A processing method of nickel-iron alloy powder

Abstract

The invention provides a method for processing nickel-iron alloy powder, comprising the following steps: S1, providing nickel-iron alloy powder; the nickel-iron alloy powder contains nickel, iron and chromium elements; S2, performing acid leaching on the nickel-iron alloy powder to obtain leaching residue and leaching liquid; cooling and crystallizing the leaching liquid to obtain solid crystals and a post-crystallization liquid; S3, performing chromium precipitation treatment on the post-crystallization liquid to obtain chromium precipitation residue and a post-impurity removal liquid; S4, performing nickel-iron separation on the post-impurity removal liquid to obtain a nickel precipitate and an iron separation liquid. The invention obtains a nickel precipitate and an iron separation liquid by processing the nickel-iron alloy powder, thereby reducing the iron doping in the nickel precipitate; the invention also effectively removes chromium before performing nickel-iron separation, thereby ensuring the acquisition of high-quality nickel products.

Description

Technical Field

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

[0002] Currently, lithium battery technology is constantly innovating, with a clear trend toward higher nickel content. This has led to a surge in demand for nickel and other metal resources. However, nickel-iron alloys are currently in oversupply. Processing nickel-iron alloys into nickel raw materials not only reduces nickel-iron alloy waste but also effectively addresses nickel raw material supply issues, resulting in nickel products for use in the battery industry. Therefore, processing nickel-iron alloys into high-yield, high-purity nickel products remains a major technical challenge in this field.

[0003] Chinese invention patent application publication number CN117380950A discloses a nickel-iron alloy dissolution process, comprising: melting the nickel-iron alloy and pulverizing it to obtain nickel-iron alloy powder; dissolving the nickel-iron alloy powder in an acid solution, while also adding a small amount of iron powder; heating and stirring the nickel-iron alloy powder, and performing solid-liquid separation to obtain an acidic nickel-iron solution and a filter residue, which is then returned to the dissolution stage for further reaction; adding an appropriate amount of sulfide to the acidic nickel-iron solution, heating and stirring the solution, and performing solid-liquid separation to obtain a ferrous sulfate solution and nickel sulfide residue; and then applying the ferrous sulfate and nickel sulfide to the battery industry.

[0004] While the aforementioned patent application achieves the processing of ferroarsenic alloys, resulting in nickel and iron products for use in the battery industry, it utilizes only conventional sulfidation nickel deposition, which introduces iron impurities into the nickel product, affecting nickel purity and increasing iron loss. Furthermore, some ferroarsenic alloys often contain chromium, which cannot be effectively removed by acid leaching and conventional sulfidation alone, thereby affecting the quality of the nickel and iron products.

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

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

[0007] To achieve the above object, the present invention provides a method for processing nickel-iron alloy powder, comprising the steps of:

[0008] S1, providing nickel-iron alloy powder; the nickel-iron alloy powder contains nickel, iron and chromium;

[0009] S2, acid leaching the nickel-iron alloy powder to obtain leached residue and leachate; cooling and crystallizing the leachate to obtain solid crystals and a post-crystallization liquid;

[0010] S3, performing chromium precipitation treatment on the crystallized liquid to obtain chromium precipitation residue and impurity-removed liquid;

[0011] The chromium precipitation treatment comprises: adjusting the pH of the crystallized liquid to 2-3, and then first mixing the crystallized liquid and iron powder;

[0012] S4, separating the impurity-removed liquid into nickel and iron to obtain a nickel precipitate and an iron separation liquid;

[0013] The nickel-iron separation includes: adjusting the pH of the impurity-removed liquid to 1.5-2.5, and performing a second mixing of the impurity-removed liquid, anionic surfactant, and sulfide; the duration of the second mixing is 50-90 minutes; the molar ratio of the sulfide to the nickel element in the impurity-removed liquid is 1-1.5:1; and the mass percentage of the anionic surfactant and the sulfide is 3-8%.

[0014] Furthermore, the mass ratio of the iron powder to the chromium element in the post-crystallization liquid is 3-10:1.

[0015] Furthermore, the temperature of the first mixing is 65-80° C.; and the duration of the first mixing is 1.5-3 hours.

[0016] Furthermore, the anionic surfactant and the sulfide are added to the impurity-removed liquid in the form of a mixed liquid; the volume ratio of the mixed liquid to the impurity-removed liquid is 1:6-10.

[0017] Furthermore, the temperature of the second mixing is 10-40°C.

[0018] Furthermore, the anionic surfactant includes one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and sodium α-olefinsulfonate; and the sulfide includes one or more of sodium sulfide, potassium sulfide, lithium sulfide, and ammonium sulfide.

[0019] Furthermore, the temperature of the cooling crystallization is 10-30°C, and the duration of the cooling crystallization is not less than 4 hours.

[0020] Furthermore, the acid solution used in the acid leaching includes a sulfuric acid solution, and the solid crystals contain ferrous sulfate; the concentration of the sulfuric acid solution is 1-2.5 mol / L.

[0021] Furthermore, the acid leaching temperature is 60-80° C.; the acid leaching time is not less than 1.5 hours; and the solid-liquid ratio used in the acid leaching is 1 g:5-15 mL.

[0022] Furthermore, the step S4 further comprises: evaporating and crystallizing the iron separation liquid.

[0023] Compared with the prior art, the present invention has at least the following advantages:

[0024] 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 before carrying out nickel-iron separation, chromium is effectively removed, and high-quality nickel product is obtained. Specifically, the nickel-iron alloy powder of the present invention is subjected to acid leaching to obtain leachate, and after cooling 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 impact 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 ferrous precipitation, as well as complex adsorption on the surface of nickel sulfide, reduce the iron content in the nickel sulfide precipitate, and obtain nickel precipitate and iron separation liquid. The present invention solves the problems such as nickel-iron separation difficulty, high iron content, high chromium impurity content, and low nickel-iron recovery rate in the nickel sulfide precipitation process, and has greater industrial application value.

[0025] During sulfidation, nickel sulfide is preferentially precipitated due to its lower solubility product, but due to sulfidation efficiency and adsorption, some iron is precipitated therewith;Therefore, the content of iron is reduced by crystallization by cooling, not only can subsequent iron recovery pressure be alleviated, but also the iron loss in subsequent sulfidation nickel precipitation step can be reduced. The present invention is by adding anionic surfactant, on the one hand, nickel sulfide is preferentially precipitated, and anionic surfactant can increase the electrostatic repulsion between solid-liquid phase interface, reduce the adsorption of iron during agglomeration, and improve nickel sulfide precipitation reaction rate and efficiency;On the other hand, anionic surfactant reduces the surface tension of solution, increases the contact area of ​​sulphur and nickel, accelerates the reaction, so as to reduce the loss of iron during nickel sulfide precipitation. It is worth noting that after anionic surfactant is added, the reaction rate and efficiency of nickel sulfide precipitation are improved, but iron still can increase and produce precipitation over time;Therefore, in order to ensure the purity of nickel sulfide, it is necessary to control the precipitation time. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0027] Figure 1 is the XRD pattern of nickel sulfide precipitate in Example 1 of the present invention;

[0028] Figure 2 This is the XRD pattern of the crystals after the ferrous sulfate solution is evaporated and crystallized in sub-step S43 in Example 1 of the present invention.

[0029] The realization of the objectives, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0031] Moreover, the technical solutions between the various embodiments of the present invention may be combined with each other, but this must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0032] When numerical ranges are given in the examples, it should be understood that unless otherwise specified herein, both endpoints of each numerical range and any value between the two endpoints may be used. Unless otherwise defined, all technical and scientific terms used herein are consistent with the prior art as understood by those skilled in the art and the description of the present invention. Any prior art methods, devices, and materials similar or equivalent to those described in the examples of the present invention may also be used to implement the present invention.

[0033] The present invention provides a method for processing nickel-iron alloy powder, comprising the steps of:

[0034] S1, providing nickel-iron alloy powder; the nickel-iron alloy powder contains nickel, iron and chromium.

[0035] As a further description of the nickel-iron alloy powder, the nickel-iron alloy powder is an alloy powder obtained after crushing the nickel-iron alloy; in the nickel-iron alloy powder, the mass proportion of nickel is 8-20%, further 8-13%; in the nickel-iron alloy powder, the mass proportion of iron is 78-90%, further 80-90% or 78-82%; in the nickel-iron alloy powder, the mass proportion of chromium is ≤5%, further, the mass proportion of chromium is 1-2%.

[0036] S2, acid leaching the nickel-iron alloy powder to obtain leaching residue and leaching liquid after solid-liquid separation; cooling and crystallizing the leaching liquid to obtain solid crystals and post-crystallization liquid after solid-liquid separation.

[0037] In the present invention, the acid solution used for acid leaching includes one or more of a sulfuric acid solution and a hydrochloric acid solution; preferably, the acid solution used for acid leaching includes a sulfuric acid solution; when the acid solution includes the sulfuric acid solution, the solid crystals contain ferrous sulfate; when the acid solution is the sulfuric acid solution, the solid crystals are crude ferrous sulfate crystals.

[0038] 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-to-volume ratio of the nickel-iron alloy powder to the acid solution.

[0039] 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 4h, further 4-10h, further 4-6h or 5-6h.

[0040] S3, performing chromium precipitation treatment on the liquid after crystallization, and obtaining chromium precipitation slag (ferrochrome slag) and impurity-removed liquid after solid-liquid separation.

[0041] In the present invention, the chromium precipitation treatment includes: adjusting the pH of the post-crystallization liquid to 2-3, further to 2-2.5 or 2.4-2.6; and first mixing the post-crystallization liquid with iron powder (reduced iron powder).

[0042] 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.

[0043] In the present invention, the mass ratio of the iron powder to the chromium element in the crystallized 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 1.5-3h, further 1.8-2.2h.

[0044] It should be understood that reduced iron powder can complex with chromium to form a precipitate; furthermore, reduced iron powder has certain adsorption properties, and can adsorb chromium ions in the solution onto its surface through physical or chemical adsorption to form a precipitate. During the chromium precipitation process of the present invention, reduced iron powder is used to remove chromium impurities, causing chromium to chelate with the reduced iron powder to form a precipitate, thereby obtaining the chromium precipitation residue, thereby achieving chromium removal.

[0045] Temperature affects the chromium precipitation and separation process. Although the chromium precipitation process of the present invention requires heating, when the temperature is too high, the ferrochrome precipitate will form a relatively viscous colloidal complex, making filtration and separation difficult. However, the appropriate temperature can cause the ferrochrome precipitate to exist in a granular form, which is more effective for filtration and separation. The reaction temperature and time also affect the nickel loss rate. Higher temperatures and longer reaction times lead to increased nickel loss, which is not conducive to economic efficiency. In addition, the present invention considers the use of iron powder to remove chromium. In addition to its effectiveness, the iron powder impurity removal process is placed before the nickel precipitation step to ensure that other ionic impurities are not introduced during the impurity removal process, which has the function of shortening the impurity removal process.

[0046] Although existing research has found a method for removing chromium by directly adjusting the pH using reduced iron powder, using iron powder to directly adjust the pH will cause the iron concentration to increase excessively, increasing the difficulty of separation. In addition, it is difficult to achieve precise pH control using only 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 the chromium removal and filtration process.

[0047] S4, performing nickel-iron separation on the impurity-removed liquid, and obtaining a nickel precipitate and an iron separation liquid after solid-liquid separation; the nickel precipitate mainly comprises nickel sulfide precipitate, and the iron separation liquid mainly comprises a ferrous sulfate solution.

[0048] In the present invention, the nickel-iron separation includes: adjusting the pH of the impurity-removed liquid to 1.5-2.5, further to 1.8-2.2, and further to 1.9-2.1; performing a second mixing on the impurity-removed liquid, an anionic surfactant, and a sulfide; the duration of the second mixing is 50-90 minutes, further to 50-80 minutes, and further to 50-70 minutes; before performing the second mixing, the anionic surfactant and the sulfide are added to the impurity-removed liquid, and stirring is performed during the addition process.

[0049] The molar ratio of the sulfide to the nickel element in the impurity-removed 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%, further 5-6%.

[0050] In the present invention, the anionic surfactant and the sulfide are added to the impurity-removed liquid in the form of a mixed liquid; the mixed liquid includes or consists of the anionic surfactant, the sulfide, and water. The volume ratio of the mixed liquid to the impurity-removed liquid is 1:6-10.

[0051] The process of performing the second mixing of the impurity-removed liquid, the anionic surfactant, and the sulfide includes: dropwise adding the mixed liquid of the sulfide and the anionic surfactant to the impurity-removed liquid, and then performing the second mixing, and stirring is performed during the dropwise addition and the second mixing; the dropping speed of the mixed liquid is 1-5 mL / min, further 1-3 mL / min; and the stirring speed is 100-300 rpm.

[0052] In the present invention, the temperature of the second mixing is 10-40° C., further 20-30° C., and can be specifically carried out at room temperature.

[0053] In the present invention, the anionic surfactant includes one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and sodium 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.

[0054] In the present invention, the acid solution is usually a sulfuric acid solution, and the iron separation solution is usually a ferrous sulfate solution.

[0055] The step S4 of the present invention may further include: evaporating and crystallizing the iron separation liquid to obtain crude ferrous sulfate crystals; and / or oxidizing and leaching the nickel precipitate with sulfuric acid to obtain a nickel sulfate solution.

[0056] As a further illustration of existing research, compared with pyrometallurgy, hydrometallurgy has advantages in energy consumption, environmental protection, and cost. Currently, nickel-iron alloys are usually dissolved in an acidic solution in industry, and then nickel products and iron products are obtained through nickel-iron separation technology; however, in the existing nickel-iron separation technology, the nickel and iron loss rates are high, and impurities are easily introduced.

[0057] In order to solve the problems of high nickel and iron loss rates and easy introduction of impurities in existing nickel-iron separation technologies, the present invention proposes a processing method for nickel-iron alloy powder. Without introducing impurities, the method achieves the effects of low nickel and iron loss rates and high separation efficiency, ensures the high purity of the nickel sulfide product and the high nickel recovery rate, and simultaneously obtains ferrous sulfate.

[0058] The following are specific examples of the present invention:

[0059] Example 1

[0060] A method for processing nickel-iron alloy powder, comprising the following steps:

[0061] 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%.

[0062] S2, the above-mentioned nickel-iron alloy was added to a 2 mol / L sulfuric acid solution at a solid-liquid ratio of 1:9 g / mL, and then dissolved at 70°C. After reacting for 2 hours, it was filtered to obtain leaching residue and nickel-iron leachate (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.

[0063] The nickel-iron leaching solution was cooled and crystallized at 25° C. for 5 h, and after centrifugation, crude ferrous sulfate crystals and a post-crystallization solution (volume 804 mL) having 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 were obtained.

[0064] S3, using 2 mol / L sodium hydroxide to adjust the pH of the above-mentioned crystallization liquid to 2.5, adding reduced iron powder, the mass ratio of reduced iron powder to chromium element in the crystallization liquid is 5:1, stirring and reacting at 70°C for 120 minutes, filtering to obtain ferrochrome slag (precipitated chromium slag) and a decontaminated liquid (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.

[0065] Compared with the liquid after crystallization, the chromium removal rate in the liquid after impurity removal was 99.45%, and the nickel loss rate was 1.22%.

[0066] S4, separating nickel and iron from the impurity-removed liquid, the specific sub-steps are:

[0067] S41, Solution A: Adjust the pH of the decontaminated solution to 2 using 1 mol / L sulfuric acid.

[0068] S42, Solution B: Dissolve sodium sulfide in 100 mL of water at a molar ratio of 1.2:1 between sodium sulfide and nickel in the purified solution, and add sodium dodecylbenzene sulfonate (5% by weight of sodium sulfide).

[0069] S43, slowly add solution B to solution A at a dropping rate of 2 mL / min, maintain a stirring speed of 200 rpm at 25°C, and after the dropwise addition is completed, stir the reaction for 60 minutes; then, filter and separate to obtain a 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.

[0070] Compared with the nickel in the liquid after impurity removal, the nickel loss rate in the nickel sulfide precipitate is 1.17% (the lost nickel enters the ferrous sulfate solution); compared with the iron in the liquid after impurity removal, the iron loss rate in the ferrous sulfate solution is 0.73% (the lost iron enters the nickel sulfide precipitate).

[0071] In this example, the XRD analysis of nickel sulfide precipitate is shown in Figure 1 In this embodiment, after evaporation and crystallization of the ferrous sulfate solution in sub-step S43, the crude ferrous sulfate crystals obtained were subjected to XRD analysis, see Figure 2 shown.

[0072] Example 2

[0073] This embodiment is a method for processing nickel-iron alloy powder. The difference from Example 1 is that the mass ratio of the reduced iron powder and the chromium element in the crystallized liquid is adjusted. The specific steps are as follows:

[0074] S1. Weigh 100 g of powdered nickel-iron alloy (same as in Example 1).

[0075] S2, adding the above nickel-iron alloy to a 2 mol / L sulfuric acid solution at a solid-liquid ratio of 1:9 g / mL, and then dissolving and reacting at 70° C., reacting for 2 hours, and filtering to obtain leaching residue and nickel-iron leachate.

[0076] The nickel-iron leaching solution was cooled and crystallized at 25° C. for 5 h, and then centrifuged to obtain crude ferrous sulfate crystals and a post-crystallization solution.

[0077] S3, using 2 mol / L sodium hydroxide to adjust the pH of the above crystallized liquid to 2.5, adding reduced iron powder, the mass ratio of reduced iron powder to chromium element in the crystallized liquid is 6:1, stirring and reacting at 70° C. for 120 minutes, and filtering to obtain ferrochrome slag and impurity-removed liquid.

[0078] Compared with the liquid after crystallization, the chromium removal rate in the liquid after impurity removal was 99.39% and the nickel loss rate was 1.72%.

[0079] S4, separating nickel and iron from the impurity-removed liquid, the specific sub-steps are:

[0080] S41, Solution A: Adjust the pH of the decontaminated solution to 2 using 1 mol / L sulfuric acid.

[0081] S42, Solution B: Dissolve sodium sulfide in 100 mL of water at a molar ratio of 1.2:1 between sodium sulfide and nickel in the purified solution, and add sodium dodecylbenzene sulfonate (5% by weight of sodium sulfide).

[0082] S43, slowly adding solution B to solution A at a dropping rate of 2 mL / min, maintaining a stirring speed of 200 rpm at 25° C. After the dropwise addition is completed, stirring and reacting for 60 minutes; then, filtering and separating to obtain nickel sulfide precipitate and ferrous sulfate solution.

[0083] Compared with the nickel in the liquid after impurity removal, the nickel loss rate in the nickel sulfide precipitate is 1.27% (the lost nickel enters the ferrous sulfate solution); compared with the iron in the liquid after impurity removal, the iron loss rate in the ferrous sulfate solution is 0.54% (the lost iron enters the nickel sulfide precipitate).

[0084] Example 3

[0085] This embodiment is a method for processing nickel-iron alloy powder. The difference from Example 1 is that the molar ratio of sodium sulfide to nickel in the impurity-removed liquid is adjusted. The specific steps are as follows:

[0086] S1. Weigh 100 g of powdered nickel-iron alloy (same as in Example 1).

[0087] S2, adding the above nickel-iron alloy to a 2 mol / L sulfuric acid solution at a solid-liquid ratio of 1:9 g / mL, and then dissolving and reacting at 70° C., reacting for 2 hours, and filtering to obtain leaching residue and nickel-iron leachate.

[0088] The nickel-iron leaching solution was cooled and crystallized at 25° C. for 5 h, and then centrifuged to obtain crude ferrous sulfate crystals and a post-crystallization solution.

[0089] S3, using 2 mol / L sodium hydroxide to adjust the pH of the above crystallized liquid to 2.5, adding reduced iron powder, the mass ratio of reduced iron powder to chromium element in the crystallized liquid being 5:1, stirring and reacting at 70° C. for 120 min, and filtering to obtain ferrochrome slag and impurity-removed liquid.

[0090] S4, separating nickel and iron from the impurity-removed liquid, the specific sub-steps are:

[0091] S41, Solution A: Adjust the pH of the decontaminated solution to 2 using 1 mol / L sulfuric acid.

[0092] S42, Solution B: Dissolve sodium sulfide in 100 mL of water at a molar ratio of sodium sulfide to nickel in the purified solution of 1.4:1, and add sodium dodecylbenzene sulfonate (5% by weight of sodium sulfide).

[0093] S43, slowly adding solution B to solution A at a dropping rate of 2 mL / min, maintaining a stirring speed of 200 rpm at 25° C. After the dropwise addition is completed, stirring and reacting for 60 minutes; then, filtering and separating to obtain nickel sulfide precipitate and ferrous sulfate solution.

[0094] Compared with the nickel in the liquid after impurity removal, the nickel loss rate in the nickel sulfide precipitate is 0.96% (the lost nickel enters the ferrous sulfate solution); compared with the iron in the liquid after impurity removal, the iron loss rate in the ferrous sulfate solution is 0.64% (the lost iron enters the nickel sulfide precipitate).

[0095] Example 4

[0096] This embodiment is a method for processing 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:

[0097] S1. Weigh 100 g of powdered nickel-iron alloy (same as in Example 1).

[0098] S2, adding the above nickel-iron alloy to a 2 mol / L sulfuric acid solution at a solid-liquid ratio of 1:9 g / mL, and then dissolving and reacting at 70° C., reacting for 2 hours, and filtering to obtain leaching residue and nickel-iron leachate.

[0099] The nickel-iron leaching solution was cooled and crystallized at 25° C. for 5 h, and then centrifuged to obtain crude ferrous sulfate crystals and a post-crystallization solution.

[0100] S3, using 2 mol / L sodium hydroxide to adjust the pH of the above crystallized liquid to 2.5, adding reduced iron powder, the mass ratio of reduced iron powder to chromium element in the crystallized liquid being 5:1, stirring and reacting at 70° C. for 120 min, and filtering to obtain ferrochrome slag and impurity-removed liquid.

[0101] S4, separating nickel and iron from the impurity-removed liquid, the specific sub-steps are:

[0102] S41, Solution A: Adjust the pH of the decontaminated solution to 2 using 1 mol / L sulfuric acid.

[0103] S42, Solution B: Dissolve sodium sulfide in 100 mL of water at a molar ratio of 1.2:1 between sodium sulfide and nickel in the purified solution, and add sodium lauryl sulfate (5% by mass of sodium sulfide).

[0104] S43, slowly adding solution B to solution A at a dropping rate of 2 mL / min, maintaining a stirring speed of 200 rpm at 25° C. After the dropwise addition is completed, stirring and reacting for 60 minutes; then, filtering and separating to obtain nickel sulfide precipitate and ferrous sulfate solution.

[0105] Compared with the nickel in the liquid after impurity removal, the nickel loss rate in the nickel sulfide precipitate is 1.36% (the lost nickel enters the ferrous sulfate solution); compared with the iron in the liquid after impurity removal, the iron loss rate in the ferrous sulfate solution is 0.57% (the lost iron enters the nickel sulfide precipitate).

[0106] Comparative Example 1

[0107] This comparative example is a method for processing nickel-iron alloy powder. The difference from Example 1 is that the temperature during the impurity removal process of the reduced iron powder is changed. The specific steps are as follows:

[0108] S1. Weigh 100 g of powdered nickel-iron alloy (same as in Example 1).

[0109] S2, adding the above nickel-iron alloy to a 2 mol / L sulfuric acid solution at a solid-liquid ratio of 1:9 g / mL, and then dissolving and reacting at 70° C., reacting for 2 hours, and filtering to obtain leaching residue and nickel-iron leachate.

[0110] The nickel-iron leaching solution was cooled and crystallized at 25° C. for 5 h, and then centrifuged to obtain crude ferrous sulfate crystals and a post-crystallization solution.

[0111] S3, using 2 mol / L sodium hydroxide to adjust the pH of the above crystallized liquid to 2.5, adding reduced iron powder, the mass ratio of reduced iron powder to chromium element in the crystallized liquid is 5:1, stirring and reacting at 60° C. for 120 minutes, and filtering to obtain the impurity-removed liquid.

[0112] Compared with the liquid after crystallization, the chromium removal rate in the liquid after impurity removal was 55.2%, and the nickel loss rate was 0.35%.

[0113] S4, separating nickel and iron from the impurity-removed liquid, the specific sub-steps are:

[0114] S41, Solution A: Adjust the pH of the decontaminated solution to 2 using 1 mol / L sulfuric acid.

[0115] S42, Solution B: Dissolve sodium sulfide in 100 mL of water at a molar ratio of 1.2:1 between sodium sulfide and nickel in the purified solution, and add sodium dodecylbenzene sulfonate (5% by weight of sodium sulfide).

[0116] S43, slowly add solution B to solution A at a dropping rate of 2 mL / min, maintain a stirring speed of 200 rpm at 25°C, and after the addition is completed, stir the reaction for 60 minutes; then, filter and separate to obtain a precipitate (recorded as nickel sulfide precipitate) and a separated liquid (recorded as ferrous sulfate solution).

[0117] Compared with the nickel in the liquid after impurity removal, the nickel loss rate in the nickel sulfide precipitate is 4.90% (the lost nickel enters the ferrous sulfate solution); compared with the iron in the liquid after impurity removal, the iron loss rate in the ferrous sulfate solution is 0.55% (the lost iron enters the nickel sulfide precipitate).

[0118] At this time, part of the chromium precipitates with the nickel sulfide, and the other part enters the ferrous sulfate solution; compared with the chromium in the liquid after impurity removal, the precipitation rate of chromium in the nickel sulfide precipitate is 75%.

[0119] Comparative Example 2

[0120] This comparative example is a method for processing nickel-iron alloy powder. The difference from Example 1 is that no anionic surfactant is added during the nickel sulfide precipitation process. The specific steps are as follows:

[0121] S1. Weigh 100 g of powdered nickel-iron alloy (same as in Example 1).

[0122] S2, adding the above nickel-iron alloy to a 2 mol / L sulfuric acid solution at a solid-liquid ratio of 1:9 g / mL, and then dissolving and reacting at 70° C., reacting for 2 hours, and filtering to obtain leaching residue and nickel-iron leachate.

[0123] The nickel-iron leaching solution was cooled and crystallized at 25° C. for 5 h, and then centrifuged to obtain crude ferrous sulfate crystals and a post-crystallization solution.

[0124] S3, using 2 mol / L sodium hydroxide to adjust the pH of the above crystallized liquid to 2.5, adding reduced iron powder, the mass ratio of reduced iron powder to chromium element in the crystallized liquid being 5:1, stirring and reacting at 70° C. for 120 min, and filtering to obtain ferrochrome slag and impurity-removed liquid.

[0125] S4, separating nickel and iron from the impurity-removed liquid, the specific sub-steps are:

[0126] S41, Solution A: Adjust the pH of the decontaminated solution to 2 using 1 mol / L sulfuric acid.

[0127] S42, Solution B: Dissolve sodium sulfide in 100 mL of water at a molar ratio of 1.2:1 between sodium sulfide and nickel in the purified solution.

[0128] S43, slowly add solution B to solution A at a dropping rate of 2 mL / min, maintain a stirring speed of 200 rpm at 25°C, and after the addition is completed, stir the reaction for 60 minutes; then, filter and separate to obtain a precipitate (recorded as nickel sulfide precipitate) and a separated liquid (recorded as ferrous sulfate solution).

[0129] Compared with the nickel in the liquid after impurity removal, the nickel loss rate in the nickel sulfide precipitate is 51.3% (the lost nickel enters the ferrous sulfate solution); compared with the iron in the liquid after impurity removal, the iron loss rate in the ferrous sulfate solution is 20.94% (the lost iron enters the nickel sulfide precipitate).

[0130] Comparative Example 3

[0131] This comparative example is a method for processing nickel-iron alloy powder. The difference from Example 1 is that the reaction time in sub-step S43 is extended. The specific steps are:

[0132] S1. Weigh 100 g of powdered nickel-iron alloy (same as in Example 1).

[0133] S2, adding the above nickel-iron alloy to a 2 mol / L sulfuric acid solution at a solid-liquid ratio of 1:9 g / mL, and then dissolving and reacting at 70° C., reacting for 2 hours, and filtering to obtain leaching residue and nickel-iron leachate.

[0134] The nickel-iron leaching solution was cooled and crystallized at 25° C. for 5 h, and then centrifuged to obtain crude ferrous sulfate crystals and a post-crystallization solution.

[0135] S3, using 2 mol / L sodium hydroxide to adjust the pH of the above crystallized liquid to 2.5, adding reduced iron powder, the mass ratio of reduced iron powder to chromium element in the crystallized liquid being 5:1, stirring and reacting at 70° C. for 120 min, and filtering to obtain ferrochrome slag and impurity-removed liquid.

[0136] S4, separating nickel and iron from the impurity-removed liquid, the specific sub-steps are:

[0137] S41, Solution A: Adjust the pH of the decontaminated solution to 2 using 1 mol / L sulfuric acid.

[0138] S42, Solution B: Dissolve sodium sulfide in 100 mL of water at a molar ratio of 1.2:1 between sodium sulfide and nickel in the purified solution, and add sodium dodecylbenzene sulfonate (5% by weight of sodium sulfide).

[0139] S43, slowly add solution B to solution A at a dropping rate of 2 mL / min, maintain a stirring speed of 200 rpm at 25°C, and after the dropwise addition is completed, stir the reaction for 120 minutes; then, filter and separate to obtain a precipitate (recorded as nickel sulfide precipitate) and a separated liquid (recorded as ferrous sulfate solution).

[0140] Compared with the nickel in the liquid after impurity removal, the nickel loss rate in the nickel sulfide precipitate is 1.47% (the lost nickel enters the ferrous sulfate solution); compared with the iron in the liquid after impurity removal, the iron loss rate in the ferrous sulfate solution is 14.44% (the lost iron enters the nickel sulfide precipitate).

[0141] The above technical solutions of the present invention are only preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention's description and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for processing nickel-iron alloy powder, characterized in that: Including steps: S1, providing nickel-iron alloy powder; the nickel-iron alloy powder contains nickel, iron and chromium; S2, acid leaching the nickel-iron alloy powder to obtain leached residue and leachate; cooling and crystallizing the leachate to obtain solid crystals and a post-crystallization liquid; S3, performing chromium precipitation treatment on the crystallized liquid to obtain chromium precipitation residue and impurity-removed liquid; The chromium precipitation treatment comprises: adjusting the pH of the crystallized liquid to 2-3, and then first mixing the crystallized liquid and iron powder; S4, separating the impurity-removed liquid into nickel and iron to obtain a nickel precipitate and an iron separation liquid; The nickel-iron separation includes: adjusting the pH of the impurity-removed liquid to 1.5-2.5, and performing a second mixing of the impurity-removed liquid, anionic surfactant, and sulfide; the duration of the second mixing is 50-90 minutes; the molar ratio of the sulfide to the nickel element in the impurity-removed liquid is 1-1.5:1; and the mass percentage of the anionic surfactant and the sulfide is 3-8%.

2. The method for processing nickel-iron alloy powder according to claim 1, wherein: The mass ratio of the iron powder to the chromium element in the crystallized liquid is 3-10:

1.

3. The method for processing nickel-iron alloy powder according to claim 1, wherein: The temperature of the first mixing is 65-80° C.; the duration of the first mixing is 1.5-3 hours.

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

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

6. The method for processing nickel-iron alloy powder according to claim 1, wherein: The anionic surfactant includes one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and sodium α-olefinsulfonate; the sulfide includes one or more of sodium sulfide, potassium sulfide, lithium sulfide, and ammonium sulfide.

7. The method for processing nickel-iron alloy powder according to claim 1, wherein: The temperature of the cooling crystallization is 10-30° C., and the duration of the cooling crystallization is not less than 4 hours.

8. The method for processing nickel-iron alloy powder according to claim 1, wherein: The acid solution used for the acid leaching includes a 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 method for processing nickel-iron alloy powder according to claim 1, wherein: The acid leaching temperature is 60-80° C.; the acid leaching time is not less than 1.5 hours; and the solid-liquid ratio used in the acid leaching is 1 g:5-15 mL.

10. The method for processing nickel-iron alloy powder according to any one of claims 1 to 9, characterized in that: The step S4 further includes: evaporating and crystallizing the iron separation liquid.

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