Nickel-iron alloy powder and its preparation method and application

Abstract

The present invention discloses a nickel-iron alloy powder and its preparation method and application, which belong to the field of battery material technology. The present invention melts the nickel-iron alloy raw material, adds a desulfurization auxiliary material and introduces an inert gas for stirring, then adds a heating auxiliary material and introduces oxygen for stirring, and introduces an inert gas for stirring, which can effectively remove impurities such as sulfur, carbon, and silicon; then, the nickel-iron alloy powder is prepared by atomization treatment and dehydration treatment. The prepared nickel-iron alloy powder has the advantages of low impurity content, low water content and good particle refinement effect, and is suitable for wet processing to prepare lithium battery positive electrode materials, such as lithium iron phosphate and nickel-cobalt-manganese ternary materials; at the same time, the method of the present invention has fewer steps, simple process, low energy consumption, high operability, low production cost, environmental friendliness, and is suitable for large-scale production of nickel-iron alloy powder.

Description

Technical Field

[0001] The present invention relates to the technical field of battery materials, and in particular to nickel-iron alloy powder, a preparation method and application thereof. Background Art

[0002] With the development of the new energy lithium battery industry, the demand for lithium battery cathode materials continues to increase annually. However, fierce competition in the lithium battery industry has led to shrinking profit margins for cathode materials, creating an urgent need for low-cost raw materials. Lithium battery cathode materials are currently primarily divided into lithium iron phosphate (LEP) and nickel-cobalt-manganese ternary materials (NCM). LEP contains up to 60% iron, while NCM, particularly high-nickel products, has a nickel content of at least 45%. Traditional cathode materials are made from high-priced raw materials such as pure iron powder, refined ferrous sulfate, and high-purity nickel.

[0003] Nickel-iron alloy is an intermediate product in the production of high-purity nickel. The price of nickel metal per ton is 20,000-30,000 yuan lower than that of pure nickel, and iron is a free-of-charge product. However, the high impurity content and large particles of nickel-iron alloy raw materials slow the acid dissolution rate of nickel-iron alloy and make subsequent impurity removal difficult. This makes the process of preparing positive electrode materials using nickel-iron alloy as raw material difficult and costly.

[0004] Therefore, there is an urgent need to develop a method for preparing nickel-iron alloy powder to reduce the impurity content of the nickel-iron alloy and refine the particle size of the nickel-iron alloy. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a nickel-iron alloy powder with low impurity content, low water content and good particle refinement effect, as well as a preparation method and application thereof.

[0006] To achieve the above objectives, the technical solutions adopted in this paper are:

[0007] In a first aspect, the present invention provides a method for preparing nickel-iron alloy powder, comprising the following steps:

[0008] S1, heating and melting the nickel-iron alloy raw material to obtain a metal mixture;

[0009] S2, adding desulfurization auxiliary materials to the metal mixture obtained in step S1, and introducing inert gas for stirring;

[0010] S3, adding a heating auxiliary material to the metal mixture treated in step S2, and introducing oxygen to stir; the temperature of the metal mixture treated in step S3 is not less than 1680° C.;

[0011] S4, introducing an inert gas into the metal mixture treated in step S3 to stir, and skimming to obtain a metal mixture after impurities are removed;

[0012] S5, the metal mixture after the impurity removal is discharged through a nozzle, and is atomized with water to obtain a slurry containing nickel-iron alloy particles;

[0013] S6. Subjecting the slurry containing the nickel-iron alloy particles to magnetic separation treatment, and then to vacuum dehydration treatment to obtain nickel-iron alloy powder.

[0014] According to the present invention, after smelting a nickel-iron alloy raw material, a desulfurization auxiliary material is added and an inert gas is introduced for stirring, a heating auxiliary material is added and oxygen is introduced for stirring, and an inert gas is introduced for stirring. By controlling the temperature of the metal mixture in each step, not only can the efficiency of the impurity removal reaction be accelerated and impurities such as sulfur, carbon, and silicon be effectively removed, but the metal mixture after impurity removal can also reach the required atomization temperature, and the process flow is simplified to reduce costs. Subsequently, atomization treatment and dehydration treatment are performed to prepare a nickel-iron alloy powder with low impurity content, low water content and good particle refining effect. The prepared nickel-iron alloy is suitable for wet processing to prepare lithium battery positive electrode materials, such as lithium iron phosphate and nickel-cobalt-manganese ternary materials.

[0015] As a preferred embodiment of the present invention, the water content of the nickel-iron alloy raw material is less than 0.5%.

[0016] As a preferred embodiment of the present invention, in step S1, the temperature of the metal mixture is not lower than 1650°C, and more preferably 1680-1720°C.

[0017] As a preferred embodiment of the present invention, at least one of the following (a)-(b):

[0018] (a) The desulfurization auxiliary material includes lime and fluorite; the mass ratio of the lime to the fluorite is (2.5-3):1;

[0019] (b) The heating auxiliary material includes a recarburizer and aluminum, and the mass ratio of the recarburizer to the aluminum is (1.4-2):1.

[0020] Furthermore, the recarburizer includes at least one of graphite powder, heat-treated needle coke, and heat-treated petroleum coke.

[0021] In the present invention, a desulfurization auxiliary material is added to the metal mixture obtained in step S1, and an inert gas is introduced for stirring, during which the following reaction may occur:

[0022] 2S+Si+4CaO=2CaS+2CaO·SiO2;

[0023] 3S+2Al+3Ca=3CaS+Al2O3;

[0024] S+C+CaO=CaS+CO;

[0025] As the reaction proceeds, the temperature of the metal mixture gradually decreases, and the CaS, 2CaO·SiO2 and Al2O3 generated by the reaction should have a higher melting point and form solid slag; the generated CO escapes as gas.

[0026] In the present invention, a heating auxiliary material is added to the metal mixture after the treatment in step S2, and oxygen is introduced and stirred, during which the following reaction may occur:

[0027] 4Al+3O2=2Al2O3;

[0028] 2C+O2=2CO;

[0029] C+O2=CO2;

[0030] S+O2=SO2;

[0031] Si+O2=SiO2;

[0032] The present invention accelerates the decarburization, desulfurization and desiliconization oxidation reactions by adding heating auxiliary materials and introducing oxygen, and finally introduces inert gas to promote the rapid escape of residual gas in the metal mixture.

[0033] As a preferred embodiment of the present invention, in step S2, the inert gas includes at least one of nitrogen and argon.

[0034] As a preferred embodiment of the present invention, in step S2, the inert gas flow rate is 2-3.5Nm 3 / (min·t), the inert gas introduction time is 5-25 min, and the inert gas pressure is 1-2 MPa.

[0035] Further preferably, in step S2, the inert gas flow rate is 2.5-3Nm 3 / (min·t), the inert gas introduction time is 10-20 min, and the inert gas pressure is 1.6-1.8 MPa.

[0036] As a preferred embodiment of the present invention, the temperature of the metal mixture after the treatment in step S2 is not less than 1500°C, and more preferably 1520-1575°C.

[0037] The present invention controls the temperature of the metal mixture while accelerating the desulfurization reaction by regulating the addition amount of the desulfurization auxiliary material and the ratio of the various components of the desulfurization auxiliary material and the ventilation process parameters (the flow rate, introduction time and pressure of the inert gas) in step S2, so as to avoid the temperature of the metal mixture being too low after the treatment in step S2, which may affect the effect of the subsequent further impurity removal reaction.

[0038] As a preferred embodiment of the present invention, in step S3, the oxygen flow rate is 1-2.5Nm 3 / (min·t), the oxygen introduction time is 25-50 min, and the oxygen pressure is 1-2 MPa.

[0039] Further preferably, in step S3, the oxygen flow rate is 1.5-2Nm 3 / (min·t), the oxygen introduction time is 30-40 min, and the oxygen pressure is 1.6-1.8 MPa.

[0040] As a preferred embodiment of the present invention, the temperature of the metal mixture after the treatment in step S3 is 1680-1750°C.

[0041] The present invention controls the addition amount of the heating auxiliary material and the ratio of the components of the heating auxiliary material and the ventilation process parameters (oxygen introduction flow rate, introduction time and pressure) in step S3, thereby accelerating the desulfurization reaction and controlling the temperature of the metal mixture after treatment in step S3, thereby increasing the reaction rate, improving the impurity removal efficiency and effect, avoiding the temperature of the metal mixture after impurity removal failing to meet the atomization requirements, and avoiding the viscosity of the metal mixture after impurity removal being too high to affect the atomization effect.

[0042] The present invention can promote the rapid reaction between the heating auxiliary material and oxygen by controlling the oxygen inlet flow rate and the oxygen pressure.

[0043] As a preferred embodiment of the present invention, in step S4, the inert gas flow rate is 1-2.5Nm 3 / (min·t)min, the inert gas introduction time is 3-10min, and the inert gas pressure is 1-2MPa.

[0044] Further preferably, in step S4, the inert gas flow rate is 1.5-2Nm 3 / (min·t)min, the inert gas introduction time is 5-8min, and the inert gas pressure is 1.6-1.8MPa.

[0045] As a preferred embodiment of the present invention, the water pressure of the atomization treatment is 10-20 MPa, and the water flow rate is 120-180 m 3 The water pressure of the atomization treatment is further preferably 15-18 MPa.

[0046] The present invention controls the water pressure of the atomization treatment within the range of 15-18 MPa, so that the water content of the prepared nickel-iron alloy powder is low and the particle refining effect is better.

[0047] As a preferred embodiment of the present invention, the aperture of the nozzle is 15-20 mm.

[0048] The metal mixture after impurities removal flows out through the nozzle to form a metal liquid flow with a diameter of 15-20 mm.

[0049] As a preferred embodiment of the present invention, the magnetic field intensity of the magnetic separation treatment is 2000-3000 GS.

[0050] As a preferred embodiment of the present invention, the conditions for the vacuum dehydration treatment are: the pore size of the filter is less than 200 μm, and the vacuum degree is -0.03 MPa ≤ ≤ 0.1 MPa.

[0051] In a second aspect, the present invention provides a nickel-iron alloy powder, which is prepared by the method for preparing the nickel-iron alloy powder described in the first aspect.

[0052] In a third aspect, the present invention provides a use of the nickel-iron alloy powder as described in the third aspect in preparing a positive electrode material for a lithium-ion battery.

[0053] The positive electrode material of the lithium-ion battery can be lithium iron phosphate or a nickel-cobalt-manganese ternary material, and the nickel-cobalt-manganese ternary material can be lithium nickel-cobalt-manganese oxide.

[0054] Compared with existing nickel-iron alloys, the nickel-iron alloy powder provided by the present invention is used as the raw material of the positive electrode material of lithium-ion batteries, which can increase the acid dissolution rate and reduce the pressure of impurity removal in subsequent processes.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] The present invention prepares nickel-iron alloy powder with low impurity content, low water content and good particle refinement effect through the process steps of smelting, impurity removal, atomization, magnetic separation and dehydration. The prepared nickel-iron alloy powder is suitable for wet processing to prepare lithium battery positive electrode materials. At the same time, the method of the present invention has fewer steps, simple process, low energy consumption, high operability, low production cost, is environmentally friendly, and is suitable for large-scale production of nickel-iron alloy powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 The process flow chart provided by the present invention. DETAILED DESCRIPTION

[0058] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0059] Unless otherwise specified, the materials used in the examples and comparative examples can be obtained through commercial channels. In the present invention, the flow rate refers to the amount of gas supplied per ton of metal mixture per unit time, and its unit is Nm3 / (min·t).

[0060] Example 1

[0061] An embodiment of the nickel-iron alloy powder and its preparation method of the present invention is shown in FIG. Figure 1 The method for preparing the nickel-iron alloy powder comprises the following steps:

[0062] S1, prepare nickel-iron alloy, in which the nickel content is 15.5%, the sulfur content is 2.4%, the silicon content is 0.08%, and the iron content is 81.7%; the nickel-iron alloy is dried by flowing air at 120° C. for 12 h to obtain a nickel-iron alloy raw material, wherein the moisture content of the nickel-iron alloy raw material is 0.5%;

[0063] The obtained nickel-iron alloy raw material is added into a medium frequency furnace twice for smelting to melt the nickel-iron alloy and heat it to 1700° C. to obtain a metal mixture;

[0064] S2, the metal mixture obtained in step S1 is transferred to an AOD furnace (argon oxygen decarburization furnace, a refining equipment of argon oxygen refining process), and the lime powder and fluorite powder are added to the AOD furnace according to the mass ratio of lime: fluorite: nickel-iron alloy raw material = 240Kg: 80Kg: 10t, and nitrogen is continuously introduced into the AOD furnace in a bottom blowing manner for stirring. The nitrogen flow rate is 3.0Nm 3 / (min·t), the nitrogen introduction time is 10 min, and the nitrogen pressure is 1.6 MPa;

[0065] The temperature of the metal mixture after the treatment in step S2 is 1560°C;

[0066] S3, according to the mass ratio of recarburizer, aluminum ingot and nickel-iron alloy raw material, recarburizer: aluminum: nickel-iron alloy raw material = 300 kg: 150 kg: 10 t, add recarburizer and aluminum ingot to the mixed metal liquid treated in step S2, and continuously introduce oxygen by bottom blowing for stirring, and the oxygen introduction flow rate is 2.0 Nm 3 / min, the oxygen introduction time is 30min, and the oxygen pressure is 1.6MPa; the recarburizer is heat-treated needle coke;

[0067] The temperature of the metal mixture after the treatment in step S3 is 1720°C;

[0068] S4, continuously introduce argon gas into the metal mixture treated in step S3 by bottom blowing to stir it, and the argon gas flow rate is 2.0 Nm 3 / (min·t), the argon introduction time is 5min, the argon pressure is 1.6MPa, and the metal mixed liquid after deslagging is obtained;

[0069] S5, pouring the metal mixture after impurity removal into an atomizing ladle, the bottom of the atomizing ladle is equipped with a nozzle, the aperture of the nozzle is 16mm, the atomizing ladle is equipped with an annular gap spray disc, the nozzle diameter of the annular gap spray disc is 0.8mm, and atomized water is introduced to break up the metal mixture after impurity removal and cool it. The pressure of the atomized water is 18MPa, and the flow rate of the atomized water is 180Nm 3 / h, forming a slurry containing nickel-iron alloy particles;

[0070] S6, the slurry containing nickel-iron alloy particles is transported to a roller magnetic separator for magnetic separation by a suspension pump, wherein the angle of the drum magnetic separator is greater than 120 °, and dehydration is carried out under the condition that the magnetic field intensity is 2800GS to obtain a nickel-iron alloy crude product; the nickel-iron alloy crude product is dehydrated in an effective dehydration area of ​​not less than 15m 2 The nickel-iron alloy product was obtained by drum vacuum dehydration under the conditions of vacuum degree of -0.08MPa, rotation speed of 60rpm and filter mesh aperture of 200μm.

[0071] Example 2

[0072] The difference between this embodiment and embodiment 1 is that the nickel-iron alloy prepared in step S1 of this embodiment has a nickel content of 12.2%, a sulfur content of 0.2%, a carbon content of 3.1%, a silicon content of 0.08%, and an iron content of 81.7%.

[0073] In step S1 of this embodiment, the temperature of the metal mixture is 1680°C;

[0074] In step S2 of this embodiment, the mass ratio of lime powder, fluorite powder and nickel-iron alloy raw material is lime:fluorite:nickel-iron alloy raw material=200 kg:80 kg:10 t;

[0075] The temperature of the metal mixture after the treatment in step S2 is 1550°C;

[0076] In step S3 of this embodiment, the ratio of recarburizer: aluminum: nickel-iron alloy raw material is 240 kg: 120 kg: 10 t; the oxygen is introduced for 38 minutes; and the temperature of the metal mixture after treatment in step S3 is 1710° C.

[0077] Example 3

[0078] The difference between this embodiment and embodiment 1 is that the nickel-iron alloy prepared in step S1 of this embodiment has a nickel content of 10.8%, a sulfur content of 0.4%, a carbon content of 3.5%, a silicon content of 0.08%, and an iron content of 85.2%.

[0079] In step S1 of this embodiment, the temperature of the metal mixture is 1720°C;

[0080] In step S2 of this embodiment, the mass ratio of lime powder, fluorite powder and nickel-iron alloy raw material is lime:fluorite:nickel-iron alloy raw material=350Kg:140Kg:10t;

[0081] The temperature of the metal mixture after the treatment in step S2 is 1575°C;

[0082] In step S3 of this embodiment, the recarburizer: aluminum: nickel-iron alloy raw material = 220 kg: 150 kg: 10 t; the oxygen introduction time is 42 minutes;

[0083] The temperature of the metal mixture after the treatment in step S3 is 1730°C.

[0084] Example 4

[0085] The difference between this embodiment and embodiment 1 is that in step S5 of this embodiment, the water pressure of the atomization treatment is 18 MPa and the water flow rate is 120 m 3 / h, the aperture of the nozzle is 15mm and the diameter of the spray hole is 0.5mm.

[0086] In step S6 of this embodiment, the magnetic field intensity of the magnetic separation treatment is 2000 GS; the vacuum degree is -0.1 MPa, the rotation speed is 60 rpm, and the filter mesh aperture is 240 μm.

[0087] Example 5

[0088] The difference between this embodiment and embodiment 1 is that in step S5 of this embodiment, the water pressure of the atomization treatment is 16 MPa and the water flow rate is 150 m 3 / h, the aperture of the nozzle is 20mm and the diameter of the spray hole is 0.6mm.

[0089] In step S6 of this embodiment, the magnetic field intensity of the magnetic separation treatment is 3000 GS; the vacuum degree is -0.03 MPa, the rotation speed is 70 rpm, and the filter mesh aperture is 180 μm.

[0090] Example 6

[0091] The difference between this embodiment and embodiment 1 is that in step S5 of this embodiment, the water pressure of the atomization treatment is 10 MPa.

[0092] Example 7

[0093] The difference between this embodiment and embodiment 1 is that in step S5 of this embodiment, the pressure of the atomized water is 12 MPa.

[0094] Example 8

[0095] The difference between this embodiment and embodiment 1 is that in step S5 of this embodiment, the pressure of the atomized water is 15 MPa.

[0096] Example 9

[0097] The difference between this embodiment and embodiment 1 is that in step S5 of this embodiment, the pressure of the atomized water is 20 MPa.

[0098] Example 10

[0099] The difference between this embodiment and embodiment 1 is that in step S2 of this embodiment, the nitrogen flow rate is 2.5Nm 3 / (min·t), the nitrogen introduction time is 20 min, and the nitrogen pressure is 1.8 MPa;

[0100] The temperature of the metal mixture after the treatment in step S2 is 1520°C;

[0101] In step S3 of this embodiment, the oxygen flow rate is 1.5 Nm 3 / (min·t), the oxygen introduction time is 40min, and the oxygen pressure is 1.8MPa;

[0102] The temperature of the metal mixture after the treatment in step S3 is 1705°C;

[0103] In step S4 of this embodiment, the flow rate of argon gas is 1.5 Nm 3 / (min·t), the argon introduction time is 8 min, and the argon pressure is 1.8 MPa.

[0104] Example 11

[0105] The difference between this embodiment and embodiment 1 is that in step S2 of this embodiment, the nitrogen flow rate is 2.0 Nm 3 / min, the nitrogen introduction time is 25min, and the nitrogen pressure is 1MPa;

[0106] The temperature of the metal mixture after the treatment in step S2 is 1535°C;

[0107] In step S3 of this embodiment, the oxygen flow rate is 1.0 Nm 3 / (min·t), the oxygen introduction time is 50min, and the oxygen pressure is 1MPa;

[0108] The temperature of the metal mixture after the treatment in step S3 is 1710°C;

[0109] In step S4 of this embodiment, the flow rate of argon gas is 1.0 Nm 3 / (min·t), the argon introduction time is 10 min, and the argon pressure is 1 MPa.

[0110] Example 12

[0111] The difference between this embodiment and embodiment 1 is that in step S2 of this embodiment, the nitrogen flow rate is 3.5 Nm 3 / (min·t), the nitrogen introduction time is 5 min, and the nitrogen pressure is 2 MPa;

[0112] The temperature of the metal mixture after the treatment in step S2 is 1555°C;

[0113] In step S3 of this embodiment, the oxygen flow rate is 2.5 Nm 3 / (min·t), the oxygen introduction time is 25min, and the oxygen pressure is 2MPa;

[0114] The temperature of the metal mixture after the treatment in step S3 is 1680°C;

[0115] In step S4 of this embodiment, the flow rate of argon gas is 2.5 Nm 3 / (min·t), the argon introduction time is 3 min, and the argon pressure is 2 MPa.

[0116] Comparative Example 1

[0117] The difference between this comparative example and Example 1 is that, in this comparative example, step S1 is heated to 1600°C, the temperature of the metal mixture after treatment in step S2 is 1480°C, and the temperature of the metal mixture after treatment in step S3 is 1650°C; in this comparative example, when performing step S5, nickel-iron alloy particles cannot be formed, the atomization treatment fails, and subsequent magnetic separation and dehydration operations are no longer performed.

[0118] Comparative Example 2

[0119] The difference between this comparative example and Example 1 is that in step S3 of this comparative example, the ratio of recarburizer: aluminum: nickel-iron alloy raw material = 300 kg: 50 kg: 10 t; the temperature of the metal mixture after treatment in step S3 is 1670°C; when performing step S5 of this comparative example, nickel-iron alloy particles cannot be formed, the atomization treatment fails, and the subsequent magnetic separation and dehydration operations are no longer performed.

[0120] Comparative Example 3

[0121] The difference between this comparative example and Example 1 is that in step S3 of this comparative example, the oxygen flow rate is 0.8 Nm 3 / (min·t), the oxygen introduction time is 40min, and the oxygen pressure is 1.5MPa;

[0122] The temperature of the metal mixture after the treatment in step S3 is 1675° C.; in this comparative example, when performing step S5, nickel-iron alloy particles cannot be formed, the atomization treatment fails, and the subsequent magnetic separation and dehydration operations are no longer performed.

[0123] Comparative Example 4

[0124] The difference between this comparative example and Example 1 is that in this comparative example, no magnetic separation is performed in step S6, but vacuum dehydration is performed directly.

[0125] Effect Example 1

[0126] The products obtained in the above examples and comparative examples were used as samples, and the quality of each sample was tested using the following method:

[0127] (1) Use an oven and a balance to test the moisture content. Weigh a certain amount of sample (the mass is recorded as m0), dry the sample to a constant weight, and then weigh it (the weighing result is recorded as m t ), calculate the moisture content according to the following formula: Moisture content (%) = (m0-m t ) / m0*100%;

[0128] (2) According to ASTM E1086, the nickel content, iron content, and silicon content of the sample dried to constant weight were measured using a spectrometer;

[0129] (3) According to the standard JJG 395-2016, the carbon content and sulfur content of the sample dried to constant weight were detected using a carbon-sulfur analyzer;

[0130] (4) A laser particle size analyzer was used to detect the particle size distribution of each sample.

[0131] The test results are shown in Table 1-2.

[0132] Table 1

[0133]

[0134] Table 2

[0135]

[0136]

[0137] As can be seen from Examples 1-12, the present invention regulates the process parameters of each step. After the nickel-iron alloy raw material is smelted, a desulfurization auxiliary material is added and an inert gas is introduced for stirring. Then, a heating auxiliary material is added and oxygen is introduced for stirring. After the inert gas is introduced for stirring, not only can impurities such as sulfur, carbon, and silicon be effectively removed, but also the temperature of the metal mixture after impurity removal can reach the required atomization temperature, the atomization dehydration effect is good, and the prepared nickel-iron alloy powder has a low impurity content, a moisture content of less than 10%, and a particle size D 50 The mesh size is greater than 70 mesh, which can meet the requirements of wet processing for preparing lithium battery positive electrode materials. In contrast, the temperature control of each step of Comparative Examples 1-3 was unreasonable, resulting in the metal mixture temperature being too low after impurity removal and the viscosity being too high. During the atomization process, nickel-iron alloy particles could not be formed, and the atomization process failed. Comparative Example 4 did not perform magnetic separation, but directly performed vacuum dehydration, resulting in the water content of the prepared nickel-iron alloy powder being too high.

[0138] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this article and are not intended to limit the scope of protection of this article. Although this application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of this article may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of this article.

Claims

1. A method for preparing nickel-iron alloy powder, characterized in that: The steps include: S1, heating and melting the nickel-iron alloy raw material to obtain a metal mixture; S2. Adding desulfurization auxiliary materials to the metal mixture obtained in step S1, and introducing inert gas for stirring; S3, adding a heating auxiliary material to the metal mixture treated in step S2, and introducing oxygen to stir; S4, introducing an inert gas into the metal mixture treated in step S3 to stir, and skimming to obtain a metal mixture after impurities are removed; S5, the metal mixture after the impurity removal is discharged through a nozzle, and is atomized with water to obtain a slurry containing nickel-iron alloy particles; S6, after the slurry containing nickel-iron alloy particles is subjected to magnetic separation treatment, vacuum dehydration treatment is performed to obtain nickel-iron alloy powder; In step S1, the temperature of the metal mixture is not less than 1650°C; In step S2, the inert gas flow rate is 2-3.5 Nm 3 / (min·t), the inert gas introduction time is 5-25min, and the inert gas pressure is 1-2MPa; The temperature of the metal mixture after the treatment in step S2 is not less than 1500° C. In step S3, the oxygen flow rate is 1-2.5Nm 3 / (min·t), the oxygen introduction time is 25-50min, and the oxygen pressure is 1-2MPa; The temperature of the metal mixture after the treatment in step S3 is 1680-1750°C; In step S4, the inert gas flow rate is 1-2.5Nm 3 / (min·t), the inert gas introduction time is 3-10 min, and the inert gas pressure is 1-2 MPa; The desulfurization auxiliary material includes lime and fluorite; the mass ratio of the lime to the fluorite is (2.5-4):1; The heating auxiliary material includes a recarburizer and aluminum, and the mass ratio of the recarburizer to the aluminum is (2-5):

1.

2. The method for preparing nickel-iron alloy powder according to claim 1, wherein: In step S5, the water pressure of the atomization treatment is 10-20 MPa, and the water flow rate is 120-180 m 3 / h; And / or, the aperture of the nozzle is 15-20 mm.

3. The method for preparing nickel-iron alloy powder according to claim 1, wherein: In step S6, the magnetic field strength of the magnetic separation treatment is 1500-3000 GS; And / or, the vacuum dehydration method is a centrifugal vacuum dehydration method, and the conditions of the centrifugal vacuum dehydration method are: the filter pore size is less than 200 μm, -0.03 MPa ≤ vacuum degree ≤ -0.1 MPa, and the rotation speed is 10-80 rpm.

4. A nickel-iron alloy powder, characterized in that The powder is prepared by the method for preparing the nickel-iron alloy powder according to any one of claims 1 to 3.

5. Use of the nickel-iron alloy powder according to claim 4 in preparing a positive electrode material for a lithium-ion battery.

Images