CN107910552B - Preparation method of hydroxyl ammonium ferric phosphate - Google Patents

Preparation method of hydroxyl ammonium ferric phosphate Download PDF

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CN107910552B
CN107910552B CN201711120399.7A CN201711120399A CN107910552B CN 107910552 B CN107910552 B CN 107910552B CN 201711120399 A CN201711120399 A CN 201711120399A CN 107910552 B CN107910552 B CN 107910552B
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phosphoric acid
ferrous salt
ferric phosphate
ammonium ferric
hydroxyl ammonium
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CN107910552A (en
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吴素文
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Shandong Huanglan Weiye New Energy Technology Co ltd
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/36Selection of substances as active materials, active masses, active liquids
    • H01M4/58Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
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    • C01B25/16Oxyacids of phosphorus; Salts thereof
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    • C01B25/45Phosphates containing plural metal, or metal and ammonium
    • C01B25/451Phosphates containing plural metal, or metal and ammonium containing metal and ammonium
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
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Abstract

The invention provides a preparation method of hydroxyl ammonium ferric phosphate, which comprises the following steps of (1) mixing ferrous salt, phosphoric acid solution and water to obtain mixed solution containing ferrous salt and phosphoric acid; (2) and mixing the mixed solution containing ferrous salt and phosphoric acid, hydrogen peroxide, urea and a surfactant, and carrying out hydrothermal reaction to obtain the hydroxyl ammonium ferric phosphate. The results of the embodiment show that the hydroxyl ammonium ferric phosphate prepared by the method provided by the invention has good crystallization performance, the yield is more than or equal to 86%, the purity is more than or equal to 98.5%, and the hydroxyl ammonium ferric phosphate can be directly used as a precursor for preparing lithium iron phosphate serving as a lithium ion battery anode material by a high-temperature solid phase method.

Description

Preparation method of hydroxyl ammonium ferric phosphate
Technical Field
The invention relates to the technical field of lithium ion battery anode materials, in particular to a preparation method of a lithium iron phosphate precursor ammonium ferric hydroxy phosphate.
Background
In recent years, lithium iron phosphate synthesized by taking ammonium ferric phosphate hydroxide as a precursor shows better electrochemical performance. The property of the hydroxyl ferric ammonium phosphate directly influences the dispersibility and the grain size of the decomposed ferric phosphate phase, and the property of the ferric phosphate phase influences the electrochemical performance of the lithium battery anode material. Therefore, how to prepare ferric ammonium phosphate hydroxide with more excellent performance becomes a research hotspot of technicians.
Several methods for preparing ammonium hydroxy iron phosphate have been disclosed in the prior art, for example, european patent No. WO2015/134948 discloses a method: with FeSO4·7H2O、NH4H2PO4Mixing the raw materials of ammonia water and DAP (1, 3-diaminopropane), oxidizing the solid by hydrogen peroxide, filtering, washing and drying the solid to obtain pure yellow hydroxyl ammonium ferric phosphate. However, the crystallization effect of the ammonium iron phosphate hydroxide obtained by the existing preparation method is generally poor.
Disclosure of Invention
The invention aims to provide a preparation method of lithium iron phosphate precursor hydroxyl ammonium ferric phosphate for a lithium ion battery anode material, which has a good crystallization effect.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a preparation method of hydroxyl ammonium ferric phosphate, which comprises the following steps:
(1) mixing ferrous salt, phosphoric acid solution and water to obtain mixed solution containing ferrous salt and phosphoric acid;
(2) and mixing the mixed solution containing ferrous salt and phosphoric acid, hydrogen peroxide, urea and a surfactant, and carrying out hydrothermal reaction to obtain the hydroxyl ammonium ferric phosphate.
Preferably, the ferrous salt is ferrous sulfate and/or ferrous chloride.
Preferably, the mass ratio of the ferrous salt to the water is 1: 5-20.
Preferably, the mass concentration of the phosphoric acid solution is 80-90%; PO in the phosphoric acid solution4 3+And the molar ratio of ferrous ions in the ferrous salt is 1 (1-1.05).
Preferably, the mass concentration of the hydrogen peroxide is 5-15%; h in the phosphoric acid solution3PO4And H in hydrogen peroxide2O2The molar ratio of (1) to (6).
Preferably, H in the phosphoric acid solution3PO4The molar ratio of the urea to the urea is 1 (0.1-0.6).
Preferably, the surfactant is one or more of polyethylene glycol, triethanolamine, stearic acid and tween.
Preferably, the mass ratio of the surfactant to the ferrous salt is (1-1.5): 100.
Preferably, the step (2) is to mix the mixed solution containing the ferrous salt and the phosphoric acid with hydrogen peroxide to obtain a first-stage mixture;
and mixing the primary mixture with urea and a surfactant, and carrying out hydrothermal reaction to obtain the hydroxyl ammonium ferric phosphate.
Preferably, the reaction temperature of the hydrothermal reaction is 110-130 ℃, and the reaction time is 6-10 hours.
The invention provides a preparation method of hydroxyl ammonium ferric phosphate, which comprises the following steps of (1) mixing ferrous salt, phosphoric acid solution and water to obtain mixed solution containing ferrous salt and phosphoric acid; (2) and mixing the mixed solution containing ferrous salt and phosphoric acid, hydrogen peroxide, urea and a surfactant, and carrying out hydrothermal reaction to obtain the hydroxyl ammonium ferric phosphate. The invention takes ferrous salt as raw material, which is oxidized in the presence of phosphoric acid and then reacts with ammonia slowly released from urea, thus effectively controlling the crystal growth and crystal morphology of hydroxyl ammonium ferric phosphate; the addition of the surfactant can effectively improve the dispersibility of the hydroxyl ammonium ferric phosphate, thereby obtaining the hydroxyl ammonium phosphate with good crystallization performance. The results of the examples show that the hydroxyl ammonium ferric phosphate prepared by the preparation method of the invention has good crystallization performance, the yield is more than or equal to 86%, and the purity is more than or equal to 98.5%.
Meanwhile, when the hydroxyl ammonium ferric phosphate obtained by the preparation method provided by the invention is used as a precursor for preparing lithium iron phosphate serving as a lithium ion battery anode material, the lithium iron phosphate has better discharge performance, rate capability and cycle performance. Meanwhile, under the charging and discharging current of 1C, after 2000 cycles of charging and discharging, the discharging specific capacity can still be kept about 80%.
Drawings
FIG. 1 is an X-ray powder diffraction pattern of ammonium iron hydroxyphosphate prepared in example 1 of the present invention;
FIG. 2 is an FTIR spectrum of ammonium ferric phosphate hydroxide prepared in example 1 of the present invention;
FIG. 3 is an SEM photograph of ammonium iron hydroxy phosphate prepared in example 1 of the present invention;
FIG. 4 is a first discharge curve of lithium battery cathode materials prepared in example 5 of the present invention at different rates;
FIG. 5 is a graph of electrochemical cycling performance of a lithium battery cathode material prepared in example 5 of the present invention;
FIG. 6 is an XRD pattern of the ammonium iron hydroxyphosphate prepared in example 1 of the present invention after calcination at different temperatures.
Detailed Description
The invention provides a preparation method of hydroxyl ammonium ferric phosphate, which comprises the following steps:
(1) mixing ferrous salt, phosphoric acid solution and water to obtain mixed solution containing ferrous salt and phosphoric acid;
(2) and mixing the mixed solution containing ferrous salt and phosphoric acid, hydrogen peroxide, urea and a surfactant, and carrying out hydrothermal reaction to obtain the hydroxyl ammonium ferric phosphate.
In the present invention, all the raw material components are commercially available products well known to those skilled in the art unless otherwise specified.
According to the invention, a ferrous salt solution, a phosphoric acid solution and water are mixed to obtain a mixed solution containing the ferrous salt and phosphoric acid. In the present invention, the ferrous salt is preferably ferrous sulfate and/or ferrous chloride; the ferrous sulfate is preferably ferrous sulfate heptahydrate; the mass ratio of the ferrous salt to the water is preferably 1: 5-20, more preferably 1: 8-15, and most preferably 1: 10-12.
In the present invention, the phosphoric acid solution preferably has a mass concentration of 80 to 90%, more preferably 82 to 88%, and most preferably 85 to 87%.
In the present invention, PO in the phosphoric acid solution4 3+The molar ratio of the ferrous ion to the ferrous salt is preferably 1 (1 to 1.05), and specifically may be 1:1, 1:1.01, 1:1.03, or 1: 1.05.
In the present invention, the water is preferably distilled water. According to the invention, preferably, ferrous salt is dissolved in water to obtain a ferrous salt solution, and then the ferrous salt solution and the phosphoric acid solution are mixed.
After a mixed solution containing ferrous salt and phosphoric acid is obtained, the mixed solution containing ferrous salt and phosphoric acid, hydrogen peroxide, urea and a surfactant are mixed for hydrothermal reaction to obtain hydroxyl ammonium ferric phosphate. In the invention, the mass concentration of the hydrogen peroxide is preferably 5-15%, more preferably 8-13%, and most preferably 10-12%.
In the present invention, H in the phosphoric acid solution3PO4And H in hydrogen peroxide2O2The molar ratio of (A) to (B) is preferably 1 (1-6), more preferably 1 (2-5), and most preferably 1 (3-4).
In the present invention, H in the phosphoric acid solution3PO4The molar ratio of urea to urea is preferably 1 (0.1-0.6), more preferably 1 (0.2-0.5), and most preferably 1 (0.3-0.4).
In the invention, the surfactant is preferably one or more of polyethylene glycol, triethanolamine, stearic acid and tween. When the surfactant is a plurality of polyethylene glycol, triethanolamine, stearic acid and Tween, the invention has no special limitation on the proportion of each component in the surfactant and can be matched according to any proportion; in the present invention, the polyethylene glycol is preferably polyethylene glycol 1000.
In the present invention, the mass ratio of the surfactant to the divalent iron salt is preferably (1-1.5): 100, more preferably (1.05-1.4): 100, and most preferably (1.2-1.3): 1.
The invention preferably mixes the mixed solution containing ferrous salt and phosphoric acid with hydrogen peroxide to obtain a first-stage mixture; and mixing the primary mixture with urea and a surfactant, and carrying out hydrothermal reaction to obtain hydroxyl ammonium ferric phosphate solid.
The invention mixes the mixed solution containing ferrous salt and phosphoric acid with hydrogen peroxide to make ferrous salt and hydrogen peroxide in hydrogen peroxide produce oxidation reaction in acid medium. In the invention, the mixing process of the mixed solution containing ferrous salt and phosphoric acid and hydrogen peroxide is preferably to drop hydrogen peroxide into the mixed solution containing ferrous salt and phosphoric acid.
In the invention, the dripping temperature is preferably 40-50 ℃, more preferably 42-48 ℃ and most preferably 43-46 ℃. The dropping speed is not particularly limited in the present invention, and may be a dropping speed known to those skilled in the art.
After the primary mixture is obtained, the primary mixture is preferably mixed with urea and a surfactant to perform hydrothermal reaction to obtain hydroxyl ammonium ferric phosphate solid.
In the invention, the mixing of the primary mixture, the urea and the surfactant is preferably carried out under the condition of heating and stirring, and the heating and stirring process can effectively regulate and control the oxidation reaction and simultaneously provide proper temperature for the addition of the urea and the surfactant. In the invention, the heating and stirring temperature is preferably 60-120 ℃, more preferably 80-110 ℃, and most preferably 90-100 ℃. The stirring speed of the heating and stirring is not particularly required, and the solute can be fully dissolved and all raw materials can be uniformly mixed by adopting the method well known by the technical personnel in the field. In the invention, the heating and stirring time is preferably 10-120 min, more preferably 20-80 min, and most preferably 30-50 min.
In the hydrothermal reaction process, as the urea can slowly release ammonia gas, the reaction rate can be effectively controlled, and further the crystal growth and the crystal morphology of the hydroxyl ammonium ferric phosphate can be controlled.
In an embodiment of the present invention, the reaction vessel for the hydrothermal reaction is preferably a 200mL polytetraethylene lined autoclave.
In the invention, the reaction temperature of the hydrothermal reaction is preferably 110-130 ℃, more preferably 115-125 ℃, and most preferably 118-123 ℃.
In the present invention, the reaction time of the hydrothermal reaction is preferably 6 to 10 hours, and may be specifically 6 hours, 7 hours, 8 hours, 9 hours, or 10 hours.
In the invention, after the hydrothermal reaction is finished, the product system is preferably sequentially cooled, filtered, washed and dried to obtain the hydroxyl ammonium ferric phosphate solid. In the invention, the cooling is preferably natural cooling, and the cooling is carried out to room temperature; the washing is preferably distilled water washing; the drying temperature is preferably 120 ℃.
The method prepares the hydroxyl ammonium ferric phosphate obtained by the method into the anode material to verify the application technical effect of the product obtained by the method. In the invention, the method for preparing the cathode material by using the ammonium ferric phosphate hydroxide obtained by the method as the raw material comprises the following steps:
calcining the hydroxyl ammonium ferric phosphate to obtain ferric phosphate;
and mixing the iron phosphate, lithium carbonate and sucrose, and calcining to obtain the lithium iron phosphate.
According to the invention, the hydroxyl ammonium ferric phosphate is calcined to obtain the ferric phosphate. In the invention, the calcining temperature is preferably 500-800 ℃, and can be specifically 600 ℃; in the present invention, the calcination time is preferably 4 to 6 hours, and may be 4 hours.
After the iron phosphate is obtained, the iron phosphate, lithium carbonate and sucrose are mixed and calcined to obtain the lithium iron phosphate. In the present invention, the ratio of the amounts of the iron phosphate to the lithium carbonate is preferably (0.5 to 2): 1, can be specifically 1: 1; in the invention, the addition amount of the sucrose is preferably 4-6% of the total mass of the mixture of the iron phosphate, the lithium carbonate and the sucrose, and can be specifically 5%; in the present invention, the atmosphere of the calcination is preferably an inert atmosphere, and may specifically be a nitrogen atmosphere; in the invention, the calcination temperature is preferably 600-800 ℃, more preferably 350-750 ℃, and can be specifically 700 ℃; in the present invention, the calcination time is preferably 1 to 3 hours, and more preferably 2 hours.
After the lithium iron phosphate is obtained, the electrochemical performance of the lithium iron phosphate is tested by using the obtained lithium iron phosphate as a positive electrode material. In the present invention, the electrochemical performance test may be a cycle performance test at a charge and discharge current of 1C and a discharge performance test at 1C, 3C, and 5C, respectively. The present invention does not require any particular method of performing the test, and may be performed by conventional methods well known to those skilled in the art.
The following examples are provided to illustrate the preparation of ferric ammonium hydroxy phosphate of the present invention in detail, but they should not be construed as limiting the scope of the present invention.
Example 1
28g of ferrous sulfate heptahydrate, 140g of distilled water and 11g of 85 wt% phosphoric acid are sequentially added into a 500mL flask with a stirring device, stirred until the ferrous sulfate heptahydrate, the distilled water and the phosphoric acid are completely dissolved, 34g of 10 wt% hydrogen peroxide is dropwise added at the temperature of 40 ℃, and the dropwise adding speed is controlled so as not to generate bubbles violently. After the dropwise addition, a light yellow solution is obtained, the solution is heated to 100 ℃, stirred for 30 minutes, added with 3.0g of urea and 0.3g of PEG1000, stirred uniformly and transferred to a 200mL high-pressure reaction kettle with a poly-tetraethylene lining. And sealing, slowly heating to 130 ℃, reacting for 8 hours, naturally cooling, filtering, washing with 50mL of distilled water, and drying at 120 ℃ to obtain 36g of green hydroxyl ammonium ferric phosphate solid. The yield is 96.5 percent by ferrous sulfate heptahydrate.
The structure spectra of the product prepared in this example are shown in fig. 1, 2 and 3, wherein fig. 1 is an X-ray powder diffraction pattern, fig. 2 is an FTIR spectrum, and fig. 3 is an SEM image. As can be seen from FIGS. 1 to 3, the product is FeOH2(NH4)(OH)(PO4)2·2H2O has good crystallization performance, and the hydroxyl ammonium ferric phosphate prepared by the invention has good dispersibility and good crystal growth.
Example 2
28g of ferrous sulfate heptahydrate, 140g of distilled water and 11g of 85 wt% phosphoric acid are sequentially added into a 500mL flask with a stirring device, uniformly stirred, and then 34g of 10 wt% hydrogen peroxide is dropwise added at 40 ℃, and the dropwise adding speed is controlled preferably so as not to generate bubbles violently. After the dropwise addition, a light yellow solution is obtained, the solution is heated to 100 ℃, stirred for 30 minutes, added with 3.0g of urea and 0.3g of stearic acid, stirred uniformly and transferred to a 200mL high-pressure reaction kettle with a poly-tetraethylene lining. And sealing, slowly heating to 130 ℃, reacting for 8 hours, naturally cooling, filtering, washing with 50mL of distilled water, and drying at 120 ℃ to obtain 34g of green hydroxyl ammonium ferric phosphate solid. The yield is 91 percent based on ferrous sulfate heptahydrate.
The product obtained in this example was subjected to structural determination, and the test results thereof were substantially in accordance with example 1, indicating that the product was ferric ammonium phosphate hydroxide Fe2(NH4)(OH)(PO4)2·2H2O has good crystallization performance, and the hydroxyl ammonium ferric phosphate prepared by the invention has good dispersibility and good crystal growth.
Example 3
28g of ferrous sulfate heptahydrate, 140g of distilled water and 11g of 85 wt% phosphoric acid are sequentially added into a 500mL flask with a stirring device, uniformly stirred, and then 34g of 10 wt% hydrogen peroxide is dropwise added at 40 ℃, and the dropwise adding speed is controlled preferably so as not to generate bubbles violently. After the dropwise addition, a light yellow solution is obtained, the solution is heated to 100 ℃, stirred for 30 minutes, added with 3.0g of urea and 0.3g of PEG1000, stirred uniformly and transferred to a 200mL high-pressure reaction kettle with a poly-tetraethylene lining. And sealing, slowly heating to 120 ℃, reacting for 8 hours, naturally cooling, filtering, washing with 50mL of distilled water, and drying at 120 ℃ to obtain 32g of green hydroxyl ammonium ferric phosphate solid. The yield is 86 percent based on ferrous sulfate heptahydrate.
The product obtained in this example was subjected to structural determination, and the test results thereof were substantially in accordance with example 1, indicating thatThe product is hydroxyl ammonium ferric ammonium phosphate Fe2(NH4)(OH)(PO4)2·2H2O has good crystallization performance, and the hydroxyl ammonium ferric phosphate prepared by the invention has good dispersibility and good crystal growth.
Example 4
28g of ferrous sulfate heptahydrate, 140g of distilled water and 11g of 85 wt% phosphoric acid are sequentially added into a 500mL flask with a stirring device, uniformly stirred, and then 34g of 10 wt% hydrogen peroxide is dropwise added at 40 ℃, and the dropwise adding speed is controlled preferably so as not to generate bubbles violently. After the dropwise addition, a light yellow solution is obtained, the solution is heated to 100 ℃, stirred for 30 minutes, added with 6.0g of urea and 0.3g of PEG1000, stirred uniformly and transferred to a 200mL high-pressure reaction kettle with a poly-tetraethylene lining. And sealing, slowly heating to 140 ℃, reacting for 8 hours, naturally cooling, filtering, washing with 50mL of distilled water, and drying at 120 ℃ to obtain 36g of green hydroxyl ammonium ferric phosphate solid. The yield is 96.5 percent by ferrous sulfate heptahydrate.
The product obtained in this example was subjected to structural determination, and the test results thereof were substantially in accordance with example 1, indicating that the product was ferric ammonium phosphate hydroxide Fe2(NH4)(OH)(PO4)2·2H2O has good crystallization performance, and the hydroxyl ammonium ferric phosphate prepared by the invention has good dispersibility and good crystal growth.
Example 5
The green ammonium iron hydroxyphosphate obtained in example 1 was calcined at 600 ℃ for 4 hours in a muffle furnace to obtain 29g of white iron phosphate. And uniformly mixing the obtained iron phosphate, lithium carbonate with the same mass and sucrose with the mass concentration of 5% by air current crushing, compacting in a crucible, and calcining at 700 ℃ for 2 hours under the nitrogen condition to obtain the lithium iron phosphate.
The obtained lithium iron phosphate was used as a positive electrode material of a lithium ion battery and subjected to rate capability and cycle performance tests, and the results are shown in fig. 4 and 5. FIG. 4 is a first discharge curve of the lithium battery cathode material prepared in example 5 of the present invention at different rates; FIG. 5 is a graph of electrochemical cycling performance of a lithium battery cathode material prepared in example 5 of the present invention; it can be seen from fig. 4 and 5 that the ammonium iron phosphate hydroxide obtained by the preparation method provided by the invention shows better discharge performance and rate capability when being used as a precursor for preparing lithium iron phosphate serving as a lithium ion battery anode material. When the discharge multiplying power is increased from 1C to 5C, the specific discharge capacity of the lithium ion battery is not changed remarkably, and meanwhile, under the charge-discharge current of 1C, the specific discharge capacity of the lithium ion battery can still be kept about 80% after 2000 cycles of charge and discharge.
From the above examples, the present invention provides a method for preparing ammonium iron phosphate hydroxide. The method directly utilizes a hydrothermal method to react with phosphoric acid and iron ions in the process of slowly decomposing urea to obtain hydroxyl ammonium ferric phosphate. Wherein, the addition of urea and surfactant has important influence on the crystallinity of the hydroxyl ammonium ferric phosphate in the synthesis process. The hydroxyl ammonium ferric phosphate obtained by the preparation method provided by the invention has good crystallization performance, the yield is more than or equal to 86%, the purity is more than or equal to 98.5%, and meanwhile, when the hydroxyl ammonium ferric phosphate obtained by the preparation method provided by the invention is used as a precursor for preparing lithium iron phosphate serving as a lithium ion battery anode material, the hydroxyl ammonium ferric phosphate shows better discharge performance and rate capability. Meanwhile, under the charging and discharging current of 1C, after 2000 cycles of charging and discharging, the discharging specific capacity can still be kept about 80%.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (6)

1. A preparation method of hydroxyl ammonium ferric phosphate comprises the following steps:
(1) mixing ferrous salt, phosphoric acid solution and water to obtain mixed solution containing ferrous salt and phosphoric acid;
(2) mixing the mixed solution containing ferrous salt and phosphoric acid, hydrogen peroxide, urea and a surfactant, and carrying out hydrothermal reaction to obtain hydroxyl ammonium ferric phosphate;
h in the phosphoric acid solution3PO4The molar ratio of the urea to the urea is 1 (0.1-0.6);
the surfactant is one or more of polyethylene glycol, triethanolamine, stearic acid and tween;
the mass ratio of the surfactant to the ferrous salt is (1-1.5): 100;
the reaction temperature of the hydrothermal reaction is 110-130 ℃, and the reaction time is 6-10 hours.
2. The method of claim 1, wherein the ferrous salt is ferrous sulfate and/or ferrous chloride.
3. The method for preparing ferric ammonium hydroxy phosphate according to claim 1 or 2, wherein the mass ratio of the ferrous salt to the water in the step (1) is 1: 5-20.
4. The method for preparing ferric ammonium hydroxy phosphate according to claim 1, wherein the mass concentration of the phosphoric acid solution is 80-90%;
PO in the phosphoric acid solution4 3-And the molar ratio of ferrous ions in the ferrous salt is 1 (1-1.05).
5. The preparation method of ammonium ferric phosphate hydroxide as claimed in claim 1 or 4, wherein the mass concentration of the hydrogen peroxide is 5-15%;
h in the phosphoric acid solution3PO4And H in hydrogen peroxide2O2The molar ratio of (1) to (6).
6. The method of claim 1, wherein the step (2) comprises:
(21) mixing the mixed solution containing ferrous salt and phosphoric acid with hydrogen peroxide to obtain a first-stage mixture;
(22) and mixing the primary mixture with urea and a surfactant, and carrying out hydrothermal reaction to obtain the hydroxyl ammonium ferric phosphate.
CN201711120399.7A 2017-11-14 2017-11-14 Preparation method of hydroxyl ammonium ferric phosphate Expired - Fee Related CN107910552B (en)

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