Laterite-nickel ore low-carbon sintering method based on rapid formation of low-melting-point liquid phase

Abstract

The invention discloses a laterite-nickel ore low-carbon sintering method based on rapid formation of a low-melting-point liquid phase, which comprises the following steps: burdening limonite type laterite-nickel ore, a novel calcium flux, quicklime, coke powder, return mine and other raw materials, uniformly mixing, granulating, igniting, sintering, cooling the sintered ore, crushing, screening, detecting and the like to obtain the finished product sintered ore. Based on an existing sintering process, a novel calcium ferrite type calcium flux is prepared in advance, and the advantages of low melting point of the novel calcium ferrite type calcium flux and the characteristics of high sintering speed and loose material layer of limonite type laterite-nickel ore are synergistically utilized, so that the novel calcium ferrite type laterite flux is prepared on the premise of not increasing additional procedures and equipment investment. More low-melting-point liquid phases in the sintering process of the limonite type laterite-nickel ore are promoted to be formed more quickly, and the technical problems that the limonite type laterite-nickel ore is poor in sintering quality and high in carbon emission are solved. According to the method, the increase of investment cost and the reduction of effective components such as nickel and chromium are avoided, the carbon emission reduction effect is remarkable, and the industrialization prospect is good.

Description

Technical Field

[0001] The invention relates to the field of iron and steel metallurgy, and in particular to a low-carbon sintering method for laterite nickel ore based on rapid formation of a low-melting-point liquid phase. Background Art

[0003] Limonite-type laterite nickel ore has a high iron grade and a low nickel grade, and is more suitable for sintering-blast furnace process in industrial production. However, due to its high physical water and crystal water content, low iron grade, many high melting point minerals, and large ignition loss, the sintering and cooling speeds are fast, the material layer shrinks greatly, the air permeability is uneven, the heat transfer efficiency is low, the liquid phase is difficult to form, and the mineralization conditions are poor, resulting in low sintered ore quality and high solid fuel consumption. The technical and economic indicators of sintered ore cannot guarantee the long-term smooth operation of sintering and blast furnace processes.

[0004] At present, the development of low-carbon sintering technology for laterite nickel ore has made great progress, mainly including optimized ore blending technology (CN201410359075.9, CN202211261380.5), enhanced granulation technology (CN201410130269.1, CN202210061501.5), pressurized densification sintering technology (CN201810025683.4), hot air circulation sintering technology (CN201810025669.4) and the coupled sintering technology of the two (CN201810025624.7), etc. However, in terms of optimized ore blending technology, due to the high content of gangue components such as SiO2, Al2O3, and MgO in limonite-type laterite nickel ore itself, the adjustment space of the chemical composition of the sintered ore is small; the addition of other iron-containing raw materials will dilute the content of nickel and chromium in the sintered ore, which is not conducive to the subsequent smelting process. Other low-carbon sintering technologies for laterite nickel ores mainly reduce carbon emissions and improve the quality indicators of sintered ore by improving the external conditions of sintering. They often require the addition of pretreatment steps or additional equipment investment, and cannot fundamentally solve the problems of difficult sintering liquid phase formation, poor quality indicators and high carbon emissions in limonite-type laterite nickel ore.

[0005] In addition, adding flux to reduce the liquid phase formation temperature and improve the liquid phase formation ability is also an effective way to strengthen the sintering of laterite nickel ore. CN201910424255.3 improves the sintering process of laterite nickel ore by adding a nickel smelting waste slag. Although the strength of the sintered ore is significantly improved, the utilization coefficient is still lower than 1.2t·m -2 ·h -1, the solid fuel consumption is still as high as 130kg / t or more, and the carbon emissions from the sintering process are still very high. CN202310222382.1 prepared a low-melting point additive by the method of reduction roasting. At its high ratio (>7.5%) and high ignition temperature (1150±50℃), pretreatment processes such as sintered return ore grinding were added at the same time. Compared with the comparative example, the drum strength and yield of the sintered ore in the optimal embodiment only increased by 4.23% and 2.98% respectively year-on-year, and the solid fuel consumption only decreased by 4.27% year-on-year. The improvement did not exceed 5%, and the improvement effect was limited. This patent does not involve changes in production indicators such as the sintered ore utilization coefficient, because the continuous increase in the amount of liquid phase in the sintering process will cause the permeability of the sintering material layer to weaken, which will lead to a slowdown in the sintering speed and fail to promote the rapid formation of a low-melting point liquid phase. It is meaningless to achieve carbon emission reduction at the expense of sintered ore production. CN201910591670.8 and CN202210050748.7 prepared a low melting point additive through a chain grate-rotary kiln oxidation roasting process. Under the premise of adding pretreatment processes such as return ore inlay and reducing fuel particle size, when the additive ratio is low (<5%), the coke powder consumption is reduced by 30% under the condition that the sintered ore quality index is equivalent to that of the comparative example. The patent also adds an additional pretreatment process, further extending the process flow, and increasing production and investment costs. The above-mentioned related patents do not involve the application of low melting point flux in the sintering process of laterite nickel ore. At the same time, the preparation method of the low melting point flux needs to be prepared by reduction roasting, oxidation roasting and other processes outside the sintering process, which undoubtedly increases the difficulty of sintering production. Some steel companies do not have relevant process equipment. At the same time, the low melting point flux pellets prepared by the above method have high strength and high grinding power consumption, which will increase the cost of sintering application of low melting point flux. Summary of the invention

[0006] In view of the above technical problems, the present invention provides a low-carbon sintering method for laterite nickel ore based on the rapid formation of low-melting-point liquid phase. First, based on the existing sintering process, conventional iron ore powder and other commonly used raw materials for sintering are used. According to the sintering mixture CaO:Fe2O3 molar ratio of 1:1 (other process conditions are consistent with conventional sintering parameters), a calcium ferrite type calcium flux with a melting point of only 1195°C is prepared at low cost; thereafter, the new calcium flux is replaced by the conventional calcium flux quicklime after simple jaw crushing, and the advantages of fast sintering speed and loose material layer of limonite type laterite nickel ore are synergistically utilized without adding additional pretreatment procedures. While reducing the sintering temperature and the liquid phase formation temperature, the decrease in sintered ore output is avoided, and the low-melting-point liquid phase is formed more and faster. In this way, the defect of fast cooling speed of limonite type laterite nickel ore can be effectively compensated, and the consolidation and crystallization process of sintered ore can be promoted to be completed at a lower temperature. Ultimately, under the condition of a lower proportion of calcium ferrite-type calcium flux, the quality indicators of sintered ore were significantly improved while carbon emissions were significantly reduced.

[0007] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0008] A low-carbon sintering method for laterite nickel ore based on rapid formation of a low-melting-point liquid phase comprises the following steps:

[0009] S1. Batching: Batching laterite nickel ore, calcium ferrite type calcium flux, quicklime, coke powder and return ore according to the corresponding proportion of the ore batching plan;

[0010] S2, mixing and granulating: the sintered mixture in S1 is put into a drum mixer, water is added, and the mixing and granulating process is completed;

[0011] S3, ignition and sintering: After placing the base material at the bottom of the sintering cup, the sintering mixture granulated in S2 is placed into the sintering cup for ignition and sintering;

[0012] S4, cooling: After sintering, the sintered ore is cooled. When the sintering flue gas temperature is lower than 100°C, unloading begins;

[0013] S5. Sintered ore testing: After the S4 sintered ore is dropped, it is screened for whole particles, the mass of sintered ore of each particle size is recorded, and the drum strength of the sintered ore is measured by a drum device.

[0014] Furthermore, in step S1, the laterite nickel ore has a total iron content of 45.32wt%, a total nickel content of 0.88wt%, a total chromium content of 2.65wt%, a CaO content of 0.25wt%, a SiO2 content of 5.35wt%, a MgO content of 4.67wt%, an Al2O3 content of 4.89wt%, and a burn loss of 13.36wt%; particle size: +8mm accounts for 9.55wt%, 5-8mm accounts for 13.64wt%, 3-5mm accounts for 25.80wt%, 1-3mm accounts for 39.75wt%, 0.5-1mm accounts for 7.16wt%, and -0.5mm accounts for 4.10wt%.

[0015] Furthermore, in step S1, the laterite nickel ore is 51.45-56.59 parts, the calcium ferrite type calcium flux is 0.00-10.00 parts, the quicklime is 1.05-5.92 parts, the coke powder is 7.00-7.50 parts, and the return ore is 30.00 parts.

[0016] Furthermore, in step S1, the coke powder has a total iron content of 1.43wt%, a CaO content of 1.10wt%, a SiO2 content of 7.22wt%, a MgO content of 0.26wt%, an Al2O3 content of 4.93wt%, and a burn loss of 83.37wt%; particle size: +8mm accounts for 0.60wt%, 3-5mm accounts for 5.74wt%, 3-5mm accounts for 13.99wt%, 1-3mm accounts for 31.73wt%, 0.5-1mm accounts for 19.16wt%, and -0.5mm accounts for 28.78wt%.

[0017] Furthermore, the calcium ferrite type calcium flux in step S1 is prepared by the following method:

[0018] (1) Batching: Weigh low-grade iron ore, quicklime, coke powder, and returned ore to obtain a mixed material;

[0019] (2) Mixing and granulating: the mixed material is loaded into a drum mixer, water is added, and the mixing and granulating process is completed to obtain a granulated mixed material;

[0020] (3) Ignition and sintering: After placing the base material at the bottom of the sintering cup, the granulated mixture is loaded into the sintering cup for ignition and sintering;

[0021] (4) Cooling: After sintering, the sintered ore is cooled. The negative pressure during cooling is 6 kPa. When the sintering flue gas temperature is lower than 100 °C, unloading begins.

[0022] (5) Sintered ore testing: The sintered ore in step (4) is dropped to a height of 2 m and three times, followed by whole-grain screening to obtain calcium ferrite-type calcium flux; the mass of sintered ore of each particle size is recorded, and the drum strength of the sintered ore is measured by a drum device.

[0023] Furthermore, in step (1), the low-grade iron ore is 44.80-45.29 parts, quicklime is 19.60-19.81 parts, coke powder is 4.90-5.60 parts, and the returned ore is 30.00 parts.

[0024] Furthermore, in the mixture of step (1), the molar ratio of CaO:Fe2O3 is 1:1, and the moisture content of the mixture is 8.5-9.0wt%.

[0025] Furthermore, in step (1), the low-grade iron ore has a total iron content of 56.04wt%, a CaO content of 0.17wt%, a SiO2 content of 4.94wt%, a MgO content of 0.13wt%, an Al2O3 content of 2.77wt%, and a burn loss of 10.38wt%; the particle size of the low-grade iron ore is: +8mm accounts for 8.08wt%, 5-8mm accounts for 7.62wt%, 3-5mm accounts for 26.70wt%, 1-3mm accounts for 28.66wt%, 0.5-1mm accounts for 11.14wt%, and -0.5mm accounts for 17.79wt%.

[0026] Furthermore, in step (5), the calcium ferrite type calcium flux has a total iron content of 38.50wt%, a CaO content of 37.62wt%, a SiO2 content of 1.35wt%, a MgO content of 0.32wt%, an Al2O3 content of 0.63wt%, and a burnout of 2.28wt%; the particle size of the calcium ferrite type calcium flux is: 3-5mm accounts for 7.12wt%, 1-3mm accounts for 11.06wt%, 0.5-1mm accounts for 20.36wt%, -0.5mm accounts for 61.46wt%, and the melting point is 1195-1205°C.

[0027] Furthermore, in step S2, the mixing time is 5 min, the granulation time is 3 min, and the mixer speed is 10 r / min. -1 , filling rate 15%, mixture moisture 17.52~18.25wt%.

[0028] Furthermore, the basicity of the sintered ore in step S3 is 1.4.

[0029] Furthermore, in step S3, the mass of the base material is 2 kg, the material layer height is 700 mm, the ignition time is 1.5 min, the ignition temperature is 1100° C., the ignition negative pressure is 6 kPa, and the sintering negative pressure is 10 kPa.

[0030] Furthermore, the cooling negative pressure in step S4 is 6 kPa.

[0031] Furthermore, in step S5, the falling height is 2 m and the number of falling times is 3 times.

[0032] Compared with the prior art, the advantages of the present invention are:

[0033] (1) The present invention is based on the existing sintering process and prepares a new type of low-melting-point calcium flux, which does not require the use of other process equipment, thereby reducing the difficulty of application and production cost in the iron ore sintering process. At the same time, the raw materials used in the preparation are from a wide range of sources, and the new type of calcium flux sintered ore products have good grindability. After simple jaw crushing, they can meet the needs of sintering applications, and have good industrial prospects.

[0034] (2) The present invention fills the gap in the application of low-melting-point flux in the sintering of limonite-type laterite nickel ore without adding additional pretreatment steps, breaks through the technical bottleneck of difficult liquid phase formation and high carbon emission in the sintering of limonite-type laterite nickel ore, and achieves a significant improvement in the quality indicators of sintered ore and a further reduction in carbon emissions under the condition of a relatively low ratio of the new flux, thereby avoiding an increase in investment cost and a reduction in effective components such as nickel and chromium. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The process flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The following is a clear and complete description of the technical solutions in the embodiments of the present invention and the comparative examples. 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 creative work are within the scope of protection of the present invention.

[0037] Embodiment 1:

[0038] A low-carbon sintering method for laterite nickel ore based on rapid formation of a low-melting-point liquid phase comprises the following steps:

[0039] Adding 2.50wt% of a new calcium flux, with a basicity of 1.4, comprises the following steps:

[0040] S1. Batching: Batching the ingredients according to the mass ratio of 55.31wt% of limonite-type laterite nickel ore, 4.69wt% of quicklime, 7.50wt% of coke powder, and 30.00wt% of return ore to form a sintering mixture;

[0041] S2, mixing and granulation: put the S1 sintered mixture into a drum mixer, add water, and complete the mixing and granulation process. The mixing time is 5 minutes, the granulation time is 3 minutes, and the mixer speed is 10 r·min -1 , filling rate 15%, sintering mixture moisture 18.06wt% after granulation;

[0042] S3, ignition and sintering: After placing the base material at the bottom of the sintering cup, the base material mass is 2kg, and the sintering mixture after granulation in S2 is loaded into the sintering cup, the material layer height is 700mm, and ignition and sintering are carried out, the ignition time is 1.5min, the ignition temperature is 1100℃, the ignition negative pressure is 6kPa, and the sintering negative pressure is 10kPa;

[0043] S4. Cooling: After sintering, the sintered ore is cooled with a cooling negative pressure of 6 kPa. When the sintering flue gas temperature is lower than 100°C, unloading begins.

[0044] S5. Sintered ore testing: After the S4 sintered ore is crushed by a double-roll crusher, it is screened for whole particles, the mass of sintered ore of each particle size is recorded, and the drum strength of the sintered ore is measured by a drum device.

[0045] Sinter drum strength 50.36%, utilization coefficient 1.05t·m -2 ·h -1 , yield rate 67.35%, solid fuel consumption 128.55kg / t.

[0046] Embodiment 2:

[0047] A low-carbon sintering method for laterite nickel ore based on rapid formation of a low-melting-point liquid phase comprises the following steps:

[0048] Add 5.00wt% new calcium flux, basicity 1.4, including the following steps:

[0049] S1. Batching: Batching the ingredients according to the mass ratio of 54.00wt% of limonite-type laterite nickel ore, 3.50wt% of quicklime, 7.50wt% of coke powder, and 30.00wt% of return ore to form a sintering mixture;

[0050] S2, mixing and granulation: put the S1 sintered mixture into a drum mixer, add water, and complete the mixing and granulation process. The mixing time is 5 minutes, the granulation time is 3 minutes, and the mixer speed is 10 r·min -1 , filling rate 15%, sintering mixture moisture 17.75wt% after granulation;

[0051] S3, ignition and sintering: After placing the base material at the bottom of the sintering cup, the base material mass is 2kg, and the sintering mixture after granulation in S2 is loaded into the sintering cup, the material layer height is 700mm, and ignition and sintering are carried out, the ignition time is 1.5min, the ignition temperature is 1100℃, the ignition negative pressure is 6kPa, and the sintering negative pressure is 10kPa;

[0052] S4. Cooling: After sintering, the sintered ore is cooled with a cooling negative pressure of 6 kPa. When the sintering flue gas temperature is lower than 100°C, unloading begins.

[0053] S5. Sintered ore testing: After the S4 sintered ore is crushed by a double-roll crusher, it is screened for whole particles, the mass of sintered ore of each particle size is recorded, and the drum strength of the sintered ore is measured by a drum device.

[0054] Sinter drum strength 54.52%, utilization coefficient 1.21t·m -2 ·h -1 , yield rate 69.65%, solid fuel consumption 105.19kg / t.

[0055] Embodiment 3:

[0056] A low-carbon sintering method for laterite nickel ore based on rapid formation of a low-melting-point liquid phase comprises the following steps:

[0057] Add 7.50wt% of new calcium flux, basicity 1.4, including the following steps:

[0058] S1. Batching: Batching the ingredients according to the mass ratio of 52.76wt% of limonite-type laterite nickel ore, 2.24wt% of quicklime, 7.50wt% of coke powder, and 30.00wt% of return ore to form a sintering mixture;

[0059] S2, mixing and granulation: put the S1 sintered mixture into a drum mixer, add water, and complete the mixing and granulation process. The mixing time is 5 minutes, the granulation time is 3 minutes, and the mixer speed is 10 r·min -1 , filling rate 15%, sintering mixture moisture 17.82wt% after granulation;

[0060] S3, ignition and sintering: After placing the base material at the bottom of the sintering cup, the base material mass is 2kg, and the sintering mixture after granulation in S2 is loaded into the sintering cup, the material layer height is 700mm, and ignition and sintering are carried out, the ignition time is 1.5min, the ignition temperature is 1100℃, the ignition negative pressure is 6kPa, and the sintering negative pressure is 10kPa;

[0061] S4. Cooling: After sintering, the sintered ore is cooled with a cooling negative pressure of 6 kPa. When the sintering flue gas temperature is lower than 100°C, unloading begins.

[0062] S5. Sintered ore testing: After the S4 sintered ore is crushed by a double-roll crusher, it is screened for whole particles, the mass of sintered ore of each particle size is recorded, and the drum strength of the sintered ore is measured by a drum device.

[0063] Sinter drum strength 56.25%, utilization factor 1.22t·m -2 ·h -1 , the yield is 71.56%, and the solid fuel consumption is 96.75kg / t.

[0064] Embodiment 4:

[0065] A low-carbon sintering method for laterite nickel ore based on rapid formation of a low-melting-point liquid phase comprises the following steps:

[0066] Adding 10.00wt% of a new calcium flux, with a basicity of 1.4, comprises the following steps:

[0067] S1. Batching: Batching the ingredients according to the mass ratio of 51.45wt% of limonite-type laterite nickel ore, 1.05wt% of quicklime, 7.50wt% of coke powder, and 30.00wt% of return ore to form a sintering mixture;

[0068] S2, mixing and granulation: put the S1 sintered mixture into a drum mixer, add water, and complete the mixing and granulation process. The mixing time is 5 minutes, the granulation time is 3 minutes, and the mixer speed is 10 r·min -1 , filling rate 15%, sintering mixture moisture 18.15wt% after granulation;

[0069] S3, ignition and sintering: After placing the base material at the bottom of the sintering cup, the base material mass is 2kg, and the sintering mixture after granulation in S2 is loaded into the sintering cup, the material layer height is 700mm, and ignition and sintering are carried out, the ignition time is 1.5min, the ignition temperature is 1100℃, the ignition negative pressure is 6kPa, and the sintering negative pressure is 10kPa;

[0070] S4. Cooling: After sintering, the sintered ore is cooled with a cooling negative pressure of 6 kPa. When the sintering flue gas temperature is lower than 100°C, unloading begins.

[0071] S5. Sintered ore testing: After the S4 sintered ore is crushed by a double-roll crusher, it is screened for whole particles, the mass of sintered ore of each particle size is recorded, and the drum strength of the sintered ore is measured by a drum device.

[0072] Sinter drum strength 57.05%, utilization coefficient 1.15t·m -2 ·h -1 , yield rate 72.70%, solid fuel consumption 80.83kg / t.

[0073] Embodiment 5:

[0074] A low-carbon sintering method for laterite nickel ore based on rapid formation of a low-melting-point liquid phase comprises the following steps:

[0075] Add 5.00wt% new calcium flux, basicity 1.4, including the following steps:

[0076] S1. Batching: Batching the ingredients according to the mass ratio of 54.00wt% of limonite-type laterite nickel ore, 3.50wt% of quicklime, 7.50wt% of coke powder, and 30.00wt% of return ore to form a sintering mixture;

[0077] S2, mixing and granulation: put the S1 sintered mixture into a drum mixer, add water, and complete the mixing and granulation process. The mixing time is 5 minutes, the granulation time is 3 minutes, and the mixer speed is 10 r·min -1 , filling rate 15%, sintering mixture moisture 17.95wt% after granulation;

[0078] S3, ignition and sintering: After placing the base material at the bottom of the sintering cup, the base material mass is 2kg, and the sintering mixture after granulation in S2 is loaded into the sintering cup, the material layer height is 700mm, and ignition and sintering are carried out, the ignition time is 1.5min, the ignition temperature is 1100℃, the ignition negative pressure is 6kPa, and the sintering negative pressure is 10kPa;

[0079] S4. Cooling: After sintering, the sintered ore is cooled with a cooling negative pressure of 6 kPa. When the sintering flue gas temperature is lower than 100°C, unloading begins.

[0080] S5. Sintered ore testing: After the S4 sintered ore is crushed by a double-roll crusher, it is screened for whole particles, the mass of sintered ore of each particle size is recorded, and the drum strength of the sintered ore is measured by a drum device.

[0081] Sinter drum strength 55.35%, utilization coefficient 1.23t·m -2 ·h -1 , yield rate 70.18%, solid fuel consumption 102.05kg / t.

[0082] Embodiment 6:

[0083] A low-carbon sintering method for laterite nickel ore based on rapid formation of a low-melting-point liquid phase comprises the following steps:

[0084] Add 5.00wt% new calcium flux, basicity 1.4, including the following steps:

[0085] S1. Batching: Batching the ingredients according to the mass ratio of 54.30wt% of limonite-type laterite nickel ore, 3.45wt% of quicklime, 7.25wt% of coke powder, and 30.00wt% of return ore to form a sintering mixture;

[0086] S2, mixing and granulation: put the S1 sintered mixture into a drum mixer, add water, and complete the mixing and granulation process. The mixing time is 5 minutes, the granulation time is 3 minutes, and the mixer speed is 10 r·min -1 , filling rate 15%, sintering mixture moisture 17.65wt% after granulation;

[0087] S3, ignition and sintering: After placing the base material at the bottom of the sintering cup, the base material mass is 2kg, and the sintering mixture after granulation in S2 is loaded into the sintering cup, the material layer height is 700mm, and ignition and sintering are carried out, the ignition time is 1.5min, the ignition temperature is 1100℃, the ignition negative pressure is 6kPa, and the sintering negative pressure is 10kPa;

[0088] S4. Cooling: After sintering, the sintered ore is cooled with a cooling negative pressure of 6 kPa. When the sintering flue gas temperature is lower than 100°C, unloading begins.

[0089] S5. Sintered ore testing: After the S4 sintered ore is crushed by a double-roll crusher, it is screened for whole particles, the mass of sintered ore of each particle size is recorded, and the drum strength of the sintered ore is measured by a drum device.

[0090] Sinter drum strength 55.01%, utilization coefficient 1.28t·m -2 ·h -1 , the yield is 79.88%, and the solid fuel consumption is 92.63kg / t.

[0091] Embodiment 7:

[0092] A low-carbon sintering method for laterite nickel ore based on rapid formation of a low-melting-point liquid phase comprises the following steps:

[0093] Add 5.00wt% new calcium flux, basicity 1.4, including the following steps:

[0094] S1. Batching: Batching the ingredients according to the mass ratio of 54.55wt% of limonite-type laterite nickel ore, 3.45wt% of quicklime, 7.25wt% of coke powder, and 30.00wt% of return ore to form a sintering mixture;

[0095] S2, mixing and granulation: put the S1 sintered mixture into a drum mixer, add water, and complete the mixing and granulation process. The mixing time is 5 minutes, the granulation time is 3 minutes, and the mixer speed is 10 r·min -1 , filling rate 15%, sintering mixture moisture 17.52wt% after granulation;

[0096] S3, ignition and sintering: After placing the base material at the bottom of the sintering cup, the base material mass is 2kg, and the sintering mixture after granulation in S2 is loaded into the sintering cup, the material layer height is 700mm, and ignition and sintering are carried out, the ignition time is 1.5min, the ignition temperature is 1100℃, the ignition negative pressure is 6kPa, and the sintering negative pressure is 10kPa;

[0097] S4. Cooling: After sintering, the sintered ore is cooled with a cooling negative pressure of 6 kPa. When the sintering flue gas temperature is lower than 100°C, unloading begins.

[0098] S5. Sintered ore testing: After the S4 sintered ore is crushed by a double-roll crusher, it is screened for whole particles, the mass of sintered ore of each particle size is recorded, and the drum strength of the sintered ore is measured by a drum device.

[0099] Sinter drum strength 54.79%, utilization coefficient 1.27t·m -2 ·h -1 , the yield is 69.54%, and the solid fuel consumption is 85.90kg / t.

[0100] Comparative Example 1:

[0101] A low-carbon sintering method for laterite nickel ore based on rapid formation of a low-melting-point liquid phase comprises the following steps:

[0102] Without adding new calcium flux, alkalinity 1.4, including the following steps:

[0103] S1. Batching: Batching the ingredients according to the mass ratio of 56.59wt% of limonite-type laterite nickel ore, 5.92wt% of quicklime, 7.50wt% of coke powder, and 30.00wt% of return ore to form a sintering mixture;

[0104] S2, mixing and granulation: put the S1 sintered mixture into a drum mixer, add water, and complete the mixing and granulation process. The mixing time is 5 minutes, the granulation time is 3 minutes, and the mixer speed is 10 r·min -1 , filling rate 15%, sintering mixture moisture 18.25wt% after granulation;

[0105] S3, ignition and sintering: After placing the base material at the bottom of the sintering cup, the base material mass is 2kg, and the sintering mixture after granulation in S2 is loaded into the sintering cup, the material layer height is 700mm, and ignition and sintering are carried out, the ignition time is 1.5min, the ignition temperature is 1100℃, the ignition negative pressure is 6kPa, and the sintering negative pressure is 10kPa;

[0106] S4, cooling: after sintering, the sintered ore is cooled, and the cooling negative pressure is 6kPa. When the sintering flue gas temperature is lower than 100℃, the unloading begins;

[0107] S5. Sintered ore testing: After the S4 sintered ore is crushed by a double-roll crusher, it is screened for whole particles, the mass of sintered ore of each particle size is recorded, and the drum strength of the sintered ore is measured by a drum device.

[0108] Sinter drum strength 46.05%, utilization coefficient 0.93t·m -2 ·h -1 , yield rate 65.18%, solid fuel consumption 142.36kg / t.

[0109] From the above data, it can be seen that in Comparative Example 1, the sintered ore of limonite-type laterite nickel ore has poor quality indicators, high carbon emissions, a drum strength of only 46.05%, and a utilization coefficient as low as 0.93t·m -2 ·h -1 In Examples 1 to 7, the new calcium flux ratio is 2.50-10.00wt%, the sintering drum strength is 50.36-57.05%, and the utilization coefficient is 1.05-1.28t·m -2 ·h -1 , the yield is 67.35-72.70%, the solid fuel consumption is 85.90-128.55 kg / t, and all the indicators of the sintered ore are significantly better than those of the comparative example 1. By adopting the method of the present invention, under the optimal conditions (Example 7), the drum strength of the sintered ore increases by 8.74%, an increase of 19.0% year-on-year, the yield increases by 4.36%, an increase of 6.7% year-on-year, and the utilization coefficient increases by 0.34 t·m -2 ·h -1 , an increase of 36.6% year-on-year, and solid fuel consumption decreased by 56.46kg / t, a decrease of 39.7% year-on-year. After removing the solid fuel consumption in the preparation process of the new calcium flux sintering method, the comprehensive solid fuel consumption still decreased by more than 55kg / t, a decrease of more than 38.6% year-on-year.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A low-carbon sintering method for laterite nickel ore based on rapid formation of a low-melting-point liquid phase, characterized in that: include: S1. Batching: weighing laterite nickel ore, calcium ferrite type calcium flux, quicklime, coke powder, and returned ore to obtain a mixture; S2, mixing and granulating: the mixture is loaded into a drum mixer, water is added, and the mixing and granulating process is completed to obtain a granulated mixture; S3, ignition and sintering: after placing the base material at the bottom of the sintering cup, the granulated mixture is loaded into the sintering cup for ignition and sintering; S4, cooling: After sintering, the sintered ore is cooled. The negative pressure during cooling is 6kPa. When the sintering flue gas temperature is lower than 100℃, unloading begins. S5. Sintered ore testing: S4 sintered ore is dropped to a height of 2m for 3 times, followed by whole-grain screening. The quality of sintered ore of each particle size is recorded, and the drum strength of the sintered ore is measured by a drum device.

2. The low-carbon sintering method of laterite nickel ore according to claim 1, wherein: In step S1, the laterite nickel ore is 51.45-56.59 parts, the calcium ferrite type calcium flux is 0.00-10.00 parts, the quicklime is 1.05-5.92 parts, the coke powder is 7.00-7.50 parts, and the return ore is 30.00 parts.

3. The low-carbon sintering method of laterite nickel ore according to claim 1, wherein: The coke powder in step S1 has a total iron content of 1.43wt%, a CaO content of 1.10wt%, a SiO2 content of 7.22wt%, a MgO content of 0.26wt%, an Al2O3 content of 4.93wt%, and a burnout of 83.37wt%; particle size: +8mm accounts for 0.60wt%, 3-5mm accounts for 5.74wt%, 3-5mm accounts for 13.99wt%, 1-3mm accounts for 31.73wt%, 0.5-1mm accounts for 19.16wt%, and -0.5mm accounts for 28.78wt%.

4. The low-carbon sintering method of laterite nickel ore according to claim 1, wherein: The laterite nickel ore in step S1 has a total iron content of 45.32wt%, a total nickel content of 0.88wt%, a total chromium content of 2.65wt%, a CaO content of 0.25wt%, a SiO2 content of 5.35wt%, a MgO content of 4.67wt%, and an Al2O3 content of 4.89wt%; a burn loss of 13.36wt%; and a particle size of +8mm accounting for 9.55wt%, 5-8mm accounting for 13.64wt%, 3-5mm accounting for 25.80wt%, 1-3mm accounting for 39.75wt%, 0.5-1mm accounting for 7.16wt%, and -0.5mm accounting for 4.10wt%.

5. The low-carbon sintering method of laterite nickel ore according to claim 1, wherein: The calcium ferrite type calcium flux in step S1 is prepared by the following method: (1) Batching: Weigh low-grade iron ore, quicklime, coke powder, and returned ore to obtain a mixed material; (2) Mixing and granulating: the mixed material is loaded into a drum mixer, water is added, and the mixing and granulating process is completed to obtain a granulated mixed material; (2) Ignition and sintering: After placing the base material at the bottom of the sintering cup, the granulated mixture is loaded into the sintering cup for ignition and sintering; (3) Cooling: After sintering, the sintered ore is cooled. The negative pressure during cooling is 6 kPa. When the sintering flue gas temperature is lower than 100 °C, unloading begins. (5) Sintered ore testing: In step (4), the sintered ore is dropped to a height of 2 m and three times, followed by whole-grain screening to obtain calcium ferrite-type calcium flux; the mass of sintered ore of each particle size is recorded, and the drum strength of the sintered ore is measured by a drum device; wherein: The calcium ferrite type calcium flux has a total iron content of 38.50wt%, a CaO content of 37.62wt%, a SiO2 content of 1.35wt%, a MgO content of 0.32wt%, an Al2O3 content of 0.63wt%, and a burnout of 2.28wt%; The particle size of calcium ferrite type calcium flux is: 3-5mm accounts for 7.12wt%, 1-3mm accounts for 11.06wt%, 0.5-1mm accounts for 20.36wt%, -0.5mm accounts for 61.46wt%, and the melting point is 1195-1205℃.

6. The low-carbon sintering method of laterite nickel ore according to claim 5, wherein: The molar ratio of CaO:Fe2O3 in the mixture of step (1) is 1:1, and the moisture content of the mixture is 8.5-9.0wt%; The low-grade iron ore has a total iron content of 56.04wt%, a CaO content of 0.17wt%, a SiO2 content of 4.94wt%, a MgO content of 0.13wt%, an Al2O3 content of 2.77wt%, and a burn loss of 10.38wt%; The particle size of the low-grade iron ore is: +8mm accounts for 8.08wt%, 5-8mm accounts for 7.62wt%, 3-5mm accounts for 26.70wt%, 1-3mm accounts for 28.66wt%, 0.5-1mm accounts for 11.14wt%, and -0.5mm accounts for 17.79wt%; The low-grade iron ore is 44.80-45.29 parts, quicklime is 19.60-19.81 parts, coke powder is 4.90-5.60 parts, and returned ore is 30.00 parts.

7. The low-carbon sintering method of laterite nickel ore according to claim 1, wherein: The mixing time in step S2 is 5 min, the granulation time is 3 min, and the mixer speed is 10 r / min -1 , filling rate 15%, mixture moisture 17.52~18.25wt%.

8. The low-carbon sintering method of laterite nickel ore according to claim 1, wherein: In step S3, the base material mass is 2 kg, the material layer height is 700 mm, the ignition time is 1.5 min, the ignition temperature is 1100° C., the ignition negative pressure is 6 kPa, and the sintering negative pressure is 10 kPa.

9. The low-carbon sintering method of laterite nickel ore according to claim 1, wherein: The basicity of the sintered ore in step S3 is 1.

4.

10. A laterite nickel ore obtained by the low-carbon sintering method of laterite nickel ore according to any one of claims 1 to 9.

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