Method for producing lithium phosphate

Abstract

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 containing the alkaline substance and phosphorus-supplying substance to grow lithium phosphate nucleus particles and 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.

Description

[Technical Field]

[0001] This invention relates to a method for producing lithium phosphate. [Background technology]

[0002] Recently, lithium-ion batteries have seen rapid growth in the field of electronic communication equipment such as tablet PCs and smartphones, and their applications have expanded to include energy for electric vehicles. As a result, research and development efforts to increase energy storage capacity are becoming increasingly concrete. Due to this growth in the lithium-ion battery market, the amount of lithium (Li), the main raw material for cathode materials, is gradually increasing.

[0003] Lithium sources include minerals, brine, and seawater. Among these, minerals such as spodumene, petalite, and lepidolite contain relatively high amounts of lithium, approximately 1 to 1.5% by weight. However, extracting lithium from minerals requires complex processes such as flotation, high-temperature heating, crushing, acid mixing, extraction, purification, concentration, and precipitation. This results in a complex recovery procedure, high energy consumption and high costs, and serious environmental pollution due to the use of acids in the lithium extraction process.

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

[0005] On the other hand, various attempts have been made to extract lithium from such saltwater. For example, lithium is concentrated to an extractable concentration using natural evaporation and then extracted using lithium chloride, lithium sulfate, lithium carbonate, lithium hydroxide, lithium fluoride, lithium phosphate, etc.

[0006] Of these, lithium phosphate is known as a compound with low solubility, making it the easiest method for extracting dissolved lithium.

[0007] However, lithium phosphate has some drawbacks: its low solubility leads to a rapid nucleation rate with changes in pH during production, resulting in the production of fine particles, and the high water content during solid-liquid separation increases the amount of impurities.

[0008] Therefore, there is a need to develop a method for producing lithium phosphate that can control the particle size of lithium phosphate, thereby reducing water content and impurities. [Overview of the project] [Problems that the invention aims to solve]

[0009] The present invention aims to provide a method for producing lithium phosphate that allows for control of the particle size of lithium phosphate, has a low water content, and contains few impurities. [Means for solving the problem]

[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 containing the alkaline substance and phosphorus-supplying substance to grow lithium phosphate nucleus particles and 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 into the lower part of the reactor. [Effects of the Invention]

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

[0012] [Figure 1] It is a diagram showing a reactor according to some embodiments of the present invention. [Figure 2] It is a diagram showing the pH gradient in the reactor among the methods for producing lithium phosphate according to some embodiments of the present invention. [Figure 3] It is a diagram showing the pH gradient in the reactor among the methods for producing lithium phosphate according to some embodiments of the present invention. [Figure 4] It is a diagram showing the D10 particle size analysis results of lithium phosphate particles produced by Examples and Comparative Examples. [Figure 5] It is a diagram showing a reactor according to a Comparative Example.

Mode for Carrying Out the Invention

[0013] Hereinafter, examples of the present invention will be described in detail. However, this is presented as an example, and the present invention is not limited thereby. The present invention is only defined by the scope of the claims described later.

[0014] In the present invention, when a member is located "above" another member, this includes not only the case where a member is directly in contact with another member, but also the case where another member is interposed between the two members.

[0015] In the present invention, when a part "includes" a certain component, this means that, unless otherwise stated, it does not exclude other components, but may further include other components.

[0016] One aspect of the present invention relates to a method for producing lithium phosphate, which includes the steps of: introducing a lithium-containing solution into a reactor; introducing an alkali substance and a phosphorus supply substance into the reactor; stirring the lithium-containing solution into which the alkali substance and the phosphorus supply substance have been introduced to grow lithium phosphate nuclei particles to obtain a lithium phosphate slurry; and performing solid-liquid separation on the slurry to obtain lithium phosphate, wherein one of the alkali substance and the phosphorus supply substance is introduced into the upper part of the reactor, and the remaining is introduced into the lower part of the reactor.

[0017] The method for producing lithium phosphate according to the present invention has the advantage that it is easy to control the particle size of lithium phosphate by forming a pH gradient in the reactor. Further, there is an advantage that lithium phosphate having a low water content and a low impurity content can be produced.

[0018] The method for producing lithium phosphate according to the present invention includes the step of introducing a lithium-containing solution into a reactor.

[0019] The lithium-containing solution may be one or more selected from the group consisting of a solution obtained by extracting lithium dissolved in the ocean, a solution generated in the process of recycling waste lithium batteries, a solution obtained by leaching lithium ore, brine, lithium-containing hot spring water, lithium-containing groundwater, and lithium-containing salt water.

[0020] In one embodiment of the present invention, the lithium-containing solution may be brine.

[0021] The 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 alkali substance can be introduced into either the upper part or the lower part of the reactor, and the remaining part can be introduced with a phosphorus supply substance.

[0022] The method for producing lithium phosphate according to the present invention includes a step of introducing an alkali substance and a phosphorus supply substance into the reactor, wherein one of the alkali substance and the phosphorus supply substance is introduced into the upper part of the reactor, and the other is introduced into the lower part of the reactor (see Figure 1).

[0023] In the present invention, the "upper part of the reactor" can refer to the space within a range of 50% in the length direction from the upper part of the internal space of the reactor, based on the cross-section of the internal space of the reactor.

[0024] In the present invention, the "lower part of the reactor" can refer to the space within a range of 50% in the length direction from the lower part of the internal space of the reactor, based on the cross-section of the internal space of the reactor.

[0025] In another embodiment of the present invention, in the step of introducing an alkali substance and a phosphorus supply substance into the reactor, the alkali substance and the phosphorus supply substance can be introduced simultaneously.

[0026] Although not wishing to be limited by theory, phosphate ions are known to form [H2PO4] - ions, [HPO4] 2- ions, [PO4] 3- ions due to the pH change in the surrounding area, and thus the following reactions are constituted in the lithium-containing solution.

[0027] [Reaction formula 1] H3PO4 + Li + +(OH) - ⇔ [Li + +(H2PO4) - + [H + +(OH) -

[0028] [Reaction formula 2] [H2PO4] - + Li + +(OH) - ⇔ [Li + +(HPO4) 2- + [H ++(OH) - ]

[0029] [Reaction Equation 3] [HPO4] 2- +Li + +(OH) - ⇔[Li + +(PO4) 3- ]+[H + +(OH) - ]

[0030] As a result, lithium compounds exist in the forms of LiH2PO4, Li2HPO4, and Li3PO4 depending on their solubility, and their precipitation behavior is determined by the solubility of each compound. In particular, in the case of Li3PO4, a rapid precipitation reaction occurs in the alkaline range due to its low solubility, while in the case of other lithium compounds, precipitation occurs under solution conditions and pH conditions with a high lithium content due to their high solubility.

[0031] In this invention, the alkaline substance and the phosphorus supplying substance are simultaneously introduced into the upper and lower parts of the reactor, respectively, so that the inside of the reactor, in other words, the lithium-containing solution, has a pH gradient (see Figures 2 and 3).

[0032] Specifically, Figure 2 shows the pH gradient when an alkaline substance is added from the top and a phosphorus-supplying substance is added from the bottom, and Figure 3 shows the pH gradient when the same procedure as in Figure 2 is followed, but the alkaline substance is added from the bottom and the phosphorus-supplying substance is added from the top.

[0033] By forming the lithium-containing solution to have a pH gradient, it is possible to control the rapid contact between phosphate ions and alkali ions, which leads to alkalization of the pH, thereby controlling the nucleation of lithium phosphate and the particle growth rate.

[0034] In this manner, when the lithium-containing solution has a pH gradient, nucleation can be performed under conditions of pH 4 or higher, and the generated nuclei can gradually grow in size as they move towards the higher pH side within the lithium-containing solution.

[0035] In yet another embodiment of the present invention, the step of stirring the lithium-containing solution to which the alkaline substance and phosphorus-supplying substance have been added to grow lithium phosphate nucleus particles to obtain a lithium phosphate slurry may include the step of forming a pH gradient in the reactor.

[0036] Specifically, the pH of the lithium-containing solution into which the alkaline substance and the phosphorus-supplying substance are added can have a gradient from 0.7 to 13.2.

[0037] In yet another embodiment of the present invention, the alkali substance and the phosphorus-supplying substance can be introduced at a separation of 40 to 100%, preferably 60 to 100%, and more preferably 80 to 100% relative to the height of the reactor. It is preferable to introduce the alkali substance and the phosphorus-supplying substance at a separation of this range because nuclei of the reaction precipitate of the alkali substance and the phosphorus-supplying substance can begin to form at a pH of 4.5 or higher.

[0038] When the alkaline substance and the phosphorus supplying substance are separated within the specified range relative to the height of the reactor, this is preferable because it provides an excellent pH gradient effect.

[0039] In yet another embodiment of the present invention, the alkaline substance and the phosphorus supplying substance can be introduced at a distance of 0 to 100% relative to the width of the reactor.

[0040] When the alkaline substance and the phosphorus supplying substance are separated within the range relative to the width of the reactor, it is preferable because it provides an excellent pH gradient effect and suppresses the phenomenon in which alkaline ions and phosphorus ions rapidly come into contact, causing the pH of the lithium-containing solution to become alkaline overall.

[0041] In yet another embodiment of the present invention, the time for introducing the alkaline substance and the phosphorus supplying substance may be 10 to 120 minutes, preferably 20 to 100 minutes, and more preferably 30 to 60 minutes.

[0042] When the time for introducing the alkaline substance and the phosphorus supplying substance satisfies the above range, it is preferable because the growth of the lithium phosphate particles is sufficient.

[0043] In yet another embodiment of the present invention, the rate at which the alkaline substance is added can be 12.6 to 23.3 g / hr / L or 1.26 to 11.65 mL / hr / L, but is not limited thereto. Specifically, when the alkaline substance is added in powder form, it can be added at a rate of 12.6 to 23.3 g / hr / L, and when it is added in liquid form, it can be added at a rate of 1.16 to 11.65 ml / hr / L, but is not limited thereto.

[0044] In yet another embodiment of the present invention, the rate at which the phosphorus supplying material is introduced can be 12.6 to 25.1 g / hr / L or 6.8 to 13.7 mL / hr / L, but is not limited thereto. Specifically, when the phosphorus supplying material is introduced in powder form, it can be introduced at a rate of 12.6 to 25.1 g / hr / L, and when it is introduced in liquid form, it can be introduced at a rate of 6.8 to 13.7 mL / hr / L, but is not limited thereto.

[0045] When the rate at which the alkaline substance and the phosphorus supplying substance are added satisfies the above range, it is preferable because it facilitates the formation of a pH gradient.

[0046] The phosphorus supplying substance can be added to the lithium-containing solution at an equivalent ratio of 0.7 to 1.3.

[0047] The alkaline substance can be added to the lithium-containing solution to a concentration of 0.7 to 1.3 in equivalent ratio.

[0048] In yet another embodiment of the present invention, the alkali substance may include, but is not limited to, one or more selected from the group consisting of NaOH, KOH, and LiOH. Specifically, the alkali substance may be NaOH.

[0049] In yet another embodiment of the present invention, the phosphorus supplying substance may be one or more selected from the group consisting of phosphoric acid, phosphates, and aqueous solutions of phosphoric acid.

[0050] The present invention provides a method for producing lithium phosphate, which includes the step of stirring the lithium-containing solution to which the alkali substance and phosphorus-supplying substance have been added to grow lithium phosphate nucleus particles to obtain a lithium phosphate slurry.

[0051] In the lithium phosphate production method according to the present invention, when the alkali substance and the phosphorus supplying substance are added, one of the alkali substance and the phosphorus supplying substance is added to the upper part of the reactor and the other is added to the lower part of the reactor, thereby creating a pH gradient within the reactor. This allows the nucleation and growth phases of lithium phosphate to be reacted separately, enabling the lithium phosphate particles to grow to a larger size and reducing the water content during solid-liquid separation, as described later.

[0052] The alkaline substance and the phosphorus supplying substance can be introduced into the upper and lower parts of the reactor, respectively, depending on the form of the substance being supplied.

[0053] For example, if the alkaline substance is in powder form and the phosphorus supplying substance is in liquid form, the alkaline substance can be supplied to the upper part of the reactor and the phosphorus supplying substance can be supplied to the lower part of the reactor.

[0054] In yet another embodiment of the present invention, the alkaline substance may be introduced into the upper part of the reactor, and the phosphorus supplying substance may be introduced into the lower part of the reactor.

[0055] Specifically, in Figure 1, 1 could be a phosphorus-supplying substance, and 2 could be an alkaline substance.

[0056] In yet another embodiment of the present invention, in the step of stirring the lithium-containing solution to which the alkali substance and phosphorus-supplying substance have been added to grow lithium phosphate nucleus particles to obtain a lithium phosphate slurry, the stirring can be performed at 30 to 500 RPM, preferably 50 to 350 RPM, and more preferably 80 to 250 RPM.

[0057] When the stirring is performed under the aforementioned conditions, it is preferable because the pH gradient can be stably maintained.

[0058] In yet another embodiment of the present invention, the step of stirring the lithium-containing solution to which the alkali substance and phosphorus-supplying substance have been added to grow lithium phosphate nucleus particles to obtain a lithium phosphate slurry can be carried out at a temperature of 0 to 90°C, preferably 5 to 70°C, and more preferably 10 to 60°C. Since neutralization heat can be generated up to about 50 to 60°C when the alkali substance and the phosphorus-supplying substance react, the step of obtaining the lithium phosphate slurry can be carried out within this temperature range.

[0059] The present invention relates to a method for producing lithium phosphate, which includes the step of obtaining lithium phosphate by solid-liquid separation of the slurry.

[0060] The solid-liquid separation can be performed using a suction device connected to a vacuum pump, a filter press, or a centrifuge.

[0061] In yet 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 lithium phosphate particles.

[0062] When the lithium phosphate slurry is subjected to solid-liquid separation to obtain a cake containing lithium phosphate particles, a function can remain in the cake where the extracted filtrate and other residual impurities coexist.

[0063] Therefore, in order to increase the lithium phosphate content, a washing process is required. However, lithium phosphate produced by the lithium phosphate production method according to the present invention has the advantage of increased filtration efficiency and a reduction in the amount of residual function and the amount of residual impurities in the cake, because the particles are relatively larger compared to lithium phosphate produced by conventional methods.

[0064] In yet another embodiment of the present invention, the cleaning can be carried out at a temperature of 10 to 90°C, preferably 30 to 80°C, and more preferably 40 to 70°C.

[0065] Lithium phosphate is known to have a solubility of 0.39 g / L at 20°C. When the washing is performed within the aforementioned temperature range, it is preferable because it is possible to suppress the loss of lithium phosphate due to dissolution during washing while increasing the efficiency of removing other impurities.

[0066] In another embodiment of the present invention, the washing can be carried out using washing water in an amount of 100 to 600 parts by weight, preferably 200 to 600 parts by weight, and more preferably 250 to 600 parts by weight, per 100g of the total weight of the cake containing the lithium phosphate particles.

[0067] When washing is performed using washing water within the aforementioned range, it is preferable because it increases the removal rate of impurities such as K, Na, B, and S.

[0068] The aforementioned cleaning can be carried out using a cleaning device, but is not limited thereto.

[0069] The washing water may be distilled water, and the washing may be performed two or more times, but is not limited to this.

[0070] The lithium phosphate cake may have a moisture content of 25% or less.

[0071] Lithium phosphate produced by the lithium phosphate production method according to the present invention may have a D10 of 5 μm or more, specifically 8 μm or more, and more specifically 11 μm or more.

[0072] The lithium phosphate production method according to the present invention allows for the separation of the nucleation and growth phases of lithium phosphate by physically adding the phosphorus supplying substance and alkaline substance, which are introduced to precipitate lithium phosphate from a lithium-containing solution, at different locations within the reactor to adjust the pH gradient. This enables the growth of larger lithium phosphate particles. Consequently, it has the advantage of reducing the water content and impurity content of the lithium phosphate cake, thereby reducing the burden on the process. [Examples]

[0073] Preferred embodiments and comparative examples of the present invention are described below. However, the following embodiments are merely preferred embodiments of the present invention, and the present invention is not limited to these embodiments.

[0074] Examples To a brine solution containing lithium with the composition shown in Table 1 below, phosphoric acid (75% by weight) was added to the bottom of a large reactor as shown in Figure 1 in an amount of 1 equivalent. NaOH was simultaneously added to the top of the reactor in an amount of 1 equivalent for 1 hour while stirring at 80 RPM.

[0075] Furthermore, the phosphoric acid and the NaOH were separated to a distance of 80% relative to the height of the reactor (the phosphoric acid was added at a position 20% from the bottom of the reactor).

[0076] [Table 1]

[0077] The lithium phosphate slurry generated by stirring was subjected to solid-liquid separation to obtain a lithium phosphate cake.

[0078] To remove impurities from the lithium phosphate cake, distilled water was used as washing water in amounts of 300, 400, 500, and 600 parts by weight (3, 4, 5, and 6 times the cake weight) per 100 parts by weight of lithium phosphate cake, as shown in Table 3 below, and washing was performed at temperatures of 20°C and 60°C, respectively.

[0079] During this process, the lithium phosphate cake was placed in a washing machine and washed by agitation.

[0080] Comparative Example 1 To a brine solution containing lithium with the composition shown in Table 1, phosphoric acid (75% by weight) was added to the top of a large reactor as shown in Figure 5 in an amount equal to 1 equivalent, while simultaneously adding NaOH to the top in an amount equal to 1 equivalent over 1 hour, while stirring at 80 RPM. The rate of addition of phosphoric acid and NaOH, and the reaction temperature were the same as in the example.

[0081] The lithium phosphate slurry generated by stirring was subjected to solid-liquid separation to obtain a lithium phosphate cake.

[0082] Comparative Example 2 To a brine solution containing lithium with the composition shown in Table 2 below, phosphoric acid (75% by weight) was added to the top of the large reactor, the same as in Comparative Example 1, in an amount of 1 equivalent. At the same time, 1 equivalent of NaOH was added all at once, and the mixture was stirred for 1 hour. The rate of phosphoric acid addition and the reaction temperature were the same as in the example.

[0083] [Table 2]

[0084] The lithium phosphate slurry generated by stirring was subjected to solid-liquid separation to obtain a lithium phosphate cake.

[0085] Experimental example (1) Moisture content and particle size analysis of lithium phosphate cake The results of the analysis of the water content and particle size of the lithium phosphate cakes produced by the examples and comparative examples are shown in Figure 4 and Table 3 below.

[0086] Furthermore, the pH gradient was measured based on the position inside the reactor during the stirring process in the examples, and the results are shown in Figure 2.

[0087] In this process, the moisture content was measured by measuring the weight change after drying at 105°C for 24 hours, using the laser diffraction method.

[0088] [Table 3]

[0089] Specifically, Figure 4 shows the D10 particle size based on the number of times the methods of Example and Comparative Example 1 were repeated. Referring to Figure 4, it was confirmed that in the case of Example, the D10 reference particle size increased. Furthermore, referring to Table 2, it was confirmed that in the case of Example, the overall particle size of lithium phosphate particles increased, and the moisture content also decreased to 25% or less.

[0090] (2) Composition of lithium phosphate powder after the washing process To remove impurities from the lithium phosphate cake obtained in the examples, 300 to 600 parts by weight (3 to 6 times the cake weight) of distilled water per 100 parts by weight of lithium phosphate cake was used as washing water, as shown in Table 3 below, and washing was carried out at temperatures of 20°C and 60°C, respectively.

[0091] At that time, the lithium phosphate cake was placed in a washing machine and washed by agitation, and the ICP analysis results of the lithium phosphate cake before and after washing are shown in Table 4 below.

[0092] [Table 4]

[0093] Referring to Table 4 above, it can be confirmed that the removal rate increases in the order of K, Na, B, and S as the amount of washing water increases. Furthermore, it can be confirmed that the removal rate is high when washing at a temperature of 60°C. This means that impurities in lithium phosphate cake recovered from saline solution containing a large amount of dissolved chlorides such as KCl and NaCl are better washed away as the temperature of the washing water rises, resulting in better washing of compounds with high solubility.

[0094] Furthermore, in order to remove impurities from the lithium phosphate cake obtained in Comparative Example 2, 600 parts by weight of distilled water was used as washing water per 100 parts by weight of lithium phosphate cake, and washing was performed at 20°C.

[0095] In this process, the lithium phosphate cake from Comparative Example 2 was placed in the same washing apparatus as in the Example and washed by stirring. The ICP analysis results of the lithium phosphate cake before and after washing are shown in Table 5 below.

[0096] [Table 5]

[0097] Referring to Tables 3 to 5 above, it can be seen that the lithium phosphate cake produced by Comparative Example 2 has a significantly smaller D10 reference particle size compared to the example, a higher water content, and a higher impurity content even after washing.

[0098] The present invention is not limited to the embodiments described above and can be manufactured in a variety of different forms. Those with ordinary skill in the art to which the invention pertains should understand that the invention can be implemented in other specific forms without altering the technical idea or essential features. Therefore, the embodiments described above should be understood to be illustrative and not limiting in all respects.

Claims

1. The step of introducing a lithium-containing solution into the reactor; Steps include introducing an alkaline substance and a phosphorus supplying substance into the reactor; A step of stirring the lithium-containing solution to which the alkaline substance and phosphorus-supplying substance have been added to grow lithium phosphate nucleus particles to obtain a lithium phosphate slurry; and, A step of obtaining lithium phosphate by separating the slurry into solid and liquid components; Includes, One of the aforementioned alkaline substance and phosphorus supplying substance is introduced into the upper part of the reactor, and the other is introduced into the lower part of the reactor. A method for producing lithium phosphate.

2. In the step of introducing an alkaline substance and a phosphorus supplying substance into the reactor, The method for producing lithium phosphate according to claim 1, wherein the alkaline substance and the phosphorus supplying substance are added simultaneously.

3. The method for producing lithium phosphate according to claim 1, wherein the alkaline substance and the phosphorus supplying substance are introduced at a distance of 40 to 100% relative to the height of the reactor.

4. The method for producing lithium phosphate according to claim 3, wherein the alkaline substance and the phosphorus supplying substance are introduced at a distance of 60 to 100% relative to the height of the reactor.

5. The method for producing lithium phosphate according to claim 1, wherein the alkaline substance and the phosphorus supplying substance are introduced at a distance of 0 to 100% relative to the width of the reactor.

6. The method for producing lithium phosphate according to claim 1, wherein the alkaline substance is introduced into the upper part of the reactor and the phosphorus supplying substance is introduced into the lower part of the reactor.

7. The method for producing lithium phosphate according to claim 1, wherein the stirring in the lithium-containing solution to which the alkaline substance and phosphorus-supplying substance have been added is performed at 30 to 500 RPM to grow lithium phosphate nucleus particles and obtain a lithium phosphate slurry.

8. The step of stirring the lithium-containing solution to which the alkaline substance and phosphorus-supplying substance have been added to grow lithium phosphate nucleus particles and obtain a lithium phosphate slurry; A method for producing lithium phosphate according to claim 1, comprising the step of forming a pH gradient in the reactor.

9. The method for producing lithium phosphate according to claim 1, wherein the time for introducing the alkaline substance and the phosphorus supplying substance is 10 to 120 minutes.

10. The method for producing lithium phosphate according to claim 1, wherein the step of stirring the lithium-containing solution to which the alkaline substance and phosphorus-supplying substance have been added to grow lithium phosphate nucleus particles to obtain a lithium phosphate slurry is performed at a temperature of 0 to 90°C.

11. The step of obtaining lithium phosphate by solid-liquid separation of the slurry is: The steps of obtaining a cake containing lithium phosphate particles by separating the slurry from its solid-liquid state; and A step of washing the cake containing the lithium phosphate particles; A method for producing lithium phosphate according to claim 1, comprising:

12. The method for producing lithium phosphate according to claim 11, wherein the washing is performed at a temperature of 10 to 90°C.

13. The method for producing lithium phosphate according to claim 11 or 12, wherein the washing is carried out using 100 to 600 parts by weight of washing water per 100 parts by weight of the cake containing the lithium phosphate particles.

14. The method for producing lithium phosphate according to claim 1, wherein the lithium-containing solution is saline solution.

15. The method for producing lithium phosphate according to claim 1, wherein the alkali substance comprises one or more selected from the group consisting of NaOH, KOH, and LiOH.

16. The method for producing lithium phosphate according to claim 1, wherein the phosphorus supplying substance is one or more selected from the group consisting of phosphoric acid, phosphates, and aqueous solutions of phosphoric acid.

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