Method for recovering nickel and cobalt elements from high-temperature alloy waste electrolytic acid leaching solution

Abstract

The present application relates to a kind of methods for recovering nickel, cobalt element from high-temperature alloy waste electrolytic acidic leaching solution, comprising the following steps: nickel element, cobalt element, aluminum element, chromium element in leaching solution are co-precipitated and recovered, and hydroxide precipitate is obtained;Hydroxide precipitate is mixed with sodium carbonate, and then sodium calcination treatment is carried out, to obtain the material after sodium calcination;Water leaching treatment is carried out to the material after sodium calcination, then remove the aqueous solution containing aluminum element and chromium element, to obtain leaching residue;Wherein, the leaching residue includes nickel oxide and cobalt oxide.Compared with the traditional extraction recovery nickel, cobalt element method, the method of the present application not only has no organic waste extraction agent emission, but also the recovery product is used to prepare high-nickel ternary precursor, and the nickel, cobalt salt recovered by extraction has higher economic value, and has good engineering application value, economic value and environmental value.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of resource recycling, in particular to a method for recovering nickel and cobalt elements from high-temperature alloy waste electrolytic acidic leaching solution. BACKGROUND

[0002] For the recovery of high-temperature alloy waste, the existing wet recovery process is to electrolytically leach the waste in a strong acid system to obtain a leaching solution (i.e., high-temperature alloy waste electrolytic acidic leaching solution). Due to the complexity of the chemical composition of the high-temperature alloy, the leaching solution is a complex metal ion solution, which makes the element separation and purification technology difficult, the recovery method has strong limitations, and the value of the recovery product is low. Therefore, how to efficiently separate and extract strategic metal elements in high-temperature alloy waste, improve the utilization rate of waste, and increase the added value of recovery is a key link in the high-value recycling technology of high-temperature alloy waste.

[0003] For the rare and precious metal element rhenium in high-temperature alloy waste, high separation and purification is achieved by ion adsorption, imprinted polymer and other methods. However, the recovery value of non-rare and precious metal elements in high-temperature alloy waste is often ignored, mainly because the remaining solution is a complex metal ion solution mainly composed of nickel, cobalt, aluminum and chromium, and the composition is complex. The cost of extracting and purifying these metal elements is high, and the recovery value is low. The leaching solution after extracting the rare and precious metal element rhenium is usually treated as waste liquid, which not only causes environmental pollution, but also causes great resource waste and reduces the recovery value of high-temperature alloy waste.

[0004] In summary, developing a high-value recovery approach for non-rare and precious strategic metals in the leaching solution is an important task to achieve clean and efficient regeneration and recycling of high-temperature alloy waste. SUMMARY

[0005] Therefore, the present application provides a method for recovering nickel and cobalt elements from high-temperature alloy waste electrolytic acidic leaching solution, and the main purpose is to recover nickel and cobalt elements in high-temperature alloy waste electrolytic acidic leaching solution.

[0006] To achieve the above purpose, the present application mainly provides the following technical solutions:

[0007] On the one hand, the embodiment of the present application provides a method for recovering nickel and cobalt elements from high-temperature alloy waste electrolytic acidic leaching solution, which comprises the following steps:

[0008] Co-precipitation step: co-precipitating and recovering nickel elements, cobalt elements, aluminum elements and chromium elements in the leaching solution to obtain a hydroxide precipitate; wherein the leaching solution is a high-temperature alloy waste electrolytic acidic leaching solution;

[0009] Sodium roasting step: mixing the hydroxide precipitate and sodium carbonate, and then performing sodium roasting treatment to obtain a sodium roasting material;

[0010] Water leaching treatment step: The sodium-roasted material is subjected to water leaching treatment, and then the aqueous solution containing aluminum and chromium elements is removed to obtain leaching residue; wherein, the leaching residue includes nickel oxide and cobalt oxide (here, nickel oxide is NiO and cobalt oxide is CoO).

[0011] Preferably, the leaching residue obtained from the water leaching treatment step is used to prepare a ternary precursor. Preferably, the ternary precursor is a high-nickel ternary precursor with a nickel, cobalt, and manganese molar ratio of 8:1:1.

[0012] Preferably, after the water leaching treatment step, the method further includes a step of preparing a ternary precursor raw material salt solution: the leaching residue is washed and dissolved in dilute sulfuric acid, and manganese sulfate is added to it. Then, the molar ratio of nickel, cobalt, and manganese is adjusted to a set molar ratio to obtain a ternary precursor raw material salt solution. Preferably, the concentration of the metal salt in the ternary precursor raw material salt solution is 2-2.5 mol / L. Preferably, the pH value of the ternary precursor raw material salt solution is 5.0-5.4.

[0013] Preferably, after the step of preparing the ternary precursor raw material salt solution, the method further includes a step of preparing the ternary precursor: preparing the ternary precursor from the ternary precursor raw material salt solution into a ternary precursor using a co-precipitation process.

[0014] Preferably, the high-temperature alloy waste electrolytic acid leachate is an acidic ionic solution after rhenium has been removed by ion adsorption.

[0015] Preferably, the high-temperature alloy waste electrolytic acid leachate includes nickel, cobalt, aluminum, and chromium.

[0016] Preferably, in the co-precipitation step: sodium hydroxide solid is added to the leachate to adjust the pH value to 10-13, ensuring complete precipitation of nickel and cobalt elements in the leachate and avoiding dissolution due to excessive alkalinity; preferably, the sodium hydroxide solid is analytical grade sodium hydroxide solid. It should be noted that adding sodium hydroxide solid to adjust the pH value is ideal and requires a small amount. Preferably, when the method for recovering nickel and cobalt elements from the electrolytic acidic leachate of high-temperature alloy waste further includes a ternary precursor preparation step: after preparing the ternary precursor, the residual alkaline waste liquid is used to add sodium hydroxide solid to the leachate for a co-precipitation step.

[0017] Preferably, in the sodium calcination step: after the hydroxide precipitate is dried, it is ball-milled and mixed with sodium carbonate, and then subjected to sodium calcination treatment.

[0018] Preferably, in the sodium roasting step, the amount of sodium carbonate used should satisfy: the amount of sodium carbonate / [2 × the amount of aluminum in the leachate + the amount of chromium in the leachate] = 2.00-2.25.

[0019] Preferably, in the sodium calcination step: the sodium calcination temperature is 850-900℃, the sodium calcination time is 1.5-3h; and / or the sodium calcination is carried out in a muffle furnace.

[0020] Preferably, in the water immersion treatment step: the sodium-calcined material and the water immersion solvent are mixed and then subjected to water immersion treatment; preferably, the solid-liquid ratio is 0.05-0.15 g / mL (i.e., the ratio of the mass of the sodium-calcined material to the volume of the water immersion solvent); preferably, the water immersion treatment is carried out in a leaching reactor; preferably, the water immersion treatment temperature is 80-90℃, the water immersion treatment time is 1.5-2.5 h, preferably, the water immersion solvent is a sodium hydroxide solution with a pH value of 13-14; preferably, mechanical stirring is required during the water immersion treatment to ensure that no material is deposited at the bottom of the container during the water immersion treatment.

[0021] Preferably, in the water immersion treatment step: the aqueous solution containing aluminum and chromium obtained after water immersion treatment is subjected to co-precipitation and calcination treatment to obtain aluminum oxide (Al2O3) and chromium oxide (Cr2O3).

[0022] Compared with the prior art, the method of the present invention for recovering nickel and cobalt from the electrolytic acidic leachate of high-temperature alloy waste has at least the following beneficial effects:

[0023] This invention discloses a method for recovering nickel and cobalt from an acidic leaching solution of high-temperature alloy waste. First, nickel, cobalt, aluminum, and chromium are recovered from the acidic leaching solution using a co-precipitation method, yielding hydroxide precipitates. Then, the hydroxide precipitates are dried and mixed with a certain amount of sodium carbonate. The mixture is then subjected to sodium roasting in a muffle furnace. After sodium roasting, nickel and cobalt exist in the material as nickel oxide (NiO) and cobalt oxide (CoO), while aluminum and chromium exist as water-soluble sodium aluminate (NaAlO2) and sodium chromate (Na2CrO4). Further, the roasted material is leached in water to remove aluminum and chromium, yielding pure nickel and cobalt oxides. These pure nickel and cobalt oxides can be used to prepare high-nickel ternary precursors. This invention provides a high-value recovery method for nickel and cobalt elements in the electrolytic acid leaching solution of high-temperature alloy waste. Compared with the traditional method of recovering nickel and cobalt elements by extraction, this invention has no organic waste extractant emissions, and the obtained nickel and cobalt oxides can be directly used to prepare high-nickel ternary precursors. It has higher economic value than nickel and cobalt salts recovered by extraction, and has better engineering application value, economic value and environmental value.

[0024] Furthermore, in the embodiment of the present invention, a method for recovering nickel and cobalt elements from an electrolytic acidic leaching solution of high-temperature alloy waste is proposed. In the co-precipitation step, solid sodium hydroxide is added to the leaching solution to adjust the pH value of the leaching solution to 10-13. Within this pH range, the nickel and cobalt elements in the leaching solution can be completely converted into precipitates. If the pH value is lower than this range, the nickel and cobalt elements in the leaching solution will not precipitate completely. If the pH value is higher than this range, the generated nickel hydroxide and cobalt hydroxide will dissolve in the strong alkaline solution.

[0025] Furthermore, this invention provides a method for recovering nickel and cobalt from the electrolytic acidic leaching solution of high-temperature alloy waste. Specifically, nickel and cobalt oxides are dissolved in dilute sulfuric acid, and manganese sulfate is added to adjust the molar ratio of nickel, cobalt, and manganese to 8:1:1, with a metal salt concentration of 2-2.5 mol / L and a pH value of 5.8-6.2. The adjusted solution is used as the raw material solution for preparing a ternary high-nickel precursor, and the ternary precursor is prepared by co-precipitation. Therefore, the method of this invention achieves high-value recovery of nickel and cobalt.

[0026] Furthermore, the present invention proposes a method for recovering nickel and cobalt elements from electrolytic acidic leaching solutions of high-temperature alloy waste. By controlling the amount of sodium carbonate added in the sodium roasting step, the temperature and time of the sodium roasting treatment, and various parameters (such as temperature, time, pH, solid-liquid ratio, etc.) in the water leaching treatment step, the leaching rate of aluminum and chromium reaches more than 99% under the synergistic effect of these control parameters, thereby ensuring the purity of the leaching residue (nickel and cobalt oxides).

[0027] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a method for recovering nickel and cobalt elements from an acidic leaching solution of high-temperature alloy waste, as proposed in an embodiment of the present invention.

[0029] Figure 2 SEM-EDS data of the leaching residue after water immersion treatment;

[0030] Figure 3 The image shows the morphology of the ternary precursor prepared in Example 1.

[0031] Figure 4 XRD phase characterization diagram of the ternary precursor prepared in Example 1;

[0032] Figure 5 This is a schematic diagram showing the effect of sodium carbonate addition on the leaching rates of aluminum and chromium.

[0033] Figure 6 A schematic diagram showing the effect of sodium roasting temperature on the leaching rates of aluminum and chromium;

[0034] Figure 7 A schematic diagram showing the effect of sodium roasting time on the leaching rates of aluminum and chromium.

[0035] Figure 8 A schematic diagram showing the effect of water immersion temperature on the leaching rates of aluminum and chromium;

[0036] Figure 9 This is a schematic diagram showing the effect of pH value of the water leaching solvent on the leaching rate of aluminum and chromium.

[0037] Figure 10 A schematic diagram showing the effect of water immersion time on the leaching rates of aluminum and chromium.

[0038] Figure 11 This is a schematic diagram illustrating the effect of the solid-liquid ratio on the leaching rate of aluminum and chromium during the water immersion treatment step. Detailed Implementation

[0039] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific embodiments, structures, features, and effects according to the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. In the following description, different "an embodiment" or "an embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0040] This invention provides a method for recovering nickel and cobalt elements from an acidic electrolytic leaching solution of high-temperature alloy waste. The main principle is as follows: First, nickel, cobalt, aluminum, and chromium elements are recovered from the acidic electrolytic leaching solution of high-temperature alloy waste using a hydroxide co-precipitation method (preferably, solid sodium hydroxide is added to the leaching solution to adjust the pH to 10 to 13. Within this pH range, nickel and cobalt elements in the leaching solution can be completely converted into precipitates. If the pH is below this range, the precipitation of nickel and cobalt elements in the leaching solution is incomplete; if it is above this range, the generated nickel hydroxide and cobalt hydroxide will dissolve in a strong alkaline solution), resulting in hydroxide precipitates. Then, the hydroxide precipitates are dried and mixed with a certain amount of sodium carbonate (preferably, ball milling is required to ensure that the hydroxide precipitates are in full contact with sodium carbonate during the sodium roasting process, ensuring complete sodium roasting reaction, and the amount of sodium carbonate added must meet the set requirements). The mixed material is subjected to sodium roasting in a muffle furnace at a temperature of 800-900℃ for 1.5-3 hours. After sodium roasting, nickel and cobalt exist in the material as nickel oxide (NiO) and cobalt oxide (CoO), while aluminum and chromium exist as water-soluble sodium aluminate (NaAlO2) and sodium chromate (Na2CrO4). Further, the roasted material is then subjected to water leaching to remove aluminum and chromium, yielding pure nickel and cobalt oxides. Preferably, the water leaching temperature is 80-90℃, the leaching time is 1.5-2.5 hours, the leaching solvent is a sodium hydroxide solution with a pH of 13-14, and the solid-liquid ratio is 0.05-0.15 g / mL. Preferably, mechanical stirring is required during the water leaching process to ensure that no material settles at the bottom of the container. The leaching residue after water leaching is washed to obtain a pure mixture of nickel oxide and cobalt oxide. Preferably, the nickel and cobalt oxides are dissolved in dilute sulfuric acid, and manganese sulfate is added to adjust the molar ratio of nickel, cobalt, and manganese to 8:1:1, with a metal salt concentration of 2-2.5 mol / L and a pH of 5.8-6.2. The adjusted solution is used as the feed solution for preparing the high-nickel ternary precursor, and the high-nickel ternary precursor is prepared by co-precipitation.

[0041] Specifically, the method for recovering nickel and cobalt from the electrolytic acidic leachate of high-temperature alloy waste proposed in this invention, such as... Figure 1 As shown, the main steps include the following:

[0042] Co-precipitation step: Nickel, cobalt, aluminum and chromium in the leachate are co-precipitated and recovered to obtain hydroxide precipitates; wherein, the leachate is an acidic leachate from the electrolysis of high-temperature alloy waste.

[0043] Among them, the high-temperature alloy waste electrolytic acid leachate refers to the leachate obtained by electrolyzing the waste in a strong acid system in the existing wet recycling process.

[0044] In the co-precipitation step: sodium hydroxide solid is added to the leachate to adjust the pH value to 10-13 to ensure that the nickel and cobalt elements in the leachate are completely precipitated and to avoid dissolution due to excessive alkalinity; preferably, the sodium hydroxide solid is analytical grade sodium hydroxide solid.

[0045] Among them, the acidic leaching solution of high-temperature alloy waste electrolysis is an acidic ionic solution after rhenium has been removed by ion adsorption. The main components are ionic solutions of nickel, cobalt, aluminum and chromium. Tungsten, molybdenum and tantalum elements in high-temperature alloy waste are present in the anode mud after electrolysis and are not in the leaching solution.

[0046] Preferably, the hydroxide precipitate is filtered and dried to obtain a powder.

[0047] Sodium roasting step: After mixing the hydroxide precipitate and sodium carbonate, sodium roasting is performed to obtain the sodium roasted material.

[0048] In this step, the hydroxide precipitate, after drying, is ball-milled with a certain amount of sodium carbonate (analytical grade anhydrous sodium carbonate powder) for 20-30 minutes to ensure sufficient contact between the hydroxide precipitate and sodium carbonate during the sodium calcination process, guaranteeing a complete sodium calcination reaction. The amount of sodium carbonate added must meet the following conditions:

[0049] n(Na2CO3) / [2n(Al)+n(Cr)]=2.00-2.25.

[0050] Preferably, the mixed material (hydroxide precipitate and sodium carbonate) is placed in an iron crucible and then placed in a muffle furnace. The sodium calcination treatment temperature is adjusted to 850-900℃ and the time is 1.5-3 hours. The calcined material is then allowed to cool naturally in the muffle furnace. This ensures that the aluminum element in the precipitate is converted from aluminum hydroxide to water-soluble sodium aluminate, and the chromium hydroxide is converted to water-soluble sodium chromate.

[0051] Water leaching treatment step: The sodium-roasted material is subjected to water leaching treatment, and then the aqueous solution containing aluminum and chromium is removed to obtain leaching residue; wherein, the leaching residue includes nickel oxide and cobalt oxide.

[0052] In this step: the sodium-calcined material is placed in a leaching reactor. The water leaching temperature is 80-90℃, the water leaching time is 1.5-2.5h, the water leaching solvent is a sodium hydroxide solution with a pH of 13-14, the solid-liquid ratio is 0.05-0.15g / mL, and mechanical stirring is carried out during the water leaching process to ensure that no material settles at the bottom of the container, so that aluminum and chromium elements are completely dissolved.

[0053] The steps for preparing the ternary precursor raw material salt solution are as follows: After washing the leaching residue (nickel oxide and cobalt oxide), dissolve it in dilute sulfuric acid and add manganese sulfate to adjust the molar ratio of nickel, cobalt and manganese to 8:1:1, and the concentration of the metal salt after adjustment is 2-2.5 mol / L, and the pH value is 5.8-6.2.

[0054] Preparation steps of ternary precursor: Using ternary precursor raw material salt solution as raw material, ternary precursor (i.e., high-nickel ternary precursor) is prepared by co-precipitation method.

[0055] Preferably, after preparing the ternary precursor, the residual alkaline waste liquid can be added to the leachate along with sodium hydroxide solid for a co-precipitation step, thereby realizing the recycling of alkaline waste liquid and avoiding direct discharge, which is more environmentally friendly.

[0056] Here, it is necessary to explain the prior art and the solutions of the present invention:

[0057] 1. One existing technology involves adding ammonium sulfate and sodium sulfite sequentially to recycled high-temperature alloy waste liquid to remove iron, chromium, and aluminum impurities from the waste liquid, thereby obtaining a high-purity nickel and cobalt salt solution.

[0058] Regarding this existing technology, it mainly uses a step-by-step precipitation method to remove impurity elements from waste liquid. In this process: First, co-precipitation will occur, and nickel and cobalt elements will precipitate out in varying amounts during the impurity removal process, resulting in nickel and cobalt loss; Second, the specialized equipment for precipitation and impurity removal is complex, and in industrial production, incomplete mixing will result in impurity residue.

[0059] Unlike the existing technologies described above, this invention uses a co-precipitation-sodium roasting-water leaching method to remove aluminum and chromium from high-temperature alloy waste. This method offers the following advantages: First, it ensures that nickel and cobalt fully precipitate during co-precipitation. After drying the precipitate, it is mixed with sodium carbonate and then subjected to sodium roasting. This transforms impurities such as aluminum and chromium (the waste liquid of this invention contains almost no iron) into water-soluble substances, allowing for thorough removal of these impurities in the water leaching step, resulting in pure nickel and cobalt oxides. Compared to the existing technologies, this invention boasts higher impurity removal efficiency (aluminum and chromium leaching rates can reach over 99%), a more industrial-grade equipment structure, simpler operation, and easier industrialization.

[0060] 2. Another existing technology is to separate nickel and cobalt from the leachate using extraction. However, the extractant will emulsify and become unusable after repeated use, generating a large amount of organic waste liquid. Furthermore, the extractant is expensive, and the co-extraction equipment is complex, limiting its industrial application.

[0061] The advantages of this invention are: it eliminates the need to separate nickel and cobalt elements, directly removing aluminum and chromium through sodium roasting and water leaching, resulting in low process costs, avoiding the use of organic extractants, and minimizing waste liquid volume. Furthermore, the alkaline waste liquid generated after preparing the ternary precursor can be directly used for the first co-precipitation step, allowing for alkaline solution recycling (by adding solid sodium hydroxide to the alkaline waste liquid), thus reducing waste liquid discharge.

[0062] The present invention will be further illustrated below with specific embodiments:

[0063] Example 1

[0064] This embodiment provides a method for recovering nickel and cobalt elements from the electrolytic acidic leachate of high-temperature alloy waste, such as... Figure 1 As shown, the main steps include the following:

[0065] Co-precipitation step: Nickel, cobalt, aluminum, and chromium were recovered from the leachate using a co-precipitation method. Specifically, analytical grade sodium hydroxide solid was added to the leachate to adjust the pH to 11, ensuring complete precipitation of nickel and cobalt without dissolution due to excessive alkalinity, resulting in hydroxide precipitates. The composition of the hydroxide precipitates was analyzed and is shown in Table 1. Table 1 shows that the main components of the hydroxides are Ni(OH)₂, Co(OH)₂, Al(OH)₃, and Cr(OH)₃.

[0066] Table 1 shows the composition of hydroxide precipitates.

[0067] Ingredients [Ni(OH)2] Co(OH)2 Al(OH)3 Cr(OH)3 Other Mass fraction % 68.697 9.998 12.731 8.158 0.415

[0068] Sodium calcination step: After drying, 3 kg of the hydroxide precipitate is weighed and mixed with a certain amount of sodium carbonate, then ball-milled. The amount of sodium carbonate added satisfies: n(Na₂CO₃) / [2n(Al)+n(Cr)]=2.00. The ball-milled material is placed in a muffle furnace for sodium calcination treatment to obtain the sodium-calcined material. The sodium calcination treatment temperature is 850℃, and the sodium calcination treatment time is 3 hours.

[0069] Water immersion treatment: The roasted material is then subjected to water immersion treatment to remove aluminum and chromium. The water immersion treatment time is 2 hours, the solid-liquid ratio is 0.1 g / mL, the water immersion temperature is 90℃, and the water immersion solvent is a sodium hydroxide solution with a pH of 13.

[0070] Among them, the SEM-EDS data of the leaching residue after water leaching treatment are as follows:Figure 2 As shown. From Figure 2 It can be seen that the leaching residue after water leaching is mainly composed of nickel and cobalt oxides, with almost no aluminum and chromium, proving that sodium roasting-water leaching can efficiently remove aluminum and chromium. XRF analysis of the leaching residue showed that the leaching rate of aluminum and chromium was over 99%. After washing, the leaching residue after water leaching yielded a pure mixture of nickel oxide and cobalt oxide.

[0071] The steps for preparing the ternary precursor raw material salt solution are as follows: Dissolve the washed leaching residue in dilute sulfuric acid, add manganese sulfate, adjust the molar ratio of nickel, cobalt and manganese to 8:1:1, and adjust the concentration of the metal salt to 2-2.5 mol / L and the pH value to 5.8-6.2.

[0072] Preparation steps of ternary precursor: Co-precipitation treatment of ternary precursor raw material salt solution to obtain ternary precursor.

[0073] The morphology of the ternary precursor prepared in this embodiment is as follows: Figure 3 As shown, the XRD phase characterization is as follows: Figure 4 As shown. From Figure 3 It can be seen that the morphology of the ternary precursor is a spherical crystal, which is consistent with the morphology of existing industrially produced precursors. Figure 4 The results show that the product prepared in this embodiment is a ternary precursor, which does not contain other impurity phases (aluminum, chromium), further proving the purity of the material prepared in this embodiment.

[0074] Example 2

[0075] This embodiment provides a method for recovering nickel and cobalt elements from the electrolytic acidic leachate of high-temperature alloy waste, which differs from Embodiment 1 in that:

[0076] In this embodiment, the amount of sodium carbonate added in the sodium roasting step satisfies the following conditions:

[0077] n(Na2CO3) / [2n(Al)+n(Cr)]=2.25

[0078] The other steps are the same as in Example 1.

[0079] Comparative Example 1

[0080] Comparative Example 1 provides a method for recovering nickel and cobalt from an electrolytic acidic leachate of high-temperature alloy waste, which differs from Example 1 in that:

[0081] In Comparative Example 1, the amount of sodium carbonate added during the sodium roasting step satisfies the following conditions:

[0082] n(Na2CO3) / [2n(Al)+n(Cr)]=1.00

[0083] The other steps are the same as in Example 1.

[0084] Comparative Example 2

[0085] Comparative Example 2 provides a method for recovering nickel and cobalt from an electrolytic acidic leachate of high-temperature alloy waste, which differs from Example 1 in that:

[0086] In Comparative Example 2, the amount of sodium carbonate added during the sodium roasting step satisfies the following conditions:

[0087] n(Na2CO3) / [2n(Al)+n(Cr)]=1.25

[0088] The other steps are the same as in Example 1.

[0089] Comparative Example 3

[0090] Comparative Example 3 provides a method for recovering nickel and cobalt from an electrolytic acidic leachate of high-temperature alloy waste, which differs from Example 1 in that:

[0091] In Comparative Example 3, the amount of sodium carbonate added during the sodium roasting step satisfies the following conditions:

[0092] n(Na2CO3) / [2n(Al)+n(Cr)]=1.50

[0093] The other steps are the same as in Example 1.

[0094] Comparative Example 4

[0095] Comparative Example 4 provides a method for recovering nickel and cobalt from an electrolytic acidic leachate of high-temperature alloy waste, which differs from Example 1 in that:

[0096] In Comparative Example 4, the amount of sodium carbonate added during the sodium roasting step satisfies the following conditions:

[0097] n(Na2CO3) / [2n(Al)+n(Cr)]=1.75

[0098] The other steps are the same as in Example 1.

[0099] Here, the leaching rates of aluminum and chromium in Examples 1-2 and Comparative Examples 1-4 are referred to Figure 5 As shown. From Figure 5 It is evident that the amount of sodium carbonate used in the sodium roasting step significantly affects the leaching rate of aluminum and chromium in the water leaching process. However, in this embodiment of the invention, by controlling the amount of sodium carbonate added: n(Na₂CO₃) / [2n(Al) + n(Cr)] = 2 - 2.25, the leaching rate of aluminum and chromium can be significantly improved, reaching over 99%.

[0100] Example 3

[0101] This embodiment provides a method for recovering nickel and cobalt elements from electrolytic acidic leachate of high-temperature alloy waste. The difference from Embodiment 1 is that in this embodiment, the sodium roasting temperature is 900°C during the sodium roasting step.

[0102] The other steps are the same as in Example 1.

[0103] Comparative Example 5

[0104] Comparative Example 5 provides a method for recovering nickel and cobalt elements from electrolytic acidic leachate of high-temperature alloy waste. The difference from Example 1 is that in the sodium roasting step of Comparative Example 5, the sodium roasting temperature is 400°C.

[0105] The other steps are the same as in Example 1.

[0106] Comparative Example 6

[0107] Comparative Example 6 provides a method for recovering nickel and cobalt elements from electrolytic acidic leachate of high-temperature alloy waste. The difference from Example 1 is that in the sodium roasting step of Comparative Example 6, the sodium roasting temperature is 500°C.

[0108] The other steps are the same as in Example 1.

[0109] Comparative Example 7

[0110] Comparative Example 7 provides a method for recovering nickel and cobalt from electrolytic acidic leachate of high-temperature alloy waste. The difference between Comparative Example 7 and Example 1 is that the sodium roasting temperature in the sodium roasting step is 600°C.

[0111] The other steps are the same as in Example 1.

[0112] Comparative Example 8

[0113] Comparative Example 8 provides a method for recovering nickel and cobalt elements from electrolytic acidic leachate of high-temperature alloy waste. The difference from Example 1 is that in the sodium roasting step of Comparative Example 8, the sodium roasting temperature is 700°C.

[0114] The other steps are the same as in Example 1.

[0115] Comparative Example 9

[0116] Comparative Example 9 provides a method for recovering nickel and cobalt elements from an electrolytic acidic leachate of high-temperature alloy waste. The difference between Comparative Example 9 and Example 1 is that the sodium roasting temperature in the sodium roasting step is 750°C.

[0117] The other steps are the same as in Example 1.

[0118] Comparative Example 10

[0119] Comparative Example 10 provides a method for recovering nickel and cobalt from an electrolytic acidic leachate of high-temperature alloy waste. The difference between Comparative Example 10 and Example 1 is that the sodium roasting temperature in the sodium roasting step is 800°C.

[0120] The other steps are the same as in Example 1.

[0121] Here, the leaching rates of aluminum and chromium in Examples 1, 3, and Comparative Examples 5-10 are as follows: Figure 6 As shown. From Figure 6 It can be seen that the temperature of the sodium calcination treatment affects the leaching rate of aluminum and chromium. However, in this embodiment of the invention, by controlling the sodium calcination treatment temperature to 850-900℃, the leaching rate of aluminum and chromium can be significantly improved, reaching over 99%.

[0122] Example 4

[0123] This embodiment provides a method for recovering nickel and cobalt elements from electrolytic acidic leachate of high-temperature alloy waste. The difference from Embodiment 1 is that the sodium roasting process in this embodiment takes 2.5 hours.

[0124] The other steps are the same as in Example 1.

[0125] Example 5

[0126] This embodiment provides a method for recovering nickel and cobalt elements from electrolytic acidic leachate of high-temperature alloy waste. The difference from Embodiment 1 is that in this embodiment, the sodium roasting process takes 2 hours.

[0127] The other steps are the same as in Example 1.

[0128] Example 6

[0129] This embodiment provides a method for recovering nickel and cobalt elements from electrolytic acidic leachate of high-temperature alloy waste. The difference from Embodiment 1 is that in this embodiment, the sodium roasting process takes 1.5 hours.

[0130] The other steps are the same as in Example 1.

[0131] Comparative Example 11

[0132] Comparative Example 11 provides a method for recovering nickel and cobalt elements from electrolytic acidic leachate of high-temperature alloy waste. The difference from Example 1 is that in the sodium roasting step of Comparative Example 11, the sodium roasting treatment time is 1.0 h.

[0133] The other steps are the same as in Example 1.

[0134] Comparative Example 12

[0135] Comparative Example 12 provides a method for recovering nickel and cobalt elements from electrolytic acidic leachate of high-temperature alloy waste. The difference from Example 1 is that in the sodium roasting step of Comparative Example 12, the sodium roasting treatment time is 0.5 h.

[0136] The other steps are the same as in Example 1.

[0137] Here, the leaching rates of aluminum and chromium in Examples 1, 4-6, and Comparative Examples 11-12 are as follows: Figure 7 As shown. From Figure 7 It can be seen that the sodium roasting time affects the leaching rate of aluminum and chromium. In this embodiment of the invention, by controlling the sodium roasting time to 1.5-3 hours, the leaching rate of aluminum and chromium can be significantly improved, reaching over 99%.

[0138] Example 7

[0139] This embodiment provides a method for recovering nickel and cobalt elements from electrolytic acidic leachate of high-temperature alloy waste. The difference from Embodiment 1 is that in this embodiment, the water immersion treatment temperature is 80°C.

[0140] The other steps are the same as in Example 1.

[0141] Comparative Example 13

[0142] Comparative Example 13 provides a method for recovering nickel and cobalt elements from an electrolytic acidic leachate of high-temperature alloy waste. The difference from Example 1 is that in the water immersion treatment step of Comparative Example 13, the water immersion treatment temperature is 50°C.

[0143] The other steps are the same as in Example 1.

[0144] Comparative Example 14

[0145] Comparative Example 14 provides a method for recovering nickel and cobalt from an electrolytic acidic leachate of high-temperature alloy waste. The difference from Example 1 is that in the water immersion treatment step of Comparative Example 14, the water immersion treatment temperature is 60°C.

[0146] The other steps are the same as in Example 1.

[0147] Comparative Example 15

[0148] Comparative Example 15 provides a method for recovering nickel and cobalt from an electrolytic acidic leachate of high-temperature alloy waste. The difference from Example 1 is that in the water immersion treatment step of Comparative Example 15, the water immersion treatment temperature is 70°C.

[0149] The other steps are the same as in Example 1.

[0150] Here, the leaching rates of aluminum and chromium in Examples 1, 7, and Comparative Examples 13-15 are as follows:Figure 8 As shown. From Figure 8 It can be seen that the temperature of the water immersion treatment affects the leaching rate of aluminum and chromium. However, the embodiments of this invention, by controlling the water immersion treatment temperature to 80-90℃, can significantly improve the leaching rate of aluminum and chromium, reaching over 99%.

[0151] Example 8

[0152] This embodiment provides a method for recovering nickel and cobalt elements from an electrolytic acidic leachate of high-temperature alloy waste. The difference from Embodiment 1 is that the pH of the water leaching solvent in this embodiment is 14 during the water leaching process.

[0153] The other steps are the same as in Example 1.

[0154] Comparative Example 16

[0155] Comparative Example 16 provides a method for recovering nickel and cobalt from an electrolytic acidic leachate of high-temperature alloy waste. The difference from Example 1 is that in the water leaching step of Comparative Example 16, the pH of the water leaching solvent is 12.

[0156] The other steps are the same as in Example 1.

[0157] Comparative Example 17

[0158] Comparative Example 17 provides a method for recovering nickel and cobalt from an electrolytic acidic leachate of high-temperature alloy waste. The difference from Example 1 is that in the water leaching step of Comparative Example 17, the pH of the water leaching solvent is 11.

[0159] The other steps are the same as in Example 1.

[0160] Comparative Example 18

[0161] Comparative Example 18 provides a method for recovering nickel and cobalt from an electrolytic acidic leachate of high-temperature alloy waste. The difference from Example 1 is that in the water leaching step of Comparative Example 18, the pH of the water leaching solvent is 10.

[0162] The other steps are the same as in Example 1.

[0163] Here, the leaching rates of Examples 1, 8, and Comparative Examples 16-18 are as follows: Figure 9 As shown. From Figure 9 It can be seen that the pH value of the water leaching solvent affects the leaching rate of aluminum and chromium. In this embodiment of the invention, by controlling the pH value of the water leaching solvent to 13-14, the leaching rate of aluminum and chromium can be significantly improved, reaching over 99%.

[0164] Example 9

[0165] This embodiment provides a method for recovering nickel and cobalt elements from electrolytic acidic leachate of high-temperature alloy waste. The difference from Embodiment 1 is that the water immersion treatment time in this embodiment is 1.5 hours.

[0166] The other steps are the same as in Example 1.

[0167] Example 10

[0168] This embodiment provides a method for recovering nickel and cobalt elements from electrolytic acidic leachate of high-temperature alloy waste. The difference from Embodiment 1 is that the water immersion treatment time in this embodiment is 2.5 hours.

[0169] The other steps are the same as in Example 1.

[0170] Comparative Example 19

[0171] Comparative Example 19 provides a method for recovering nickel and cobalt elements from an electrolytic acidic leachate of high-temperature alloy waste. The difference from Example 1 is that in the water immersion treatment step of Comparative Example 19, the water immersion treatment time is 0.5 hours.

[0172] The other steps are the same as in Example 1.

[0173] Comparative Example 20

[0174] Comparative Example 20 provides a method for recovering nickel and cobalt elements from an electrolytic acidic leachate of high-temperature alloy waste. The difference from Example 1 is that in the water immersion treatment step of Comparative Example 20, the water immersion treatment time is 1.0 h.

[0175] The other steps are the same as in Example 1.

[0176] Here, the leaching rates of Examples 1, 9-10, and Comparative Examples 19-20 are as follows: Figure 10 As shown. From Figure 10 It can be seen that the leaching time affects the leaching rate of aluminum and chromium. In this embodiment of the invention, by controlling the leaching time to 1.5-2.5 hours, the leaching rate of aluminum and chromium can be significantly improved, reaching over 99%.

[0177] Example 11

[0178] This embodiment provides a method for recovering nickel and cobalt elements from electrolytic acidic leachate of high-temperature alloy waste. The difference from Embodiment 1 is that in the water leaching step of this embodiment, the solid-liquid ratio is 0.05 g / mL.

[0179] The other steps are the same as in Example 1.

[0180] Example 12

[0181] This embodiment provides a method for recovering nickel and cobalt elements from electrolytic acidic leachate of high-temperature alloy waste. The difference from Embodiment 1 is that in the water leaching step of this embodiment, the solid-liquid ratio is 0.15 g / mL.

[0182] The other steps are the same as in Example 1.

[0183] Comparative Example 21

[0184] Comparative Example 21 provides a method for recovering nickel and cobalt elements from an electrolytic acidic leachate of high-temperature alloy waste. The difference from Example 1 is that in the water leaching step of Comparative Example 21, the solid-liquid ratio is 0.20 g / mL.

[0185] The other steps are the same as in Example 1.

[0186] Comparative Example 22

[0187] Comparative Example 22 provides a method for recovering nickel and cobalt from an electrolytic acidic leachate of high-temperature alloy waste. The difference from Example 1 is that in the water leaching step of Comparative Example 22, the solid-liquid ratio is 0.25 g / mL.

[0188] The other steps are the same as in Example 1.

[0189] Here, the leaching rates of Examples 1, 11-12, and Comparative Examples 21-22 are as follows: Figure 11 As shown. From Figure 11 It can be seen that the solid-liquid ratio in the water leaching process affects the leaching rate of aluminum and chromium. However, the embodiments of this invention, by controlling the solid-liquid ratio to 0.05-0.15 g / mL, can significantly improve the leaching rate of aluminum and chromium, reaching over 99%.

[0190] As can be seen from the above embodiments and comparative examples, the parameters of the sodium roasting treatment step and the water leaching treatment step have a significant impact on the leaching rate of aluminum and chromium, thereby affecting the purity of the leaching residue and the purity of the ternary precursor. This invention, through synergistic control of these parameters, achieves a leaching rate of over 99% for aluminum and chromium in the water leaching treatment step, ultimately realizing the recovery of high-purity nickel and cobalt elements.

[0191] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for recovering nickel and cobalt elements from an electrolytic acidic leachate of high-temperature alloy waste, characterized in that, It includes the following steps: Co-precipitation step: Nickel, cobalt, aluminum and chromium in the leachate are co-precipitated and recovered to obtain hydroxide precipitates; wherein, the leachate is an acidic leachate from the electrolysis of high-temperature alloy waste; Sodium roasting step: The hydroxide precipitate and sodium carbonate are mixed and then subjected to sodium roasting treatment to obtain the sodium roasted material; Water leaching treatment step: The sodium-roasted material is subjected to water leaching treatment, and then the aqueous solution containing aluminum and chromium is removed to obtain leaching residue; wherein, the leaching residue includes nickel oxide and cobalt oxide.

2. The method for recovering nickel and cobalt from the electrolytic acidic leachate of high-temperature alloy waste according to claim 1, characterized in that, The leaching residue obtained from the water leaching treatment step is used to prepare ternary precursors.

3. The method for recovering nickel and cobalt elements from the electrolytic acidic leachate of high-temperature alloy waste according to claim 2, characterized in that, The ternary precursor is a high-nickel ternary precursor with a nickel, cobalt, and manganese molar ratio of 8:1:

1.

4. The method for recovering nickel and cobalt elements from the electrolytic acidic leachate of high-temperature alloy waste according to claim 1, characterized in that, Following the water immersion treatment step, the method further includes: The steps for preparing the ternary precursor raw material salt solution are as follows: the leaching residue is washed and dissolved in dilute sulfuric acid, and manganese sulfate is added to it. Then, the molar ratio of nickel, cobalt and manganese is adjusted to the set molar ratio to obtain the ternary precursor raw material salt solution.

5. The method for recovering nickel and cobalt from the electrolytic acidic leachate of high-temperature alloy waste according to claim 4, characterized in that, In the ternary precursor raw material salt solution, the concentration of the metal salt is 2-2.5 mol / L; the pH value of the ternary precursor raw material salt solution is 5.0-5.

4.

6. The method for recovering nickel and cobalt from the electrolytic acidic leachate of high-temperature alloy waste according to claim 4, characterized in that, After the step of preparing the ternary precursor raw material salt solution, the method further includes: The steps for preparing the ternary precursor are as follows: The ternary precursor raw material salt solution is prepared into a ternary precursor by co-precipitation process.

7. The method for recovering nickel and cobalt from the electrolytic acidic leachate of high-temperature alloy waste according to claim 1, characterized in that, The electrolytic acidic leachate of the high-temperature alloy waste is an acidic ionic solution after rhenium has been removed by ion adsorption; and / or The acidic leaching solution for the high-temperature alloy waste contains nickel, cobalt, aluminum, and chromium.

8. The method for recovering nickel and cobalt from the electrolytic acidic leachate of high-temperature alloy waste according to claim 1, characterized in that, In the coprecipitation step: Add solid sodium hydroxide to the leachate and adjust the pH to 10-13 to ensure that the nickel and cobalt elements in the leachate are completely precipitated and to avoid dissolution due to excessive alkalinity.

9. The method for recovering nickel and cobalt from the electrolytic acidic leachate of high-temperature alloy waste according to claim 8, characterized in that, The sodium hydroxide solid used is analytical grade sodium hydroxide solid.

10. The method for recovering nickel and cobalt from the electrolytic acidic leachate of high-temperature alloy waste according to claim 8, characterized in that, When the method for recovering nickel and cobalt from the electrolytic acidic leachate of high-temperature alloy waste further includes a step of preparing a ternary precursor: after preparing the ternary precursor, the remaining alkaline waste liquid is added to the leachate along with sodium hydroxide solid for a co-precipitation step.

11. The method for recovering nickel and cobalt from the electrolytic acidic leachate of high-temperature alloy waste according to claim 1, characterized in that, In the sodium calcination step: After the hydroxide precipitate is dried, it is ball-milled and mixed with sodium carbonate, and then subjected to sodium calcination treatment.

12. The method for recovering nickel and cobalt from the electrolytic acidic leachate of high-temperature alloy waste according to claim 1, characterized in that, In the sodium calcination step, the amount of sodium carbonate used must meet the following requirements: The amount of sodium carbonate / [2 × the amount of aluminum in the leachate + the amount of chromium in the leachate] = 2.00 - 2.

25.

13. The method for recovering nickel and cobalt from the electrolytic acidic leachate of high-temperature alloy waste according to claim 1, characterized in that, In the sodium calcination step: The sodium calcination treatment is performed at a temperature of 850-900℃ for a duration of 1.5-3 hours; and / or The sodium roasting process is carried out in a muffle furnace.

14. The method for recovering nickel and cobalt from the electrolytic acidic leachate of high-temperature alloy waste according to claim 1, characterized in that, In the water immersion treatment step: The sodium-calcined material is mixed with a water-soluble solvent and then subjected to water immersion treatment.

15. The method for recovering nickel and cobalt from the electrolytic acidic leachate of high-temperature alloy waste according to claim 14, characterized in that, In the water immersion treatment step, the solid-liquid ratio is 0.05-0.15 g / mL.

16. The method for recovering nickel and cobalt from the electrolytic acidic leachate of high-temperature alloy waste according to claim 14, characterized in that, The water immersion treatment is carried out in a leaching reactor.

17. The method for recovering nickel and cobalt from the electrolytic acidic leachate of high-temperature alloy waste according to claim 14, characterized in that, The water immersion treatment temperature is 80-90℃, and the water immersion treatment time is 1.5-2.5h.

18. The method for recovering nickel and cobalt from the electrolytic acidic leachate of high-temperature alloy waste according to claim 14, characterized in that, The water immersion solvent should be a sodium hydroxide solution with a pH of 13-14.

19. The method for recovering nickel and cobalt from the electrolytic acidic leachate of high-temperature alloy waste according to claim 14, characterized in that, During the water immersion process, mechanical stirring is required to ensure that no material settles at the bottom of the container.

20. The method for recovering nickel and cobalt from the electrolytic acidic leachate of high-temperature alloy waste according to claim 1, characterized in that, In the water immersion treatment step: The aqueous solution containing aluminum and chromium obtained after water immersion treatment was subjected to co-precipitation and calcination to obtain aluminum oxide and chromium oxide.

Images