Method for producing high-grade nickel matte using nickel laterite

Abstract

The present application belongs to the field of nickel laterite treatment methods, and specifically relates to a method for producing high-grade nickel matte using nickel laterite. Nickel laterite (such as limonite-type nickel laterite) having high iron content and low nickel and silicon content is used as a raw material, and sequentially undergoes steps such as over-reduction roasting, magnetic separation, and reduction-sulfidation roasting, to prepare high-grade nickel matte. In the process route provided by the present invention, existing equipment such as rotary kilns, electric furnaces, and magnetic separators can be used for production; the process is easy to control, and costs are low. The process route provided by the present application can also achieve the purpose of directly using limonite-type nickel laterite to produce high-grade nickel matte, while ensuring the nickel recovery rate.

Description

A method for producing high-nickel matte using laterite nickel ore Technical Field

[0001] The present disclosure belongs to the technical field of laterite nickel ore processing methods, and in particular, relates to a method for producing high-nickel matte by utilizing laterite nickel ore. Background Art

[0002] With the increasing scarcity of nickel sulfide ores, laterite nickel ore has become an important raw material for smelting nickel products. Currently, the RKEF (rotary kiln + submerged arc furnace) process is the most widely used laterite nickel ore smelting process. However, the lack of high-grade laterite nickel ore limits its widespread application. The development and utilization of lower-priced limonitic laterite nickel ore is urgently needed.

[0003] Currently, the main process for producing high-nickel matte from laterite nickel ore is as follows: the laterite nickel ore is first smelted to produce low-nickel-sulfur, which is then blown to produce high-nickel matte. However, the ferronickel product obtained by pyrometallurgical processing of low-grade limonitic laterite nickel ore has a low nickel grade, low yield, and low efficiency. For example, patent CN110983043A describes a method for producing high-grade ferronickel from low- and medium-grade laterite nickel ore. The crushed laterite nickel ore is mixed with a reducing agent to form agglomerates. Under a protective atmosphere, the autoreduction product is selectively oxidized in a weakly oxidizing atmosphere to produce an oxidation product. The oxidation product is then melted and the metal is separated from the gangue to obtain a high-grade ferronickel alloy. This method produces a high-grade ferronickel alloy product with a nickel content of 30%.

[0004] Limonitic laterite nickel ore is a type of ore with high iron content and low nickel, silicon, and magnesium content. Due to its low nickel grade, the direct production of ferronickel and nickel matte using pyrometallurgical processes is uneconomical. Therefore, limonitic laterite nickel ore is currently primarily processed using hydrometallurgical processes. However, the hydrometallurgical processes produce large amounts of leaching residue, which is difficult to handle. Currently, no existing laterite nickel acid leaching projects in operation around the world have implemented comprehensive leaching residue recycling, and most have resorted to deep-sea landfills and tailings ponds for storage.

[0005] In view of this, the present disclosure is proposed.

[0006] Summary of the Invention

[0007] The purpose of the present disclosure includes providing a method for producing high-nickel matte using laterite nickel ore, aiming to improve production efficiency and reduce process costs while ensuring nickel recovery rate.

[0008] In order to achieve the above-mentioned purpose of the present disclosure, the following technical solutions can be adopted:

[0009] The solution provided by the present disclosure includes a method for producing high-nickel matte using laterite nickel ore, comprising: subjecting the laterite nickel ore to reduction roasting at 600°C-850°C, subjecting the roasted product to magnetic separation to obtain nickel-containing magnetite concentrate, and subjecting the nickel-containing magnetite concentrate to reduction sulfidation roasting at 1100°C-1300°C;

[0010] Among them, laterite nickel ore is limonitic laterite nickel ore.

[0011] In some embodiments of the present disclosure, the process includes: mixing laterite nickel ore with a reducing agent, subjecting the mixture to reduction roasting at 600°C-850°C for 40-60 min, subjecting the roasted product to magnetic separation to obtain nickel-containing magnetite concentrate, subjecting the nickel-containing magnetite concentrate to reduction and sulfurization roasting with a reducing agent and a sulfurizing agent at 1100°C-1300°C for 20-40 min to obtain crude high-nickel matte, and subjecting the crude high-nickel matte to melting and impurity removal to obtain the desired high-nickel matte product.

[0012] In some embodiments of the present disclosure, the over-reduction roasting temperature is 750° C.-850° C., and the over-reduction roasting time is 40 min-120 min.

[0013] In some embodiments of the present disclosure, the mass ratio of laterite nickel ore to reducing agent is 1:(0.1-0.3).

[0014] In some embodiments of the present disclosure, the reducing agent used in the over-reduction roasting process is reduced coal.

[0015] In some embodiments of the present disclosure, over-reduction roasting is performed in a rotary kiln, and an inert protective gas is introduced during the roasting process.

[0016] In some embodiments of the present disclosure, the magnetic separation intensity is controlled to be 1000 GS-3000 GS.

[0017] In some embodiments of the present disclosure, the roasted product after over-reduction roasting is crushed and ground and then subjected to magnetic separation to obtain nickel-containing magnetite concentrate and magnetic separation tailings.

[0018] In some embodiments of the present disclosure, the crushing is performed by grinding, and the particle size after crushing is controlled to be less than or equal to 0.075 mm.

[0019] In some embodiments of the present disclosure, the method further includes: oxidizing and roasting the magnetic separation tailings and performing magnetic separation treatment to obtain magnetite and iron-containing quartz sand.

[0020] In some embodiments of the present disclosure, during the oxidation roasting of the magnetic separation tailings, the roasting temperature is controlled to be 500° C.-800° C., and the roasting time is controlled to be 30 min-120 min.

[0021] In some embodiments of the present disclosure, when magnetic separation is performed after oxidative roasting, the magnetic separation intensity is controlled to be 800 GS-1400 GS.

[0022] In some embodiments of the present disclosure, the temperature of the reduction-sulfurization roasting is 1200° C.-1250° C., and the time of the reduction-sulfurization roasting is 35 min-40 min.

[0023] In some embodiments of the present disclosure, during the reduction-sulfurization roasting process, the mass ratio of the nickel-containing magnetite concentrate to the reducing agent and the sulfiding agent is controlled to be 1:(0.08-0.10):(0.30-0.50).

[0024] In some embodiments of the present disclosure, the sulfurizing agent used in the reduction sulfurization roasting process is sulfur.

[0025] In some embodiments of the present disclosure, the reducing agent used in the reduction sulfidation roasting process is reduced coal.

[0026] In some embodiments of the present disclosure, the reduction-sulfurization roasting is carried out in a rotary kiln, and an inert protective gas is introduced during the roasting process.

[0027] In some embodiments of the present disclosure, during the melt removal process, the operating temperature is controlled to be 1300° C.-1500° C., and the operating time is 10 min-30 min.

[0028] The present invention uses limonitic laterite nickel ore as raw material and performs over-reduction roasting by controlling the reduction temperature. During this process, the iron oxide in the raw material is first reduced to ferroferric oxide and then to ferrous oxide. Then, by utilizing the non-magnetic property of ferrous oxide, the ferrous oxide is removed by magnetic separation to obtain nickel-containing magnetite concentrate. The nickel-containing magnetite concentrate is then subjected to reduction-sulfurization roasting and the roasting temperature is controlled to allow sulfur to enter the nickel-iron phase, forming a solid solution of nickel sulfide and ferrous sulfide to obtain high-nickel matte. The process route provided by the present invention can be produced using existing equipment such as rotary kilns, electric furnaces, and magnetic separators. The process is easy to control and the cost is low. The process route provided by the present invention also achieves the purpose of directly using limonitic laterite nickel ore to produce high-nickel matte while ensuring the nickel recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0030] FIG1 is a schematic diagram of the main process steps for producing high-nickel matte using laterite nickel ore provided by the present disclosure;

[0031] FIG2 is a process flow chart for producing high-nickel matte using laterite nickel ore provided in the present disclosure. DETAILED DESCRIPTION

[0032] The embodiments of the present disclosure will be described in detail below with reference to the examples. However, those skilled in the art will appreciate that the following examples are intended only to illustrate the present disclosure and should not be construed as limiting the scope of the present disclosure. Where specific conditions are not specified in the examples, the experiments were performed under conventional conditions or the conditions recommended by the manufacturer. Where the manufacturer of the reagents or instruments is not specified, all are commercially available conventional products.

[0033] The endpoints of the ranges and any values ​​disclosed in this disclosure are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed herein.

[0034] The present disclosure provides a method for producing high-nickel matte from laterite nickel ore. Referring to FIG1 , the main steps include sequentially performing over-reduction roasting, magnetic separation, and reduction-sulfidation roasting. The laterite nickel ore is over-reduction roasted at 600°C to 850°C, the roasted product is subjected to magnetic separation to obtain nickel-containing magnetite concentrate, and the nickel-containing magnetite concentrate is subjected to reduction-sulfidation roasting at 1100°C to 1300°C.

[0035] It should be noted that laterite nickel ore with high iron and low nickel, silicon and magnesium content (such as limonitic laterite nickel ore) is used as raw material, and reduction roasting is carried out by controlling the reduction temperature. In this process, it is first reduced to ferroferric oxide and then to ferrous oxide. Then, by utilizing the non-magnetic property of ferrous oxide, ferrous oxide is removed by magnetic separation to obtain nickel-containing magnetite concentrate. The nickel-containing magnetite concentrate is then subjected to reduction sulfide roasting and the roasting temperature is controlled to allow sulfur to enter the nickel-iron phase, forming a solid solution of nickel sulfide and ferrous sulfide to obtain high-nickel matte.

[0036] Specifically, referring to FIG. 2 , the method for producing high-nickel matte using laterite nickel ore provided in the present disclosure includes the following steps:

[0037] S1. Over-reduction roasting

[0038] After mixing the laterite nickel ore with the reducing agent, it is subjected to reduction roasting at 600℃-850℃ for 40min-120min. At this reduction temperature, the iron oxide in the laterite nickel ore is first reduced to ferroferric oxide and then further reduced to ferrous oxide. If the reduction temperature is too high, such as exceeding 1000℃, it will be directly reduced to elemental iron.

[0039] The so-called "over-reduction roasting" means that by controlling the reduction temperature, the iron oxide in the laterite nickel ore is first reduced to ferroferric oxide and then further reduced to ferrous oxide. The reduction steps are two steps.

[0040] Specifically, during over-reduction roasting, the reduction temperature can be 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, etc., and the reduction roasting time can be 40 min, 45 min, 50 min, 55 min, 60 min, etc.

[0041] The method provided in the embodiments of the present disclosure is suitable for processing laterite nickel ore with high iron, low nickel and low silicon content, such as limonite laterite nickel ore, but is not limited thereto.

[0042] In a preferred embodiment of the present disclosure, the over-reduction roasting temperature is 750°C-800°C, and the over-reduction roasting time is 40min-120min. By optimizing the temperature and time of the over-reduction roasting, more iron is converted into ferrous oxide and removed by magnetic separation, thereby obtaining an intermediate product with a high nickel grade.

[0043] In some embodiments of the present disclosure, the mass ratio of laterite nickel ore to reducing agent is 1:(0.1-0.3). The amount of reducing agent is preferably controlled within the above range to achieve more complete conversion of iron oxides. Specifically, the mass ratio of laterite nickel ore to reducing agent can be 1:0.1, 1:0.2, 1:0.3, etc. The reducing agent used in the over-reduction roasting process can be, but is not limited to, reducing coal.

[0044] In some embodiments of the present disclosure, over-reduction roasting may be performed in a rotary kiln, and an inert protective gas is introduced during the roasting process. The type of the inert protective gas is not limited and may be nitrogen, argon, or the like.

[0045] S2, magnetic separation

[0046] The roasted product is subjected to magnetic separation to obtain nickel-containing magnetite concentrate. Most of the iron in S1 is converted into ferrous oxide, which can be removed by magnetic separation due to its non-magnetic properties.

[0047] To more fully remove ferrous oxide, the calcined product after over-reduction roasting can be crushed and ground before magnetic separation to produce nickel-containing magnetite concentrate and magnetic separation tailings. During magnetic separation, the magnetic separation intensity is controlled between 1000 GS and 3000 GS to fully remove iron impurities and improve the nickel grade of the product. Specifically, the magnetic separation intensity can be 1000 GS, 1500 GS, 2000 GS, 2500 GS, 3000 GS, etc.

[0048] The crushing and grinding methods and the particle size after grinding are not limited, as long as the ferrous oxide can be better removed. In some embodiments of the present disclosure, crushing and grinding can be used to control the particle size after crushing and grinding to be less than or equal to 0.075 mm.

[0049] In some embodiments of the present disclosure, the magnetic tailings can be further processed to obtain products with market application value. The magnetic tailings can be oxidized, roasted, and magnetically separated to obtain magnetite and iron-containing quartz sand. Both magnetite and iron-containing quartz sand are products with market value and can be sold.

[0050] Furthermore, during the oxidation roasting of the magnetic separation tailings, the roasting temperature is controlled to be 500° C.-800° C., and the roasting time is 30 min-120 min. Ferrous oxide can be oxidized into ferrosoferric oxide through oxidation roasting.

[0051] Furthermore, when magnetic separation is performed after oxidation roasting, the magnetic separation intensity is controlled to be 800GS-1400GS to better separate the magnetite and the iron-containing quartz sand.

[0052] S3, reduction sulfidation roasting

[0053] The nickel-containing magnetite concentrate is reduced and sulfided with a reducing agent and a sulfiding agent at 1100-1300°C for 20-40 minutes to obtain crude high-nickel matte. The nickel-containing magnetite concentrate is reduced and sulfided and the roasting temperature is controlled to allow sulfur to enter the nickel-iron phase, forming a solid solution of nickel sulfide and iron sulfide, directly obtaining high-nickel matte. If the roasting temperature is too high or too low, the target product cannot be obtained.

[0054] Specifically, the temperature of the reduction-sulfurization roasting can be 1100° C., 1150° C., 1200° C., 1250° C., 1300° C., etc., and the time of the reduction-sulfurization can be 20 min, 25 min, 30 min, 35 min, 40 min, etc.

[0055] In a preferred embodiment of the present disclosure, the temperature of the reduction sulfidation roasting is 1200° C.-1250° C., and the time of the reduction sulfidation roasting is 35 min-40 min. By optimizing the temperature and time of the reduction sulfidation, the yield of high nickel matte can be further improved.

[0056] Furthermore, during the reduction-sulfurization roasting process, the mass ratio of the nickel-containing magnetite concentrate to the reducing agent and the sulfiding agent is controlled to be 1:(0.08-0.10):(0.30-0.50), and the amount of raw materials is preferably controlled within the above range to further improve the yield of the product while avoiding the waste of raw materials. Specifically, the mass ratio of the nickel-containing magnetite concentrate to the reducing agent and the sulfiding agent can be 1:0.08:0.30, 1:0.09:0.40, 1:0.10:0.50, etc.

[0057] In some embodiments of the present disclosure, the sulfiding agent used in the reduction-sulfurization roasting process is sulfur, and the reducing agent is reduced coal, but the present invention is not limited thereto. The reduction-sulfurization roasting process can be carried out in a rotary kiln, and an inert protective gas is introduced during the roasting process. The type of inert protective gas is not limited, and can be nitrogen, argon, etc.

[0058] S4, melt removal

[0059] The crude high-nickel matte is melted and decontaminated to remove impurities such as silicon and aluminum introduced during the magnetic separation process. The small amount of slag produced is general solid waste and can be used as building material.

[0060] In some embodiments of the present disclosure, during the melt removal process, the operating temperature is controlled to be 1300°C-1500°C and the operating time is 10 minutes-30 minutes to fully remove impurities and improve the purity of the product. Specifically, the operating temperature can be 1300°C, 1350°C, 1400°C, 1450°C, 1500°C, etc., and the operating time can be 10 minutes, 20 minutes, 30 minutes, etc.

[0061] It should be noted that limonitic laterite nickel ore has large reserves, a wide range of raw materials, and is simple to mine. However, the traditional RKEF process has difficulty processing low-grade limonitic laterite nickel ore. The method provided by the embodiments of the present disclosure realizes the feasibility of directly producing high-nickel matte from limonitic laterite nickel ore. The process is simple, without high energy consumption steps, and the nickel matte product is more conducive to the subsequent wet leaching process. The production can be achieved using existing rotary kilns, electric furnaces, and magnetic separators, making the process easy to control and low-cost.

[0062] The features and performance of the present disclosure are further described in detail below with reference to the embodiments.

[0063] It should be noted that the composition of the limonitic laterite nickel ore treated in the following examples and comparative examples is as follows: by mass fraction, it contains 1.27% nickel, 48.88% iron, 0.59% magnesium, and 8.23% silicon.

[0064] Example 1

[0065] This embodiment provides a method for producing high-nickel matte using laterite nickel ore, comprising the following steps:

[0066] (1) The limonitic laterite nickel ore and semi-coke were mixed in a mass ratio of 1:0.12, and then subjected to reduction roasting in a rotary kiln 1 at 800°C for 50 min, with N2 being introduced as a protective gas during the process.

[0067] (2) The product of step (1) is ground to a particle size of 0.075 mm or less, and then magnetically separated at a magnetic separation intensity of 1100 GS to obtain nickel-containing magnetite concentrate and magnetic separation tailings. The magnetic separation tailings are oxidatively roasted at 700° C. and magnetically separated at 1000 GS to produce magnetite (Fe: 61.2%) and iron-containing quartz sand (SiO2: 81.3%, Fe3O4: 18.1%).

[0068] (3) The obtained nickel-containing iron concentrate is mixed with reducing coal and sulfur in a mass ratio of 1:0.9:0.4 and then added to the rotary kiln 2. The temperature is set to 1200°C and the reaction time is 40 minutes. During the process, N2 is introduced as a protective gas to obtain crude high-nickel sulfur.

[0069] (4) The obtained crude high-nickel sulfur is melted and impurities are removed in an electric furnace to obtain a high-nickel matte product. The operating temperature is 1300°C and the melting and impurity removal time is 10 minutes.

[0070] After testing, the obtained high-nickel matte product contained Ni: 71.41%, S: 24.64%, Fe: 2.82%, and Si: 0.09% by mass; the nickel recovery rate was 89.3%.

[0071] Example 2

[0072] This embodiment provides a method for producing high-nickel matte using laterite nickel ore, which differs from Example 1 only in the following operating parameters: the over-reduction roasting temperature in rotary kiln 1 is 750°C, and the roasting time is 40 minutes; the reduction sulfidation roasting temperature in rotary kiln 2 is 1250°C, and the reaction time is 35 minutes; the electric furnace melting and impurity removal temperature is 1350°C, and the melting and impurity removal time is 15 minutes.

[0073] After testing, the obtained high-nickel matte product contained Ni: 70.28%, S: 25.35%, Fe: 2.61%, and Si: 0.12% by mass; the nickel recovery rate was 90.1%.

[0074] Example 3

[0075] This embodiment provides a method for producing high-nickel matte using laterite nickel ore, which is different from the embodiment 1 only in that the over-reduction roasting temperature in the rotary kiln 1 is 850°C.

[0076] After testing, the obtained high-nickel matte product contained Ni: 72.12%, S: 23.41%, Fe: 1.31%, and Si: 0.14% by mass; the nickel recovery rate was 91.2%.

[0077] Comparative Example 1

[0078] This embodiment provides a method for producing high-nickel matte using laterite nickel ore, which is different from the embodiment 1 only in that the over-reduction roasting temperature in the rotary kiln 1 is 1100°C.

[0079] After testing, the obtained high-nickel matte product contained Ni: 48.24%, S: 17.13%, Fe: 30.26%, and Si: 0.08% by mass; and the nickel recovery rate was 85.5%.

[0080] Comparative Example 2

[0081] This embodiment provides a method for producing high-nickel matte using laterite nickel ore, which is different from the embodiment 1 only in that the over-reduction roasting temperature in the rotary kiln 1 is 500°C.

[0082] After testing, the obtained nickel matte product contained Ni: 3.56%, S: 6.22%, Fe: 88.78%, Si: 2.14% by mass; the nickel recovery rate was 48.3%.

[0083] Comparative Example 3

[0084] This comparative example provides a traditional method for processing limonitic laterite nickel ore, and the specific steps are as follows:

[0085] (1) The limonitic laterite nickel ore was mixed with semi-coke and sulfiding agent in a mass ratio of 1:0.06:0.1, and then pre-reduced in a rotary kiln at 900 °C for 100 min, with N2 as the protective gas during the process.

[0086] (2) The product of step (1) is mixed with blue coke and a sulfiding agent in a mass ratio of 1:0.04:0.1, and then added to a smelting pool for smelting to obtain a low-nickel matte product. The product content is: Ni: 2.57%, S: 13.22%, Fe: 83.98%, Si: 0.12%; and the nickel recovery rate is 93.4%.

[0087] (3) The obtained low-grade nickel matte is mixed with quartz sand in a mass ratio of 1:0.5 and then added into a converter for blowing. The temperature is set to 1550°C and the reaction time is 40 minutes. O2 is introduced during the process to obtain a high-nickel-sulfur product.

[0088] After testing, the obtained high-nickel matte product contained Ni: 47.02%, S: 20.38%, Fe: 31.14%, Si: 0.52% by mass; the nickel recovery rate was 75.3%. Industrial Applicability

[0089] The present invention uses high-iron, low-nickel, and low-silicon laterite nickel ore as raw material, sequentially undergoing reduction roasting, magnetic separation, and reduction-sulfidation roasting to produce high-nickel matte. The process provided by the present invention also achieves the goal of directly producing high-nickel matte from limonitic laterite nickel ore while ensuring a high nickel recovery rate. The process provided by the present invention utilizes existing equipment such as rotary kilns, electric furnaces, and magnetic separators, resulting in easy process control, low cost, and excellent industrial applicability.

Claims

1. A method for producing high-nickel matte using laterite nickel ore, characterized in that: include: The laterite nickel ore is subjected to reduction roasting at 600° C.-850° C., the roasted product is subjected to magnetic separation to obtain a nickel-containing magnetite concentrate, and the nickel-containing magnetite concentrate is subjected to reduction sulfide roasting at 1100° C.-1300° C.; Wherein, the laterite nickel ore is limonitic laterite nickel ore.

2. The method according to claim 1, characterized in that include: The laterite nickel ore is mixed with a reducing agent and subjected to reduction roasting at 600°C-850°C for 40min-60min. The roasted product is subjected to magnetic separation to obtain a nickel-containing magnetite concentrate. The nickel-containing magnetite concentrate is reduced and sulfurized roasted with a reducing agent and a sulfurizing agent at 1100°C-1300°C for 20min-40min to obtain a crude high-nickel matte, and the crude high-nickel matte is melted to remove impurities.

3. The method according to claim 1 or 2, characterized in that: The over-reduction roasting temperature is 750°C-850°C, and the over-reduction roasting time is 40min-120min.

4. The method according to claim 2 or 3, characterized in that: The mass ratio of the laterite nickel ore to the reducing agent is 1:(0.1-0.3).

5. The method according to any one of claims 2 to 4, characterized in that: The reducing agent used in the over-reduction roasting process is reducing coal.

6. The method according to any one of claims 1 to 5, characterized in that The over-reduction roasting is carried out in a rotary kiln, and an inert protective gas is introduced during the roasting process.

7. The method according to any one of claims 1 to 6, characterized in that The magnetic separation intensity is controlled to be 1000GS-3000GS.

8. The method according to any one of claims 1 to 7, characterized in that The roasted product after the over-reduction roasting is crushed and then subjected to magnetic separation to obtain the nickel-containing magnetite concentrate and magnetic separation tailings.

9. The method according to claim 8, characterized in that The crushing is carried out by grinding, and the particle size after crushing is controlled to be less than or equal to 0.075mm.

10. The method according to claim 8 or 9, characterized in that: Also includes: The magnetic separation tailings are subjected to oxidation roasting and magnetic separation treatment to obtain magnetite and iron-containing quartz sand.

11. The method according to claim 10, characterized in that During the oxidation roasting of the magnetic separation tailings, the roasting temperature is controlled to be 500° C.-800° C., and the roasting time is controlled to be 30 min-120 min.

12. The method according to claim 10 or 11, characterized in that: When magnetic separation is performed after the oxidation roasting, the magnetic separation intensity is controlled to be 800GS-1400GS.

13. The method according to any one of claims 1 to 12, characterized in that The temperature of the reduction-sulfurization roasting is 1100° C.-1300° C., and the time of the reduction-sulfurization roasting is 35 min-40 min.

14. The method according to any one of claims 2 to 13, characterized in that During the reduction sulfidation roasting process, the mass ratio of the nickel-containing magnetite concentrate to the reducing agent and the sulfiding agent is controlled to be 1: (0.08-0.10): (0.30-0.50).

15. The method according to any one of claims 2 to 14, characterized in that The vulcanizing agent used in the reduction-sulfurization roasting process is one or both of sulfur and desulfurized gypsum.

16. The method according to any one of claims 2 to 15, characterized in that The reducing agent used in the reduction sulfidation roasting process is reduced coal.

17. The method according to any one of claims 1 to 16, characterized in that The reduction sulfurization roasting is carried out in a rotary kiln, and an inert protective gas is introduced during the roasting process.

18. The method according to any one of claims 2 to 17, characterized in that During the melt removal process, the operating temperature is controlled to be 1300° C.-1500° C., and the operating time is 10 min-30 min.

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