Method for recycling of nf3 electrolysis raffinate

Abstract

The application discloses a recycling method of NF3 electrolysis residual solution and relates to the technical field of electrolysis residual solution recycling treatment. The method comprises the following steps: step 1: removing Fe ions in the electrolysis residual solution; first, hydrogen peroxide or oxygen is added into the electrolysis residual solution to oxidize the divalent iron ions into trivalent iron ions, and then ammonia water and sodium hydroxide or ammonium hydrogen carbonate and sodium hydroxide are added into the solution to react, so that the trivalent iron ions are precipitated in the form of iron hydroxide; step 2: the electrolyte solution after the removal of iron is adjusted to a pH of 3-12 by adding hydrofluoric acid, enters an extraction system, extracts the nickel element in the ammonium hydrogen fluoride, and purifies the ammonium hydrogen fluoride; and step 3: the nickel element separated from the electrolyte solution enters a second extraction to synthesize a nickel sulfate product.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrolytic residual liquid recovery treatment, in particular to a recovery and utilization method of NF3 electrolytic residual liquid. BACKGROUND

[0002] Currently, the electrolytic residual liquid generated by the nitrogen trifluoride production enterprises in the industry mainly adopts two treatment methods: 1. High-temperature calcination to prepare nickel-iron alloy; 2. Water washing and dissolution, adding sodium hydroxide to remove iron, and finally adding sodium hydroxide to precipitate nickel to prepare crude nickel hydroxide. The direct high-temperature calcination method can obtain nickel-iron alloy, but a large amount of toxic gas will be generated; and the water washing and then adding sodium hydroxide to remove iron will cause about 30-35% of nickel loss. In the above methods, the products have not realized efficient resource utilization, causing resource waste, and the treatment process is relatively complex, and additional three wastes will be generated in the treatment process, which is extremely inconvenient.

[0003] Therefore, we propose a recovery and utilization method of NF3 electrolytic residual liquid to solve the problems raised in the above background.

[0004] The above information disclosed in the background of the application is only used to increase the understanding of the background of the application, and therefore, it can include prior art known to those skilled in the art. SUMMARY

[0005] The purpose of the present application is to provide a recovery and utilization method of NF3 electrolytic residual liquid to solve the problems raised in the above background.

[0006] To achieve the above purpose, the present application provides the following technical scheme: a recovery and utilization method of NF3 electrolytic residual liquid, comprising the following steps:

[0007] Step 1: removal of Fe ions in the electrolytic residual liquid

[0008] First, add hydrogen peroxide or oxygen to the electrolytic residual liquid to react, oxidize the divalent iron ions to trivalent iron ions, and then add ammonia water + sodium hydroxide or ammonium bicarbonate + sodium hydroxide to the solution to react, so that the trivalent iron ions are precipitated as iron hydroxide;

[0009] Step 2: extraction and separation of ammonium hydrogen fluoride

[0010] The electrolyte solution after removing iron is adjusted to a pH of 3-12 by adding hydrofluoric acid, enters the extraction system, extracts the nickel element in the ammonium hydrogen fluoride, and purifies the ammonium hydrogen fluoride;

[0011] Step 3:

[0012] The nickel element separated from the electrolyte enters the second extraction to synthesize nickel sulfate product, and the main process is as follows:

[0013] Step 3.1: Extraction 1

[0014] The process temperature is 25-70℃, the mixing residence time is 5-10 minutes, and the process is divided into sodium soap, nickel soap, washing, stripping, iron washing, and chlorine washing procedures;

[0015] P204 / P507 / P538 sodium soap is added with sodium hydroxide;

[0016] P204 / P507 / P538 nickel soap is added with dilute nickel;

[0017] P204 / P507 / P538 extraction is performed on the filtrate after neutralization to remove impurities;

[0018] P204 / P507 / P538 washing is performed by adding hydrochloric acid to wash the organic phase containing impurities;

[0019] The organic phase is regenerated, and a part of zinc and iron organic phase impurities are removed by adding excess hydrochloric acid;

[0020] The waste acid is separated from the organic phase, and the regenerated organic phase after removing impurities is reused for closed loop circulation;

[0021] Step 3.2: Extraction 2

[0022] The Cy272 / Cy301 / Cy923 extraction system includes sodium soap, nickel soap, extraction, washing, stripping, iron washing, and organic phase closed loop circulation. The process temperature is 25-70℃, and the mixing residence time is 5-10 minutes;

[0023] Cy272 / Cy301 / Cy923 sodium soap is added with sodium hydroxide;

[0024] Cy272 / Cy301 / Cy923 nickel soap is added with dilute nickel;

[0025] Cy272 / Cy301 / Cy923 extraction is performed to extract pure nickel sulfate solution;

[0026] Cy272 / Cy301 / Cy923 washing is performed by adding sulfuric acid to mainly wash the magnesium organic phase;

[0027] The organic phase enters Cy272 / Cy301 / Cy923 regeneration, and a part of iron organic phase impurities are removed by adding excess hydrochloric acid;

[0028] The regenerated organic phase after removing impurities is reused for closed loop circulation.

[0029] Preferably, in the step 1, the concentration of hydrogen peroxide is 5% to 30%, the oxygen input is 5L / min to 50L / min, the reaction is carried out at 30 to 100℃ for 1 to 5h, the concentration of ammonia is 5% to 30%, the concentration of ammonium bicarbonate is 10% to 40%, and the concentration of sodium hydroxide is 5% to 30%.

[0030] Preferably, in the step 2, the concentration of hydrofluoric acid is 5% to 40%.

[0031] Preferably, the principle equation of the step 1 is:

[0032] 2Fe 2+ + H2O2 + 2H + = 2Fe 3+ + 2H2O.

[0033] 4Fe 2+ + O2 + 4H + = 4Fe 3+ + 2H2O.

[0034] Fe 3+ + 2NH4HCO3 = Fe(OH)3 + 2NH 4+ (aq) + 2CO2.

[0035] Fe 3+ + 3NaOH(aq) → Fe(OH)3 + 3Na + .

[0036] Fe 3+ + NH3(aq) → Fe(OH)3 + NH 4+ (aq).

[0037] Preferably, the principle equation of the step 2 is:

[0038] xNi[H(R2PO4)2]2 + 2Mex + → 2Me[H(R2PO4)2]x + xNi 2+ .

[0039] Preferably, in the step 3.1, the equation of adding sodium hydroxide to P204 / P507 / P538 sodium soap is:

[0040] NaOH + (HX) → Na(X) + H2O.

[0041] The equation of adding P204 / P507 / P538 nickel soap to dilute nickel is:

[0042] NiSO4 + 2Na(X) → Ni(X)2 + Na2SO4.

[0043] The equation for removing impurities from the filtrate after neutralization by P204 / P507 / P538 extraction is:

[0044] ZnSO4+ Ni(X)2→ Zn(X)2+ NiSO4;

[0045] MnSO4+ Ni(X)2→ Mn(X)2+ NiSO4;

[0046] MgSO4+ Ni(X)2→ Mg(X)2+ NiSO4;

[0047] Fe2(SO4)3+ 3Ni(X)2→ 2Fe(X)3+ 3NiSO4;

[0048] CoSO4+ Ni(X)2→ Co(X)2+ NiSO4;

[0049] The equation for washing the organic phase containing impurities by adding hydrochloric acid to P204 / P507 / P538 washing is:

[0050] 2HCL + Ni(X)2→ 2(HX) + NiCl2;

[0051] 2HCL + Co(X)2→ 2(HX) + CoCl2;

[0052] 2HCL + Mg(X)2→ 2(HX) + MgCl2;

[0053] 3HCL + Fe(X)3→ 3(HX) + FeCl3;

[0054] 2HCL + Zn(X)2→ 2(HX) + ZnCl2;

[0055] 2HCL + Mn(X)2→ 2(HX) + MnCl2;

[0056] The equation for regenerating the organic phase, while bringing along a portion of zinc and iron organic phase impurities, by adding excess hydrochloric acid to remove impurities is:

[0057] 3HCL + Fe(X)3→ 3(HX) + FeCl3;

[0058] 2HCL + Zn(X)2→ 2(HX) + ZnCl2.

[0059] Preferably, in step 3.2, the equation for adding sodium Cy272 / Cy301 / Cy923 soap to sodium hydroxide is:

[0060] NaOH + (HX) → Na(X) + H2O;

[0061] The equation for adding Cy272 / Cy301 / Cy923 nickel soap to dilute nickel is:

[0062] NiSO4 + 2Na(X) → Ni(X)2 + Na2SO4

[0063] Equation for extracting pure nickel sulfate solution by Cy272 / Cy301 / Cy923 extraction:

[0064] CoSO4 + Ni(X)2 → Co(X)2 + NiSO4

[0065] MgSO4 + Ni(X)2 → Mg(X)2 + NiSO4

[0066] Equation for washing the organic phase mainly containing magnesium by adding sulfuric acid in Cy272 / Cy301 / Cy923 washing:

[0067] Mg(X)2 + H2SO4 → MgSO4 + 2(HX)

[0068] Equation for the organic phase entering Cy272 / Cy301 / Cy923 regeneration while part of the iron organic phase impurities are removed by adding excess hydrochloric acid:

[0069] 3HCL + Fe(X)3 → 3(HX) + FeCl3

[0070] 2HCL + Mg(X)2 → 2(HX) + MgCl2

[0071] Compared with the prior art, the present application has the following advantages:

[0072] (1) The present application adopts a purification and iron removal technology. The traditional iron removal method uses sodium hydroxide to adjust the pH value of the solution to promote the precipitation of iron ions, which reduces the recovery rate of nickel. The present application innovatively introduces ammonium ions for iron removal while adding sodium hydroxide. Ammonium ions not only have the function of adjusting the pH value of the solution, but also can form a complex with nickel ions, thereby reducing the loss of nickel. When sodium hydroxide is used alone for iron removal, the loss rate of nickel is as high as 30-35%. When ammonia and sodium hydroxide are used for iron removal, the loss rate of nickel is reduced to less than 10%. This technical innovation not only improves the recovery rate of nickel, but also avoids the introduction of too many other ions, thereby reducing the risk of secondary pollution.

[0073] (2) The application adopts extraction technology. In the purification process of ammonium bifluoride and nickel sulfate, the extraction technology has the advantages of high efficiency separation, energy saving and environmental protection, compact equipment, simple operation and the like; in the purification process of ammonium bifluoride, by selecting a suitable extractant, ammonium bifluoride can be efficiently extracted from a solution containing impurities, while most of the metal ions and non-metal impurities are removed. High-purity ammonium bifluoride product is obtained; in the purification process of nickel sulfate, by adjusting the pH value of the solution and selecting a suitable extractant, efficient separation of nickel sulfate and impurity ions is realized; in the extraction process, first, part of the metal impurities are transferred from the aqueous phase to the organic phase, and then the nickel is transferred from the aqueous phase to the organic phase to realize the purification of nickel ions, and then sulfuric acid is used to strip the nickel ions in the organic phase to obtain industrial-grade nickel sulfate. The whole process can realize continuous operation, synchronous feeding and by-product output, at the same time, the extractant can be reused, effectively reducing the project research and industrialization cost.

[0074] (3) The extraction method of the application can effectively remove impurity metal ions more thoroughly, with a minimum of less than 1 mg / L, which can meet the national standard grade of ammonium bifluoride and nickel sulfate products; and the extraction method does not cause loss of nickel, can realize efficient resource utilization and avoid resource waste.

[0075] (4) The whole process flow equipment of the application is in a sealed form, which prevents harmful gas from volatilizing into the air, avoiding the impact on the surrounding environment and the health of workers.

[0076] The above summary is only for the purpose of the description and is not intended to limit in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present application will be readily apparent from a reading of the following detailed description of the application, taken in conjunction with the accompanying drawings and the appended claims. BRIEF DESCRIPTION OF DRAWINGS

[0077] Figure 1 The above summary is only for the purpose of the description and is not intended to limit in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present application will be readily apparent from a reading of the following detailed description of the application, taken in conjunction with the accompanying drawings and the appended claims. DETAILED DESCRIPTION

[0078] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0079] Embodiment one

[0080] Please refer to Figure 1 A method for recycling NF3 electrolysis residual solution, comprising the following steps:

[0081] Step 1: Removal of Fe ions in electrolysis residual liquid

[0082] Add 5% to 30% concentration hydrogen peroxide or oxygen to the electrolysis residual liquid, and oxygen is introduced at a rate of 5L / min to 50L / min, and the reaction is carried out at 30 to 100℃ for 1 to 5 hours, so that the divalent iron ions in the solution are oxidized to trivalent iron ions. Then, 5% to 30% concentration ammonia water + sodium hydroxide or 10% to 40% concentration ammonium bicarbonate + 5% to 30% concentration sodium hydroxide is added to the solution, so that the trivalent iron ions are precipitated in the form of iron hydroxide.

[0083] The electrolysis residual liquid contains a large amount of Fe 3+ and Fe 2+ In the extraction process, the nickel ions are also divalent ions, and the extraction process cannot separate Fe 2+ and Ni 2+ Therefore, Fe 2+ is oxidized to Fe 3+ in advance, and then removed by extraction process.

[0084] The principle equation is:

[0085] 2Fe 2+ + H2O2 + 2H + = 2Fe 3+ + 2H2O

[0086] 4Fe 2+ + O2 + 4H + = 4Fe 3+ + 2H2O

[0087] Fe 3+ + 2NH4HCO3 = Fe(OH)3 + 2NH 4+ (aq) + 2CO2

[0088] Fe 3+ + 3NaOH(aq) → Fe(OH)3 + 3Na + ;

[0089] Fe 3+ + NH3(aq) → Fe(OH)3 + NH 4+ (aq)

[0090] Step 2: Extraction separation of ammonium bifluoride

[0091] The electrolyte solution after removing iron is adjusted to a pH of 3 to 12 by adding 5% to 40% concentration hydrofluoric acid, and then enters the extraction system to extract nickel, iron and other impurity elements in the ammonium bifluoride, so as to purify the ammonium bifluoride.

[0092] xNi[H(R2PO4)2]2+2Mex+→2Me[H(R2PO4)2]x+xNi 2+ ;

[0093] Step 3:

[0094] The nickel element separated from the electrolyte enters the second stage of extraction to synthesize nickel sulfate product, and the main process is as follows:

[0095] Step 3.1: Extraction 1

[0096] The temperature of this process is normal temperature, the mixing residence time is 5 minutes, and it is divided into sodium soap, nickel soap, washing, stripping, iron washing, and chlorine washing processes;

[0097] Step 3.1.1: P204 / P507 / P538 sodium soap is added with sodium hydroxide, and the equation is:

[0098] NaOH+(HX)→Na(X)+H2O

[0099] Step 3.1.2: P204 / P507 / P538 nickel soap is added with dilute nickel (nickel sulfate, water), and the equation is:

[0100] NiSO4+2Na(X)→Ni(X)2+Na2SO4(waste water)

[0101] Step 3.1.3: P204 / P507 / P538 extraction is used to remove impurities from the filtrate after neutralization, and the equation is:

[0102] ZnSO4+Ni(X)2→Zn(X)2+NiSO4

[0103] MnSO4+Ni(X)2→Mn(X)2+NiSO4

[0104] MgSO4+Ni(X)2→Mg(X)2+NiSO4

[0105] Fe2(SO4)3+3Ni(X)2→2Fe(X)3+3NiSO4

[0106] CoSO4+Ni(X)2→Co(X)2+NiSO4

[0107] Step 3.1.4: P204 / P507 / P538 washing is used to wash the organic phase containing impurities by adding hydrochloric acid, and the equation is:

[0108] 2HCL+Ni(X)2→2(HX)+NiCl2

[0109] 2HCL+Co(X)2→2(HX)+CoCl2

[0110] 2HCL + Mg(X)2→ 2(HX) + MgCl2

[0111] 3HCL + Fe(X)3→ 3(HX) + FeCl3

[0112] 2HCL + Zn(X)2→ 2(HX) + ZnCl2

[0113] 2HCL + Mn(X)2→ 2(HX) + MnCl2

[0114] Step 3.1.5: Regeneration of organic phase, while also bringing a part of zinc, iron organic phase impurities, need to add excess hydrochloric acid to remove impurities, the equation is:

[0115] 3HCL + Fe(X)3→ 3(HX) + FeCl3(waste acid)

[0116] 2HCL + Zn(X)2→ 2(HX) + ZnCl2(waste acid)

[0117] Step 3.1.6: waste acid and organic phase are layered, and the organic phase after removing impurities is regenerated and reused for closed loop circulation;

[0118] Step 3.2: extraction 2

[0119] Cy272 / Cy301 / Cy923 extraction system includes sodium soap, nickel soap, extraction, washing, stripping, washing iron, and organic phase closed loop circulation. The process temperature is room temperature, and the mixing residence time is 5 minutes.

[0120] Step 3.2.1: Cy272 / Cy301 / Cy923 sodium soap is added with sodium hydroxide, and the equation is:

[0121] NaOH + (HX) → Na(X) + H2O

[0122] Step 3.2.2: Cy272 / Cy301 / Cy923 nickel soap is added with dilute nickel (nickel sulfate, water), and the equation is:

[0123] NiSO4 + 2Na(X) → Ni(X)2 + Na2SO4(waste water)

[0124] Step 3.2.3: Cy272 / Cy301 / Cy923 extraction extracts pure nickel sulfate solution, and the equation is:

[0125] CoSO4 + Ni(X)2 → Co(X)2 + NiSO4

[0126] MgSO4 + Ni(X)2 → Mg(X)2 + NiSO4

[0127] Step 3.2.4: Washing of the organic phase with sulfuric acid mainly removes magnesium, equation:

[0128] Mg(X)2 + H2SO4→ MgSO4 + 2(HX)

[0129] Step 3.2.5: The organic phase enters Cy272 / Cy301 / Cy923 regeneration, while there will be a part of iron organic phase impurities, need to add excess hydrochloric acid to remove impurities, equation:

[0130] 3HCL + Fe(X)3→ 3(HX) + FeCl3(waste acid)

[0131] 2HCL + Mg(X)2→ 2(HX) + MgCl2(waste acid)

[0132] Step 3.2.6: The organic phase after removing impurities is regenerated and reused, closed loop cycle.

[0133] Table 1: Electrolyte residue plus hydrogen peroxide and sodium hydroxide to remove iron

[0134]

[0135] Table 2: Electrolyte residue plus hydrogen peroxide, ammonia and sodium hydroxide to remove iron

[0136]

[0137] Table 3: Electrolyte residue plus hydrogen peroxide, ammonium bicarbonate and sodium hydroxide to remove iron

[0138]

[0139] From Table 1, Table 2, Table 3, when using sodium hydroxide to remove iron, the loss rate of nickel is as high as 30-35%; and after introducing ammonium, the loss rate of nickel is reduced to less than 10%.

[0140] Table 4: Ammonium bifluoride extraction impurity removal data

[0141] Test element Na Mg Al Si Ca Ti Cr Unit ppm ppm ppm ppm ppm ppm ppm Content 150.73 0.16 1.45 367.68 0.25 0.54 5.01 Extracted sample 1 6.54 0.32 1.145 0.54 0.14 3.54 ND Extracted sample 2 5.45 0.41 1.24 0.14 0.03 4.25 ND

[0142] Table 4 (continued): Ammonium bifluoride extraction impurity removal data

[0143] Test element Mn Fe Co Ni Cu Zn Unit ppm ppm ppm ppm ppm ppm Content 0.33 12.21 0.07 7456.56 2.67 1.11 Extracted sample 1 ND 0.24 0.81 0.34 ND 0.035 Extracted sample 2 ND 0.15 0.94 0.54 ND ND

[0144] Table 5: Ammonium bifluoride product data

[0145]

[0146]

[0147] Table 6: Nickel sulfate extraction impurity removal data

[0148] Element Ca Cd Co Cr Cu Fe Hg Unit ppm ppm ppm ppm ppm ppm ppm National standard 20 2 10 3 5 5 2 Extracted sample 1 0.36 ND 0.85 ND ND 0.49 ND Extracted sample 2 0.123 ND 0.812 ND 1.54 0.064 /

[0149] Table 6: Nickel sulfate extraction impurity removal data

[0150] Element Mg Mn Na Pb Zn Ni Unit ppm ppm ppm ppm ppm ％ National standard 20 10 200 10 5 22.2 Extracted sample 1 2.05 ND 6.87 ND 0.03 22.36 Extracted sample 2 0.72 ND 6.59 ND ND 23.59

[0151] From Table 1, Table 2, it can be seen that the impurity metal ions can be removed more thoroughly by the extraction method, and the minimum can be less than 1 mg / L, which can reach the national standard grade of ammonium bifluoride and nickel sulfate products.

[0152] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. Furthermore, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0153] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application, and the person skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A method for recycling NF3 electrolysis residual liquid, characterized in that, It comprises the following steps: Step 1: removal of Fe ions in electrolytic residual liquid First, hydrogen peroxide or oxygen is added to the electrolytic residual liquid to oxidize the divalent iron ions to trivalent iron ions, and then ammonia water + sodium hydroxide or ammonium bicarbonate + sodium hydroxide is added to the solution to precipitate the trivalent iron ions as iron hydroxide; Step 2: extraction and separation of ammonium bifluoride After removing iron, the electrolyte solution is adjusted to pH 3-12 by adding hydrofluoric acid, enters the extraction system, and extracts the nickel element in ammonium bifluoride to purify the ammonium bifluoride; Step 3: The nickel element separated from the electrolyte enters the second stage of extraction to synthesize nickel sulfate product, and the main process is as follows: Step 3.1: extraction 1 The temperature of this process is 25-70℃, the mixing residence time is 5-10 minutes, and it is divided into sodium soap, nickel soap, extraction, washing, stripping, iron washing, and chlorine washing processes; P204 / P507 / P538 sodium soap is added with sodium hydroxide; P204 / P507 / P538 nickel soap is added with dilute nickel; P204 / P507 / P538 extraction removes impurities from the filtrate after neutralization; P204 / P507 / P538 washing is added with hydrochloric acid to wash the organic phase containing impurities; The organic phase is regenerated, and a part of zinc and iron organic phase impurities is removed by adding excess hydrochloric acid; The waste acid is separated from the organic phase, and the regenerated organic phase after removing impurities is reused in closed circuit; Step 3.2: extraction 2 Cy272 / Cy301 / Cy923 extraction system includes sodium soap, nickel soap, extraction, washing, stripping, and iron washing, and the organic phase is closed loop circulation, the temperature of this process is 25-70℃, the mixing residence time is 5-10 minutes; Cy272 / Cy301 / Cy923 sodium soap is added with sodium hydroxide; Cy272 / Cy301 / Cy923 nickel soap is added with dilute nickel; Cy272 / Cy301 / Cy923 extraction extracts pure nickel sulfate solution; Cy272 / Cy301 / Cy923 washing is added with sulfuric acid to mainly wash the magnesium organic phase; The organic phase enters Cy272 / Cy301 / Cy923 regeneration, and a part of iron organic phase impurities is removed by adding excess hydrochloric acid; The regenerated organic phase after removing impurities is reused in closed circuit.

2. The method of claim 1, wherein: In step 1, the concentration of hydrogen peroxide is 5%-30%, the oxygen inlet amount is 5L / min-50L / min, the reaction is carried out at 30-100℃ for 1-5h, the concentration of ammonia water is 5%-30%, the concentration of ammonium bicarbonate is 10%-40%, and the concentration of sodium hydroxide is 5%-30%.

3. The method of claim 1, wherein: In step 2, the concentration of hydrofluoric acid is 5%-40%.

4. The method of claim 1, wherein: The principle equation of step 1 is: 2Fe 2+ + H2O2 + 2H + = 2Fe 3+ + 2H2O; 4Fe 2+ + O2+ 4H + = 4Fe 3+ + 2H2O; Fe 3+ + 2NH4HCO3 = Fe(OH)3+ 2NH 4+ (aq) + 2CO2; Fe 3+ + 3 NaOH (aq) → Fe(OH)3+ 3 Na + ; Fe 3+ + NH3(aq) → Fe(OH)3+ NH 4+ (aq).

5. The method of claim 1, wherein: The principle equation of step 2 is: x Ni[H(R2PO4)2]2+ 2 Me x+ → 2 Me[H(R2PO4)2] x + x Ni 2+ .

6. The method of claim 1, wherein: In step 3.1, the equation of P204 / P507 / P538 sodium soap added with sodium hydroxide is: NaOH+(HX)→Na(X)+H2O; The equation of P204 / P507 / P538 nickel soap added with dilute nickel is: NiSO4+2Na(X)→Ni(X)2+Na2SO4; The equation for removing impurities from the filtrate after neutralization by P204 / P507 / P538 extraction is: ZnSO4+Ni(X)2→Zn(X)2+NiSO4; MnSO4+Ni(X)2→Mn(X)2+NiSO4; MgSO4+Ni(X)2→Mg(X)2+NiSO4; Fe2(SO4)3+3Ni(X)2→2Fe(X)3+3NiSO4; CoSO4+Ni(X)2→Co(X)2+NiSO4; The equation for washing the organic phase containing impurities by adding hydrochloric acid to P204 / P507 / P538 washing is: 2HCL+Ni(X)2→2(HX)+NiCl2; 2HCL+Co(X)2→2(HX)+CoCl2; 2HCL+Mg(X)2→2(HX)+MgCl2; 3HCL+Fe(X)3→3(HX)+FeCl3; 2HCL+Zn(X)2→2(HX)+ZnCl2; 2HCL+Mn(X)2→2(HX)+MnCl2; The equation for regenerating the organic phase while removing some zinc and iron organic phase impurities by adding excess hydrochloric acid is: 3HCL+Fe(X)3→3(HX)+FeCl3; 2HCL+Zn(X)2→2(HX)+ZnCl2.

7. The method of claim 1, wherein: In step 3.2, the equation for adding sodium Cy272 / Cy301 / Cy923 soap to sodium hydroxide is: NaOH+(HX)→Na(X)+H2O; The equation for adding Cy272 / Cy301 / Cy923 nickel soap to dilute nickel is: NiSO4+2Na(X)→Ni(X)2+Na2SO4; The equation for extracting pure nickel sulfate solution by Cy272 / Cy301 / Cy923 extraction is: CoSO4+Ni(X)2→Co(X)2+NiSO4; MgSO4+Ni(X)2→Mg(X)2+NiSO4; The equation for washing the organic phase mainly containing magnesium by adding sulfuric acid to Cy272 / Cy301 / Cy923 washing is: Mg(X)2+H2SO4→MgSO4+2(HX); The equation for regenerating the organic phase by Cy272 / Cy301 / Cy923 while removing some iron organic phase impurities by adding excess hydrochloric acid is: 3HCL+Fe(X)3→3(HX)+FeCl3; 2HCL+Mg(X)2→2(HX)+MgCl2.

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