A method for strengthening the sintering of limonite-type laterite nickel ore

Abstract

The present invention discloses a method for strengthening the sintering of limonite-type laterite nickel ore. The sintering raw materials including limonite-type laterite nickel ore, iron concentrate, fuel, flux and return fines are successively mixed, granulated and sintered to obtain limonite-type laterite nickel ore sinter. By adjusting the aluminum content of the sintering mixture within an appropriate range, this method can reduce the liquid phase formation temperature, increase the liquid phase formation amount, improve the ore-forming conditions of the sinter, and enhance the strength of the limonite-type laterite nickel ore sinter. Moreover, this method reduces costs, has simple operation and strong practicability, and has obvious economic benefits.

Description

Technical Field

[0001] The present invention relates to a method for smelting laterite nickel ore, in particular to a method for strengthening the sintering of limonite-type laterite nickel ore, and belongs to the technical field of iron and steel metallurgy. Background Art

[0002] Nickel resources worldwide are divided into two categories: sulfide nickel ore and laterite nickel ore. With the overexploitation of high-grade and easily mined sulfide nickel ore and the gradual maturity of the smelting process of limonite-type laterite nickel ore and other factors, the production of nickel products using laterite nickel ore has become the focus.

[0003] Currently, the smelting process of laterite nickel ore mainly uses pyrometallurgy. However, smelting low-grade limonite-type laterite nickel ore using the rotary kiln electric furnace method (RKEF method) will increase energy consumption and costs.

[0004] Limonite-type laterite nickel ore has characteristics such as high contents of physical water and crystal water, large burn-off, fast sintering speed, short high-temperature holding time of sinter, low sintering end temperature, and fast cooling speed of the burden surface, resulting in problems such as low strength of sinter and low finished product rate in the actual production process of limonite-type laterite nickel ore sintering.

[0005] In addition, the melting points of various conventional aluminates (calcium aluminate, magnesium aluminate, etc.) are relatively high, all higher than 1450 °C. For conventional iron ore sintering, a high aluminum content will increase the liquid phase formation temperature, increase fuel consumption, reduce the strength of sinter, and deteriorate the metallurgical properties of sinter. Therefore, a habitual conclusion has been formed that aluminum is not conducive to the sintering of limonite-type laterite nickel ore. Currently, there are literature reports (Mineralization mechanism of limonitic laterite sinter under different fuel dosage: Effect of FeO, Yikang Tu, et al., Powder Technology 398 (2022) 117064) that during the sintering process of limonite-type laterite nickel ore, alumina can participate in the formation of the liquid phase, and its liquid phase SFCA (complex calcium ferrite composed of SiO2, Fe2O3, CaO, Al2O3, and ferrous iron), SFCA is a compound with no fixed chemical formula and complex composition, and its physical and chemical properties are quite different from those of calcium aluminate, magnesium aluminate, etc. However, these literatures only report that alumina can participate in the liquid phase formation, and do not disclose the relevant content of controlling the liquid phase formation and improving the sintering ore-forming conditions by adjusting the aluminum content in the sintering raw materials. Summary of the Invention

[0006] Aiming at the problems existing in the actual production process of sintering limonite-type laterite nickel ore, such as low strength of sintered ore and low finished product rate, the purpose of the present invention is to provide a method for strengthening the sintering of limonite-type laterite nickel ore. This method adjusts the aluminum content in the sintering raw materials by adding an aluminum source or directly using high-aluminum laterite nickel ore, reduces the liquid phase formation temperature, increases the liquid phase formation amount, improves the ore formation conditions of the sintered ore, and improves the strength of the limonite-type laterite nickel ore sintered ore, providing high-quality and low-cost limonite-type laterite nickel ore sintered ore for nickel-iron alloy smelting, and having broad application prospects.

[0007] In order to achieve the above technical purpose, the present invention provides a method for strengthening the sintering of limonite-type laterite nickel ore. The method successively mixes, granulates and sinters the sintering raw materials including limonite-type laterite nickel ore, iron concentrate, fuel, flux and return fines to obtain limonite-type laterite nickel ore sintered ore; the aluminum mass percentage content in the sintering raw materials is controlled within the range of 6.3-9.2%, wherein the aluminum mass is measured by the mass of Al2O3.

[0008] The key to the technical solution of the present invention lies in strictly controlling the aluminum content in the limonite-type laterite nickel ore sintering raw materials to reduce the liquid phase formation temperature, increase the liquid phase formation amount, improve the ore formation conditions of the sintered ore, and obtain high-quality limonite-type laterite nickel ore sintered ore. Based on the fact that the liquid phase of limonite-type laterite nickel ore sintered ore is mainly SFCA (complex calcium ferrite) composed of SiO2, Fe2O3, CaO, Al2O3 and ferrous iron, and alumina is a component in the SFCA liquid phase. The inventor unexpectedly found that when the aluminum content in the sintering raw materials is adjusted within an appropriate range, the sintering process of limonite-type laterite nickel ore can be adjusted to the optimal state to achieve the best sintering effect. When the aluminum mass percentage content in the sintering raw materials is less than 6.3%, it is difficult for the sintered ore to form enough liquid phase, thus bonding into a high-hardness spinel phase, resulting in a decrease in the strength of the sintered ore. When the aluminum mass percentage content in the sintering raw materials is greater than 9.2%, excessive aluminum will enter the spinel phase, resulting in a decrease in the hardness of the spinel phase, and then affecting the strength of the sintered ore. Therefore, the aluminum content in the limonite-type laterite nickel ore sintering raw materials should be controlled within the range of 6.3-9.2%.

[0009] As a preferred solution, when the aluminum mass percentage content in the sintering raw materials is less than 6.3%, the aluminum mass percentage content is adjusted within the range of 6.3%-9.2% by adding an external aluminum source, wherein the aluminum mass is measured by the mass of Al2O3. When the laterite nickel ore in the sintering raw materials is low-aluminum laterite nickel ore, an external aluminum source often needs to be added, while when high-aluminum laterite nickel ore is used, the sintering raw materials often meet the requirement that the aluminum mass percentage content is within the range of 6.3%-9.2%.

[0010] As a more preferred solution, the aluminum source includes at least one of aluminum slag, aluminum ash, bauxite, aluminum ash inertized slag and red mud.

[0011] As a preferred solution, the particle size of the aluminum source is such that the mass ratio of particles smaller than 1 mm reaches more than 80%. If the proportion of particles with a particle size smaller than 1 mm in the aluminum source is too small, it is difficult for the aluminum source to be evenly distributed in the sintering mixture, resulting in a decrease in the production quality index of the sinter. Further preferably, the particle size of the aluminum source is such that the mass ratio of particles smaller than 1 mm reaches more than 90%.

[0012] As a preferred solution, the mass of the iron concentrate accounts for 4 - 8% of the mass of the sinter raw materials. Due to problems such as the low density and poor granulation effect of limonite-type laterite nickel ore, by adding an appropriate amount of iron concentrate, the granulation effect of limonite-type laterite nickel ore can be strengthened, the air permeability of the sintering material layer can be improved, and the smooth progress of suction sintering can be ensured. The mass of the iron concentrate is further preferably 6 - 8% of the mass of the sinter raw materials.

[0013] As a preferred solution, the mass of the solid fuel accounts for 5.8 - 8.0% of the mass of the sinter raw materials. The solid fuel mainly provides the heat required during the sintering process. Due to the high content of crystal water and serious shrinkage of the material layer in limonite-type laterite nickel ore, resulting in large heat losses, therefore, the fuel consumption during the sintering process of limonite-type laterite nickel ore is higher than that of ordinary iron ore sintering process (3.0 - 4.5%). The mass of the fuel is further preferably 6.0 - 7.6% of the mass of the sinter raw materials.

[0014] As a preferred solution, the mass of the returned ore powder accounts for 25 - 30% of the mass of the sinter raw materials. The yield of limonite-type laterite nickel ore sintering is usually 70 - 75%. To ensure the balance of the returned ore, the returned ore ratio is determined to be 25 - 30%.

[0015] As a preferred solution, the mass of the flux is used to adjust the binary basicity of the sinter raw materials to 1.4 - 1.8, and the magnesium-aluminum ratio of the sinter raw materials is controlled to be 0.20 - 0.50. Further preferably, the mass of the flux is used to adjust the binary basicity of the sinter raw materials to 1.5 - 1.7, and the magnesium-aluminum ratio of the sinter raw materials is controlled to be 0.30 - 0.40.

[0016] As a more preferred solution, the fuel is coke powder and / or anthracite; the particle size of the fuel is such that the mass ratio of -1 mm particles is 20 - 50%, and the mass ratio of +5 mm particles is <15%. If the proportion of fine-grained solid fuel is too high, it will cause the combustion during the sintering process to be too fast, resulting in a mismatch between the combustion front and the heat transfer front, and a decrease in the strength of the sinter. If the proportion of +5 mm fuel is too large, there will be insufficient fuel combustion and the heat required for the sintering process cannot be provided. Further preferably, the particle size of the fuel is such that the mass ratio of -1 mm particles is 30 - 40%, and the mass ratio of +5 mm particles is <10%.

[0017] As a more preferred embodiment, the particle size of the returned ore powder is less than 5 mm.

[0018] As a more preferred embodiment, the flux is at least one of quicklime, dolomite, and serpentine.

[0019] As a preferred embodiment, the water content of the granulated material obtained by granulation is 18-21%, and the average particle size is 2.50-3.20 mm. The average particle size of the granulated material is further preferably 2.60-2.90 mm. An appropriate particle size can ensure the sintering rate. If the particle size of the granular material is too large, the air permeability of the sintering material layer is too good, resulting in too fast sintering speed and too short holding time in the high-temperature zone, and the quality indexes of the sintered ore are poor. If the particle size is too small, the air permeability of the sintering material layer will be poor, which will also affect the sintering effect.

[0020] As a preferred embodiment, the sintering is carried out by suction sintering.

[0021] As a preferred embodiment, during the sintering process, the ignition temperature is 1150±50°C, the ignition time is 2-3 min, the heat preservation time is 0.5-1.05 min, the negative pressure for ignition and heat preservation is 6-8 kPa, and the sintering negative pressure is 8-12 kPa.

[0022] As a preferred embodiment, the aluminum mass percentage content of the sintering raw material is controlled within the range of 6.4-7.8%, wherein the aluminum mass is measured by the mass of Al2O3.

[0023] Compared with the prior art, the beneficial technical effects brought by the technical solution of the present invention:

[0024] By regulating the aluminum content in the sintering raw material of limonite-type laterite nickel ore, the technical solution of the present invention can effectively reduce the liquid phase formation temperature, increase the liquid phase formation amount of the sintered ore, improve the ore-forming conditions of the sintered ore, increase the strength of the laterite nickel ore sintered ore, and reduce the cost.

[0025] The technical solution of the present invention can directly use low-cost high-aluminum laterite nickel ore as the raw material or add a low-cost aluminum source as an additive, and can obtain high-quality laterite nickel ore sintered ore, with low cost, simple operation, strong practicability, obvious economic benefits and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is the SRM-EDS diagram of the limonite-type laterite nickel ore sintered ore of Example 1 and Comparative Example 1 and Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0027] The following further elaborates on the content of the present invention in conjunction with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0028] The main components of the aluminum source and laterite nickel ore used in the following examples are as follows:

[0029] The main components of the aluminum source by mass percentage are as follows:

[0030] Aluminum ash: The content of Al2O3 is 76.98wt%, the content of SiO2 is 12.69wt%, the content of MgO is 1.04wt%, and the content of CaO is 1.85wt%.

[0031] Bauxite: The content of Al2O3 is 53.47wt%, the content of SiO2 is 7.40wt%, the content of MgO is 0.27wt%, and the content of CaO is 0.09wt%.

[0032] The main components of the laterite nickel ore by mass percentage are as follows:

[0033] Laterite nickel ore 1: The content of Al2O3 is 4.47wt%, the content of SiO2 is 3.20wt%, the content of MgO is 1.41wt%, the content of Fe2O3 is 71.74wt%, the content of CaO is 0.034wt%, and the content of Cr2O3 is 3.05wt%.

[0034] Laterite nickel ore 2: The content of Al2O3 is 6.19wt%, the content of SiO2 is 2.22wt%, the content of MgO is 0.59wt%, the content of Fe2O3 is 52.61wt%, the content of CaO is 0.062wt%, and the content of Cr2O3 is 3.13wt%.

[0035] Laterite nickel ore 3: The content of Al2O3 is 7.44wt%, the content of SiO2 is 2.95wt%, the content of MgO is 1.26wt%, the content of Fe2O3 is 47.25wt%, the content of CaO is 0.057wt%, and the content of Cr2O3 is 4.11wt%.

[0036] The iron concentrate, fuel, flux, etc. are all raw materials used in the conventional sintering and pelletizing process.

[0037] Example 1

[0038] Mix laterite nickel ore, iron concentrate powder, fuel, flux, return ore powder, and aluminum source to obtain a mixed material. After adjusting the moisture content of the mixed material, pelletize it through mixing to obtain pelletized material, and then distribute the pelletized material onto a sintering machine for suction sintering to obtain limonite-type laterite nickel ore sinter.

[0039] In Example 1 above:

[0040] The aluminum source is aluminum ash.

[0041] The laterite nickel ore is Laterite Nickel Ore 1, and the aluminum content of the sinter is adjusted to 7.57% by adding an aluminum source.

[0042] The moisture content of the pelletized material is 18.90%.

[0043] The average particle size of the pelletized material is 2.67 mm.

[0044] The addition amount of the iron concentrate powder is 7%.

[0045] The proportion of particles smaller than 1 mm in the aluminum source is 93.02%.

[0046] The fuel is a mixture of coke powder and anthracite (the mass ratio of coke powder to anthracite is 1:9), and the addition amount is 6.5%.

[0047] The proportion of particles smaller than 1 mm in the fuel is 31.2%, and the proportion of particles larger than 5 mm is 8.3%.

[0048] The proportion of the return ore powder is 30%, and the particle size is smaller than 5 mm.

[0049] The flux is quicklime and dolomite, the binary basicity is adjusted to 1.56, and the magnesium-aluminum ratio is controlled to be 0.23.

[0050] The ignition and heat preservation negative pressure is 8 kPa, and the sintering negative pressure is 10 kPa.

[0051] The ignition temperature is 1150 ± 50 °C; the ignition time is 2.5 min, and the heat preservation time is 1 min.

[0052] The height of the sintering material layer is 900 mm.

[0053] The sintering speed in this Example 1 is 25.46 mm·min -1 , the finished product rate is 69.36%, the drum strength is 58.34%, and the production and quality indexes of the sinter are good. The SEM-EDS diagrams of the specific limonite-type laterite nickel ore sinter are as shown in Figure 1 (c) and Figure 1 (d).

[0054] Example 2

[0055] Mix laterite nickel ore, iron concentrate powder, fuel, flux, return ore powder, and an aluminum source to obtain a mixed material. After adjusting the moisture content of the mixed material, obtain pelletized material through mixing and granulation. Then, distribute the pelletized material onto a sintering machine for suction sintering to obtain limonite-type laterite nickel ore sinter.

[0056] In the above Example 2:

[0057] The aluminum source is bauxite.

[0058] The laterite nickel ore is Laterite Nickel Ore 2, and the aluminum content of the sinter is adjusted to 6.76% by adding an aluminum source.

[0059] The moisture content of the pelletized material is 19.5%.

[0060] The average particle size of the pelletized material is 2.75 mm.

[0061] The addition amount of the iron concentrate powder is 6%.

[0062] The proportion of particles smaller than 1 mm in the aluminum source is 96.3%.

[0063] The fuel is anthracite, and the addition amount is 7.3%.

[0064] The proportion of particles -1 mm in the fuel is 39.5%, and the proportion of particles +5 mm is 5.5%.

[0065] The proportion of the return ore powder is 30%, and the particle size is smaller than 5 mm.

[0066] The flux is quicklime and dolomite, adjust the binary basicity to 1.61, and control the magnesium-aluminum ratio to 0.29.

[0067] The ignition and heat preservation negative pressure is 7 kPa, and the sintering negative pressure is 12 kPa.

[0068] The ignition temperature is 1150 ± 50 °C; the ignition time is 2.5 min, and the heat preservation time is 1 min.

[0069] The height of the sintering material layer is 800 mm.

[0070] The sintering speed in this Example 2 is 27.12 mm·min -1 , the yield is 67.26%, the drum strength is 56.27%, and the production and quality indexes of the sinter are relatively good.

[0071] Example 3

[0072] Mix Laterite Nickel Ore 3, iron concentrate powder, fuel, flux, and return ore powder to obtain a mixed material. After adjusting the moisture content of the mixed material, obtain pelletized material through mixing and granulation. Then, distribute the pelletized material onto a sintering machine for suction sintering to obtain limonite-type laterite nickel ore sinter.

[0073] In Example 3 above:

[0074] The aluminum content of the laterite nickel ore is 7.44%, no aluminum source needs to be added, and the aluminum content of the sinter is 7.25%.

[0075] The moisture content of the granular material is 20.21%.

[0076] The average particle size of the granular material is 2.78 mm.

[0077] The addition amount of iron concentrate powder is 6%.

[0078] The fuel is a mixture of coke powder and anthracite (the mass ratio of coke powder to anthracite is 1:9), and the addition amount is 6.5%.

[0079] The proportion of -1mm particles in the fuel is 41.3%, and the proportion of +5mm particles is 4.7%.

[0080] The proportion of returned ore powder is 30%, and the particle size is less than 5 mm.

[0081] The flux is quicklime and serpentine, adjusting the binary basicity to 1.68 and controlling the magnesium-aluminum ratio to 0.38.

[0082] The ignition and heat preservation negative pressure is 6 kPa, and the sintering negative pressure is 8 kPa.

[0083] The ignition temperature is 1150 ± 50 °C; the ignition time is 2.5 min, and the heat preservation time is 1 min.

[0084] The height of the sintering material layer is 900 mm.

[0085] The sintering speed in this Example 3 is 23.16 mm·min -1 The yield is 72.15%, the drum strength is 60.31%, and the sinter product quality index is good.

[0086] Comparative Example 1

[0087] Mix laterite nickel ore, iron concentrate powder, fuel, flux, returned ore powder, and aluminum source to obtain a mixed material. After adjusting the moisture content of the mixed material, obtain granular material through mixing and granulation, and then distribute the granular material on the sintering machine for suction sintering to obtain limonite-type laterite nickel ore sinter.

[0088] The only difference from Example 1 is that: adding an aluminum source to adjust the aluminum content of the sinter to 5.33%.

[0089] The sintering speed in this Comparative Example 1 is 27.17 mm·min -1, the finished product rate is 57.64%, the drum strength is 48.34%, and the sinter output and quality indexes are relatively poor. Comparing this Comparative Example 1 with Example 1, it is mainly a comparison of the aluminum content in the sinter. When the alumina content in the sinter is less than 6.3%, it is difficult for the aluminum in the mixture to form sufficient calcium ferrite, resulting in poor sinter quality. The specific SEM-EDS diagrams of the limonite-type laterite nickel ore sinter are as Figure 1 (a) and Figure 1 (b) shown.

[0090] Comparative Example 2

[0091] Mix laterite nickel ore, iron concentrate, fuel, flux, return ore powder, and aluminum source to obtain a mixture. After adjusting the moisture of the mixture, obtain pelletized materials through mixing and granulation, and then spread the pelletized materials on a sintering machine for suction sintering to obtain limonite-type laterite nickel ore sinter.

[0092] The only difference from Example 1 is that an aluminum source is added to adjust the aluminum content in the sinter to 10.34%.

[0093] The sintering speed of this Comparative Example 2 is 26.15 mm·min -1 , the finished product rate is 60.18%, the drum strength is 45.17%, and the sinter output and quality indexes are relatively poor. Comparing this Comparative Example 2 with Example 1, it is mainly a comparison of the aluminum content in the sinter. When the alumina content in the sinter is higher than 9.2%, a large amount of aluminum in the sinter enters the spinel phase, forming a relatively soft aluminum spinel phase, resulting in poor sinter quality. The specific SEM-EDS diagrams of the limonite-type laterite nickel ore sinter are as Figure 1 (e) and Figure 1 (f) shown.

[0094] Comparative Example 3

[0095] Mix laterite nickel ore, iron concentrate, fuel, flux, return ore powder, and aluminum source to obtain a mixture. After adjusting the moisture of the mixture, obtain pelletized materials through mixing and granulation, and then spread the pelletized materials on a sintering machine for suction sintering to obtain limonite-type laterite nickel ore sinter.

[0096] Compared with Example 2, the only difference is that the proportion of particles smaller than 1 mm in the aluminum source is 54.3%.

[0097] The sintering speed of this Comparative Example 3 is 27.19 mm·min -1 , the finished product rate is 60.21%, the drum strength is 50.34%, and the sinter output quality indexes are poor. Comparing this Comparative Example 2 with Example 2, it is mainly a comparison of whether the proportion of particles smaller than 1 mm in the aluminum source reaches 80%. Since the particle size of the aluminum source is too coarse, it is difficult to be evenly dispersed in the sintering raw materials, resulting in poor sinter output and quality indexes.

[0098] Comparative Example 4

[0099] The laterite nickel ore, iron concentrate powder, fuel, flux, and return ore powder are mixed to obtain a mixed material. After adjusting the moisture content of the mixed material, pelletized material is obtained through mixing and granulation. Then, the pelletized material is distributed onto a sintering machine for suction sintering to obtain laterite nickel ore sinter ore of limonite type.

[0100] Compared with Example 3, the only difference is that the average particle size of the pelletized material is 3.35 mm.

[0101] The sintering speed of this Comparative Example 4 is 30.19 mm·min -1 , the finished product rate is 50.21%, the drum strength is 42.34%, and the quality indexes of the sinter ore are relatively poor. The comparison between this Comparative Example 4 and Example 3 mainly focuses on whether the average particle size of the pelletized material is 2.5 - 3.2 mm. Due to the too large particle size of the pelletized material, the air permeability of the sintering material layer is too good, resulting in too fast sintering speed, too short retention time in the high-temperature zone, and poor quality indexes of the sinter ore.

[0102] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be encompassed by the present invention.

[0103] In addition, it should be understood that although this specification is described according to the embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other implementation solutions understandable by those skilled in the art.

Claims

1. A method for strengthening the sintering of limonite-type laterite nickel ore, characterized in that: Sintering raw materials including limonite-type laterite nickel ore, iron concentrate, fuel, flux and return ore powder are successively mixed, granulated and sintered to obtain limonite-type laterite nickel ore sinter; the mass percentage content of aluminum in the sintering raw materials is less than 6.3%, and the mass percentage content of aluminum is adjusted to be in the range of 6.3% - 9.2% by adding an external aluminum source, wherein the mass of aluminum is measured by the mass of Al2O3; the particle size of the aluminum source meets the requirement that the mass percentage of particles smaller than 1 mm reaches more than 80%; the moisture content of the granulated material obtained by granulation is 18 - 21%, and the average particle size is 2.50 - 3.20 mm.

2. The method for strengthening the sintering of limonite-type laterite nickel ore according to claim 1, characterized in that: The aluminum source includes at least one of aluminum slag, aluminum ash, bauxite, and red mud.

3. A method for strengthening the sintering of limonite-type laterite nickel ore according to claim 1, characterized in that: The mass of the iron concentrate accounts for 4 - 8% of the mass of the sintering raw materials; The mass of the fuel accounts for 5.8 - 8.0% of the mass of the sintering raw materials; The mass of the return ore powder accounts for 25 - 30% of the mass of the sintering raw materials; The mass of the flux is measured by adjusting the binary basicity of the sintering raw materials to 1.4 - 1.8 and controlling the magnesium-aluminum ratio of the sintering raw materials to be 0.20 - 0.

50.

4. A method for strengthening the sintering of limonite-type laterite nickel ore according to claim 1 or 3, characterized in that: The fuel is coke powder and / or anthracite; The particle size of the fuel meets the requirement that the mass percentage of -1 mm particles is 20 - 50%, and the mass percentage of +5 mm particles is <15%; The particle size of the return ore powder is less than 5 mm; The flux is at least one of quicklime, dolomite, and serpentine.

5. A method for strengthening the sintering of limonite-type laterite nickel ore according to claim 1, characterized in that: The sintering is carried out by suction sintering.

6. A method for strengthening the sintering of limonite-type laterite nickel ore according to claim 1, characterized in that: During the sintering process, the ignition temperature is 1150 ± 50 °C, the ignition time is 2 - 3 min, the heat preservation time is 0.5 - 1.05 min, the ignition and heat preservation negative pressure is 6 - 8 kPa, and the sintering negative pressure is 8 - 12 kPa.

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