Recycling method of NF3 electrolytic residual liquid

Abstract

The invention discloses a recycling method of NF3 residual electrolysis liquid, and relates to the technical field of residual electrolysis liquid recycling treatment. The method comprises the following steps: step 1, removing Fe ions in the electrolytic residual liquid: firstly, adding hydrogen peroxide or oxygen into the electrolytic residual liquid for reaction, oxidizing ferrous ions into ferric ions, then adding ammonia water and sodium hydroxide or ammonium bicarbonate and sodium hydroxide into the solution for reaction, precipitating ferric ions in the form of ferric hydroxide; 2, hydrofluoric acid is added into the electrolyte solution obtained after iron removal to adjust the pH of filtrate to 3-12, the filtrate enters an extraction system, the nickel element in ammonium hydrogen fluoride is extracted out, and ammonium hydrogen fluoride is purified; and step 3, the nickel element separated from the electrolyte enters a second section to be extracted and synthesized into a nickel sulfate product.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytic residual liquid recovery and treatment, in particular to a method for recovering and utilizing NF3 electrolytic residual liquid. Background Art

[0002] Currently, nitrogen trifluoride production companies primarily use two methods to treat the residual electrolyte solution: 1. High-temperature calcination to produce nickel-iron alloy; 2. Water washing and dissolution, followed by the addition of sodium hydroxide to remove iron, and finally the addition of sodium hydroxide to precipitate the nickel into crude nickel hydroxide. Direct high-temperature calcination can produce nickel-iron alloy, but it produces a large amount of toxic gases. Washing followed by sodium hydroxide removal results in a nickel loss of approximately 30-35%. None of these methods achieve efficient resource utilization, resulting in wasteful treatment. Furthermore, the treatment process is complex and generates additional waste, waste, and waste products, making it extremely inconvenient.

[0003] Therefore, we propose a method for recycling NF3 electrolytic residual liquid in order to solve the above problems.

[0004] The above information disclosed in this background technology is only for enhancing understanding of the background technology of the present invention and therefore it may contain information that does not constitute the prior art that is already known to a person of ordinary skill in the art. Summary of the Invention

[0005] The object of the present invention is to provide a method for recycling NF3 electrolytic residual liquid to solve the problems raised by the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for recycling NF3 electrolytic residual liquid, comprising the following steps:

[0007] Step 1: Removal of Fe ions from residual electrolyte

[0008] First, hydrogen peroxide or oxygen is added to the residual electrolytic solution to react and oxidize the divalent iron ions into trivalent iron ions. Then, ammonia water + sodium hydroxide or ammonium bicarbonate + sodium hydroxide are added to the solution to react and precipitate the trivalent iron ions in the form of ferric hydroxide.

[0009] Step 2: Extraction and separation of ammonium bifluoride

[0010] The electrolyte solution after iron removal is adjusted to a pH of 3 to 12 by adding hydrofluoric acid, and then enters the extraction system to extract the nickel element in the ammonium bifluoride and purify the ammonium bifluoride;

[0011] Step 3:

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

[0013] Step 3.1: Extraction 1

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

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

[0016] P204 / P507 / P538 nickel soap adds dilute nickel;

[0017] The neutralized filtrate was extracted with P204 / P507 / P538 to remove impurities;

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

[0019] The organic phase is regenerated, and a portion of zinc and iron organic phase impurities are brought along. Excess hydrochloric acid is added to remove the impurities.

[0020] The waste acid and the organic phase are separated and the organic phase is regenerated and reused after the impurities are removed in a closed loop;

[0021] Step 3.2: Extraction 2

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

[0023] Sodium soap of Cy272 / Cy301 / Cy923 was added with sodium hydroxide;

[0024] Cy272 / Cy301 / Cy923 nickel soaps are added to dilute nickel;

[0025] Cy272 / Cy301 / Cy923 extractions were performed to extract pure nickel sulfate solution;

[0026] Cy272 / Cy301 / Cy923 washing adds sulfuric acid to mainly wash the organic phase of magnesium;

[0027] The organic phase enters Cy272 / Cy301 / Cy923 regeneration, and there is a portion of iron impurities in the organic phase, which are removed by adding excess hydrochloric acid;

[0028] The organic phase after impurities are removed is regenerated and reused in a closed loop.

[0029] Preferably, in step 1, the concentration of hydrogen peroxide is 5% to 30%, the oxygen introduction rate is 5 L / min to 50 L / min, the reaction is carried out at 30 to 100° C. for 1 to 5 hours, the concentration of ammonia water 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 step 2, the concentration of hydrofluoric acid is 5% to 40%.

[0031] Preferably, the principle equation of 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 step 2 is:

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

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

[0040] NaOH + (HX) → Na (X) + H2O;

[0041] The equation for 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 neutralized filtrate 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] P204 / P507 / P538 Washing The equation for adding hydrochloric acid to wash the organic phase containing impurities 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 organic phase is regenerated, and a portion of zinc and iron organic phase impurities are brought along. The equation for removing impurities by adding excess hydrochloric acid 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 hydroxide to Cy272 / Cy301 / Cy923 sodium soap 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] The equation for extracting pure nickel sulfate solution by Cy272 / Cy301 / Cy923 is:

[0064] CoSO4+Ni(X)2→Co(X)2+NiSO4;

[0065] MgSO4+Ni(X)2→Mg(X)2+NiSO4;

[0066] The formula for washing Cy272 / Cy301 / Cy923 by adding sulfuric acid to wash the organic phase of magnesium is:

[0067] Mg(X)2+H2SO4→MgSO4+2(HX);

[0068] The organic phase enters Cy272 / Cy301 / Cy923 regeneration, and there is a portion of iron organic phase impurities. The equation for adding excess hydrochloric acid to remove impurities is:

[0069] 3HCL+Fe(X)3→3(HX)+FeCl3;

[0070] 2HCL+Mg(X)2→2(HX)+MgCl2.

[0071] Compared with the prior art, the present invention has the following beneficial effects:

[0072] (1) The present invention adopts 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 will reduce the nickel recovery rate. The present invention innovatively introduces ammonium ions to remove iron while adding sodium hydroxide. Ammonium ions not only have the function of adjusting the pH value of the solution, but also can form complexes with nickel ions, thereby reducing nickel loss. When sodium hydroxide is used alone to remove iron, the nickel loss rate is as high as 30-35%. When ammonia and sodium hydroxide are used to remove iron, the nickel loss rate is reduced to less than 10%. This technological innovation not only improves the nickel recovery rate, but also avoids the excessive introduction of other ions, reducing the risk of secondary pollution.

[0073] (2) The present invention adopts extraction technology. In the purification process of ammonium bifluoride and nickel sulfate, the extraction technology has significant advantages such as efficient separation, energy saving and environmental protection, compact equipment, and simple operation; in the purification process of ammonium bifluoride, by selecting a suitable extractant, ammonium bifluoride can be efficiently extracted from the solution containing impurities, and most of the metal ions and non-metallic impurities can be removed at the same time. A 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 achieved; in the extraction process, part of the metal impurities are first transferred from the aqueous phase to the oil-engine phase, and then the nickel is transferred from the aqueous phase to the organic phase to achieve the purification of nickel ions, and then sulfuric acid is used to back-extract the nickel ions in the organic phase to obtain industrial-grade nickel sulfate. The entire process can achieve continuous operation, synchronous feeding and output of by-products, and at the same time, the extractant can be reused, effectively reducing the project research and development and industrialization costs.

[0074] (3) The extraction method used in the present invention can effectively remove impurity metal ions more thoroughly, with the lowest concentration being less than 1 mg / L, and can achieve ammonium bifluoride and nickel sulfate products that meet national standards; and the extraction method does not cause nickel loss, can achieve efficient resource utilization and avoid resource waste.

[0075] (4) The entire process equipment of the present invention is sealed to prevent harmful gases from volatilizing into the air, thereby avoiding impact on the surrounding environment and affecting the health of workers.

[0076] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present invention will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0078] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0079] Example 1

[0080] See also Figure 1 A method for recycling NF3 electrolytic residual liquid comprises the following steps:

[0081] Step 1: Removal of Fe ions from residual electrolyte

[0082] Add 5% to 30% hydrogen peroxide or oxygen to the residual electrolytic solution at an oxygen flow rate of 5 L / min to 50 L / min and react at 30 to 100° C. for 1 to 5 hours to oxidize the divalent iron ions into trivalent iron ions. Then, add 5% to 30% ammonia water + sodium hydroxide or 10% to 40% ammonium bicarbonate + 5% to 30% sodium hydroxide to the solution to precipitate the trivalent iron ions in the form of ferric hydroxide.

[0083] The residual electrolyte contains a large amount of Fe 3+ and Fe 2+ During the extraction process, nickel ions are also divalent ions, and the extraction process cannot remove Fe 2+ and Ni 2+ Separate, so Fe 2+ Oxidized to Fe 3+ , 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 and separation of ammonium bifluoride

[0091] The electrolyte solution after iron removal is adjusted to a pH of 3 to 12 by adding hydrofluoric acid with a concentration of 5% to 40%, and then enters the extraction system to extract impurity elements such as nickel and iron in the ammonium bifluoride 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. The main process is as follows:

[0095] Step 3.1: Extraction 1

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

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

[0098] NaOH+(HX)→Na(X)+H2O

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

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

[0101] Step 3.1.3: P204 / P507 / P538 extraction is used to remove impurities from the neutralized filtrate. 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: Add hydrochloric acid to wash the organic phase containing impurities. 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: Organic phase regeneration will also bring some zinc and iron organic phase impurities, which need to be removed by adding excess hydrochloric acid. 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: The spent acid and the organic phase are separated and the organic phase is regenerated and reused after the impurities are removed in a closed loop;

[0118] Step 3.2: Extraction 2

[0119] 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 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, the equation is:

[0121] NaOH+(HX)→Na(X)+H2O

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

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

[0124] Step 3.2.3: Extraction of Cy272 / Cy301 / Cy923 to obtain pure nickel sulfate solution. 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: Cy272 / Cy301 / Cy923 washing: Sulfuric acid is added to wash the organic phase of magnesium. The equation is:

[0128] Mg(X)2+H2SO4→MgSO4+2(HX)

[0129] Step 3.2.5: The organic phase enters the Cy272 / Cy301 / Cy923 regeneration process. At the same time, there will be some iron impurities in the organic phase. Excess hydrochloric acid needs to be added to remove the impurities. The equation is:

[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 impurities are removed is regenerated and reused in a closed loop.

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

[0134]

[0135] Table 2: Iron removal by adding hydrogen peroxide, ammonia and sodium hydroxide to the residual electrolytic solution

[0136]

[0137] Table 3: Iron removal by adding hydrogen peroxide, ammonium bicarbonate and sodium hydroxide to the residual electrolyte

[0138]

[0139] It can be seen from Tables 1, 2 and 3 that when sodium hydroxide is used to remove iron, the nickel loss rate is as high as 30-35%; however, after the introduction of ammonium ions, the nickel loss rate is reduced to less than 10%.

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

[0141] Test Elements 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 Extraction sample 1 6.54 0.32 1.145 0.54 0.14 3.54 ND Extraction sample 2 5.45 0.41 1.24 0.14 0.03 4.25 ND

[0142] Table 4: Ammonium bifluoride extraction and impurity removal data

[0143] Test Elements 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 Extraction sample 1 ND 0.24 0.81 0.34 ND 0.035 Extraction sample 2 ND 0.15 0.94 0.54 ND ND

[0144] Table 5: Ammonium bifluoride finished product data

[0145]

[0146]

[0147] Table 6: Nickel sulfate extraction and 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 Extraction sample 1 0.36 ND 0.85 ND ND 0.49 ND Extraction sample 2 0.123 ND 0.812 ND 1.54 0.064 /

[0149] Table 6: Nickel sulfate extraction and 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 Extraction sample 1 2.05 ND 6.87 ND 0.03 22.36 Extraction sample 2 0.72 ND 6.59 ND ND 23.59

[0151] As can be seen from Tables 1 and 2, the extraction method used in the present invention can effectively remove impure metal ions more thoroughly, with the lowest concentration being less than 1 mg / L, and can produce ammonium bifluoride and nickel sulfate products that meet national standards.

[0152] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do 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. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0153] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for recycling NF3 electrolytic residual liquid, characterized in that: The steps include: Step 1: Removal of Fe ions from residual electrolyte First, hydrogen peroxide or oxygen is added to the residual electrolytic solution to react and oxidize the divalent iron ions into trivalent iron ions. Then, ammonia water + sodium hydroxide or ammonium bicarbonate + sodium hydroxide are added to the solution to react and precipitate the trivalent iron ions in the form of ferric hydroxide. Step 2: Extraction and separation of ammonium bifluoride The electrolyte solution after iron removal is adjusted to a pH of 3 to 12 by adding hydrofluoric acid, and then enters the extraction system to extract the nickel element in the ammonium bifluoride and purify the ammonium bifluoride; Step 3: The nickel element separated from the electrolyte enters the second stage of extraction to synthesize nickel sulfate product. The main process is as follows: Step 3.1: Extraction 1 The process temperature is 25-70°C, the mixing residence time is 5-10 minutes, and it is divided into sodium soap, nickel soap, washing, stripping, iron washing, and chlorine washing steps; P204 / P507 / P538 sodium soap added with sodium hydroxide; P204 / P507 / P538 nickel soap adds dilute nickel; The neutralized filtrate was extracted with P204 / P507 / P538 to remove impurities; P204 / P507 / P538 washing: adding hydrochloric acid to wash the organic phase containing impurities; The organic phase is regenerated, and a portion of zinc and iron organic phase impurities are brought along. Excess hydrochloric acid is added to remove the impurities. The waste acid and the organic phase are separated and the organic phase is regenerated and reused after the impurities are removed in a closed loop; Step 3.2: Extraction 2 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. Sodium soap of Cy272 / Cy301 / Cy923 was added with sodium hydroxide; Cy272 / Cy301 / Cy923 nickel soaps are added to dilute nickel; Cy272 / Cy301 / Cy923 extractions were performed to extract pure nickel sulfate solution; Cy272 / Cy301 / Cy923 washing adds sulfuric acid to mainly wash the organic phase of magnesium; The organic phase enters Cy272 / Cy301 / Cy923 regeneration, and there is a portion of iron impurities in the organic phase, which are removed by adding excess hydrochloric acid; The organic phase after impurities are removed is regenerated and reused in a closed loop.

2. The method for recycling NF3 electrolytic residual liquid according to claim 1, wherein: In the step 1, the concentration of hydrogen peroxide is 5% to 30%, the oxygen introduction rate is 5 L / min to 50 L / min, the reaction is carried out at 30 to 100° C. for 1 to 5 hours, the concentration of ammonia water is 5% to 30%, the concentration of ammonium bicarbonate is 10% to 40%, and the concentration of sodium hydroxide is 5% to 30%.

3. The method for recycling NF3 electrolytic residual liquid according to claim 1, wherein: In step 2, the concentration of hydrofluoric acid is 5% to 40%.

4. The method for recycling NF3 electrolytic residual liquid according to claim 1, wherein: The principle equation of step 1 is: <h2 style=";text-align:left;direction:ltr">2Fe<h2 style=";text-align:left;direction:ltr"> 2+ <h2 style=";text-align:left;direction:ltr"> +H2O2+2H+=2Fe<h2 style=";text-align:left;direction:ltr"> 3+ <h2 style=";text-align:left;direction:ltr"> +2H2O; 4Fe 2+ +O2+4H+=4Fe 3+ +2H2O; <h2 style=";text-align:left;direction:ltr">Fe<h2 style=";text-align:left;direction:ltr"> 3+ <h2 style=";text-align:left;direction:ltr"> +2NH4HCO3 = Fe(OH)3 + 2NH<h2 style=";text-align:left;direction:ltr"> 4+ <h2 style=";text-align:left;direction:ltr"> (aq)+2CO2; <h2 style=";text-align:left;direction:ltr">Fe<h2 style=";text-align:left;direction:ltr"> 3+ <h2 style=";text-align:left;direction:ltr"> +3NaOH(aq)→Fe(OH)3+3Na<h2 style=";text-align:left;direction:ltr"> + <h2 style=";text-align:left;direction:ltr"> ; Fe 3+ +NH3(aq)→Fe(OH)3+NH 4+ (aq)。 5. The method for recycling NF3 electrolytic residual liquid according to claim 1, wherein: The principle equation of step 2 is: xNi[H(R2PO4)2]2+2Mex+→2Me[H(R2PO4)2]x+xNi 2+ 。 6. The method for recycling NF3 electrolytic residual liquid according to claim 1, characterized in that: In step 3.1, the equation for adding sodium hydroxide to P204 / P507 / P538 sodium soap is: NaOH + (HX) → Na (X) + H2O; The equation for adding P204 / P507 / P538 nickel soap to dilute nickel is: NiSO4+2Na(X)→Ni(X)2+Na2SO4; The equation for removing impurities from the neutralized filtrate 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; P204 / P507 / P538 Washing The equation for adding hydrochloric acid to wash the organic phase containing impurities 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 organic phase is regenerated, and a portion of zinc and iron organic phase impurities are brought along. The equation for removing impurities by adding excess hydrochloric acid is: 3HCL+Fe(X)3→3(HX)+FeCl3; 2HCL+Zn(X)2→2(HX)+ZnCl2.

7. The method for recycling NF3 electrolytic residual liquid according to claim 1, characterized in that: In step 3.2, the equation for adding sodium hydroxide to Cy272 / Cy301 / Cy923 sodium soap 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 is: CoSO4+Ni(X)2→Co(X)2+NiSO4; MgSO4+Ni(X)2→Mg(X)2+NiSO4; The formula for washing Cy272 / Cy301 / Cy923 by adding sulfuric acid to wash the organic phase of magnesium is: Mg(X)2+H2SO4→MgSO4+2(HX); The organic phase enters Cy272 / Cy301 / Cy923 regeneration, and there is a portion of iron organic phase impurities. The equation for adding excess hydrochloric acid to remove impurities is: 3HCL+Fe(X)3→3(HX)+FeCl3; 2HCL+Mg(X)2→2(HX)+MgCl2.

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