A method for high-value recovery and recycling of high-calcium manganese chloride wastewater in cobalt smelting

Abstract

The application discloses a method for high-value recovery and recycling of high-calcium manganese chloride wastewater in cobalt smelting, which aims to solve the problems of difficult pollution control, low resource recycling rate and high treatment cost in the treatment of high-calcium manganese chloride wastewater in cobalt smelting by conventional technology. The high-calcium manganese chloride wastewater in cobalt smelting is subjected to high-value recovery and recycling through steps of hydrochloric acid back extraction, alternating electromagnetic field assisted impurity removal, Cy272 linkage optimized extraction and NaCl solution electrolysis synthesis. The application adopts hydrochloric acid back extraction to avoid the calcium sulfate scaling problem caused by sulfuric acid back extraction P204; the alternating electromagnetic field assisted impurity removal can effectively improve the particle size of the precipitate and the solid-liquid separation efficiency, and reduce the penetration rate; the linkage optimized extraction for calcium removal avoids the environmental hazards of calcium removal by fluorine compound precipitation. The application has the characteristics of high Mn recovery rate, high waste liquid comprehensive utilization rate and low treatment cost, realizes the high-value recovery of Cu, Mn and other components, and realizes the green recycling of process pollutants such as NaOH solution and HCl solution, and is easy to popularize in industry.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of comprehensive recovery of nickel-cobalt hydrometallurgy wastewater, and particularly relates to a high-value recovery and recycling method for high-calcium manganese chloride wastewater in cobalt smelting. BACKGROUND

[0002] China is short of cobalt resources, and cobalt intermediates are usually prepared in countries such as the Democratic Republic of the Congo and then transported back to China for refining. Cobalt intermediates are generally purified through steps such as dilute sulfuric acid leaching, pre-removal of iron and aluminum, filtration, and extraction separation. Extraction separation is a cobalt purification process, and P204 is usually used to extract Mn, Cu, Zn, Al, Ca and other impurity metals in the leaching solution. In order to reuse the P204 organic phase loaded with impurity metals, sulfuric acid is usually used for stripping to make the impurity metals in the organic phase enter the aqueous phase, and the aqueous phase is the stripping solution. However, because the stripping solution contains a certain amount of Ca element combined with sulfate, calcium sulfate precipitate is easily generated. After long-term operation of the equipment, the calcium sulfate precipitate will gradually block the pipeline, which is not conducive to continuous production.

[0003] The conventional stripping solution treatment method is to add liquid alkali or lime to precipitate heavy metals, and then filter and reuse the filtrate. The heavy metal precipitate has low economic value and is difficult to dispose as solid waste. The heavy metal precipitate usually contains a large amount of Mn and Ca, and a small amount of Cu and Zn, which are not reasonably utilized.

[0004] In order to obtain high-purity manganese sulfate solution, the industry generally uses fluoride precipitation method to remove calcium and magnesium in the solution, but this method has problems such as generation of fluorine-containing waste residue and wastewater, and corrosion of equipment.

[0005] Chinese Patent CN112626337B discloses a treatment process for cobalt-containing copper raffinate and a treatment process for copper-cobalt ore. After pre-leaching the copper-cobalt ore, the pre-leaching solution is used as washing water for the copper-cobalt ore leaching residue. After washing, the solution is subjected to copper extraction, and then copper, zinc, cobalt, iron and manganese ions are precipitated. The precipitated solution is used to pre-leach the copper-cobalt ore again, and the process is repeated. The precipitate is leached with sulfuric acid to separate manganese, iron and cobalt in steps. The leached cobalt-rich solution is used to produce crude cobalt hydroxide or refined cobalt sulfate and other cobalt salts. The remaining precipitate is rich in copper and can be sold or further processed. In the invention, H2S gas is used to precipitate copper, zinc, cobalt, iron and manganese ions from the copper raffinate; the precipitated solution is returned to the pre-leaching of the copper-cobalt ore; and the precipitate is leached with sulfuric acid to separate valuable metals. This process easily generates a large amount of toxic H2S gas, which requires high sealing performance of the equipment and has obvious safety hazards. SUMMARY

[0006] (1) Technical problems to be solved

[0007] In view of the deficiencies of the prior art, the purpose of the present application is to provide a cobalt smelting high-calcium manganese chloride wastewater high-value recovery and recycling method, which aims to solve the problems of high waste liquid recovery and treatment cost, poor recovery effect and other industry problems, and has the characteristics of high waste liquid utilization rate, low treatment cost, high auxiliary material recycling rate and the like, and has economic and environmental double benefits.

[0008] (2) Technical scheme

[0009] In order to solve the above technical problems, the present application provides a cobalt smelting high-calcium manganese chloride wastewater high-value recovery and recycling method, and the specific steps are as follows:

[0010] (A) P204 hydrochloric acid instead of sulfuric acid stripping: the P204 loaded organic phase of the cobalt purification line contains Ca, Mn, Cu, Zn, Al, Co and other impurity elements; in order to recycle the organic phase, under the condition of 30℃-50℃, a certain concentration of hydrochloric acid is used for stripping, so that Ca, Mn, Cu, Zn, Al, Co and other elements in the organic phase enter the aqueous phase, and the aqueous phase is the stripping solution; using hydrochloric acid instead of sulfuric acid as a stripping agent solves the problem of CaSO4 fouling during sulfuric acid stripping;

[0011] (B) Electromagnetic field assisted impurity removal: the stripping solution obtained in step (A) is subjected to the action of an alternating electromagnetic field with a certain frequency, Na2S2O3 is added, and NaOH or / and Na2CO3 is added, and stirring is carried out at a speed of 60r / min-300r / min for a period of time, and copper sulfide residue, zinc aluminum residue and impurity-removed liquid are obtained by filtration separation; the specific steps are as follows:

[0012] (B-1) Copper removal: turn on the alternating electromagnetic field, add 0.95-1.0 times the theoretical amount of sodium thiosulfate, stir for 1h-2h, and then perform solid-liquid separation, the solid phase is copper sulfide residue with a purity of more than 98%, which is directly sold, and the liquid phase is copper-removed liquid;

[0013] (B-2) Aluminum removal: turn on the alternating electromagnetic field, heat the copper-removed liquid to 85℃-95℃, slowly add an appropriate amount of NaOH or / and Na2CO3, adjust the pH to 4.5-5.5, stir in the reaction tank for 2h-8h, precipitate aluminum ions as aluminum hydroxide, and the Al content in the solution is required to be less than 5mg / L;

[0014] (B-3) Zinc removal: add an appropriate amount of sodium thiosulfate solution or solid and stir for 2h-4h, and the Zn 2+ , a small amount of Cu 2+ , Co 2+Convert into zinc sulfide, copper sulfide, cobalt sulfide, and require Cu, Zn, Co content less than 1 mg / L, and then solid-liquid separation; solid phase is zinc aluminum slag, mainly zinc sulfide and aluminum hydroxide, containing a small amount of copper sulfide, manganese sulfide and cobalt sulfide, and is directly sold; the liquid phase is the impurity-removed liquid, mainly composed of MnCl2, NaCl and CaCl2;

[0015] (C) Cy272 linkage optimization extraction: the impurity-removed liquid obtained in step (B) is subjected to Cy272 linkage optimization extraction to obtain battery-grade MnSO4 solution, CaCl2 solution and NaCl solution;

[0016] Cy272 linkage optimization extraction includes the following steps:

[0017] (C-1) pH adjustment: HCl solution is added to the impurity-removed liquid obtained in step (B) to adjust the pH to 2.8-3.7 to obtain a separation feed liquid (Na / Ca / Mn);

[0018] (C-2) Sodium soap: the Cy272 blank organic phase (volume composition: 25%-30% Cy272, the rest being sulfonated kerosene) is saponified with NaOH solution (obtained from step E) to obtain a negative sodium organic phase;

[0019] (C-3) Optimization extraction: the separation feed liquid (Na / Ca / Mn) obtained in (C-1) and part of the aqueous phase obtained in (C-4-2) Ca / Mn separation section are combined as the aqueous phase, and part of the negative Ca organic phase obtained in the Na / Ca separation section in (C-4) linkage extraction is subjected to countercurrent extraction, all Mn 2+ , 20%-80% of Ca 2+ enter the organic phase, and the Na content is less than 1 mg / L, i.e. to obtain an organic phase free of Na; the remaining Ca 2+ and all Na + stay in the aqueous phase, and the Mn content is less than 1 mg / L, i.e. to obtain an aqueous phase free of Mn;

[0020] Note: Optimization extraction refers specifically to the Ca 2+ which does not need to be fixed and can be varied within a large range, which can effectively reduce process control links and detection costs;

[0021] (C-4) Linkage extraction: divided into Na / Ca separation section and Ca / Mn separation section;

[0022] (C-4-1) Na / Ca separation section: the aqueous phase free of Mn obtained in (C-3) optimization extraction and part of the aqueous phase of the Ca / Mn separation section in (C-4-2) are combined as the aqueous phase of the Na / Ca separation section, and the negative sodium organic phase obtained in (C-2) sodium soap is subjected to countercurrent extraction to realize Na / Ca separation;

[0023] As the water phase containing the easily extracted component Ca flows forward and is mixed with the organic phase containing the difficultly extracted component Na, an exchange reaction occurs: Na (organic phase) + Ca (water phase) = Ca (organic phase) + Na (water phase), the Ca component in the water phase exchanges the Na component in the organic phase to the water phase, and is carried to the water phase outlet along the flow direction of the water phase, and is discharged as a high-purity NaCl solution; the Ca component exchanged into the organic phase forms a negative Ca organic phase, part of which is used as the organic phase for optimized extraction (C-3), and the other part is used as the organic phase for the Ca / Mn separation section (C-4-2), and the specific proportion is determined according to the calculation results;

[0024] (C-4-2) Ca / Mn separation section: the organic phase obtained from the optimized extraction (C-3) and the part of the negative Ca organic phase obtained from the Na / Ca separation section (C-4-1) are combined as the organic phase for the Ca / Mn separation section, and are countercurrently extracted with the water phase obtained from the stripping I (C-5), and the Ca / Mn separation is performed;

[0025] As the water phase containing the easily extracted component Mn flows forward and is mixed with the organic phase containing the difficultly extracted component Ca, an exchange reaction occurs: Ca (organic phase) + Mn (water phase) = Mn (organic phase) + Ca (water phase), the Ca component in the organic phase is exchanged by the Mn component in the water phase to the water phase, and is carried to the water phase outlet along the flow direction of the water phase, and is discharged as a high-purity CaCl2 solution; the other part of the water phase enters the optimized extraction (C-3), and the specific proportion is determined according to the calculation results; the Mn component exchanged into the organic phase forms a negative Mn organic phase, and flows to the organic phase outlet;

[0026] (C-5) Stripping I: the negative Mn organic phase obtained at the outlet of the organic phase of the Ca / Mn separation section (C-4-2) is stripped with a certain concentration of HCl, a small amount of Ca and Mn in the organic phase is stripped into the water phase, and a high-purity negative Mn organic phase is obtained; the water phase enters the Ca / Mn separation section (C-4-2);

[0027] (C-6) Stripping II: after the high-purity negative Mn organic phase obtained from the stripping I (C-5) is stripped with a certain concentration of H2SO4, a high-purity MnSO4 solution and a blank organic phase are obtained, and the blank organic phase is returned to the sodium soap process (C-2);

[0028] In the above optimized extraction and linked extraction process, because the separation coefficients of Cy272 for Na / Mn, Na / Ca and Ca / Mn are all large, a few stages can achieve good separation effect;

[0029] The above high-purity MnSO4 solution, high-purity CaCl2 solution and high-purity NaCl solution refer to that the content of the remaining impurity elements in the solution is lower than 1 mg / L, except for the substance and water;

[0030] (D) Crystallization and drying: The high-purity CaCl2 solution obtained in the Ca / Mn separation section of step (C-4-2) is evaporated and crystallized, and dried at 120°C to 150°C for 2h to 4h to obtain the calcium chloride product, which is directly sold;

[0031] The high-purity MnSO4 solution obtained in step (C-6) of stripping II is evaporated and crystallized, filtered while hot, and dried at 75°C to 85°C for 2h to 4h to obtain a high-purity manganese sulfate product that meets the requirements of first-class manganese sulfate for battery use;

[0032] (E) NaCl solution membrane electrolysis and synthesis: The high-purity NaCl solution obtained in the Na / Ca separation section of step (C-4-1) is subjected to chelating resin to remove calcium and magnesium to below 0.02 mg / L, and then concentrated by evaporation to a NaCl content of 300 g / L to 320 g / L. Then, ion-exchange membrane electrolysis is performed to obtain a NaOH solution, Cl2 (anode), and H2 (cathode). Finally, Cl2 and H2 are reacted in a synthesis tower to produce HCl gas, which is dissolved in water to obtain an HCl solution. The obtained NaOH solution and HCl solution can be recycled. The NaOH solution can be reused in the sodium soap step (C-2) and the aluminum removal step (B-2) of electromagnetic field-assisted impurity removal. The HCl solution can be reused in the P204 hydrochloric acid-substituted sulfuric acid stripping step (A) and can also be used in the stripping step (C-5).

[0033] Preferably, during the hydrochloric acid stripping in step (A), the hydrochloric acid concentration is 4 mol / L to 4.5 mol / L, and the temperature is 35° C. to 45° C.;

[0034] Preferably, step (B) uses an alternating electromagnetic field of 40kHz to 100kHz to assist in impurity removal;

[0035] Preferably, in step (B-3) zinc removal, the new ecological S generated by Na2S2O3 2- Can also be used with Mn 2+ The ions react with the side reaction to generate MnS. To reduce the occurrence of side reactions, the amount of Na2S2O3 added should be minimized. The amount of Na2S2O3 used is usually 1.1 to 1.5 times the theoretical amount.

[0036] Preferably, step (C-5) back extraction I is performed using 6 mol / L to 10 mol / L hydrochloric acid;

[0037] Preferably, in step (C-6) stripping II, 2 mol / to 2.5 mol / L sulfuric acid is used to strip the Mn-negative organic phase to obtain a high-purity MnSO4 solution with a Mn content of 120 g / L to 150 g / L.

[0038] In this technical solution, the chemical reaction principle involved is:

[0039] In step (A), the hydrochloric acid back extraction reaction is as follows:

[0040] R2-Me + 2HCl = MeCl2 + 2R-H

[0041] R-H refers to P204, and Me refers to Ca, Mn, Cu, Zn, Co, etc.

[0042] In step (B), when copper is removed, under the action of an alternating magnetic field, the generated precipitated particles are larger, which helps to reduce the penetration of small particles and improve the solid-liquid separation efficiency. The following reactions mainly occur in this step:

[0043] Na2S2O3 + H2O = Na2SO4 + H2S↑

[0044] CuSO4 + H2S = CuS↓ + H2SO4

[0045] H2S can provide new S 2- , S 2- In addition to the reaction with Cu 2+ , it can also co-precipitate with Mn 2+ , Zn 2+ , but because the solubility product of CuS is much smaller than that of ZnS and MnS, as long as the solution still contains Cu 2+ ions, it will undergo a displacement reaction with the generated ZnS and MnS to form CuS. Therefore, Cu 2+ can be selectively precipitated, achieving the effect of precise copper removal.

[0046] In step (B), during the removal of aluminum and zinc, the following reactions mainly occur:

[0047] When adjusting the pH with NaOH,

[0048] HCl + NaOH = H2O + NaCl

[0049] AlCl3 + 3NaOH = Al(OH)3↓ + 3NaCl

[0050] When adjusting the pH with Na2CO3,

[0051] 2HCl + Na2CO3 = 2NaCl + H2O + CO2↑

[0052] AlCl3 + 3H2O = Al(OH)3↓ + 3HCl

[0053] When removing zinc with sodium thiosulfate,

[0054] Na2S2O3 + H2O = Na2SO4 + H2S↑

[0055] H2S + MeCl2 = 2HCl + MeS↓, Me refers to Cu, Zn, Co, Mn

[0056] Wherein the generation of MnS is a side reaction, which reduces the recovery rate of Mn. Compared with using sodium sulfide as a removing agent, sodium thiosulfate can effectively reduce the occurrence of side reactions.

[0057] Step (C) linkage optimization extraction, mainly the following reactions occur:

[0058] (C-2) Sodium soap: NaOH + R-H = R-Na + H2O, R-H refers to Cy272

[0059] (C-3) Optimize extraction:

[0060] 2R-Na + MnCl2 = R2-Mn + 2NaCl

[0061] 2R-Na + CaCl2 = R2-Ca + 2NaCl

[0062] (C-5) Stripping I: R2-Ca + 2HCl = CaCl2 + 2R-H

[0063] R2-Mn + 2HCl = MnCl2 + 2R-H

[0064] (C-6) Stripping II: R2-Mn + H2SO4 = MnSO4 + 2R-H

[0065] In step (E), the following reactions occur during electrolysis:

[0066] Anode reaction: 2Cl - (Chloride ion) - 2e = Cl2↑ (chlorine)

[0067] Cathode reaction: 2H + (Hydrogen ion) + 2e = H2↑ (hydrogen)

[0068] Total electrolysis reaction: 2NaCl + 2H2O = 2NaOH + H2↑ + Cl2↑

[0069] Reaction during synthesis: H2 + Cl2 = 2HCl↑

[0070] Compared with the prior art, the beneficial effects of the present application are:

[0071] 1. The present application uses hydrochloric acid instead of sulfuric acid to strip the P204 loaded organic phase, solving the problem of calcium sulfate scaling produced during sulfuric acid stripping;

[0072] 2. The graded treatment of the present application effectively recovers copper, manganese, calcium, zinc, aluminum and other resources, and sodium hydroxide, hydrochloric acid and other auxiliary materials are recycled, saving the recovery and treatment cost of cobalt smelting wastewater;

[0073] 3. Compared with using Na2S, the application uses Na2S2O3 as a copper-zinc removing agent to significantly reduce the amount of MnS generated and improve the recovery rate of Mn, and the recovery rate of Mn is greater than 95%;

[0074] 4. The application uses an alternating electromagnetic field to assist in impurity removal, which can effectively improve the particle size of the precipitate and the solid-liquid separation efficiency, and reduce the penetration rate;

[0075] 5. The copper sulfide slag obtained by the application has a purity of greater than 98% and high value, and can be directly sold externally;

[0076] 6. The application uses Cy272 linkage optimization extraction technology to separate Na / Ca / Mn, compared with conventional calcium removal by fluorides, not only avoids the harm of fluorine-containing waste residues and waste water to the environment, but also reduces equipment corrosion;

[0077] 7. The application uses Cy272 linkage optimization extraction technology, which cleverly connects and connects multiple separation modules with certain separation functions, forms a linkage, and obtains three separation products with one process. Compared with traditional extraction separation technology, it is beneficial to extraction operation and process management control; reduces process links, charging costs (refers to the fact that because the extraction tank volume is smaller, the organic phase and raw materials are less accumulated, reducing inventory) and equipment investment; realizes the reuse of part of the extraction amount and the washing amount, thereby reducing acid and alkali consumption and production cost, and improving the processing capacity of the unit volume extraction tank.

[0078] 8. The battery-grade manganese sulfate obtained by the application has high purity and is particularly suitable for making manganese-containing lithium batteries.

[0079] In summary, the application realizes the high-value recovery of high-calcium manganese chloride wastewater containing cobalt, has the characteristics of full resource utilization, high recovery rate, low treatment cost, high auxiliary material recycling rate, realizes the high-value recovery of copper, manganese and other components, and has dual benefits of economy and environmental protection. BRIEF DESCRIPTION OF DRAWINGS

[0080] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only one embodiment of the present application, and those skilled in the art can obtain other drawings according to these drawings without creating any creative labor.

[0081] Figure 1 It is a schematic diagram of the overall process flow of embodiments 1-5 of the application;

[0082] Figure 2The schematic diagram of the extraction process of the step (C) of the Cy272 linkage optimization in the embodiments 1-5 of the present application is shown in the figure.

[0083] Figure 3 The schematic diagram of the extraction process of the step (C) of the Cy272 traditional extraction separation process in the comparative example 8 of the present application is shown in the figure. DETAILED DESCRIPTION

[0084] In order to make the technical means, creative features, purposes and effects of the present application easy to understand, the technical solutions in the specific embodiments of the present application are described clearly and completely below to further illustrate the present application. Obviously, the described specific embodiments are only a part of the embodiments of the present application, not all.

[0085] Embodiment 1

[0086] As shown in the figure, the steps and processes of the present specific embodiment are as follows: Figures 1-2

[0087] (A) P204 hydrochloric acid displacement sulfuric acid stripping: the P204 loaded organic phase of the cobalt purification line contains Ca, Mn, Cu, Zn, Al, Co and other impurity elements; in order to recycle the organic phase, hydrochloric acid is used for stripping, so that Ca, Mn, Cu, Zn, Al and other elements in the organic phase enter the aqueous phase, and the aqueous phase is the stripping solution; when the hydrochloric acid stripping is performed, the temperature is 40℃, and the concentration of the hydrochloric acid is 4 mol / L; the composition (g / L) of the stripping solution is as follows: Ca 6.0, Mn 30.5, Cu 0.6, Zn 0.9, Al 0.06, and Co 0.2.

[0088] (B) Electromagnetic field assisted impurity removal: the stripping solution obtained in the step (A) is subjected to stirring under the action of an alternating electromagnetic field with a frequency of 60 kHz, Na2S2O3 and NaOH or / and Na2CO3 are added, and stirring is performed at a speed of 120 r / min for a period of time, and then filtration separation is performed to obtain copper sulfide residue, zinc aluminum residue and impurity-removed solution; the specific steps are as follows:

[0089] (B-1) Copper removal: the alternating electromagnetic field is turned on, 1.0 times of the theoretical amount of sodium thiosulfate is added, and after stirring for 1 h, solid-liquid separation is performed, the solid phase is copper sulfide residue with a purity of more than 98%, and is directly sold; and the liquid phase is the copper-removed solution;

[0090] (B-2) Aluminum removal: the alternating electromagnetic field is turned on, the copper-removed solution is heated to 85℃-95℃, an appropriate amount of NaOH or / and Na2CO3 is slowly added, the pH is adjusted to 4.5-5.5, and stirring is performed in the reaction tank for 4 h, so that the aluminum ions are precipitated as aluminum hydroxide, and the Al content in the solution is required to be less than 5 mg / L;

[0091] (B-3) Zinc removal: 1.1 times of the theoretical amount of sodium thiosulfate solution is added and stirred for 3 h, and the Zn 2+ ​, the rest of the small amount of Cu 2+ , Co 2+ Convert to zinc sulfide, copper sulfide, cobalt sulfide, and require Cu, Zn, Co content less than 1 mg / L, and then solid-liquid separation; solid phase is zinc aluminum slag, mainly zinc sulfide, aluminum hydroxide, containing a small amount of copper sulfide, manganese sulfide and cobalt sulfide, and is directly sold; the liquid phase is the impurity-removed liquid, mainly composed of MnCl2, NaCl and CaCl2;

[0092] (C) Cy272 linkage optimization extraction: the impurity-removed liquid obtained in step (B) is subjected to Cy272 linkage optimization extraction to obtain battery-grade MnSO4 solution, CaCl2 solution and NaCl solution;

[0093] Cy272 linkage optimization extraction includes the following steps:

[0094] (C-1) pH adjustment: add HCl solution to the impurity-removed liquid obtained in step (B) to adjust the pH to 3.2 to obtain a separation feed liquid (Na / Ca / Mn);

[0095] (C-2) Sodium soap: the Cy272 blank organic phase (volume composition: 25%-30% Cy272, the rest is sulfonated kerosene) is saponified with NaOH solution (which can be obtained from step E) to obtain a negative sodium organic phase;

[0096] (C-3) Optimization extraction: the separation feed liquid (Na / Ca / Mn) obtained in (C-1) and part of the aqueous phase obtained in (C-4-2) Ca / Mn separation section are combined as the aqueous phase, and part of the negative Ca organic phase obtained in the Na / Ca separation section in (C-4) linkage extraction is subjected to countercurrent extraction, all Mn 2+ , 20%-80% of Ca 2+ into the organic phase, and the Na content is less than 1 mg / L, that is, the organic phase without Na is obtained; the rest of the Ca 2+ and all Na + are left in the aqueous phase, and the Mn content is less than 1 mg / L, that is, the aqueous phase without Mn is obtained;

[0097] (C-4) Linkage extraction: divided into Na / Ca separation section and Ca / Mn separation section;

[0098] (C-4-1) Na / Ca separation section: the aqueous phase without Mn obtained in (C-3) optimization extraction and part of the aqueous phase of (C-4-2) Ca / Mn separation section are combined as the aqueous phase of the Na / Ca separation section, and the negative sodium organic phase obtained in (C-2) sodium soap is subjected to countercurrent extraction to realize Na / Ca separation;

[0099] As the water phase containing the easily extracted component Ca flows forward and is mixed with the organic phase containing the difficultly extracted component Na, an exchange reaction occurs: Na (organic phase) + Ca (water phase) = Ca (organic phase) + Na (water phase), the Ca component in the water phase exchanges the Na component in the organic phase to the water phase, and is carried to the water phase outlet along the flow direction of the water phase, and is discharged as a high-purity NaCl solution; the Ca component exchanges to the negative Ca organic phase, and part of the negative Ca organic phase is used as the organic phase for optimized extraction (C-3), and the other part is used as the organic phase for the Ca / Mn separation section (C-4-2), and the specific proportion is determined according to the calculation results;

[0100] The Ca / Mn separation section (C-4-2): the organic phase obtained by the optimized extraction (C-3) and part of the negative Ca organic phase obtained by the Na / Ca separation section (C-4-1) are combined as the organic phase for the Ca / Mn separation section, and are countercurrently extracted with the water phase obtained by the stripping I (C-5), and Ca / Mn separation is performed;

[0101] As the water phase containing the easily extracted component Mn flows forward and is mixed with the organic phase containing the difficultly extracted component Ca, an exchange reaction occurs: Ca (organic phase) + Mn (water phase) = Mn (organic phase) + Ca (water phase), the Ca component in the organic phase is exchanged by the Mn component in the water phase to the water phase, and is carried to the water phase outlet along the flow direction of the water phase, and is discharged as a high-purity CaCl2 solution; the other part of the water phase enters the optimized extraction (C-3), and the specific proportion is determined according to the calculation results; the Mn component exchanges to the negative Mn organic phase, and flows to the organic phase outlet;

[0102] The stripping I (C-5): the negative Mn organic phase obtained at the organic phase outlet of the Ca / Mn separation section (C-4-2) is stripped by using 6 mol / L of HCl, a small amount of Ca and the Mn in the organic phase are stripped into the water phase, and a high-purity negative Mn organic phase is obtained; the water phase enters the Ca / Mn separation section (C-4-2);

[0103] The stripping II (C-6): after the high-purity negative Mn organic phase obtained by the stripping I (C-5) is stripped by 2 mol / L of H2SO4, a high-purity MnSO4 solution and a blank organic phase are obtained, and the blank organic phase is returned to the sodium soap process (C-2);

[0104] In the above-mentioned optimized extraction and linked extraction process, because the separation coefficients of Cy272 for Na / Mn, Na / Ca and Ca / Mn are all large, a few stages can achieve good separation effect;

[0105] The above-mentioned high-purity MnSO4 solution, high-purity CaCl2 solution and high-purity NaCl solution refer to that the content of the remaining impurity elements in the solution is lower than 1 mg / L except the substance and water;

[0106] (D) crystallization, drying: evaporate the high-purity CaCl2 solution obtained from the Ca / Mn separation section of step (C-4-2) to crystallize, dry at 120-150°C for 2-4h to obtain the calcium chloride product, which is directly sold; evaporate the high-purity MnSO4 solution obtained from the back extraction II of step (C-6) to crystallize, filter while hot, dry at 75-85°C for 2-4h to obtain the high-purity manganese sulfate product, which meets the requirements of the first-grade manganese sulfate for batteries;

[0107] (E) NaCl solution membrane electrolysis, synthesis: the high-purity NaCl solution with less than 1 mg / L of Ca, Mg and other impurities obtained from the Na / Ca separation section of step (C-4-1) is treated with chelating resin to remove Ca and Mg to less than 0.02 mg / L, then concentrated by evaporation to a NaCl content of 300-320 g / L, followed by ion membrane electrolysis to obtain NaOH solution, Cl2(anode) and H2(cathode), finally Cl2 and H2 are used to prepare HCl in a synthesis tower, which is dissolved in water to obtain HCl solution; the NaOH solution and HCl solution can be recycled for use, the NaOH solution can be recycled for use in the sodium soap process of step (C-2) and also in the aluminum removal process assisted by electromagnetic field of step (B); the HCl solution can be recycled for use in the P204 hydrochloric acid displacement of sulfuric acid back extraction process of step (A) and also in the back extraction I process of (C-5).

[0108] The main implementation results of this example are shown in Table 1, and the consumption of auxiliary materials for extraction is shown in Table 2.

[0109] Example 2

[0110] This example is implemented on the basis of Example 1 by adjusting the following process parameters, and the steps and process parameters not specifically mentioned are consistent with those of Example 1:

[0111] In the P204 hydrochloric acid displacement of sulfuric acid back extraction of step (A), the temperature is controlled at 40°C; the concentration of hydrochloric acid is 4.2 mol / L;

[0112] In the electromagnetic field assisted impurity removal of step (B), the frequency of the electromagnetic field is 40 kHz; the stirring speed is 60 r / min;

[0113] In the copper removal of step (B-1), the amount of sodium thiosulfate is 0.95 times the theoretical amount; the stirring time is 1h;

[0114] In the aluminum removal of step (B-2), the stirring time is 2h;

[0115] In the zinc removal of step (B-3), the amount of sodium thiosulfate is 1.2 times the theoretical amount; the stirring time is 3.5h;

[0116] In the pH adjustment of step (C-1), the pH is adjusted to 2.8;

[0117] In step (C-5) back extraction I, the concentration of hydrochloric acid used is 7 mol / L;

[0118] In step (C-6) back extraction II, the concentration of sulfuric acid used is 2.1 mol / L;

[0119] In step (D) crystallization and drying, the drying temperature of calcium chloride dihydrate is 120°C; the drying temperature of manganese sulfate monohydrate is 75°C.

[0120] The main implementation results of this example are shown in Table 1.

[0121] Example 3

[0122] This example is implemented on the basis of Example 1 by adjusting the following process parameters, and the steps and process parameters not specifically mentioned are consistent with those of Example 1:

[0123] In step (A) P204 hydrochloric acid substitution sulfuric acid back extraction, the temperature is controlled at 30°C; the concentration of hydrochloric acid is 4.3 mol / L;

[0124] In step (B) electromagnetic field assisted impurity removal, the electromagnetic field frequency is 60 kHz; the stirring speed is 150 r / min;

[0125] In step (B-1) copper removal, the amount of sodium thiosulfate used is 0.98 times the theoretical amount; the stirring time is 2 h;

[0126] In step (B-2) aluminum removal, the stirring time is 8 h;

[0127] In step (B-3) zinc removal, the amount of sodium thiosulfate used is 1.3 times the theoretical amount; the stirring time is 4 h;

[0128] In step (C-1) pH adjustment, the pH is adjusted to 3.0;

[0129] In step (C-5) back extraction I, the concentration of hydrochloric acid used is 8 mol / L;

[0130] In step (C-6) back extraction II, the concentration of sulfuric acid used is 2.5 mol / L;

[0131] In step (D) crystallization and drying, the drying temperature of calcium chloride dihydrate is 130°C; the drying temperature of manganese sulfate monohydrate is 80°C.

[0132] The main implementation results of this example are shown in Table 1.

[0133] Example 4

[0134] This example is implemented on the basis of Example 1 by adjusting the following process parameters, and the steps and process parameters not specifically mentioned are consistent with those of Example 1:

[0135] In step (A) P204 hydrochloric acid instead of sulfuric acid stripping, the temperature is controlled at 35℃; the concentration of hydrochloric acid is 4.5 mol / L;

[0136] In step (B) electromagnetic field assisted impurity removal, the frequency of electromagnetic field is 80 kHz; the stirring speed is 200 r / min;

[0137] In step (B-1) copper removal, the amount of sodium thiosulfate is 0.99 times of the theoretical amount; the stirring time is 1.5 h;

[0138] In step (B-2) aluminum removal, the stirring time is 6 h;

[0139] In step (B-3) zinc removal, the amount of sodium thiosulfate is 1.4 times of the theoretical amount; the stirring time is 2.5 h;

[0140] In step (C-1) pH adjustment, the pH is adjusted to 3.5;

[0141] In step (C-5) stripping I, the concentration of hydrochloric acid used is 10 mol / L;

[0142] In step (C-6) stripping II, the concentration of sulfuric acid used is 2.2 mol / L;

[0143] In step (D) crystallization and drying, the drying temperature of calcium chloride dihydrate is 140℃; the drying temperature of manganese sulfate monohydrate is 85℃.

[0144] The main implementation results of this example are shown in Table 1.

[0145] Example 5

[0146] This example is implemented on the basis of Example 1 by adjusting the following process parameters, and the steps and process parameters not specifically mentioned are consistent with those of Example 1:

[0147] In step (A) P204 hydrochloric acid instead of sulfuric acid stripping, the temperature is controlled at 50℃; the concentration of hydrochloric acid is 4.5 mol / L;

[0148] In step (B) electromagnetic field assisted impurity removal, the frequency of electromagnetic field is 100 kHz; the stirring speed is 300 r / min;

[0149] In step (B-1) copper removal, the amount of sodium thiosulfate is 1.0 times of the theoretical amount; the stirring time is 2 h;

[0150] In step (B-2) aluminum removal, the stirring time is 4 h;

[0151] In step (B-3) zinc removal, the amount of sodium thiosulfate is 1.5 times of the theoretical amount; the stirring time is 2 h;

[0152] In step (C-1) pH adjustment, the pH is adjusted to 3.7;

[0153] In step (C-5), the concentration of hydrochloric acid used is 9 mol / L;

[0154] In step (C-6), the concentration of sulfuric acid used is 2 mol / L;

[0155] In step (D), the drying temperature of calcium chloride dihydrate is 130°C and the drying temperature of manganese sulfate monohydrate is 80°C.

[0156] The main results of this example are shown in Table 1.

[0157] Comparative Example 6

[0158] This comparative example was carried out on the basis of Example 1, with the removal of the electromagnetic field, and using sodium sulfide instead of sodium thiosulfate in the removal of copper, and adjusting the process parameters as follows. The other steps and process parameters not specifically mentioned were the same as in Example 1.

[0159] In step (A), the temperature control was 40°C and the concentration of hydrochloric acid was 4 mol / L.

[0160] In step (B), the stirring speed was 120 r / min.

[0161] In step (B-1), the amount of sodium sulfide used was 1 times the theoretical amount and the stirring time was 1 h.

[0162] In step (B-2), the stirring time was 4 h.

[0163] In step (B-3), the amount of sodium thiosulfate used was 1.1 times the theoretical amount and the stirring time was 3 h.

[0164] The main results of this comparative example are shown in Table 1.

[0165] Comparative Example 7

[0166] This comparative example was carried out on the basis of Example 1, with the removal of the electromagnetic field, and adjusting the process parameters as follows. The other steps and process parameters not specifically mentioned were the same as in Example 1.

[0167] In step (A), the temperature control was 40°C and the concentration of hydrochloric acid was 4 mol / L.

[0168] In step (B), the stirring speed was 120 r / min.

[0169] In step (B-1), the amount of sodium thiosulfate used was 1.0 times the theoretical amount and the stirring time was 1 h.

[0170] In step (B-2) for removing aluminum, the stirring time was 4 h.

[0171] In step (B-3) for removing zinc, the amount of sodium thiosulfate was 1.1 times the theoretical amount, and the stirring time was 3 h.

[0172] The main implementation results of the present comparative example are shown in Table 1.

[0173] Comparative Example 8

[0174] The present comparative example is based on Example 1, and uses the traditional Cy272 extraction separation technology in the separation of Na / Ca / Mn. The specific process flow is shown in Figure 3 It can be seen from Figure 3 that the traditional Cy272 extraction separation separates Mn first, and then separates Ca and Na; there are four small steps of saponification, extraction, washing, and stripping in the separation of Mn or the separation of Ca and Na; there are three HCl inlets, one H2SO4 inlet, and two NaOH inlets, and the consumption of acid and alkali is large.

[0175] The main implementation results of the present comparative example are shown in Table 1, and the consumption of auxiliary materials for extraction is shown in Table 2.

[0176] Table 1 Main implementation results table

[0177]

[0178] Table 2 Comparison of auxiliary material consumption per mole of Mn for different extraction processes (unit: mol / mol)

[0179] Adjuvants Comparative Example 8 Example 1 Savings NaOH 3.31 2.61 21.26％ HCl 0.79 0.65 17.45％ Sulfuric acid 1.3 1.29 0.42％ Total 5.40 4.55 15.70％

[0180] According to the data in Table 1, it can be seen from the comparison of Example 1 and Comparative Example 6 that after using sodium thiosulfate instead of sodium sulfide, the purity of copper sulfide slag is increased from 93.3% to 98.4%, and the recovery rate of Mn is increased from 90.3% to 95.6%. It can be seen from the comparison of Examples 1-5 and Comparative Examples 6-7 that after using electromagnetic field assisted impurity removal, the filtration time of copper slag and zinc aluminum slag is reduced by 40%-50%, which significantly improves the filtration efficiency.

[0181] According to the data in Table 1 and Table 2, comparing Example 1 and Comparative Example 8, compared with the traditional Cy272 traditional extraction separation process, the product quality of the Cy272 linkage optimization extraction process of the application is basically unchanged, but the acid and alkali consumption is saved by 15.7%. At the same time, the Cy272 linkage optimization extraction technology of the application cleverly connects multiple separation modules with certain separation function in parallel and series to form linkage, which is beneficial to extraction operation and process management control, reduces process links and equipment investment, reduces acid and alkali consumption and production cost, improves the processing capacity of unit volume extraction tank, and obtains multiple separation products with one process. Compared with the traditional Cy272 extraction separation technology, it has obvious advantages.

[0182] It can be known from Table 1 that the copper sulfide residue obtained by the technology has a high grade and can be sold at a high price. The monohydrate manganese sulfate product obtained by the technology meets the requirements of first-class battery manganese sulfate. The dihydrate calcium chloride product obtained by the technology has a CaCl2 content of more than 74%, meeting the requirements of industrial calcium chloride type II, and realizing the high-value recycling of Cu, Mn, Ca and other components in the waste liquid.

[0183] The above describes the main technical features, basic principles and related advantages of the application. For those skilled in the art, it is obvious that the application is not limited to the details of the above exemplary embodiments, and the application can be implemented in other specific forms without departing from the concept or basic features of the application. Therefore, no matter from which point of view, the above-mentioned specific embodiments should be regarded as exemplary and non-limiting, the scope of the application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the application.

[0184] In addition, although the present specification is described according to each embodiment, not every embodiment contains only one independent technical solution, and the description manner of the specification is only for the sake of clarity, those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A method for high-value recovery and recycling of high-calcium manganese chloride wastewater from cobalt smelting, characterized in that: The specific steps are: (A) P204 loaded organic phase back extraction: The organic phase loaded on the cobalt purification line P204 contains Ca, Mn, Cu, Zn, Al, and Co impurity elements. At 30°C to 50°C, a certain concentration of hydrochloric acid is used instead of sulfuric acid for back extraction, so that the Ca, Mn, Cu, Zn, Al, and Co elements in the organic phase enter the aqueous phase, and the aqueous phase is the back extraction liquid; (B) Electromagnetic field-assisted impurity removal: The stripping solution obtained in step (A) is subjected to an alternating electromagnetic field of 40 kHz to 100 kHz, and Na2S2O3 and NaOH and / or Na2CO3 are added thereto. The solution is stirred at a speed of 60 rpm to 300 rpm for a period of time, and filtered to separate the copper sulfide slag, the zinc-aluminum slag, and the impurity-removed solution. The specific steps are as follows: (B-1) Copper removal: Turn on the alternating electromagnetic field, add 0.95 to 1.0 times the theoretical amount of sodium thiosulfate, stir for 1 to 2 hours, and then perform solid-liquid separation. The solid phase is copper sulfide slag with a purity greater than 98%, and the liquid phase is the copper-removed liquid; (B-2) Aluminum removal: Turn on the alternating electromagnetic field and heat the copper-removed solution to 85°C to 95°C. Slowly add an appropriate amount of NaOH and / or Na2CO3 to adjust the pH to 4.5 to 5.

5. Stir in the reaction tank for 2 to 8 hours to precipitate aluminum ions into aluminum hydroxide. The Al content in the solution must be less than 5 mg / L. (B-3) Zinc removal: Add appropriate amount of sodium thiosulfate solution or solid and stir for 2h~4h to remove Zn 2+ 、The remaining small amount of Cu 2+ 、Co 2+ Converted into zinc sulfide, copper sulfide, and cobalt sulfide, requiring the content of Cu, Zn, and Co to be less than 1 mg / L, and then undergoing solid-liquid separation; the solid phase is zinc-aluminum slag, mainly composed of zinc sulfide and aluminum hydroxide, with a small amount of copper sulfide, manganese sulfide, and cobalt sulfide; the liquid phase is the impurity-removed liquid, the main components of which are MnCl2, NaCl, and CaCl2; (C) Cy272-linked optimized extraction: The impurity-removed solution obtained in step (B) is subjected to Cy272-linked optimized extraction to obtain battery-grade MnSO4 solution, CaCl2 solution, and NaCl solution; The Cy272-linked optimized extraction includes the following steps: (C-1) pH adjustment: adding HCl solution to the impurity-removed solution obtained in step (B) to adjust the pH to 2.8-3.7, thereby obtaining a solution to be separated (Na / Ca / Mn); (C-2) Sodium soap: The Cy272 blank organic phase was saponified with NaOH solution to obtain a negative sodium organic phase; (C-3) Optimized extraction: The liquid to be separated (Na / Ca / Mn) obtained in (C-1) and part of the aqueous phase obtained in the Ca / Mn separation section of (C-4-2) are combined as the aqueous phase and subjected to countercurrent extraction with part of the negative Ca organic phase obtained in the Na / Ca separation section of the linkage extraction (C-4-1). All Mn 2+ , 20% to 80% Ca 2+ Entering the organic phase, and the Na content is less than 1 mg / L, that is, the organic phase without Na is obtained; the remaining Ca 2+ and all Na + Remain in the aqueous phase, and the Mn content is less than 1 mg / L, that is, a Mn-free aqueous phase is obtained; (C-4) Linked extraction: divided into Na / Ca separation section and Ca / Mn separation section; (C-4-1) Na / Ca separation section: The Mn-free aqueous phase obtained by the optimized extraction (C-3) and part of the aqueous phase from the Ca / Mn separation section (C-4-2) are combined as the aqueous phase for the Na / Ca separation section, and subjected to countercurrent extraction with the sodium-negative organic phase obtained by the sodium soap (C-2) to achieve Na / Ca separation; As the aqueous phase containing the easily extractable component Ca flows forward, it mixes and contacts with the organic phase containing the difficult-to-extract component Na, and an exchange reaction occurs: Na(organic phase) + Ca(aqueous phase) = Ca(organic phase) + Na(aqueous phase). The Ca component in the aqueous phase exchanges the Na component in the organic phase with the aqueous phase, which is carried to the aqueous phase outlet along the flow direction of the aqueous phase and discharged as a high-purity NaCl solution. The negative Ca organic phase formed by the exchange of the Ca component in the organic phase serves as the organic phase for the optimized extraction (C-3) and the organic phase for the Ca / Mn separation section (C-4-2). (C-4-2) Ca / Mn separation section: The Na-free organic phase obtained from the optimized extraction (C-3) and the partially Ca-negative organic phase obtained from the Na / Ca separation section (C-4-1) are combined as the organic phase for the Ca / Mn separation section and countercurrently extracted with the aqueous phase obtained from back extraction I (C-5) for Ca / Mn separation. As the aqueous phase containing the easily extractable component Mn flows forward, it mixes and contacts with the organic phase containing the difficult-to-extract component Ca, and an exchange reaction occurs: Ca(organic phase) + Mn(aqueous phase) = Mn(organic phase) + Ca(aqueous phase). The Ca component in the organic phase is exchanged with the Mn component in the aqueous phase into the aqueous phase, and is carried to the aqueous phase outlet along the flow direction of the aqueous phase and discharged as a high-purity CaCl2 solution. Another part of the aqueous phase enters (C-3) for optimized extraction, and the Mn component is exchanged with the organic phase to form a negative Mn organic phase, which flows to the organic phase outlet. (C-5) Stripping I: The Mn-negative organic phase obtained at the organic phase outlet of the (C-4-2) Ca / Mn separation section is stripped with a certain concentration of HCl to strip a small amount of Ca and Mn in the organic phase into the aqueous phase to obtain a high-purity Mn-negative organic phase; the aqueous phase then enters the (C-4-2) Ca / Mn separation section; (C-6) Stripping II: The high-purity negative Mn organic phase obtained in stripping I (C-5) is stripped with a certain concentration of H2SO4 to obtain a high-purity MnSO4 solution and a blank organic phase. The blank organic phase is reused in the sodium soap step (C-2). The above-mentioned high-purity MnSO4 solution, high-purity CaCl2 solution and high-purity NaCl solution refer to solutions in which the content of other impurities, excluding the substance and water, is less than 1 mg / L; (D) Crystallization and Drying: The high-purity CaCl2 solution obtained in the Ca / Mn separation section of step (C-4-2) is subjected to evaporative crystallization and dried at 120°C to 150°C for 2h to 4h to obtain a calcium chloride product; The high-purity MnSO4 solution obtained in step (C-6) of stripping II is evaporated and crystallized, filtered while hot, and dried at 75°C to 85°C for 2h to 4h to obtain a high-purity manganese sulfate product; (E) NaCl solution membrane electrolysis and synthesis: The high-purity NaCl solution obtained in the Na / Ca separation section of step (C-4-1) is subjected to chelating resin to remove calcium and magnesium to below 0.02 mg / L, and then concentrated by evaporation to a NaCl content of 300 g / L to 320 g / L. Subsequently, ion membrane electrolysis is performed to obtain NaOH solution, Cl2 and H2. Finally, Cl2 and H2 are reacted in a synthesis tower to produce HCl gas, which is dissolved in water to obtain HCl solution. The NaOH solution and HCl solution are recycled, and the NaOH solution is recycled to the sodium soap step (C-2) and / or the aluminum removal step (B-2). The HCl solution is recycled to the P204-loaded organic back extraction step (A) and / or the back extraction I step (C-5).

2. A method for high-value recovery and recycling of cobalt smelting high-calcium manganese chloride wastewater according to claim 1, characterized in that: In step (A) hydrochloric acid stripping, the concentration of hydrochloric acid is 4 mol / L to 4.5 mol / L, and the temperature is 35° C. to 45° C.

3. A method for high-value recovery and recycling of cobalt smelting high-calcium manganese chloride wastewater according to claim 1, characterized in that: In step (B-3), the amount of Na2S2O3 added is 1.1 to 1.5 times the theoretical amount.

4. A method for high-value recovery and recycling of cobalt smelting high-calcium manganese chloride wastewater according to claim 1, characterized in that: In step (C-2), the volume composition of the Cy272 blank organic phase is 25% to 30% Cy272, and the remainder is sulfonated kerosene.

5. A method for high-value recovery and recycling of cobalt smelting high-calcium manganese chloride wastewater according to claim 1, characterized in that: Step (C-5) Stripping I uses 6 mol / L to 10 mol / L hydrochloric acid for stripping to obtain a high-purity negative Mn organic phase.

6. A method for high-value recovery and recycling of cobalt smelting high-calcium manganese chloride wastewater according to claim 1, characterized in that: In step (C-6), stripping II, 2 mol / L to 2.5 mol / L sulfuric acid is used to strip the high-purity Mn-negative organic phase to obtain a high-purity MnSO4 solution with a Mn content of 120 g / L to 150 g / L.

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