Method for separating and recovering nickel and iron from ferronickel phosphoric acid waste liquid

Abstract

The present application relates to a kind of methods for separating and recovering nickel and iron in nickel-iron phosphoric acid waste liquor, and belongs to the technical field of waste recovery.The present application removes solid precipitate by solid-liquid separation of nickel-iron phosphoric acid waste liquor to obtain impurity-removed nickel-iron phosphoric acid waste liquor;The nickel-iron phosphoric acid waste liquor contains nickel ions, iron ions and phosphate ions, and the pH value of the nickel-iron phosphoric acid waste liquor is 1.2-2.1;The impurity-removed nickel-iron phosphoric acid waste liquor is heated to a temperature of 30-60℃, and carbonates solution is added dropwise into the impurity-removed nickel-iron phosphoric acid waste liquor under stirring to obtain waste liquor A;Then barium salt solution is added dropwise into waste liquor A under stirring to obtain waste liquor B and Ba3(PO4)2 precipitate;Ammonium sulfate solution is added dropwise into waste liquor B under stirring to obtain waste liquor C and (NH4)2Ni(SO4)2·6H2O precipitate;Lye is added dropwise into waste liquor C under stirring to obtain waste liquor D and Fe(OH)3 precipitate.The present application can realize efficient recovery of nickel, iron and phosphate.

Description

Technical Field

[0001] This invention relates to a method for separating and recovering nickel and iron from nickel-iron-phosphate waste liquid, belonging to the field of waste recycling technology. Background Technology

[0002] Nickel-iron-phosphate waste liquid is a type of waste liquid generated during industrial processes such as lithium battery production, nickel-iron smelting, ore processing, and electroplating. It contains valuable metals such as nickel and iron, as well as a certain amount of impurities. The rational and efficient recovery of valuable metals from nickel-iron waste liquid can not only reduce resource waste but also lower environmental pollution and save costs. Currently, the key issue in recovering nickel-iron-phosphate waste liquid lies in the process separation and extraction technologies used in its treatment.

[0003] Existing methods for recovering nickel-iron-phosphate waste liquid include: 1. Solvent extraction: This method uses specific organic solvents to separate and extract the metal from other components in the waste liquid. However, this method suffers from high costs, difficulty in solvent recovery, and potential environmental impacts of organic solvents. 2. Hydrothermal method: This method utilizes the solvent properties under hydrothermal conditions to convert metal ions from the waste liquid into other forms for recovery. However, this method requires high temperature and pressure, resulting in high energy consumption, high operational difficulty, and the potential generation of other toxic compounds during waste liquid treatment. 3. Electrochemical method: This method uses the principle of electrolysis to reduce metal ions to electrodes via electric current, achieving recovery. However, this method consumes a lot of electricity, is complex to operate, and requires a large amount of electrode material, leading to high equipment costs. 4. Membrane separation method: This method uses special membrane materials to separate metal ions from the waste liquid for recovery. However, this method is costly, the membrane materials are susceptible to corrosion, have a short service life, and are easily clogged by impurities, requiring frequent maintenance and replacement. Summary of the Invention

[0004] To address the problems existing in the recovery methods of nickel-iron-phosphate waste liquid, this invention proposes a method for separating and recovering nickel and iron from nickel-iron-phosphate waste liquid, namely, adding a carbonate solution to the nickel-iron-phosphate waste liquid to reduce the H+ content in the solution. + With CO3 2- The solution is neutralized by combining the addition of barium salt solution to the waste liquid, thereby neutralizing the PO4 in the solution. 3- with Ba 2+ A white precipitate of Ba3(PO4)2 is formed; ammonium sulfate solution is then added to the waste liquid to make Ni 2+ With NH4 + SO4 2- The combination produces a green precipitate of (NH4)2Ni(SO4)2·6H2O; finally, an alkaline solution is added to the waste liquid to neutralize the Fe in the solution. 3+ With OH - The combination produces a brick-red precipitate of Fe(OH)3; PO4 is then added sequentially. 3- Ni2+ and Fe 3+ Ni was recovered in the forms of Ba3(PO4)2, (NH4)2Ni(SO4)2·6H2O and Fe(OH)3, respectively; Ni in nickel-iron-phosphate waste liquid 2+ and Fe 3+ The recovery rates of phosphate ions reached 99.98%, 97.89%, and 98.86%, respectively.

[0005] A method for separating and recovering nickel and iron from nickel-iron-phosphate waste liquid, the specific steps of which are as follows:

[0006] (1) The nickel-iron-phosphate waste liquid is subjected to solid-liquid separation to remove solid precipitates and obtain impurity-free nickel-iron-phosphate waste liquid; the nickel-iron-phosphate waste liquid contains nickel ions, iron ions and phosphate ions, and the pH value of the nickel-iron-phosphate waste liquid is 1.2~2.1;

[0007] (2) Prepare carbonate solutions, barium salt solutions, ammonium sulfate solutions, and alkaline solutions;

[0008] (3) Heat the impurity-removed nickel-iron-phosphate waste liquid to 30~60℃, turn on the stirrer, add the carbonate solution dropwise to the impurity-removed nickel-iron-phosphate waste liquid and stir until no bubbles are generated to obtain waste liquid A. Then add the barium salt solution dropwise to waste liquid A and stir until no white precipitate is generated. Solid-liquid separation is performed to obtain waste liquid B and Ba3(PO4)2 precipitate. Add the ammonium sulfate solution dropwise to waste liquid B and stir until no green precipitate is generated. Solid-liquid separation is performed to obtain waste liquid C and (NH4)2Ni(SO4)2·6H2O precipitate. Add the alkali solution dropwise to waste liquid C and stir until no brick-red precipitate is generated. Solid-liquid separation is performed to obtain waste liquid D and Fe(OH)3 precipitate.

[0009] In step (2), the carbonate is sodium carbonate, sodium bicarbonate or potassium carbonate; the barium salt is barium chloride, barium sulfate or barium nitrate; and the alkaline solution is sodium hydroxide solution, potassium hydroxide solution or ammonium hydroxide solution.

[0010] In step (2), the concentration of carbonate solution is 1~3 mol / L, the concentration of barium salt solution is 1~3 mol / L, the concentration of ammonium sulfate solution is 1~3 mol / L, and the concentration of alkali solution is 1~3 mol / L.

[0011] The stirring rate in step (3) is 100~600 r / min.

[0012] In step (3), the drop acceleration rate of carbonate solution is 1~2 dps, the drop acceleration rate of barium salt solution is 1~2 dps, the drop acceleration rate of ammonium sulfate solution is 1~2 dps, and the drop acceleration rate of alkali solution is 1~2 dps.

[0013] In step (3), the pH value of waste liquid A is 7.0~7.9, the pH value of waste liquid B is 7.0~8.0, the pH value of waste liquid C is 7.0~8.0, and the pH value of waste liquid D is 12.01~12.05.

[0014] The beneficial effects of this invention are:

[0015] (1) In this invention, a carbonate solution is added to nickel-iron-phosphate waste liquid to reduce the H+ content in the solution. + With CO3 2- The solution is neutralized by combining the addition of barium salt solution to the waste liquid, thereby neutralizing the PO4 in the solution. 3- with Ba 2+ A white precipitate of Ba3(PO4)2 is formed; ammonium sulfate solution is then added to the waste liquid to make Ni 2+ With NH4 + SO4 2- The combination produces a green precipitate of (NH4)2Ni(SO4)2·6H2O; finally, an alkaline solution is added to the waste liquid to neutralize the Fe in the solution. 3+ With OH - The combination produces a brick-red precipitate of Fe(OH)3; PO4 is then added sequentially. 3- Ni 2+ and Fe 3+ They were recovered in the forms of Ba3(PO4)2, (NH4)2Ni(SO4)2·6H2O and Fe(OH)3, respectively.

[0016] (2) Ni in the nickel-iron-phosphate waste liquid of the present invention 2+ and Fe 3+ The recovery rates of phosphate ions can reach 99.98%, 97.89%, and 98.86%, respectively; the pH value of the nickel-iron-phosphate waste liquid after treatment is 12.01~12.05, realizing the efficient recovery of nickel, iron and phosphate ions in nickel-iron-phosphate waste liquid and the treatment of acidic waste liquid;

[0017] (3) The process of the present invention is simple, low cost, and makes reasonable use of raw materials to achieve the purpose of recovering valuable metal elements in nickel iron phosphate waste liquid and treating acidic waste liquid into alkaline waste liquid. It does not pollute the environment, does not waste raw materials, and has high recovery efficiency. Attached Figure Description

[0018] Figure 1 This is a graph showing the nickel recovery efficiency at different ammonium sulfate concentrations in Example 1;

[0019] Figure 2 This is a graph showing the iron recovery efficiency at different sodium hydroxide concentrations in Example 1;

[0020] Figure 3 This is a graph showing the phosphate ion recovery efficiency at different barium chloride concentrations in Example 1.

[0021] Figure 4 The graph shows the nickel recovery efficiency at different temperatures in Example 2.

[0022] Figure 5 This is a graph showing the iron recovery efficiency at different temperatures in Example 2;

[0023] Figure 6 The graph shows the phosphate ion recovery efficiency at different temperatures in Example 2. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0025] Example 1: The nickel-iron-phosphate waste liquid in this example is the waste liquid obtained after anodic oxidation of nickel-iron alloy in dilute phosphoric acid solution. The elemental composition is shown in Table 1.

[0026] Table 1. Main elemental composition (wt%) of nickel-iron-phosphate waste liquid

[0027] A method for separating and recovering nickel and iron from nickel-iron-phosphate waste liquid, the specific steps of which are as follows:

[0028] (1) The nickel-iron-phosphate waste liquid is subjected to solid-liquid separation to remove solid precipitates and obtain impurity-free nickel-iron-phosphate waste liquid; the nickel-iron-phosphate waste liquid contains nickel ions, iron ions and phosphate ions, and the pH value of the nickel-iron-phosphate waste liquid is 1.14;

[0029] (2) Prepare 1 mol / L sodium carbonate solution, barium chloride solution (1.00, 1.25, 1.50, 1.75 and 2.00 mol / L, respectively), ammonium sulfate solution (1.00, 1.25, 1.50, 1.75 and 2.00 mol / L, respectively) and sodium hydroxide solution (1.00, 1.25, 1.50, 1.75 and 2.00 mol / L, respectively);

[0030] (3) Heat the impurity-removed nickel iron phosphate waste liquid in a water bath to 60°C, turn on the stirrer at a stirring rate of 400 r / min, add sodium carbonate solution dropwise to the impurity-removed nickel iron phosphate waste liquid at a dropping rate of 1 dps and stir until no bubbles are generated to obtain waste liquid A, the pH value of waste liquid A is 8.23; then add barium chloride solution dropwise to waste liquid A at a dropping rate of 1 dps and stir until no white precipitate is generated, and separate the solid and liquid to obtain waste liquid B and Ba3(PO4)2 precipitate, the pH value of waste liquid B is about 7.52;

[0031] (4) Place waste liquid B in a water bath and heat it to 60°C. At a stirring rate of 400 r / min, add ammonium sulfate solution dropwise to waste liquid B at a dropping rate of 1 dps and stir until no green precipitate is produced. Solid-liquid separation is performed to obtain waste liquid C and (NH4)2Ni(SO4)2·6H2O precipitate. The pH value of waste liquid C is about 7.52.

[0032] (5) Place waste liquid C in a water bath and heat it to 60°C. Add sodium hydroxide solution dropwise to waste liquid C at a stirring rate of 1 dps and stir until no brick-red precipitate is produced. Separate the solid and liquid to obtain waste liquid D and Fe(OH)3 precipitate. The pH value of waste liquid D is about 12.01.

[0033] The content of each element in waste liquid D was determined by ICP-OES, and its recovery efficiency was calculated.

[0034] The nickel recovery efficiency graph for different ammonium sulfate concentrations in this embodiment is shown below. Figure 1 The iron recovery efficiency for different sodium hydroxide concentrations is shown in the figure. Figure 2 The phosphate ion recovery efficiency for different barium chloride concentrations is shown in the figure. Figure 3 ,from Figure 1 and 2 As can be seen, the recovery rates of nickel, iron, and phosphate ions increase with the increase of ammonium sulfate, sodium hydroxide, and barium chloride concentrations. When the ammonium sulfate solution concentration is 2 mol / L, the recovery rate of Ni ions reaches 99.98%; when the sodium hydroxide solution concentration is 2 mol / L, the recovery rate of Fe ions reaches 97.89%; and when the barium chloride solution concentration is 2 mol / L, the recovery rate of phosphate ions reaches 98.86%. In this embodiment, the optimal concentrations of barium chloride solution, ammonium sulfate solution, and sodium hydroxide solution are 2 mol / L.

[0035] Example 2: The nickel-iron-phosphate waste liquid in this example is the waste liquid obtained after anodizing nickel-iron alloy in dilute phosphoric acid solution, and the elemental composition is the same as in Example 1.

[0036] A method for separating and recovering nickel and iron from nickel-iron-phosphate waste liquid, the specific steps of which are as follows:

[0037] (1) The nickel-iron-phosphate waste liquid is subjected to solid-liquid separation to remove solid precipitates and obtain impurity-free nickel-iron-phosphate waste liquid; the nickel-iron-phosphate waste liquid contains nickel ions, iron ions and phosphate ions, and the pH value of the nickel-iron-phosphate waste liquid is 1.14;

[0038] (2) Prepare 1 mol / L sodium carbonate solution, 2.00 mol / L barium chloride solution, 2.00 mol / L ammonium sulfate solution and 2.00 mol / L sodium hydroxide solution;

[0039] (3) The impurity-removed nickel iron phosphate waste liquid was placed in a water bath and heated to 30℃, 40℃, 50℃ and 60℃ respectively. Stirring was started at a stirring rate of 400 r / min. Sodium carbonate solution was added dropwise to the impurity-removed nickel iron phosphate waste liquid at a dropping rate of 1 dps and stirred until no bubbles were generated to obtain waste liquid A. The pH value of waste liquid A was 8.23. Then, barium chloride solution was added dropwise to waste liquid A at a dropping rate of 1 dps and stirred until no white precipitate was generated. Solid-liquid separation was performed to obtain waste liquid B and Ba3(PO4)2 precipitate. The pH value of waste liquid B was about 7.52.

[0040] (4) Place waste liquid B in a water bath and heat it to 30℃, 40℃, 50℃ and 60℃ respectively. At a stirring rate of 400 r / min, add ammonium sulfate solution dropwise to waste liquid B at a dropping rate of 1 dps and stir until no green precipitate is produced. Solid-liquid separation yields waste liquid C and (NH4)2Ni(SO4)2·6H2O precipitate. The pH value of waste liquid C is about 7.52.

[0041] (5) Place waste liquid C in a water bath and heat it to 30℃, 40℃, 50℃ and 60℃ respectively. At a stirring rate of 400 r / min, add sodium hydroxide solution dropwise to waste liquid C at a dropping rate of 1 dps and stir until no brick red precipitate is produced. Solid-liquid separation is performed to obtain waste liquid D and Fe(OH)3 precipitate. The pH value of waste liquid D is about 12.01.

[0042] The content of each element in waste liquid D was determined by ICP-OES, and its recovery efficiency was calculated.

[0043] The nickel recovery efficiency graph at different temperatures in this embodiment is shown below. Figure 4 The iron recovery efficiency at different temperatures is shown in the figure. Figure 5 The phosphate ion recovery efficiency at different temperatures is shown in the figure. Figure 6 As shown in the figure, the recovery rates of nickel, iron, and phosphate ions increase with the increase of reaction temperature. When the temperature of waste liquid A is 60℃, the recovery rate of phosphate ions reaches 98.86%; when the temperature of waste liquid B is 60℃, the recovery rate of Ni element reaches 99.98%; and when the temperature of waste liquid C is 60℃, the recovery rate of Fe element reaches 97.89%.

[0044] Example 3: The nickel-iron-phosphate waste liquid in this example is the waste liquid obtained after anodic oxidation of nickel-iron alloy in dilute phosphoric acid solution. The elemental composition is shown in Table 2.

[0045] Table 2. Main elemental composition (wt%) of nickel-iron-phosphate waste liquid

[0046] A method for separating and recovering nickel and iron from nickel-iron-phosphate waste liquid, the specific steps of which are as follows:

[0047] (1) The nickel-iron-phosphate waste liquid is subjected to solid-liquid separation to remove solid precipitates and obtain impurity-free nickel-iron-phosphate waste liquid; the nickel-iron-phosphate waste liquid contains nickel ions, iron ions and phosphate ions, and the pH value of the nickel-iron-phosphate waste liquid is 1.13;

[0048] (2) Prepare 2 mol / L sodium bicarbonate solution, 2 mol / L barium sulfate solution, 2 mol / L ammonium sulfate solution and 2 mol / L potassium hydroxide solution;

[0049] (3) Heat the impurity-removed nickel-iron-phosphate waste liquid in a water bath to 60°C, turn on the stirrer at a stirring rate of 300 r / min, add sodium bicarbonate solution dropwise to the impurity-removed nickel-iron-phosphate waste liquid at a dropping rate of 2 dps and stir until no bubbles are generated to obtain waste liquid A, the pH value of waste liquid A is 8.12; then add barium sulfate solution dropwise to waste liquid A at a dropping rate of 2 dps and stir until no white precipitate is generated, and separate the solid and liquid to obtain waste liquid B and Ba3(PO4)2 precipitate, the pH value of waste liquid B is about 7.43;

[0050] (4) Place waste liquid B in a water bath and heat it to 60°C. At a stirring rate of 300 r / min, add barium sulfate solution dropwise to waste liquid B at a dropping rate of 2 dps and stir until no green precipitate is produced. Solid-liquid separation yields waste liquid C and (NH4)2Ni(SO4)2·6H2O precipitate. The pH value of waste liquid C is approximately 7.72.

[0051] (5) Place waste liquid C in a water bath and heat it to 60°C. At a stirring rate of 300 r / min, add potassium hydroxide solution dropwise to waste liquid C at a dropping rate of 2 dps and stir until no brick-red precipitate is produced. Solid-liquid separation is performed to obtain waste liquid D and Fe(OH)3 precipitate. The pH value of waste liquid D is about 11.98.

[0052] The content of each element in waste liquid D was determined by ICP-OES, and its recovery efficiency was calculated.

[0053] In this embodiment, the recovery rate of Ni ions reached 99.68%; the recovery rate of Fe ions reached 98.89%; and the recovery rate of PO4 reached 99.68%. 3- The recovery rate was 96.37%.

[0054] Example 4: The nickel-iron-phosphate waste liquid in this example is the waste liquid obtained after anodic oxidation of nickel-iron alloy in dilute phosphoric acid solution. The elemental composition is shown in Table 3.

[0055] Table 3. Main elemental composition (wt%) of nickel-iron-phosphate waste liquid

[0056] A method for separating and recovering nickel and iron from nickel-iron-phosphate waste liquid, the specific steps of which are as follows:

[0057] (1) The nickel-iron-phosphate waste liquid is subjected to solid-liquid separation to remove solid precipitates and obtain impurity-free nickel-iron-phosphate waste liquid; the nickel-iron-phosphate waste liquid contains nickel ions, iron ions and phosphate ions, and the pH value of the nickel-iron-phosphate waste liquid is 1.11;

[0058] (2) Prepare 2 mol / L potassium carbonate solution, 2.5 mol / L barium nitrate solution, 2.5 mol / L ammonium sulfate solution and 2.5 mol / L ammonium hydroxide solution;

[0059] (3) Heat the impurity-removed nickel-iron-phosphate waste liquid in a water bath to 60°C, turn on the stirrer at a stirring rate of 350 r / min, add potassium carbonate solution dropwise to the impurity-removed nickel-iron-phosphate waste liquid at a dropping rate of 1.5 dps and stir until no bubbles are generated to obtain waste liquid A, the pH value of waste liquid A is 8.09; then add barium nitrate solution dropwise to waste liquid A at a dropping rate of 1.5 dps and stir until no white precipitate is generated, and separate the solid and liquid to obtain waste liquid B and Ba3(PO4)2 precipitate, the pH value of waste liquid B is about 7.45;

[0060] (4) Place waste liquid B in a water bath and heat it to 60°C. At a stirring rate of 350 r / min, add barium sulfate solution dropwise to waste liquid B at a dropping rate of 1.5 dps and stir until no green precipitate is produced. Solid-liquid separation yields waste liquid C and (NH4)2Ni(SO4)2·6H2O precipitate. The pH value of waste liquid C is approximately 7.59.

[0061] (5) Place waste liquid C in a water bath and heat it to 60°C. At a stirring rate of 350 r / min, add ammonium hydroxide solution dropwise to waste liquid C at a dropping rate of 1.5 dps and stir until no brick-red precipitate is produced. Solid-liquid separation is performed to obtain waste liquid D and Fe(OH)3 precipitate. The pH value of waste liquid D is about 11.66.

[0062] The content of each element in waste liquid D was determined by ICP-OES, and its recovery efficiency was calculated.

[0063] In this embodiment, the recovery rate of Ni ions reached 99.58%; the recovery rate of Fe ions reached 98.23%; and the recovery rate of PO4 ions reached 99.58%. 3- The recovery rate was 97.31%.

[0064] Example 5: The nickel-iron-phosphate waste liquid in this example is the waste liquid obtained after anodic oxidation of nickel-iron alloy in dilute phosphoric acid solution, and the elemental composition is the same as in Example 4.

[0065] A method for separating and recovering nickel and iron from nickel-iron-phosphate waste liquid, the specific steps of which are as follows:

[0066] (1) The nickel-iron-phosphate waste liquid is subjected to solid-liquid separation to remove solid precipitates and obtain impurity-free nickel-iron-phosphate waste liquid; the nickel-iron-phosphate waste liquid contains nickel ions, iron ions and phosphate ions, and the pH value of the nickel-iron-phosphate waste liquid is 1.11;

[0067] (2) Prepare 3 mol / L sodium carbonate solution, 3 mol / L barium sulfate solution, 3 mol / L ammonium sulfate solution and 3 mol / L sodium hydroxide solution;

[0068] (3) Heat the impurity-removed nickel-iron-phosphate waste liquid in a water bath to 60°C, turn on the stirrer at a stirring rate of 400 r / min, add sodium carbonate solution dropwise to the impurity-removed nickel-iron-phosphate waste liquid at a dropping rate of 2 dps and stir until no bubbles are generated to obtain waste liquid A, the pH value of waste liquid A is 7.31; then add barium sulfate solution dropwise to waste liquid A at a dropping rate of 2 dps and stir until no white precipitate is generated, and separate the solid and liquid to obtain waste liquid B and Ba3(PO4)2 precipitate, the pH value of waste liquid B is about 7.32;

[0069] (4) Place waste liquid B in a water bath and heat it to 60°C. At a stirring rate of 400 r / min, add barium sulfate solution dropwise to waste liquid B at a dropping rate of 2 dps and stir until no green precipitate is produced. Solid-liquid separation is performed to obtain waste liquid C and (NH4)2Ni(SO4)2·6H2O precipitate. The pH value of waste liquid C is about 7.32.

[0070] (5) Place waste liquid C in a water bath and heat it to 60°C. Add sodium hydroxide solution dropwise to waste liquid C at a stirring rate of 2dps and stir until no brick-red precipitate is produced. Separate the solid and liquid to obtain waste liquid D and Fe(OH)3 precipitate. The pH value of waste liquid D is about 12.07.

[0071] The content of each element in waste liquid D was determined by ICP-OES, and its recovery efficiency was calculated.

[0072] In this embodiment, the recovery rate of Ni ions reached 99.34%; the recovery rate of Fe ions reached 97.23%; and the recovery rate of PO4 ions reached 99.34%. 3- The recovery rate was 96.31%.

[0073] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for separating and recovering nickel and iron from nickel-iron-phosphate waste liquid, characterized in that, The specific steps are as follows: (1) The nickel-iron-phosphate waste liquid is separated into solid and liquid to remove solid precipitates and obtain impurity-free nickel-iron-phosphate waste liquid; the nickel-iron-phosphate waste liquid contains nickel ions, iron ions and phosphate ions, and the pH value of the nickel-iron-phosphate waste liquid is 1.11, 1.13 or 1.

14. (2) Prepare carbonate solution, barium salt solution, ammonium sulfate solution and alkaline solution; wherein the carbonate solution concentration is 1~3 mol / L, the barium salt solution concentration is 1~3 mol / L, the ammonium sulfate solution concentration is 1~3 mol / L and the alkaline solution concentration is 1~3 mol / L; (3) Heat the impurity-removed nickel-iron-phosphate waste liquid to 30~60℃, turn on the stirrer, add the carbonate solution dropwise to the impurity-removed nickel-iron-phosphate waste liquid and stir until no bubbles are generated to obtain waste liquid A. Then add the barium salt solution dropwise to waste liquid A and stir until no white precipitate is generated. Separate the solid and liquid to obtain waste liquid B and Ba3(PO4)2 precipitate. Add the ammonium sulfate solution dropwise to waste liquid B and stir until no green precipitate is generated. Separate the solid and liquid to obtain waste liquid C and (NH4)2Ni(SO4)2·6H2O precipitate. Add the alkali solution dropwise to waste liquid C and stir until no brick-red precipitate is generated. Separate the solid and liquid to obtain waste liquid D and Fe(OH)3 precipitate. The drop acceleration rate of the carbonate solution is 1~2dps, the drop acceleration rate of the barium salt solution is 1~2dps, the drop acceleration rate of the ammonium sulfate solution is 1~2dps, and the drop acceleration rate of the alkali solution is 1~2dps.

2. The method for separating and recovering nickel and iron from nickel-iron-phosphate waste liquid according to claim 1, characterized in that: Step (2) The carbonate is sodium carbonate, sodium bicarbonate or potassium carbonate; the barium salt is barium chloride, barium sulfate or barium nitrate; the alkaline solution is sodium hydroxide solution, potassium hydroxide solution or ammonium hydroxide solution.

3. The method for separating and recovering nickel and iron from nickel-iron-phosphate waste liquid according to claim 1, characterized in that: The stirring rate in step (3) is 100~600 r / min.

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