Manufacturing method for lithium phosphate

Abstract

A method for manufacturing lithium phosphate, according to the present invention, comprises the steps of: adding a lithium-containing solution into a reactor; adding an alkaline material and a phosphorus source material into the reactor; stirring the lithium-containing solution in which the alkaline material and the phosphorus source material are added, to grow lithium phosphate nucleus particles, thereby obtaining a lithium phosphate slurry; and subjecting the slurry to solid-liquid separation to thereby obtain lithium phosphate, wherein one of the alkaline material and the phosphorus source material is added into the upper portion of the reactor, and the other thereof is added into the lower portion of the reactor.

Description

Method for producing lithium phosphate

[0001] The present invention relates to a method for producing lithium phosphate.

[0002] Recently, lithium secondary batteries have experienced rapid growth in electronic communication devices such as tablet PCs and smartphones, and their applications are expanding to include powering electric vehicles. Research and development efforts to increase energy storage capacity are becoming increasingly concrete. This growth in the lithium secondary battery market is also driving a gradual increase in the use of lithium (Li), the primary raw material for cathode materials.

[0003] Lithium sources include minerals, brine, and seawater. Among these, minerals such as spodumene, petalite, and lepidolite contain relatively high lithium contents, at approximately 1 to 1.5 wt%. However, extracting lithium from minerals requires processes such as flotation, high-temperature heating, crushing, acid mixing, extraction, purification, concentration, and precipitation. This complicates the recovery process, requires high energy consumption, and is therefore costly. Furthermore, the use of acid in the lithium extraction process can cause severe environmental pollution.

[0004] Currently, lithium is mainly extracted from brine, which is produced from natural salt lakes and contains dissolved salts such as lithium, Mg, Ca, B, Na, K, and SO4.

[0005] Meanwhile, various attempts are being made to extract lithium from these brine solutions. For example, natural evaporation is used to concentrate lithium to an extractable concentration, and lithium is then extracted as lithium chloride, lithium sulfate, lithium carbonate, lithium hydroxide, lithium fluoride, and lithium phosphate.

[0006] Among these, lithium phosphate is a compound with low solubility and is known as the easiest method to extract dissolved lithium.

[0007] However, lithium phosphate has a low solubility, so when lithium phosphate is manufactured, the nucleation rate increases along with the change in pH, and it is manufactured into fine particles, so there is a problem that the content of impurities increases due to the high moisture content during solid-liquid separation.

[0008] Therefore, there is a need to develop a method for manufacturing lithium phosphate that can control the particle size of lithium phosphate to lower the moisture content and reduce impurities.

[0009] The present invention aims to provide a method for producing lithium phosphate, which can control the particle size of lithium phosphate, has a low moisture content, and has a low content of impurities.

[0010] The present invention provides a method for producing lithium phosphate, comprising the steps of: introducing a lithium-containing solution into a reactor; introducing an alkaline substance and a phosphorus-supplying substance into the reactor; stirring the lithium-containing solution into which the alkaline substance and the phosphorus-supplying substance have been introduced to grow lithium phosphate core particles to obtain a lithium phosphate slurry; and separating the slurry into solid and liquid to obtain lithium phosphate, wherein one of the alkaline substance and the phosphorus-supplying substance is introduced into the upper part of the reactor, and the other is introduced into the lower part of the reactor.

[0011] The method for producing lithium phosphate according to the present invention has the advantage of facilitating control of the particle size of lithium phosphate. Furthermore, it has the advantage of facilitating the production of lithium phosphate with a low water content and a low impurity content.

[0012] FIG. 1 is a diagram illustrating a reactor according to some embodiments of the present invention.

[0013] Figures 2 and 3 are diagrams showing the pH gradient within a reactor during a method for producing lithium phosphate according to some embodiments of the present invention.

[0014] Figure 4 is a diagram showing the results of D10 particle size analysis of lithium phosphate particles manufactured according to examples and comparative examples.

[0015] Figure 5 is a diagram showing a reactor according to a comparative example.

[0016] Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples and are not intended to limit the present invention. The present invention is defined solely by the scope of the claims set forth below.

[0017] In the present invention, when it is said that a member is located “on” another member, this includes not only cases where a member is in direct contact with another member, but also cases where another member is interposed between the two members.

[0018] When a part of the present invention is said to "include" a certain component, this does not mean that other components are excluded, but rather that other components may be included, unless otherwise specifically stated.

[0019]

[0020] One aspect of the present invention relates to a method for producing lithium phosphate, comprising the steps of: introducing a lithium-containing solution into a reactor; introducing an alkaline substance and a phosphorus supplying substance into the reactor; stirring the lithium-containing solution into which the alkaline substance and the phosphorus supplying substance have been introduced to grow lithium phosphate core particles to obtain a lithium phosphate slurry; and separating the slurry into solids and liquids to obtain lithium phosphate, wherein one of the alkaline substance and the phosphorus supplying substance is introduced into the upper portion of the reactor, and the other is introduced into the lower portion of the reactor.

[0021] The method for producing lithium phosphate according to the present invention has the advantage of easily controlling the particle size of lithium phosphate by forming a pH gradient within the reactor. In addition, it has the advantage of being able to produce lithium phosphate with a low moisture content and a low content of impurities.

[0022]

[0023] The method for producing lithium phosphate according to the present invention includes a step of introducing a lithium-containing solution into a reactor.

[0024] The above lithium-containing solution may be at least one selected from the group consisting of a solution extracted from lithium dissolved in the ocean, a solution generated in a process of recycling spent lithium batteries, a solution obtained by leaching lithium ore, brine, lithium-containing hot spring water, lithium-containing groundwater, and lithium-containing brine.

[0025] In one embodiment of the present invention, the lithium-containing solution may be a saline solution.

[0026]

[0027] The above reactor may be a continuous reactor, a batch reactor, or a semi-batch reactor, but its form is not particularly limited as long as an alkaline substance can be introduced into either the upper or lower portion of the reactor and a phosphorus supply substance can be introduced into the remainder.

[0028]

[0029] The method for producing lithium phosphate according to the present invention includes a step of introducing an alkaline substance and a phosphorus supplying substance into the reactor, wherein one (2) of the alkaline substance and the phosphorus supplying substance is introduced into the upper part of the reactor, and the other (1) is introduced into the lower part of the reactor (see Fig. 1).

[0030] In the present invention, the “upper part of the reactor” may refer to a space within a range of 50% in the longitudinal direction from the upper part of the internal space of the reactor based on the cross-section of the internal space of the reactor.

[0031] In the present invention, the “lower part of the reactor” may refer to a space within a range of 50% in the longitudinal direction from the lower part of the internal space of the reactor based on the cross-section of the internal space of the reactor.

[0032] In another embodiment of the present invention, in the step of introducing an alkaline substance and a phosphorus supplying substance into the reactor, the alkaline substance and the phosphorus supplying substance may be introduced simultaneously.

[0033]

[0034] Although we do not wish to be limited by theory, phosphate ions are known to react with [H2PO4] in response to changes in the surrounding pH. - ion, [HPO4] 2- ion, [PO4] 3- It is known that ions are formed, and accordingly the following reaction is formed in the lithium-containing solution.

[0035]

[0036] [Reaction Formula 1]

[0037] H3PO4+ Li + + (OH) - [Li + + (H2PO4) - ] + [H + + (OH) - ]

[0038] [Reaction Formula 2]

[0039] [H2PO4] - + Li + + (OH) - [Li + +(HPO4) 2- ] + [H + + (OH) - ]

[0040] [Reaction Formula 3]

[0041] [HPO4] 2- + Li + + (OH) - [Li + + (PO4) 3- ] + [H + + (OH) - ]

[0042]

[0043] Accordingly, depending on the solubility of the lithium compound, compounds in the form of LiH2PO4, Li2HPO4, and Li3PO4 exist, and the precipitation behavior appears depending on the solubility of each compound. In particular, in the case of Li3PO4, the precipitation reaction occurs quickly in the alkaline region due to its low solubility, and in the case of other lithium compounds, due to its high solubility, precipitation occurs under solution conditions with a high lithium content and pH conditions.

[0044] Accordingly, in the present invention, an alkaline substance and a phosphorus supply substance are simultaneously introduced into the upper and lower portions of the reactor, respectively, so that the lithium-containing solution within the reactor, in other words, has a pH gradient (see FIGS. 2 and 3).

[0045] Specifically, Fig. 2 is a diagram showing the pH gradient when an alkaline substance is injected from above and a phosphorus supply substance is injected from below, and Fig. 3 is a diagram showing the pH gradient when the same process as Fig. 2 is performed but an alkaline substance is injected from below and a phosphorus supply substance is injected from above.

[0046] By forming the above lithium-containing solution to have a pH gradient, it is possible to control rapid contact between phosphate ions and alkaline ions to alkalize the pH, and to control the nucleation and particle growth rate of lithium phosphate.

[0047] In this way, when the lithium-containing solution has a pH gradient, nuclei can be generated at a pH of 4 or higher, and the size of the particles can gradually grow as the generated nuclei move toward a higher pH within the lithium-containing solution.

[0048]

[0049] In another embodiment of the present invention, the step of stirring the lithium-containing solution into which the alkaline substance and the phosphorus supply substance are added to grow lithium phosphate core particles and obtain a lithium phosphate slurry may include a step of forming a pH gradient within the reactor.

[0050] Specifically, the pH of the lithium-containing solution into which the alkaline substance and the phosphorus supply substance are added may have a gradient of 0.7 to 13.2.

[0051]

[0052] In another embodiment of the present invention, the alkaline substance and the phosphorus supplying substance may be introduced at a distance of 40 to 100%, preferably 60 to 100%, and more preferably 80 to 100%, relative to the height of the reactor. Since nuclei of reaction precipitates of the alkaline substance and the phosphorus supplying substance may begin to form under conditions of pH 4.5 or higher, it is preferable that the alkaline substance and the phosphorus supplying substance be introduced at a distance of the distance within the above range.

[0053] When the above alkaline substance and the above phosphorus supply substance are spaced within the above range with respect to the height of the reactor, the pH gradient effect is excellent, which is preferable.

[0054]

[0055] In another embodiment of the present invention, the alkaline material and the phosphorus supply material can be introduced at a distance of 0 to 100% with respect to the width of the reactor.

[0056] When the alkaline substance and the phosphorus supply substance are spaced within the above range with respect to the width of the reactor, the pH gradient effect is excellent, and the phenomenon of the alkaline ions and phosphorus ions rapidly coming into contact and the pH of the lithium-containing solution becoming alkaline as a whole can be suppressed, which is preferable.

[0057]

[0058] In another embodiment of the present invention, the time for adding the alkaline substance and the phosphorus supply substance may be 10 to 120 minutes, preferably 20 to 100 minutes, and more preferably 30 to 60 minutes.

[0059] When the injection time of the alkaline substance and the phosphorus supply substance satisfies the above range, the growth of the lithium phosphate particles is sufficient and thus preferable.

[0060]

[0061] In another embodiment of the present invention, the injection rate of the alkaline substance may be, but is not limited to, 12.6 to 23.3 g / hr / L or 1.26 to 11.65 mL / hr / L. Specifically, when the alkaline substance is injected in powder form, it may be injected at 12.6 to 23.3 g / hr / L, and when it is injected in liquid form, it may be injected at 1.16 to 11.65 ml / hr / L, but is not limited thereto.

[0062] In another embodiment of the present invention, the injection rate of the phosphorus supply material may be, but is not limited to, 12.6 to 25.1 g / hr / L or 6.8 to 13.7 mL / hr / L. Specifically, when the phosphorus supply material is injected in powder form, it may be injected at 12.6 to 25.1 g / hr / L, and when it is injected in liquid form, it may be injected at 6.8 to 13.7 mL / hr / L, but is not limited thereto.

[0063] When the injection rate of the alkaline substance and the phosphorus supply substance satisfies the above range, it is preferable to easily form a pH gradient.

[0064]

[0065] The above-mentioned phosphorus supply material can be added to the lithium-containing solution at a concentration of 0.7 to 1.3 in equivalent ratio.

[0066] The above alkaline substance can be added to the lithium-containing solution at a concentration of 0.7 to 1.3 in an equivalent ratio.

[0067]

[0068] In another embodiment of the present invention, the alkaline substance may include, but is not limited to, one or more selected from the group consisting of NaOH, KOH, and LiOH. Specifically, the alkaline substance may be NaOH.

[0069] In another embodiment of the present invention, the phosphorus supplying material may be at least one selected from the group consisting of phosphoric acid, phosphate, and phosphoric acid aqueous solution.

[0070]

[0071] The method for producing lithium phosphate according to the present invention includes a step of stirring the lithium-containing solution into which the alkaline substance and phosphorus supply substance are added to grow lithium phosphate core particles, thereby obtaining a lithium phosphate slurry.

[0072] In the method for producing lithium phosphate according to the present invention, when the alkaline substance and the phosphorus supplying substance are introduced, one of the alkaline substance and the phosphorus supplying substance is introduced into the upper part of the reactor, and the other is introduced into the lower part of the reactor, thereby creating a pH gradient within the reactor. This makes it possible to separate the nucleation zone and the growth zone of lithium phosphate and react them, thereby significantly increasing the particle size of lithium phosphate and reducing the moisture content during solid-liquid separation, which will be described later.

[0073] The above alkaline substance and the above phosphorus supply substance can be respectively introduced into the upper and lower portions of the reactor depending on the form of the supplied substance.

[0074] For example, when the alkaline substance is in powder form and the phosphorus supply substance is in liquid form, the alkaline substance may be supplied to the upper part of the reactor and the phosphorus supply substance may be supplied to the lower part of the reactor.

[0075] In another embodiment of the present invention, the alkaline material may be introduced into the upper part of the reactor, and the phosphorus supply material may be introduced into the lower part of the reactor.

[0076] Specifically, in Fig. 1, (1) may be a phosphorus supply material, and (2) may be an alkaline material.

[0077]

[0078] In another embodiment of the present invention, in the step of growing lithium phosphate core particles by stirring the lithium-containing solution into which the alkaline substance and the phosphorus supply substance are added to obtain a lithium phosphate slurry, the stirring may be performed at 30 to 500 RPM, preferably 50 to 350 RPM, and more preferably 80 to 250 RPM.

[0079] It is preferable that the pH gradient be stably maintained when the above stirring is performed under the above conditions.

[0080]

[0081] In another embodiment of the present invention, the step of stirring the lithium-containing solution into which the alkaline substance and the phosphorus supplying substance have been added to grow lithium phosphate core particles and obtain a lithium phosphate slurry may be performed at a temperature of 0 to 90°C, preferably 5 to 70°C, and more preferably 10 to 60°C. Since neutralization heat of up to about 50 to 60°C may be generated when the alkaline substance and the phosphorus supplying substance react, the step of obtaining the lithium phosphate slurry may be performed within the above temperature range.

[0082]

[0083] The method for producing lithium phosphate according to the present invention includes a step of obtaining lithium phosphate by solid-liquid separation of the slurry.

[0084] The above solid-liquid separation can be performed using a suction device, filter press, centrifuge, etc. connected to a vacuum pump.

[0085]

[0086] In another embodiment of the present invention, the step of obtaining lithium phosphate by solid-liquid separation of the slurry may include the step of obtaining a cake containing lithium phosphate particles by solid-liquid separation of the slurry; and the step of washing the cake containing the lithium phosphate particles.

[0087] When the above lithium phosphate slurry is subjected to solid-liquid separation to obtain a cake containing lithium phosphate particles, a functional substance containing the extracted residue and other residual impurities may remain in the cake.

[0088] Accordingly, in order to increase the content of the lithium phosphate, a washing process is performed. Since the lithium phosphate manufactured by the method for manufacturing lithium phosphate according to the present invention has relatively larger particles than the lithium phosphate manufactured by the conventional method, the filtration efficiency increases, and the amount of residual water decreases, resulting in the advantage of reducing the content of impurities remaining in the cake.

[0089]

[0090] In another embodiment of the present invention, the washing may be performed at a temperature of 10 to 90°C, preferably 30 to 80°C, and more preferably 40 to 70°C.

[0091] Lithium phosphate is known to have a solubility of 0.39 g / L at 20°C. When the washing is performed within the above temperature range, the phenomenon of lithium phosphate loss due to dissolution during washing can be suppressed, while the efficiency of removing other impurities can be increased, which is preferable.

[0092]

[0093] In another embodiment of the present invention, the washing may be performed using 100 to 600 parts by weight, preferably 200 to 600 parts by weight, and more preferably 250 to 600 parts by weight of washing water relative to 100 parts by weight of the total cake containing the lithium phosphate particles.

[0094] When washing is performed using washing water in the above range, it is preferable because the removal rate of impurities such as K, Na, B, and S increases.

[0095] The above washing may be performed using a washing machine, but is not limited thereto.

[0096]

[0097] The above washing water may be distilled water, and the washing may be performed two or more times, but is not limited thereto.

[0098]

[0099] The above lithium phosphate cake may have a moisture content of 25% or less.

[0100] Lithium phosphate manufactured by the method for manufacturing lithium phosphate according to the present invention is D 10 It may be 5㎛ or more, specifically 8㎛ or more, and more specifically 11㎛ or more.

[0101] The method for producing lithium phosphate according to the present invention comprises physically introducing a phosphorus supply material and an alkaline material at different locations to precipitate lithium phosphate from a lithium-containing solution, thereby adjusting a pH gradient within the reactor, thereby separating the nucleation and growth sections of lithium phosphate and causing them to react, thereby significantly increasing the growth of lithium phosphate particles. Accordingly, the moisture content and impurity content of the lithium phosphate cake can be reduced, thereby providing the advantage of reducing the burden of the process.

[0102]

[0103] Hereinafter, preferred embodiments and comparative examples of the present invention are described. However, the following examples are only preferred embodiments of the present invention, and the present invention is not limited to the following examples.

[0104]

[0105] Example

[0106] Phosphoric acid (75 wt%) was added (1) to the bottom of a large reactor having the same shape as Fig. 1 in an amount of 1 equivalent to lithium dissolved in brine having a composition as shown in Table 1 below, and NaOH was simultaneously added (2) to the top of the reactor for 1 hour while stirring was performed at 80 RPM.

[0107] Additionally, phosphoric acid and the above NaOH were spaced 80% apart with respect to the height of the reactor (phosphoric acid was injected at a position 20% from the bottom of the reactor).

[0108]

[0109] Classification (g / L) LiSCaMgBKNapHSaline solution4.0911.0270.0080.0021.07238.5394.3710.85

[0110] The lithium phosphate slurry produced through stirring was subjected to solid-liquid separation to obtain a lithium phosphate cake.

[0111] In order to remove impurities from the lithium phosphate cake, as shown in Table 3 below, 300, 400, 500, and 600 parts by weight of distilled water (3, 4, 5, and 6 times the cake weight) were used as washing water for 100 parts by weight of the lithium phosphate cake, and washing was performed at temperature conditions of 20°C and 60°C, respectively.

[0112] At this time, the lithium phosphate cake was placed in a washing machine and stirred to wash it.

[0113]

[0114] Comparative Example 1

[0115] Into a brine containing lithium having a composition as shown in Table 1 above, phosphoric acid (75 wt%) was added (1) in an amount of 1 equivalent from the top of a large reactor as shown in Fig. 5, and simultaneously, NaOH was added (2) in an amount of 1 equivalent from the top for 1 hour, while stirring was performed at 80 RPM. At this time, the injection speeds of phosphoric acid and NaOH and the reaction temperature were the same as in the examples.

[0116] The lithium phosphate slurry produced through stirring was subjected to solid-liquid separation to obtain a lithium phosphate cake.

[0117]

[0118] Comparative Example 2

[0119] In brine containing lithium having a composition as shown in Table 2 below, phosphoric acid (75 wt%) was added to the upper portion of a large reactor identical to Comparative Example 1 in an amount of 1 equivalent, while NaOH was added in batches in an amount of 1 equivalent, and stirring was performed simultaneously for 1 hour. At this time, the phosphoric acid addition rate and reaction temperature were the same as in the example.

[0120]

[0121] Classification (g / L) LiSCaMgBKNapHSaline solution 4.2751.0420.0070.0111.13940.9097.1910.27

[0122] The lithium phosphate slurry produced through stirring was subjected to solid-liquid separation to obtain a lithium phosphate cake.

[0123]

[0124] Experimental example

[0125] (1) Moisture content and particle size analysis of lithium phosphate cake

[0126] The results of analyzing the moisture content and particle size of the lithium phosphate cake manufactured according to the examples and comparative examples are shown in Fig. 4 and Table 3 below.

[0127] In addition, in the example, the pH gradient according to the position inside the reactor was measured during the stirring process, and the results are shown in Fig. 2.

[0128] At this time, the moisture content was measured by measuring the weight change after drying at 105℃ for 24 hours, and was measured using the laser diffraction method.

[0129]

[0130] Separation Function Rate (%) Particle Size Analysis (㎛) D 10 D 50 D 90 D 100 Example <25% 11.15 22.40 37.41 79.30 Comparative Example 1 <35% 4.61 13.89 27.78 39.82 Comparative Example 25 2% 0.97 04 9.67 6.30

[0131] Specifically, Fig. 4 shows D according to the number of times the method of Example 1 and Comparative Example 1 were repeated. 10 As shown in Fig. 4, in the case of the embodiment, D 10 It was confirmed that the standard particle size increased. In addition, referring to Table 2, it can be confirmed that in the case of the example, the overall particle size of the lithium phosphate particles increased, and the moisture content also decreased to less than 25%.

[0132]

[0133] (2) Composition of lithium phosphate powder according to washing process

[0134] In order to remove impurities from the lithium phosphate cake obtained according to the example, washing was performed at temperature conditions of 20°C and 60°C using 300 to 600 parts by weight (3 to 6 times the cake weight) of distilled water as washing water for 100 parts by weight of the lithium phosphate cake, as shown in Table 3 below.

[0135] At this time, the lithium phosphate cake was placed in a washing machine and stirred to perform washing, and the ICP analysis results of the lithium phosphate cake before and after washing are shown in Table 4 below.

[0136]

[0137] Classification (wt%) LiSPCaMgBKNa Before washing 14.77 0.31 42 1.57 0.026 0.027 0.78 30.76 33.147 Drainage 20℃ 16.11 0.26 62 3.54 0.026 0.026 0.68 30.159 1.12 0 60℃ 16.67 0.13 32 4.3 20.026 0.027 0.43 9 0.08 80.61 24 Drainage 20℃ 16.15 0.23 9 23.6 20.025 0.026 0.63 70.107 0.88 0 60℃ 16.56 0.12 024.280.0270.0280.4040.0790.4965Multiple 20℃16.240.24523.600.0270.0260.6250.1050.81460℃16.880.10924.400.0270.0280.3760.0580.3756Multiple 20℃16.320.23423.600.0260.0270.6090.0980.74560℃16.760.11124.360.0260.0260.3690.0540.359

[0138] Referring to Table 4 above, it can be confirmed that as the amount of washing water increases, the removal rate increases in the order of K, Na, B, and S. In addition, it can be confirmed that the removal rate increases when washing is performed under temperature conditions of 60℃. This means that impurities in the lithium phosphate cake recovered from brine with a lot of dissolved chloride, such as KCl and NaCl, are well washed away as highly soluble compounds as the washing water temperature increases.

[0139]

[0140] In addition, in order to remove impurities from the lithium phosphate cake obtained according to Comparative Example 2, washing was performed at 20°C using 600 parts by weight of distilled water as washing water for 100 parts by weight of the lithium phosphate cake.

[0141] At this time, the lithium phosphate cake according to Comparative Example 2 was washed by placing it in the same washing machine as the example and stirring it, and the results of ICP analysis of the lithium phosphate cake before and after washing are shown in Table 5 below.

[0142]

[0143] Classification (wt.%) LiSPCaMgBKNaBefore washing9.340.2613.410.0100.00050.554.4714.90After washing (20℃)15.310.1621.370.0960.03300.491.074.48

[0144] Referring to Tables 3 to 5 above, it can be seen that the lithium phosphate cake manufactured according to Comparative Example 2 has a much smaller particle size based on D10 compared to the examples, and has a high moisture content and a high content of impurities even after washing.

[0145]

[0146] The present invention is not limited to the above-described embodiments, but can be manufactured in a variety of different forms. Those skilled in the art will appreciate that the present invention can be implemented in other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

1. Step of introducing a lithium-containing solution into the reactor; A step of introducing an alkaline substance and a phosphorus supply substance into the reactor; A step of stirring the lithium-containing solution into which the alkaline substance and the phosphorus supply substance are added to grow lithium phosphate core particles to obtain a lithium phosphate slurry; and A step of obtaining lithium phosphate by separating the above slurry into solid and liquid; Including, One of the above alkaline substance and the above phosphorus supply substance is introduced into the upper part of the reactor, and the other is introduced into the lower part of the reactor. Method for producing lithium phosphate.

2. In paragraph 1, In the step of introducing an alkaline substance and a phosphorus supply substance into the reactor, A method for producing lithium phosphate, wherein the above alkaline substance and phosphorus supply substance are introduced simultaneously.

3. In paragraph 1, A method for producing lithium phosphate, wherein the alkaline substance and the phosphorus supply substance are introduced at a distance of 40 to 100% with respect to the height of the reactor.

4. In paragraph 3, A method for producing lithium phosphate, wherein the alkaline substance and the phosphorus supply substance are introduced at a distance of 60 to 100% with respect to the height of the reactor.

5. In paragraph 1, A method for producing lithium phosphate, wherein the alkaline substance and the phosphorus supply substance are introduced at a distance of 0 to 100% with respect to the width of the reactor.

6. In paragraph 1, A method for producing lithium phosphate, wherein the alkaline substance is injected into the upper part of the reactor, and the phosphorus supply substance is injected into the lower part of the reactor.

7. In paragraph 1, A method for producing lithium phosphate, comprising: a step of stirring the lithium-containing solution into which the alkaline substance and the phosphorus supply substance are added to grow lithium phosphate core particles and obtain a lithium phosphate slurry; wherein the stirring is performed at 30 to 500 RPM.

8. In paragraph 1, The step of obtaining a lithium phosphate slurry by stirring the lithium-containing solution into which the alkaline substance and the phosphorus supply substance are added to grow lithium phosphate core particles; A method for producing lithium phosphate, comprising: a step of forming a pH gradient within the reactor.

9. In paragraph 1, A method for producing lithium phosphate, wherein the injection time of the alkaline substance and the phosphorus supply substance is 10 to 120 minutes.

10. In paragraph 1, A method for producing lithium phosphate, wherein the step of stirring the lithium-containing solution into which the alkaline substance and the phosphorus supply substance are added to grow lithium phosphate core particles and obtain a lithium phosphate slurry is performed at a temperature of 0 to 90°C.

11. In paragraph 1, The step of obtaining lithium phosphate by separating the above slurry into solid and liquid; A step of obtaining a cake containing lithium phosphate particles by separating the above slurry into solid and liquid; and A step of washing a cake containing the lithium phosphate particles; Including Method for producing lithium phosphate.

12. In paragraph 11, A method for producing lithium phosphate, wherein the above washing is performed at a temperature of 10 to 90°C.

13. In paragraph 11, A method for producing lithium phosphate, wherein the washing is performed using 100 to 600 parts by weight of washing water based on 100 parts by weight of the entire cake containing the lithium phosphate particles.

14. In paragraph 1, A method for producing lithium phosphate, wherein the lithium-containing solution is a saline solution.

15. In paragraph 1, A method for producing lithium phosphate, wherein the alkaline substance comprises at least one selected from the group consisting of NaOH, KOH, and LiOH.

16. In paragraph 1, A method for producing lithium phosphate, wherein the phosphorus supplying material is at least one selected from the group consisting of phosphoric acid, phosphate, and phosphoric acid aqueous solution.

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