NANO-SHEET FERRIC PHOSPHATE, PREPARATION METHOD THEREFOR AND USE THEREOF

Abstract

Disclosed in the present invention are nano-meter sheet ferric phosphate, a preparation method therefor and the use thereof. The preparation method includes the following steps: dissolving a phosphorus source and an iron source in an acidic solution, adding an oxidant, and mixing same to obtain a solution containing phosphorus and iron; adding a precipitation auxiliary agent into part of the solution containing phosphorus and iron, heating same until boiling, and then diluting same for a reaction to obtain a primary ferric phosphate slurry; and dropwise adding the remaining solution containing phosphorus and iron into the primary ferric phosphate slurry, and then heating same for a reaction to obtain ferric phosphate. In the present invention, a primary ferric phosphate is prepared by means of a dilution precipitation reaction, and the precipitation auxiliary agent is then added for two-step precipitation to regulate the growth of the ferric phosphate.

Claims

1. A method for preparing a nano-sheet ferric phosphate, comprising the following steps: (1) dissolving a phosphorus source and an iron source in an acidic solution to obtain a solution containing phosphorus and iron; (2) heating part of the solution containing phosphorus and iron to boiling, adding a precipitation auxiliary agent, and performing dilution for a reaction to obtain a primary ferric phosphate slurry; and (3) adding the remaining solution containing phosphorus and iron dropwise into the primary ferric phosphate slurry, and performing heating for a reaction to obtain ferric phosphate.

2. The method according to claim 1, wherein step (3) further comprises filtering, washing, and drying the ferric phosphate.

3. The method according to claim 1, wherein in step (1), the iron source is at least one of elementary iron, ferric salt, ferrous salt, magnetite, or hematite; preferably, in a case where the iron source is elementary iron and/or ferrous salt, an oxidant is further added to the solution containing phosphorus and iron.

4. The method according to claim 1, wherein in step (1), the phosphorus source is at least one of phosphoric acid, dihydrogen phosphate, hydrogen phosphate, hydroxyethylidene diphosphonate, or amino trimethylene phosphate.

5. The method according to claim 1, wherein in step (2), the acidic solution is at least one of sulfuric acid, hydrochloric acid, and nitric acid.

6. The method according to claim 1, wherein in step (2), water is added for dilution during the dilution for the reaction, wherein a volume ratio of the added water to the part of the solution containing phosphorus and iron is (2-20):1; preferably, in step (2), the dilution for the reaction comprises diluting by adding water and aging.

7. The method according to claim 1, wherein in step (2), the precipitation auxiliary agent is at least one of titanium chloride, titanium sulfate, titanium dioxide, aluminum chloride, aluminum sulfate, or ferric phosphate.

8. The method according to claim 1, wherein step (3) further comprises adding the precipitation auxiliary agent into the remaining solution containing phosphorus and iron before adding the remaining solution containing phosphorus and iron into the primary ferric phosphate slurry.

9. A nano-sheet ferric phosphate, which is prepared by the method according to claim 1, wherein the nano-sheet ferric phosphate has a sheet diameter D50 of 200 nm to 300 nm, a specific surface area of 40 m.sup.2/g to 43 m.sup.2/g, and a compaction density of 2.4 g/cm.sup.3 to 2.8 g/cm.sup.3.

10. A lithium iron phosphate, which is prepared from the nano-sheet ferric phosphate according to claim 9.

11. A nano-sheet ferric phosphate, which is prepared by the method according to claim 2, wherein the nano-sheet ferric phosphate has a sheet diameter D50 of 200 nm to 300 nm, a specific surface area of 40 m.sup.2/g to 43 m.sup.2/g, and a compaction density of 2.4 g/cm.sup.3 to 2.8 g/cm.sup.3.

12. A nano-sheet ferric phosphate, which is prepared by the method according to claim 3, wherein the nano-sheet ferric phosphate has a sheet diameter D50 of 200 nm to 300 nm, a specific surface area of 40 m.sup.2/g to 43 m.sup.2/g, and a compaction density of 2.4 g/cm.sup.3 to 2.8 g/cm.sup.3.

13. A nano-sheet ferric phosphate, which is prepared by the method according to claim 4, wherein the nano-sheet ferric phosphate has a sheet diameter D50 of 200 nm to 300 nm, a specific surface area of 40 m.sup.2/g to 43 m.sup.2/g, and a compaction density of 2.4 g/cm.sup.3 to 2.8 g/cm.sup.3.

14. A nano-sheet ferric phosphate, which is prepared by the method according to claim 5, wherein the nano-sheet ferric phosphate has a sheet diameter D50 of 200 nm to 300 nm, a specific surface area of 40 m.sup.2/g to 43 m.sup.2/g, and a compaction density of 2.4 g/cm.sup.3 to 2.8 g/cm.sup.3.

15. A nano-sheet ferric phosphate, which is prepared by the method according to claim 6, wherein the nano-sheet ferric phosphate has a sheet diameter D50 of 200 nm to 300 nm, a specific surface area of 40 m.sup.2/g to 43 m.sup.2/g, and a compaction density of 2.4 g/cm.sup.3 to 2.8 g/cm.sup.3.

16. A nano-sheet ferric phosphate, which is prepared by the method according to claim 7, wherein the nano-sheet ferric phosphate has a sheet diameter D50 of 200 nm to 300 nm, a specific surface area of 40 m.sup.2/g to 43 m.sup.2/g, and a compaction density of 2.4 g/cm.sup.3 to 2.8 g/cm.sup.3.

17. A nano-sheet ferric phosphate, which is prepared by the method according to claim 8, wherein the nano-sheet ferric phosphate has a sheet diameter D50 of 200 nm to 300 nm, a specific surface area of 40 m.sup.2/g to 43 m.sup.2/g, and a compaction density of 2.4 g/cm.sup.3 to 2.8 g/cm.sup.3.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0039] The present disclosure will be further described below with reference to the accompanying drawings and examples, in which:

[0040] FIG. 1 shows a scanning electron microscope (SEM) image of a ferric phosphate product of Example 1 of the present disclosure; and

[0041] FIG. 2 shows an X-Ray Diffraction (XRD) pattern of the ferric phosphate product of Example 1 of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

[0042] The concept and the technical effects of the present disclosure will be described clearly and completely hereinafter with reference to the examples for a thorough understanding of the purposes, features and effects of the present disclosure. It is apparent that the described examples are only a part of the examples of the present disclosure, and not all of the examples, and other examples obtained by those skilled in the art based on the examples of the present disclosure without creative efforts fall within the protection scope of the present disclosure.

Example 1

[0043] A method for preparing a nano-sheet ferric phosphate provided by this example included the following steps. [0044] (1) Sodium phosphate and iron nitrate were dissolved in 2 mol/L of sulfuric acid solution to obtain a solution containing phosphorus and iron with an iron concentration of 45 g/L and a phosphorus concentration of 25 g/L. The solution containing phosphorus and iron was divided into two parts A and B (with a volume ratio of 1:1) for use. [0045] (2) The solution containing phosphorus and iron A was heated to boiling, and after adding titanium sulfate with an amount of 5% of the total amount of phosphorus and iron in the solution containing phosphorus and iron A, the reaction system was diluted for a reaction by adding water, wherein water was added for 30 minutes. After adding water, the reaction system was allowed to stand for aging for 120 minutes, and then a primary ferric phosphate slurry was obtained. [0046] (3) 2% of titanium sulfate was added to the solution containing phosphorus and iron B, then the solution containing phosphorus and iron B was added to the primary ferric phosphate slurry for 60 minutes, and then heated and stirred and reacted at 80? C. for 120 minutes to obtain ferric phosphate. [0047] (4) The obtained ferric phosphate was filtered, washed, and dried to obtain a ferric phosphate product.

[0048] FIG. 1 showed an SEM image of the ferric phosphate product of Example 1 of the present disclosure. It could be seen from FIG. 1 that the ferric phosphate particles prepared in Example 1 were uniformly distributed and had a sheet-like structure with a particle size of about 250 nm without agglomeration.

[0049] FIG. 2 showed an XRD pattern of the ferric phosphate product of Example 1 of the present disclosure. It could be seen from FIG. 2 that the XRD pattern of the prepared ferric phosphate exhibits characteristic peaks corresponding to the standard card (72-0471) pattern, its diffraction peaks were sharp, the characteristic peaks were obvious, and there were no unnecessary impurity peaks, indicating that ferric phosphate with high crystallinity was obtained.

Example 2

[0050] A method for preparing a nano-sheet ferric phosphate provided by this example included the following steps. [0051] (1) Sodium hydrogen phosphate and iron sulfate were dissolved in 3 mol/L of sulfuric acid solution to obtain a solution containing phosphorus and iron with an iron concentration of 53 g/L and a phosphorus concentration of 29 g/L. The solution containing phosphorus and iron was divided into two parts A and B (with a volume ratio of 1:1) for use. [0052] (2) The solution containing phosphorus and iron A was heated to boiling, and after adding aluminum sulfate with an amount of 6% of the total amount of phosphorus and iron, water was continuously added for 50 minutes by 6 times the volume of the solution containing phosphorus and iron. After adding water, the reaction system was allowed to stand for aging for 150 minutes, and a primary ferric phosphate slurry was obtained. [0053] (3) 2% of aluminum sulfate was added to the solution containing phosphorus and iron B, then the solution containing phosphorus and iron B was continuously added to the primary ferric phosphate slurry for 40 minutes, and then heated and stirred and reacted at 90? C. for 90 minutes to obtain ferric phosphate. [0054] (4) The obtained ferric phosphate was filtered, washed, and dried to obtain a ferric phosphate product.

Example 3

[0055] A method for preparing a nano-sheet ferric phosphate provided by this example included the following steps. [0056] (1) Potassium phosphate and iron chloride were dissolved in 2 mol/L of sulfuric acid solution to obtain a solution containing phosphorus and iron with an iron concentration of 49 g/L and a phosphorus concentration of 26 g/L. The solution containing phosphorus and iron was divided into two parts A and B (with a volume ratio of 1:1) for use. [0057] (2) The solution containing phosphorus and iron A was heated to boiling, and after adding titanium chloride with an amount of 3% of the total amount of phosphorus and iron, water was continuously added for 40 minutes by 5 times the volume of the solution containing phosphorus and iron. After adding water, the reaction system was allowed to stand for aging for 120 minutes, and a primary ferric phosphate slurry was obtained. [0058] (3) 3% of titanium chloride was added to the solution containing phosphorus and iron B, then the solution containing phosphorus and iron B was continuously added to the primary ferric phosphate slurry for 50 minutes, and then heated and stirred and reacted at 85? C. for 100 minutes to obtain ferric phosphate. [0059] (4) The obtained ferric phosphate was filtered, washed, and dried to obtain a ferric phosphate product.

Comparative Example 1

[0060] A method for preparing a nano-sheet ferric phosphate provided by this comparative example included the following steps. [0061] (1) Sodium phosphate and ferrous sulfate were dissolved in 2 mol/L of sulfuric acid, respectively, to obtain an acidic iron solution and an acidic phosphorus solution, which were prepared into an acidic solution containing phosphorus and iron at a ratio of iron to phosphorus of 1:1.03. [0062] (2) Oxygen was introduced into the acidic solution containing phosphorus and iron to oxidize for 2 hours until Fe.sup.2+ in the solution had been oxidized to Fe.sup.3+, then aqueous ammonia was added to adjust the pH to 3, the mixture was reacted at 90? C. for 3 hours, and then ferric phosphate was obtained by liquid-solid separation. [0063] (3) The obtained ferric phosphate was washed, filtered, and dried to obtain a ferric phosphate product.

Comparative Example 2

[0064] A method for preparing a nano-sheet ferric phosphate provided by this comparative example included the following steps. [0065] (1) Preparation of iron raw material liquid: according to molar ratios of Fe.sub.2(SO.sub.4).sub.3:(H.sub.2SO.sub.4+H.sub.3PO.sub.4)=1:0.2 and H.sub.2SO.sub.4:H.sub.3PO.sub.4=9:1, iron sulfate solution, sulfuric acid solution, and phosphoric acid solution were mixed to obtain an iron sulfate raw material liquid, wherein the iron sulfate raw material liquid had a pH of 1.03, and a mass concentration of iron element in the iron sulfate raw material liquid was 84 g/L. [0066] (2) Preparation of phosphate raw material liquid: ammonium phosphate was dissolved in water to obtain a phosphate raw material liquid. A mass concentration of phosphorus element in the phosphate raw material liquid was 45 g/L. [0067] (3) Proceeding of the synthesis reaction: the phosphate raw material liquid obtained in step (2) was gradually added into the iron sulfate raw material liquid obtained in step (1) under stirring, according to a ratio that a molar ratio of iron in the iron sulfate raw material liquid to phosphorus in the phosphate solution was 1:1, to obtain a mixed solution. Then, the mixed solution was heated to 90? C. and reacted for 3 hours to obtain a ferric phosphate slurry. [0068] (4) The obtained ferric phosphate was washed, filtered, and dried to obtain a ferric phosphate product.

Comparative Example 3

[0069] A method for preparing a nano-sheet ferric phosphate provided by this comparative example included the following steps. [0070] (1) An aqueous solution containing 0.05 mol/L of iron nitrate and 0.05 mol/L of phosphoric acid was prepared to obtain a raw material A. [0071] (2) 0.1 mol/L of ammonium phosphate aqueous solution was prepared to obtain a raw material B, and 1 L of the raw material A and 1 L of the raw material B were quickly mixed by using a membrane dispersion micro-mixer to obtain a slurry C. [0072] (3) The slurry C was subjected to hydrothermal treatment under atmospheric pressure for 0.2 hour at a treatment temperature of 100? C., then a precipitate was filtered out from the slurry C, and then the precipitate was washed and dried to obtain a ferric phosphate product.

Comparative Example 4

[0073] Comparing this comparative example with Example 1: no precipitation auxiliary agent was added in step (2).

Comparative Example 5

[0074] Comparing this comparative example with Example 1: the reaction system was not diluted for a reaction by water in step (2).

TABLE-US-00001 TABLE 1 Comparison of specific test data of the ferric phosphate prepared in Examples 1-3 and the ferric phosphate prepared in Comparative Examples Particle size Compaction density Specific surface D50 (nm) (g/cm.sup.3) area (m.sup.2/g) Example 1 249 2.57 41.32 Example 2 260 2.41 40.20 Example 3 255 2.47 40.63 Comparative 3200 2.19 22.96 Example 1 Comparative 5300 1.96 17.63 Example 2 Comparative 3700 2.11 20.42 Example 3 Comparative 2980 1.97 24.3 Example 4 Comparative 2200 2.15 30.65 Example 5

[0075] It can be seen from the data in Table 1 that the ferric phosphate prepared in Examples of the present disclosure was nano-scale ferric phosphate, while the ferric phosphate prepared in Comparative Examples was micro-scale ferric phosphate. The data comparation showed that the prepared nano-scale ferric phosphate can significantly improve the specific surface area and compaction density of ferric phosphate.

[0076] The embodiments of the present disclosure are described in detail above, but the present disclosure is not limited to the above-mentioned embodiments, and various changes can be made without departing from the purpose of the present disclosure within the scope of knowledge possessed by those of ordinary skill in the art. In addition, embodiments in the present disclosure and features in the embodiments can be combined with each other under the premise of no conflict.