Processing method of nickel-iron alloy powder

Abstract

The invention provides a processing method of nickel-iron alloy powder. The processing method comprises the following steps: S1, providing the nickel-iron alloy powder; the nickel-iron alloy powder contains a nickel element, an iron element and a chromium element; s2, the nickel-iron alloy powder is subjected to acid leaching, and leaching residues and leaching liquid are obtained; cooling and crystallizing the leachate to obtain solid crystals and crystallized liquid; s3, the crystallized liquid is subjected to chromium precipitation treatment, and chromium precipitation slag and impurity-removed liquid are obtained; s4, carrying out nickel-iron separation on the impurity-removed liquid to obtain a nickel precipitate and an iron separation liquid; according to the method, the nickel precipitate and the iron separation liquid are obtained by processing the nickel-iron alloy powder, and doping of iron in the nickel precipitate is reduced; in addition, before nickel and iron are separated, chromium is effectively removed, and it is guaranteed that a high-quality nickel product is obtained.

Description

Technical Field

[0001] The present invention relates to the field of metal powder processing, and particularly to a processing method for nickel-iron alloy powder. Background Art

[0002] Currently, lithium battery technology is constantly innovating, and the trend of high nickelization is obvious, resulting in an increasing demand for metal resources such as nickel; while nickel-iron alloy is currently in a surplus state. Processing nickel-iron alloy into nickel raw materials can not only handle nickel-iron alloy waste resources, but also effectively solve the problem of nickel raw material supply, and obtain nickel products applied to the battery industry. Therefore, how to process nickel-iron alloy into nickel products with high yield and high purity is a major technical difficulty to be solved in this field.

[0003] The Chinese patent application with the publication number CN117380950A discloses a dissolution process for nickel-iron alloy; including: melting and powdering the nickel-iron alloy to obtain nickel-iron alloy powder; adding acid solution to the nickel-iron alloy powder for dissolution, and at the same time, a small amount of iron powder should be added, then heating and stirring are carried out, followed by solid-liquid separation to obtain an acidic nickel-iron solution and filter residue, and the filter residue is returned to the dissolution stage for continuous reaction; adding an appropriate amount of sulfide to the acidic nickel-iron solution, heating and stirring are carried out, and then solid-liquid separation is carried out to obtain a ferrous sulfate solution and nickel sulfide slag; then the ferrous sulfate and nickel sulfide are applied to the battery industry.

[0004] Although the above patent application realizes the processing of nickel-iron alloy and obtains nickel products and iron products applied to the battery industry; however, the above patent application only uses the conventional sulfide method to precipitate nickel, which will cause iron impurities to be mixed into the nickel products, not only affecting the purity of nickel, but also increasing the iron loss rate. Moreover, some nickel-iron alloys usually contain chromium. If only acid leaching and conventional sulfide treatment are carried out, chromium cannot be effectively removed, thus affecting the quality of nickel products and iron products.

[0005] In view of this, it is necessary to provide a processing method for nickel-iron alloy powder to solve or at least alleviate the technical problem of how to reduce the iron doping in nickel products and effectively remove chromium. Summary of the Invention

[0006] The main object of the present invention is to provide a processing method for nickel-iron alloy powder, aiming to solve the technical problem of how to reduce the iron doping in nickel products and effectively remove chromium.

[0007] To achieve the above object, the present invention provides a processing method for nickel-iron alloy powder, including the steps: S1, providing nickel-iron alloy powder; the nickel-iron alloy powder contains nickel element, iron element and chromium element; S2, acid leaching the nickel-iron alloy powder to obtain leaching residue and leaching solution; cooling and crystallizing the leaching solution to obtain solid crystals and post-crystallization solution; S3. Perform chromium precipitation treatment on the post-crystallization solution to obtain chromium precipitation residue and impurity-removed solution; The chromium precipitation treatment includes: adjusting the pH of the post-crystallization solution to 2 - 3, and then performing first mixing on the post-crystallization solution and iron powder; S4. Perform nickel-iron separation on the impurity-removed solution to obtain nickel precipitation and iron separation solution; The nickel-iron separation includes: adjusting the pH of the impurity-removed solution to 1.5 - 2.5, performing second mixing on the impurity-removed solution, an anionic surfactant, and a sulfide; the duration of the second mixing is 50 - 90 min; the molar ratio of the sulfide to nickel element in the impurity-removed solution is 1 - 1.5:1; the mass percentage of the anionic surfactant and the sulfide is 3 - 8%.

[0008] Further, the mass ratio of the iron powder to chromium element in the post-crystallization solution is 3 - 10:1.

[0009] Further, the temperature of the first mixing is 65 - 80 °C; the duration of the first mixing is 1.5 - 3 h.

[0010] Further, the anionic surfactant and the sulfide are added to the impurity-removed solution in the form of a mixed solution; the volume ratio of the mixed solution to the impurity-removed solution is 1:6 - 10.

[0011] Further, the temperature of the second mixing is 10 - 40 °C.

[0012] Further, the anionic surfactant includes one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and α-olefin sulfonate; the sulfide includes one or more of sodium sulfide, potassium sulfide, lithium sulfide, and ammonium sulfide.

[0013] Further, the temperature of the cooling crystallization is 10 - 30 °C, and the duration of the cooling crystallization is not less than 4 h.

[0014] Further, the acid solution used in the acid leaching includes sulfuric acid solution, and the solid crystal contains ferrous sulfate; the concentration of the sulfuric acid solution is 1 - 2.5 mol / L.

[0015] Further, the temperature of the acid leaching is 60 - 80 °C; the duration of the acid leaching is not less than 1.5 h; the solid-liquid ratio used in the acid leaching is 1 g:5 - 15 mL.

[0016] Further, step S4 further includes: performing evaporation crystallization on the iron separation solution.

[0017] Compared with the prior art, the present invention has at least the following advantages: The present invention obtains nickel precipitate and iron separation liquid by processing nickel-iron alloy powder, reduces the doping of iron in nickel precipitate, and effectively removes chromium before separating nickel and iron, and obtains high-quality nickel products. Specifically, the nickel-iron alloy powder of the present invention is subjected to acid leaching to obtain a leachate, and after cooling and crystallization, a certain amount of iron can be recovered; the pH of the liquid after crystallization is adjusted, and then reduced iron powder is added, and at a certain temperature, the impurity chromium in the solution can be removed to avoid subsequent influence on the purity of nickel and iron; the present invention adds an appropriate amount of sulfide and anionic surfactant to form a sulfide precipitate with nickel, and the anionic surfactant will effectively control the ferrous precipitation, as well as the complex adsorption on the surface of nickel sulfide, reduce the iron content in the nickel sulfide precipitation, and obtain nickel precipitate and iron separation liquid. The present invention solves the problems of difficulty in separating nickel and iron, high iron content in the process of nickel precipitation of sulfide, high chromium impurity content, low nickel and iron recovery rate, and has great industrial application value.

[0018] During the sulfidation process, nickel sulfide will precipitate preferentially due to its lower solubility product, but due to the reasons of sulfidation efficiency and adsorption, some iron will precipitate therewith; Therefore, by reducing the content of iron by cooling crystallization, it is not only possible to alleviate the subsequent iron recovery pressure, but also to reduce the iron loss in the subsequent sulfidation nickel precipitation step. The present invention is by adding anionic surfactants, on the one hand, nickel sulfide is preferentially precipitated, and anionic surfactants can increase the electrostatic repulsion between the solid-liquid phase interface, reduce the adsorption of iron during the agglomeration process, and improve the precipitation reaction rate and efficiency of nickel sulfide; On the other hand, anionic surfactants reduce the surface tension of the solution, increase the contact area between sulfur and nickel, accelerate the reaction, thereby reducing the loss of iron during the precipitation of nickel sulfide. It is worth noting that after the anionic surfactants are added, the reaction rate and efficiency of nickel sulfide precipitation are improved, but iron still precipitates as time increases; Therefore, in order to ensure the purity of nickel sulfide, it is necessary to control the precipitation time. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0020] Figure 1 is the XRD pattern of nickel sulfide precipitate in Example 1 of the present invention; Figure 2 This is an XRD diagram of the crystals after the ferrous sulfate solution in sub-step S43 is evaporated and crystallized in Example 1 of the present invention.

[0021] The realization, functional features and advantages of the objectives of the present invention will be further described in conjunction with the embodiments with reference to the accompanying drawings. Specific Embodiments

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0023] Moreover, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0024] When the embodiments give numerical ranges, it should be understood that unless otherwise specified in the present invention, both endpoints of each numerical range and any value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention, based on the understanding of those of ordinary skill in the art of the prior art and the description of the present invention, can also use any methods, devices and materials of the prior art similar or equivalent to those described in the embodiments of the present invention to implement the present invention.

[0025] The present invention provides a processing method for nickel-iron alloy powder, comprising the steps of: S1, providing nickel-iron alloy powder; the nickel-iron alloy powder contains nickel element, iron element and chromium element.

[0026] As a further description of the nickel-iron alloy powder, the nickel-iron alloy powder is an alloy powder obtained by crushing nickel-iron alloy; in the nickel-iron alloy powder, the mass ratio of nickel is 8-20%, further 8-13%; in the nickel-iron alloy powder, the mass ratio of iron is 78-90%, further 80-90% or 78-82%; in the nickel-iron alloy powder, the mass ratio of chromium ≤ 5%, further, the mass ratio of chromium is 1-2%.

[0027] S2, subjecting the nickel-iron alloy powder to acid leaching, and after solid-liquid separation, obtaining leaching residue and leaching solution; cooling and crystallizing the leaching solution, and after solid-liquid separation, obtaining solid crystals and post-crystallization solution.

[0028] In the present invention, the acid solution used in the acid leaching includes one or more of sulfuric acid solution and hydrochloric acid solution; preferably, the acid solution used in the acid leaching includes sulfuric acid solution; when the acid solution includes the sulfuric acid solution, ferrous sulfate is contained in the solid crystal; when the acid solution is the sulfuric acid solution, the solid crystal is crude ferrous sulfate crystal.

[0029] In the present invention, the concentration of the sulfuric acid solution is 1 - 2.5 mol / L, further 1.8 - 2.2 mol / L or 1 - 2 mol / L; the temperature of the acid leaching is 60 - 80 °C, further 65 - 75 °C; the duration of the acid leaching is not less than 1.5 h, further 1.5 - 5 h, further 1.8 - 5 h, further 1.8 - 2.5 h; the solid-liquid ratio used in the acid leaching is 1 g:5 - 15 mL, further 1 g:8 - 10 mL, and the solid-liquid ratio is the mass-volume ratio of the nickel-iron alloy powder and the acid solution.

[0030] In the present invention, the temperature of the cooling crystallization is 10 - 30 °C, further 20 - 30 °C; the duration of the cooling crystallization is not less than 4 h, further 4 - 10 h, further 4 - 6 h or 5 - 6 h.

[0031] S3. Perform chromium precipitation treatment on the post-crystallization liquid, and obtain chromium precipitation slag (chromium-iron slag) and impurity-removed liquid after solid-liquid separation.

[0032] In the present invention, the chromium precipitation treatment includes: adjusting the pH of the post-crystallization liquid to 2 - 3, further 2 - 2.5 or 2.4 - 2.6; performing first mixing on the post-crystallization liquid and iron powder (reduced iron powder).

[0033] In the present invention, the pH of the post-crystallization liquid is adjusted by adding an alkaline substance, and the alkaline substance includes one or more of sodium hydroxide and potassium hydroxide.

[0034] In the present invention, the mass ratio of the iron powder to the chromium element in the post-crystallization liquid is 3 - 10:1, further 5 - 8:1, further 5 - 7:1, further 5 - 6:1; the temperature of the first mixing is 65 - 80 °C, further 65 - 75 °C, further 68 - 75 °C, further 68 - 72 °C, further 70 - 72 °C; the duration of the first mixing is 1.5 - 3 h, further 1.8 - 2.2 h.

[0035] It should be understood that the reducing iron powder can complex with chromium to form a precipitate; in addition, the reduced iron powder has certain adsorption properties, and can adsorb chromium ions in the solution on the surface by physical or chemical adsorption and form a precipitate. In the process of the chromium precipitation treatment in the present invention, reduced iron powder is used to remove chromium impurities, so that chromium chelates with it to form a precipitate, obtaining the chromium precipitation slag, thereby realizing the removal of chromium.

[0036] The temperature will affect the precipitation separation effect of chromium. Although the chromium precipitation treatment in the present invention requires heating, when the temperature is too high, the chromium-iron precipitate will form a relatively viscous colloidal complex, resulting in difficult filtration separation. While an appropriate temperature can make the chromium-iron precipitate exist in the form of particles, and the filtration separation effect is better. The reaction temperature and time will also affect the nickel loss rate. Higher temperature and longer reaction time will lead to an increase in the nickel loss rate, which is not conducive to economy. In addition, in the present invention, iron powder is considered for chromium removal. Besides the effect, the iron powder impurity removal process is placed before the nickel precipitation step to ensure that no other ionic impurities are introduced during the impurity removal process, and it has the function of shortening the impurity removal process.

[0037] Although there is a chromium removal method in existing research that uses reduced iron powder to directly adjust the pH, the method of directly adjusting the pH with iron powder will cause the iron concentration to increase excessively, increasing the separation difficulty. Moreover, it is very difficult to precisely control the pH only with iron powder. At the same time, in a high-concentration iron ion solution, a colloidal precipitate of iron hydroxide is formed in the solution, which is not conducive to chromium removal and the filtration process.

[0038] S4. Perform nickel-iron separation on the post-impurity removal liquid. After solid-liquid separation, nickel precipitate and iron separation liquid are obtained. The nickel precipitate mainly includes nickel sulfide precipitate, and the iron separation liquid mainly includes ferrous sulfate solution.

[0039] In the present invention, the nickel-iron separation includes: adjusting the pH of the post-impurity removal liquid to 1.5 - 2.5, further to 1.8 - 2.2, and further to 1.9 - 2.1; performing a second mixing of the post-impurity removal liquid, an anionic surfactant, and a sulfide; the duration of the second mixing is 50 - 90 min, further 50 - 80 min, and further 50 - 70 min. Before performing the second mixing in the present invention, the anionic surfactant and the sulfide are added to the post-impurity removal liquid, and stirring is performed during the addition process.

[0040] The molar ratio of the sulfide to the nickel element in the post-impurity removal liquid is 1 - 1.5:1, further 1.1 - 1.5:1, further 1.2 - 1.4:1 or 1.1 - 1.3:1 or 1.3 - 1.5:1; the mass percentage of the anionic surfactant and the sulfide is 3 - 8%, further 4 - 6%, and further 5 - 6%.

[0041] In the present invention, the anionic surfactant and the sulfide are added to the post-impurity removal liquid in the form of a mixed liquid; the mixed liquid includes or is the anionic surfactant, the sulfide, and water. The volume ratio of the mixed liquid to the post-impurity removal liquid is 1:6 - 10.

[0042] The process of performing the second mixing of the impurity-removed liquid, the anionic surfactant, and the sulfide includes: after dropping the mixed liquid of the sulfide and the anionic surfactant into the impurity-removed liquid, performing the second mixing, and stirring is carried out during both the dropping and the second mixing processes; the dropping speed of the mixed liquid is 1 - 5 mL / min, further 1 - 3 mL / min; the rotation speed of the stirring is 100 - 300 rpm.

[0043] In the present invention, the temperature of the second mixing is 10 - 40 °C, further 20 - 30 °C, and specifically it can be carried out at room temperature.

[0044] In the present invention, the anionic surfactant includes one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and α-olefin sulfonate; further, the anionic surfactant includes one or more of sodium dodecylbenzenesulfonate and sodium dodecyl sulfate. In the present invention, the sulfide includes one or more of sodium sulfide, potassium sulfide, lithium sulfide, and ammonium sulfide; further, the sulfide includes sodium sulfide.

[0045] In the present invention, the acid solution is usually a sulfuric acid solution, and the iron separation liquid is usually a ferrous sulfate solution.

[0046] The step S4 of the present invention may further include: performing evaporation crystallization on the iron separation liquid to obtain crude ferrous sulfate crystals; and / or, performing sulfuric acid oxidation leaching on the nickel precipitate to obtain a nickel sulfate solution.

[0047] As a further illustration of existing research, compared with pyrometallurgy, hydrometallurgy has advantages in terms of energy consumption, environmental protection, cost, etc. Currently, in industry, nickel-iron alloy is usually dissolved in an acidic solution, and then nickel products and iron products are obtained through nickel-iron separation technology; however, in existing nickel-iron separation technologies, the loss rates of nickel and iron are high, and impurities are easily introduced.

[0048] To solve the problems in existing nickel-iron separation technologies, such as high loss rates of nickel and iron and easy introduction of impurities, the present invention proposes a processing method for nickel-iron alloy powder, which achieves the effects of low loss rates of nickel and iron and high separation efficiency without introducing impurities, ensures the high purity of nickel sulfide products and the high recovery rate of nickel, and simultaneously obtains ferrous sulfate.

[0049] The following are specific examples of the present invention: Example 1 A processing method for nickel-iron alloy powder, the specific steps are as follows: S1, Weigh 100 g of powdered nickel-iron alloy; in the nickel-iron alloy, the mass proportion of Fe is 80.03%, the mass proportion of Ni is 11.37%, the mass proportion of Si is 2.30%, the mass proportion of Cr is 1.55%, and the mass proportion of C is 1.96%.

[0050] S2, Add the above nickel-iron alloy to 2 mol / L sulfuric acid solution according to a solid-liquid ratio of 1:9 g / mL, then carry out a dissolution reaction at 70 °C. After reacting for 2 h, filter to obtain leaching residue and a nickel-iron leaching solution (volume 810 mL) with a nickel concentration of 14.02 g / L, an iron concentration of 97.56 g / L, and a chromium concentration of 1.74 g / L.

[0051] Cool the above nickel-iron leaching solution at 25 °C for 5 h for crystallization, and after centrifugation, obtain crude ferrous sulfate crystals and a post-crystallization solution (volume 804 mL) with an iron concentration of 57.36 g / L, a nickel concentration of 14.07 g / L, and a chromium concentration of 1.75 g / L.

[0052] S3, Use 2 mol / L sodium hydroxide to adjust the pH of the above post-crystallization solution to 2.5, add reduced iron powder, and the mass ratio of the reduced iron powder to the chromium element in the post-crystallization solution is 5:1. Stir and react at 70 °C for 120 min, then filter to obtain chromium-iron slag (chromium precipitation slag) and a post-impurity-removal solution (volume 776 mL) with an iron concentration of 59.43 g / L, a nickel concentration of 14.40 g / L, and a chromium concentration of 0.01 g / L.

[0053] Compared with the post-crystallization solution, in the post-impurity-removal solution, the removal rate of chromium is 99.45%, and the loss rate of nickel is 1.22%.

[0054] S4, Carry out nickel-iron separation on the post-impurity-removal solution. The specific sub-steps are as follows: S41, Solution A: Adjust the pH of the post-impurity-removal solution to 2 with 1 mol / L sulfuric acid.

[0055] S42, Solution B: According to a molar ratio of sodium sulfide to nickel element in the post-impurity-removal solution of 1.2:1, dissolve sodium sulfide in 100 mL of water and add sodium dodecylbenzenesulfonate accounting for 5% of the mass of sodium sulfide.

[0056] S43, Slowly drip Solution B into Solution A at a dripping rate of 2 mL / min. At 25 °C, keep the stirring speed at 200 rpm. After dripping is completed, stir and react for 60 min; then, filter and separate to obtain nickel sulfide precipitate and a ferrous sulfate solution (volume 869 mL) with a nickel concentration of 0.15 g / L and an iron concentration of 52.68 g / L.

[0057] In the nickel sulfide precipitate, the loss rate of nickel is 1.17% compared with that in the nickel in the solution after impurity removal (the lost nickel enters the ferrous sulfate solution); in the ferrous sulfate solution, the loss rate of iron is 0.73% compared with that in the iron in the solution after impurity removal (the lost iron enters the nickel sulfide precipitate).

[0058] In this embodiment, the XRD analysis of the nickel sulfide precipitate is shown in Figure 1 as follows; in this embodiment, after the ferrous sulfate solution in sub-step S43 is evaporated and crystallized, the obtained crude ferrous sulfate crystals are subjected to XRD analysis, as shown in Figure 2 as follows.

[0059] Example 2 This embodiment is a processing method of nickel-iron alloy powder. The difference from Example 1 is that the mass ratio of reduced iron powder to chromium element in the crystallized solution is adjusted. The specific steps are as follows: S1, Weigh 100 g of powdery nickel-iron alloy (the same as in Example 1).

[0060] S2, Add the above nickel-iron alloy to 2 mol / L sulfuric acid solution according to the solid-liquid ratio of 1:9 g / mL, and then carry out a dissolution reaction at 70 °C. After reacting for 2 h, filter to obtain leaching residues and nickel-iron leaching solution.

[0061] Cool the above nickel-iron leaching solution at 25 °C for 5 h for crystallization, and after centrifugation, obtain crude ferrous sulfate crystals and crystallized solution.

[0062] S3, Use 2 mol / L sodium hydroxide to adjust the pH of the above crystallized solution to 2.5, add reduced iron powder, and the mass ratio of reduced iron powder to chromium element in the crystallized solution is 6:1. Stir and react at 70 °C for 120 min, and filter to obtain chromium-iron slag and impurity-removed solution.

[0063] Compared with the crystallized solution, in the impurity-removed solution, the removal rate of chromium is 99.39%, and the loss rate of nickel is 1.72%.

[0064] S4, Carry out nickel-iron separation on the impurity-removed solution. The specific sub-steps are as follows: S41, Solution A: Adjust the pH of the impurity-removed solution to 2 with 1 mol / L sulfuric acid.

[0065] S42, Solution B: According to the molar ratio of sodium sulfide to nickel element in the impurity-removed solution of 1.2:1, dissolve sodium sulfide in 100 mL of water and add sodium dodecylbenzenesulfonate accounting for 5% of the mass of sodium sulfide.

[0066] S43, Slowly drop Solution B into Solution A at a dropping rate of 2 mL / min. At 25 °C, keep the stirring speed at 200 rpm. After the dropping is completed, stir and react for 60 min; then, filter and separate to obtain nickel sulfide precipitate and ferrous sulfate solution.

[0067] Compared with nickel in the solution after impurity removal, the loss rate of nickel in nickel sulfide precipitate is 1.27% (the lost nickel enters the ferrous sulfate solution); compared with iron in the solution after impurity removal, the loss rate of iron in the ferrous sulfate solution is 0.54% (the lost iron enters the nickel sulfide precipitate).

[0068] Example 3 This example is a processing method of nickel-iron alloy powder. The difference from Example 1 is that the molar ratio of sodium sulfide to nickel element in the solution after impurity removal is adjusted. The specific steps are as follows: S1, Weigh 100 g of powdery nickel-iron alloy (the same as in Example 1).

[0069] S2, Add the above nickel-iron alloy to 2 mol / L sulfuric acid solution according to the solid-liquid ratio of 1:9 g / mL, and then carry out a dissolution reaction at 70 °C. After reacting for 2 h, filter to obtain leaching residue and nickel-iron leaching solution.

[0070] Cool the above nickel-iron leaching solution for crystallization at 25 °C for 5 h, and obtain crude ferrous sulfate crystals and post-crystallization solution after centrifugation.

[0071] S3, Use 2 mol / L sodium hydroxide to adjust the pH of the above post-crystallization solution to 2.5, add reduced iron powder, and the mass ratio of reduced iron powder to chromium element in the post-crystallization solution is 5:1. Stir and react at 70 °C for 120 min, and filter to obtain chromium-iron slag and solution after impurity removal.

[0072] S4, Carry out nickel-iron separation on the solution after impurity removal. The specific sub-steps are as follows: S41, Solution A: Adjust the pH of the solution after impurity removal to 2 with 1 mol / L sulfuric acid.

[0073] S42, Solution B: According to the molar ratio of sodium sulfide to nickel element in the solution after impurity removal being 1.4:1, dissolve sodium sulfide in 100 mL of water and add sodium dodecylbenzenesulfonate accounting for 5% of the mass of sodium sulfide.

[0074] S43, Slowly drip Solution B into Solution A at a dripping speed of 2 mL / min. At 25 °C, keep the stirring speed at 200 rpm. After the dripping is completed, stir and react for 60 min; then, filter and separate to obtain nickel sulfide precipitate and ferrous sulfate solution.

[0075] Compared with nickel in the solution after impurity removal, the loss rate of nickel in nickel sulfide precipitate is 0.96% (the lost nickel enters the ferrous sulfate solution); compared with iron in the solution after impurity removal, the loss rate of iron in the ferrous sulfate solution is 0.64% (the lost iron enters the nickel sulfide precipitate).

[0076] Example 4 This example is a processing method for nickel-iron alloy powder. The difference from Example 1 is that the specific substance of the anionic surfactant is adjusted. The specific steps are as follows: S1, Weigh 100 g of powdered nickel-iron alloy (the same as in Example 1).

[0077] S2, Add the above nickel-iron alloy to a 2 mol / L sulfuric acid solution according to a solid-liquid ratio of 1:9 g / mL, and then carry out a dissolution reaction at 70 °C. After reacting for 2 h, filter to obtain leached residue and nickel-iron leachate.

[0078] Cool the above nickel-iron leachate to crystallize at 25 °C for 5 h, and obtain crude ferrous sulfate crystals and crystallized solution after centrifugation.

[0079] S3, Use 2 mol / L sodium hydroxide to adjust the pH of the above crystallized solution to 2.5, add reduced iron powder, and the mass ratio of reduced iron powder to chromium element in the crystallized solution is 5:1. Stir and react at 70 °C for 120 min, and filter to obtain chromium-iron slag and impurity-removed solution.

[0080] S4, Carry out nickel-iron separation on the impurity-removed solution. The specific sub-steps are as follows: S41, Solution A: Adjust the pH of the impurity-removed solution to 2 with 1 mol / L sulfuric acid.

[0081] S42, Solution B: According to a molar ratio of sodium sulfide to nickel element in the impurity-removed solution of 1.2:1, dissolve sodium sulfide in 100 mL of water and add sodium dodecyl sulfate accounting for 5% of the mass of sodium sulfide.

[0082] S43, Slowly drip Solution B into Solution A at a dripping rate of 2 mL / min. At 25 °C, keep the stirring speed at 200 rpm. After dripping is completed, stir and react for 60 min; then, filter and separate to obtain nickel sulfide precipitate and ferrous sulfate solution.

[0083] Compared with the nickel in the impurity-removed solution, in the nickel sulfide precipitate, the loss rate of nickel is 1.36% (the lost nickel enters the ferrous sulfate solution); compared with the iron in the impurity-removed solution, in the ferrous sulfate solution, the loss rate of iron is 0.57% (the lost iron enters the nickel sulfide precipitate).

[0084] Comparative Example 1 This comparative example is a processing method for nickel-iron alloy powder. The difference from Example 1 is that the temperature in the process of removing impurities with reduced iron powder is changed. The specific steps are as follows: S1, Weigh 100 g of powdered nickel-iron alloy (the same as in Example 1).

[0085] S2, Add the above nickel-iron alloy to a 2 mol / L sulfuric acid solution according to a solid-liquid ratio of 1:9 g / mL, and then carry out a dissolution reaction at 70 °C. After reacting for 2 h, filter to obtain leaching residue and nickel-iron leaching solution.

[0086] Cool the above nickel-iron leaching solution at 25 °C for 5 h, and obtain crude ferrous sulfate crystals and crystallized solution after centrifugation.

[0087] S3, Use 2 mol / L sodium hydroxide to adjust the pH of the above crystallized solution to 2.5, add reduced iron powder, and the mass ratio of the reduced iron powder to the chromium element in the crystallized solution is 5:1. Stir and react at 60 °C for 120 min, and filter to obtain the solution after impurity removal.

[0088] Compared with the crystallized solution, in the solution after impurity removal, the removal rate of chromium is 55.2%, and the loss rate of nickel is 0.35%.

[0089] S4, Carry out nickel-iron separation on the solution after impurity removal. The specific sub-steps are as follows: S41, Solution A: Adjust the pH of the solution after impurity removal to 2 with 1 mol / L sulfuric acid.

[0090] S42, Solution B: According to the molar ratio of sodium sulfide to nickel element in the solution after impurity removal being 1.2:1, dissolve sodium sulfide in 100 mL of water, and add sodium dodecylbenzenesulfonate accounting for 5% of the mass of sodium sulfide.

[0091] S43, Slowly add Solution B to Solution A at a dropping rate of 2 mL / min. At 25 °C, keep the stirring speed at 200 rpm. After the dropping is completed, stir and react for 60 min; then, filter and separate to obtain a precipitate (denoted as nickel sulfide precipitate) and a separated solution (denoted as ferrous sulfate solution).

[0092] Compared with the nickel in the solution after impurity removal, in the nickel sulfide precipitate, the loss rate of nickel is 4.90% (the lost nickel enters the ferrous sulfate solution); compared with the iron in the solution after impurity removal, in the ferrous sulfate solution, the loss rate of iron is 0.55% (the lost iron enters the nickel sulfide precipitate).

[0093] At this time, a part of chromium follows the nickel sulfide precipitate, and another part enters the ferrous sulfate solution; compared with the chromium in the solution after impurity removal, in the nickel sulfide precipitate, the precipitation rate of chromium is 75%.

[0094] Comparative Example 2 This comparative example is a processing method of nickel-iron alloy powder. The difference from Example 1 is that no anionic surfactant is added during the nickel precipitation with sulfide. The specific steps are as follows: S1, Weigh 100 g of powdered nickel-iron alloy (the same as in Example 1).

[0095] S2. Add the above nickel-iron alloy into a 2 mol / L sulfuric acid solution according to a solid-liquid ratio of 1:9 g / mL, then carry out a dissolution reaction at 70 °C. After reacting for 2 h, filter to obtain a leaching residue and a nickel-iron leaching solution.

[0096] Cool the above nickel-iron leaching solution at 25 °C for 5 h for crystallization, and obtain crude ferrous sulfate crystals and a crystallized solution after centrifugation.

[0097] S3. Use 2 mol / L sodium hydroxide to adjust the pH of the above crystallized solution to 2.5, add reduced iron powder, and the mass ratio of the reduced iron powder to the chromium element in the crystallized solution is 5:1. Stir and react at 70 °C for 120 min, and filter to obtain a chromium-iron residue and a purified solution.

[0098] S4. Carry out nickel-iron separation on the purified solution. The specific sub-steps are as follows: S41. Solution A: Adjust the pH of the purified solution to 2 with 1 mol / L sulfuric acid.

[0099] S42. Solution B: Dissolve sodium sulfide in 100 mL of water according to a molar ratio of sodium sulfide to nickel element in the purified solution of 1.2:1.

[0100] S43. Slowly drip Solution B into Solution A at a dripping rate of 2 mL / min. At 25 °C, keep the stirring speed at 200 rpm. After dripping is completed, stir and react for 60 min; then, filter and separate to obtain a precipitate (denoted as nickel sulfide precipitate) and a separated solution (denoted as ferrous sulfate solution).

[0101] Compared with the nickel in the purified solution, in the nickel sulfide precipitate, the loss rate of nickel is 51.3% (the lost nickel enters the ferrous sulfate solution); compared with the iron in the purified solution, in the ferrous sulfate solution, the loss rate of iron is 20.94% (the lost iron enters the nickel sulfide precipitate).

[0102] Comparative Example 3 This comparative example is a processing method of nickel-iron alloy powder. The difference from Example 1 is that the reaction time in sub-step S43 is extended. The specific steps are as follows: S1. Weigh 100 g of powdered nickel-iron alloy (the same as in Example 1).

[0103] S2. Add the above nickel-iron alloy into a 2 mol / L sulfuric acid solution according to a solid-liquid ratio of 1:9 g / mL, then carry out a dissolution reaction at 70 °C. After reacting for 2 h, filter to obtain a leaching residue and a nickel-iron leaching solution.

[0104] Cool the above nickel-iron leaching solution at 25 °C for 5 h for crystallization, and obtain crude ferrous sulfate crystals and a crystallized solution after centrifugation.

[0105] S3. Adjust the pH of the above post-crystallization solution to 2.5 with 2 mol / L sodium hydroxide. Add reduced iron powder, and the mass ratio of the reduced iron powder to the chromium element in the post-crystallization solution is 5:1. Stir and react at 70 °C for 120 min, and filter to obtain chromium-iron slag and post-impurity-removal solution.

[0106] S4. Perform nickel-iron separation on the post-impurity-removal solution. The specific sub-steps are as follows: S41. Solution A: Adjust the pH of the post-impurity-removal solution to 2 with 1 mol / L sulfuric acid.

[0107] S42. Solution B: According to the molar ratio of sodium sulfide to nickel element in the post-impurity-removal solution being 1.2:1, dissolve sodium sulfide in 100 mL of water and add sodium dodecylbenzenesulfonate accounting for 5% of the mass of sodium sulfide.

[0108] S43. Slowly drip Solution B into Solution A at a dripping rate of 2 mL / min. At 25 °C, keep the stirring speed at 200 rpm. After the dripping is completed, stir and react for 120 min; then, filter and separate to obtain a precipitate (denoted as nickel sulfide precipitate) and a separated solution (denoted as ferrous sulfate solution).

[0109] Compared with the nickel in the post-impurity-removal solution, in the nickel sulfide precipitate, the loss rate of nickel is 1.47% (the lost nickel enters the ferrous sulfate solution); compared with the iron in the post-impurity-removal solution, in the ferrous sulfate solution, the loss rate of iron is 14.44% (the lost iron enters the nickel sulfide precipitate).

[0110] In the above technical solution of the present invention, the above is only the preferred embodiment of the present invention, and does not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made under the technical concept of the present invention by using the content of the specification and drawings of the present invention, or any direct / indirect application in other related technical fields is included in the patent protection scope of the present invention.

Claims

1. A processing method of nickel-iron alloy powder, characterized in that, Including the steps: S1. Provide nickel-iron alloy powder; the nickel-iron alloy powder contains nickel element, iron element and chromium element; S2. Acid-leach the nickel-iron alloy powder to obtain leaching residue and leaching solution; cool and crystallize the leaching solution to obtain solid crystals and post-crystallization solution; S3. Perform chromium precipitation treatment on the post-crystallization solution to obtain chromium precipitation residue and impurity-removed solution; The chromium precipitation treatment includes: adjusting the pH of the post-crystallization solution to 2-3, and then mixing the post-crystallization solution and iron powder for the first time; S4. Separate nickel and iron from the impurity-removed solution to obtain nickel precipitate and iron separation solution; The nickel-iron separation includes: adjusting the pH of the impurity-removed solution to 1.5-2.5, mixing the impurity-removed solution, anionic surfactant and sulfide for the second time; the duration of the second mixing is 50-90 min; the molar ratio of the sulfide to the nickel element in the impurity-removed solution is 1-1.5:1; the mass percentage of the anionic surfactant and the sulfide is 3-8%; 2. The processing method of the nickel-iron alloy powder according to claim 1, characterized in that, The mass ratio of the iron powder to the chromium element in the post-crystallization solution is 3-10:

1.

3. The processing method of the nickel-iron alloy powder according to claim 1, characterized in that The temperature of the first mixing is 65-80 °C; the duration of the first mixing is 1.5-3 h.

4. The processing method of the nickel-iron alloy powder according to claim 1, characterized in that, The anionic surfactant and the sulfide are added to the impurity-removed solution in the form of a mixed solution; the volume ratio of the mixed solution to the impurity-removed solution is 1:6-10.

5. The processing method of the nickel-iron alloy powder according to claim 1, characterized in that, The temperature of the second mixing is 10-40 °C.

6. The processing method of the nickel-iron alloy powder according to claim 1, characterized in that, The anionic surfactant includes one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and α-olefin sulfonate; the sulfide includes one or more of sodium sulfide, potassium sulfide, lithium sulfide, and ammonium sulfide.

7. The processing method of the nickel-iron alloy powder according to claim 1, characterized in that, The temperature of the cooling crystallization is 10-30 °C, and the duration of the cooling crystallization is not less than 4 h.

8. The processing method of the nickel-iron alloy powder according to claim 1, characterized in that, The acid solution used for the acid leaching includes sulfuric acid solution, and the solid crystals contain ferrous sulfate; the concentration of the sulfuric acid solution is 1-2.5 mol / L.

9. The processing method of the nickel-iron alloy powder according to claim 1, characterized in that, The temperature of the acid leaching is 60-80 °C; the duration of the acid leaching is not less than 1.5 h; the solid-liquid ratio used for the acid leaching is 1 g:5-15 mL.

10. The processing method of the nickel-iron alloy powder according to any one of claims 1-9, characterized in that, Step S4 further includes: performing evaporation crystallization on the iron separation solution.

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