
[0035] Figure 3 This is a SEM image of the dihydrate filter cake prepared in Comparative Example 2.
[0036] Figure 4 This is a SEM image of the finished ferrophosphorus product prepared in Comparative Example 2.
[0037] Figure 5 This is a SEM image of the dihydrate filter cake prepared in Comparative Example 3.
[0038] Figure 6 This is a SEM image of the finished ferrophosphorus product prepared in Comparative Example 3. Detailed Implementation
[0039] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.
[0040] <Example 1>
[0041] A method for preparing high-pressure titanium-doped iron phosphate includes the following steps:
[0042] (1) Weigh 54.4 kg of ammonium dihydrogen phosphate solid (molar ratio with iron salt is 0.85), add water to dissolve and make up to 0.3 m³. 3 Weigh 16.25 kg (molar ratio to iron salt of 0.25) of an 85% phosphoric acid solution and pour it into the solution, then add water to bring the volume to 0.4 m. 3 Weigh 0.38 m of a ferrous sulfate solution with a ferrous concentration of 82 g / L. 3 Add water to a final concentration of 0.4 ml. 3 Weigh 2.11 kg of titanium sulfate (0.5% by mass) and add it to the ferrous sulfate solution, stirring until the liquid is clear and uniform; weigh 44 kg of hydrogen peroxide solution with a mass concentration of 28%.
[0043] (2) Pour the titanium-containing iron salt into the reactor, turn on the stirring at 30 Hz, and add the hydrogen peroxide solution into the reactor at 60 min. After the feeding is completed, add the prepared phosphate salt solution into the reactor at 60 min.
[0044] (3) Heat the temperature to 95℃, and keep it warm for 120 minutes after the slurry turns white;
[0045] (4) Use a filter press to separate the slurry into solid and liquid. The resulting slurry is discharged into the wastewater treatment system for treatment. The resulting filter cake is left in the filter chamber of the filter press and rinsed with hot pure water at 60°C until the conductivity of the wash water drops to 670μS / cm.
[0046] (5) The filter cake is blown in the filter press and then discharged to obtain iron phosphate dihydrate filter cake (dihydrate filter cake). After drying at 120°C for 12 hours and calcining at 540°C for 3 hours, battery-grade anhydrous iron phosphate material (finished iron phosphate) is obtained.
[0047] <Example 2>
[0048] Except for the titanium doping amount being 0.6% during the experiment, this experiment was the same as Example 1.
[0049] A method for preparing high-pressure titanium-doped iron phosphate includes the following steps:
[0050] (1) Weigh 54.4 kg of ammonium dihydrogen phosphate solid (molar ratio with iron salt is 0.85), add water to dissolve and make up to 0.3 m³. 3 Weigh 16.25 kg (molar ratio to iron salt of 0.25) of an 85% phosphoric acid solution and pour it into the solution, then add water to bring the volume to 0.4 m. 3 Weigh 0.38 m of a ferrous sulfate solution with a ferrous concentration of 82 g / L. 3 Add water to a final concentration of 0.4 ml. 3 Weigh 2.53 kg of titanium sulfate (0.5% by mass) and add it to the ferrous sulfate solution, stirring until the liquid is clear and uniform; weigh 44 kg of hydrogen peroxide solution with a mass concentration of 28%.
[0051] (2) Pour the titanium-containing iron salt into the reactor, turn on the stirring at 30 Hz, and add the hydrogen peroxide solution into the reactor at 60 min. After the feeding is completed, add the prepared phosphate salt solution into the reactor at 60 min.
[0052] (3) Heat the temperature to 95℃, and keep it warm for 120 minutes after the slurry turns white;
[0053] (4) Use a filter press to separate the slurry into solid and liquid. The resulting slurry is discharged into the wastewater treatment system for treatment. The resulting filter cake is left in the filter chamber of the filter press and rinsed with hot pure water at 60°C until the conductivity of the wash water drops to 670μS / cm.
[0054] (5) The filter cake is blown in the filter press and then discharged to obtain iron phosphate dihydrate filter cake. After drying at 120°C for 12 hours and calcining at 540°C for 3 hours, battery-grade anhydrous iron phosphate material is obtained.
[0055] <Comparative Example 1>
[0056] The experiment was the same as in Example 1, except that the ratio of phosphate to iron salt was 0.5 and the ratio of total iron to total phosphorus was 1:1.35.
[0057] A method for preparing high-pressure titanium-doped iron phosphate includes the following steps:
[0058] (1) Weigh 54.4 kg of ammonium dihydrogen phosphate solid (molar ratio with iron salt is 0.85), add water to dissolve and make up to 0.3 m³. 3 Weigh 32.5 kg (molar ratio to iron salt of 0.5) of an 85% phosphoric acid solution and pour it into the solution, then add water to bring the volume to 0.4 m³. 3 Weigh 0.38 m of a ferrous sulfate solution with a ferrous concentration of 82 g / L. 3 Add water to a final concentration of 0.4 ml. 3 Weigh 2.11 kg of titanium sulfate (0.5% by mass) and add it to the ferrous sulfate solution, stirring until the liquid is clear and uniform; weigh 44 kg of hydrogen peroxide solution with a mass concentration of 28%.
[0059] (2) Pour the titanium-containing iron salt into the reactor, turn on the stirring at 30 Hz, and add the hydrogen peroxide solution into the reactor at 60 min. After the feeding is completed, add the prepared phosphate salt solution into the reactor at 60 min.
[0060] (3) Heat the temperature to 95℃, and keep it warm for 120 minutes after the slurry turns white;
[0061] (4) Use a filter press to separate the slurry into solid and liquid. The resulting slurry is discharged into the wastewater treatment system for treatment. The resulting filter cake is left in the filter chamber of the filter press and rinsed with hot pure water at 60°C until the conductivity of the wash water drops to 670μS / cm.
[0062] (5) The filter cake is blown in the filter press and then discharged to obtain iron phosphate dihydrate filter cake. After drying at 120°C for 12 hours and calcining at 540°C for 3 hours, battery-grade anhydrous iron phosphate material is obtained.
[0063] <Comparative Example 2>
[0064] The experiment was the same as in Example 1, except that the ratio of phosphorus salt to iron salt molar was 1.2 and the ratio of total iron to total phosphorus molar was 1:1.45.
[0065] (1) Weigh 76.8 kg of ammonium dihydrogen phosphate solid (molar ratio with iron salt is 1.2), add water to dissolve and make up to 0.3 m³. 3 Weigh 16.25 kg (molar ratio to iron salt of 0.25) of an 85% phosphoric acid solution and pour it into the solution, then add water to bring the volume to 0.4 m. 3 Weigh 0.38 m of a ferrous sulfate solution with a ferrous concentration of 82 g / L. 3 Add water to a final concentration of 0.4 ml. 3Weigh 2.11 kg of titanium sulfate (0.5% by mass) and add it to the ferrous sulfate solution, stirring until the liquid is clear and uniform; weigh 44 kg of hydrogen peroxide solution with a mass concentration of 28%.
[0066] (2) Pour the titanium-containing iron salt into the reactor, turn on the stirring at 30 Hz, and add the hydrogen peroxide solution into the reactor at 60 min. After the feeding is completed, add the prepared phosphate salt solution into the reactor at 60 min.
[0067] (3) Heat the temperature to 95℃, and keep it warm for 120 minutes after the slurry turns white;
[0068] (4) Use a filter press to separate the slurry into solid and liquid. The resulting slurry is discharged into the wastewater treatment system for treatment. The resulting filter cake is left in the filter chamber of the filter press and rinsed with hot pure water at 60°C until the conductivity of the wash water drops to 670μS / cm.
[0069] (5) The filter cake is blown in the filter press and then discharged to obtain iron phosphate dihydrate filter cake. After drying at 120°C for 12 hours and calcining at 540°C for 3 hours, battery-grade anhydrous iron phosphate material is obtained.
[0070] <Comparative Example 3>
[0071] The experiment was the same as in Example 1, except that titanium doping was not performed during the experiment.
[0072] (1) Weigh 54.4 kg of ammonium dihydrogen phosphate solid (molar ratio with iron salt is 0.85), add water to dissolve and make up to 0.3 m³. 3 Weigh 16.25 kg (molar ratio to iron salt of 0.25) of an 85% phosphoric acid solution and pour it into the solution, then add water to bring the volume to 0.4 m. 3 Weigh 0.38 m of a ferrous sulfate solution with a ferrous concentration of 82 g / L. 3 Add water to a final concentration of 0.4 ml. 3 Weigh 44 kg of a 28% hydrogen peroxide solution.
[0073] (2) Pour the iron salt into the reactor, turn on the stirring at 30 Hz, and add the hydrogen peroxide solution into the reactor at 60 min. After the feeding is completed, add the prepared phosphate salt solution into the reactor at 60 min.
[0074] (3) Heat the temperature to 95℃, and keep it warm for 120 minutes after the slurry turns white;
[0075] (4) Use a filter press to separate the slurry into solid and liquid. The resulting slurry is discharged into the wastewater treatment system for treatment. The resulting filter cake is left in the filter chamber of the filter press and rinsed with hot pure water at 60°C until the conductivity of the wash water drops to 670μS / cm.
[0076] (5) The filter cake is blown in the filter press and then discharged to obtain iron phosphate dihydrate filter cake. After drying at 120°C for 12 hours and calcining at 540°C for 3 hours, battery-grade anhydrous iron phosphate material is obtained.
[0077] <Experimental Testing>
[0078] The iron phosphate prepared in Examples 1 and 2, and Control Examples 1, 2, and 3 were sent for ICP and Fe / P analysis. The results of Ti element content and iron-phosphorus ratio are shown in Table 1. The dihydrate filter cake and finished FP from Examples 1 and Control Examples 2 and 3 were sent for scanning electron microscopy analysis. Figures 1-6 .
[0079] Depend on Figure 1 , 2 It can be seen that the titanium-doped ferric phosphate dihydrate particles in the qualified sample are small flakes, overlapping and stacked together. After calcination, the small flakes shrink into spherical particles with clear inter-particle gaps; this meets the microstructure requirements of high-pressure compacted ferric phosphate. Figure 3 , 4 It can be seen that the primary particles are plate-like, stacked on top of each other, and fuse together after calcination, which does not meet the microstructure requirements of high-pressure compacted ferric phosphate. Figure 5 , 6 It can be seen that the primary particles are dispersed large flakes, which remain in their original state after calcination, and do not meet the microstructure requirements of high-pressure compacted ferric phosphate.
[0080] Table 1. Detection results of Ti content and Fe / P ratio in the examples and comparative examples.
[0081]
[0082] Currently, the market demand for ferric phosphorus is typically between 0.96 and 0.975 for the iron-to-phosphorus ratio. Table 1 shows the ICP and Fe / P analysis results for each experiment. In Examples 1 and 2, the Ti content was 4980 ppm and 6010 ppm, respectively, which is basically consistent with the theoretical doping amount, and the retention rate is close to 100%. Furthermore, the Fe / P ratios of 0.965 and 0.962 meet the standard requirements for ferric phosphorus. In Comparative Example 1, the Ti content was significantly reduced to 4010 ppm, with a retention rate of 80%. In Comparative Example 2, the Ti content was 4900 ppm, with a relatively high retention rate, but the Fe / P ratio of 0.948 was far below the standard market requirements. The undoped sample in Comparative Example 3 was within the normal range. Combining the ICP, XRD, and Fe / P test results, it can be demonstrated that the ferric phosphorus prepared using the technical solution of this invention can achieve Ti doping, and the product meets the mainstream market requirements.
[0083] The iron phosphates obtained in Examples 1 and 2 and Comparative Examples 1, 2 and 3 were respectively converted into lithium iron phosphate by high-temperature solid-state method. The powder compaction density, 0.1C discharge capacity and 1C discharge capacity of lithium iron phosphate were then tested. The specific results are shown in Table 2.
[0084] As shown in Table 2, Experiments 1 and 2 represent the technical solutions of this invention. Lithium iron phosphate was prepared using the iron phosphate prepared in Experiments 1 and 2, and the powder compaction densities were 2.563 g / cm³, respectively. 3 2552g / cm 3 The 0.1C discharge capacities are 159.12 mAh / g and 160.69 mAh / g, respectively; the 1C discharge capacities are 140.55 mAh / g and 142.89 mAh / g, respectively, both of which are relatively high.
[0085] Compared to the comparative example, the 0.1C discharge capacity increased by 3–5 mAh / g, the 1C discharge capacity increased by 2–7 mAh / g, and the compaction density increased by 0.08–0.1. The iron phosphate product prepared by the examples, due to its unique morphology and suitable iron-to-phosphorus ratio, possesses both high compaction and high capacity characteristics, and is suitable for industrial-scale production.
[0086] Table 2 Performance test results of lithium iron phosphate
[0087]
[0088] The above embodiments are only for illustrating the technical solutions and features of the present invention, and are intended to enable those skilled in the art to implement them better. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention are within the scope of protection of the present invention. The parts not described in detail are prior art.
Claims
1. A method for preparing high-pressure titanium-doped iron phosphate, characterized in that, Includes the following steps: S1. Prepare 40-85 wt% phosphoric acid solution, 2-28 wt% hydrogen peroxide solution, Ti salt, phosphate salt solution and ferrous salt solution for later use. S2. Mix the Ti salt and ferrous salt solution evenly to obtain a titanium-containing ferric salt solution; The phosphoric acid solution and the phosphate salt solution are mixed and stirred evenly to obtain the phosphorus source solution; S3. Add the titanium-iron salt solution to the reactor and add the hydrogen peroxide solution to the reactor within 30 to 120 minutes while stirring at 100 to 450 rpm. S4. After the hydrogen peroxide feeding is completed, add the phosphorus source solution into the reactor within 30~120 minutes to obtain a yellow slurry; S5. Heat to 80~98℃. After the slurry turns white, keep it at that temperature for 30~180 min to obtain a white slurry. S6. The above white slurry is subjected to solid-liquid separation, the slurry liquid is removed, and then hot pure water is added to wash the filter cake until the conductivity of the wash water is reduced to below 2000 μS / cm to obtain ferric phosphate dihydrate filter cake. S7, ferric phosphate dihydrate filter cake is dried at 80~150℃ for 6~24h, and then calcined at 500~580℃ for 2~5h to obtain Ti-doped battery-grade anhydrous ferric phosphate; The phosphorus concentration in the phosphate salt solution described in S1 is 0.5~2 mol / L; the phosphate salt solution is any one or a mixture of ammonium hydrogen phosphate, ammonium dihydrogen phosphate, sodium monohydrogen phosphate, sodium dihydrogen phosphate, and sodium phosphate. The concentration of iron in the ferrous salt solution described in S1 is 0.5~1.8 mol / L, and the ferrous salt solution is any one or a mixture of ferrous sulfate, ferrous nitrate, and ferrous chloride. In S4, the molar ratio of iron to phosphorus in the yellow slurry is controlled at 1:1 to 1:1.4; and the molar ratio of phosphorus in the phosphoric acid solution to the phosphate salt solution is controlled at 1:2.4 to 1:3.
6.
2. The method for preparing high-pressure titanium-doped iron phosphate according to claim 1, characterized in that, The titanium salt in S1 is any one or a mixture of titanium sulfate, titanium oxysulfate, and titanium chloride, wherein the Ti doping amount is 0.01~0.8wt%.
3. The method for preparing high-pressure titanium-doped iron phosphate according to claim 1, characterized in that, The reaction temperature in S3 is 25~65℃.
4. The method for preparing high-pressure titanium-doped iron phosphate according to claim 1, characterized in that, The solid-liquid separation method in S6 is any one of centrifugation, pressure filtration, or filtration.
5. The method for preparing high-pressure titanium-doped iron phosphate according to claim 1, characterized in that, The mass ratio of the filter cake to hot pure water in S6 is 0.3:1 to 1:
1.
6. The method for preparing high-pressure titanium-doped iron phosphate according to claim 1, characterized in that, The temperature of the hot pure water mentioned in S6 is 40~90℃.