Ultralow-temperature sintering method for iron ore added with prefabricated flux

Abstract

The invention discloses an iron ore ultralow-temperature sintering method by adding a prefabricated flux, which comprises the following steps: blending raw materials such as blended ore, the prefabricated flux, quicklime, biomass fuel, coke powder and return mine, and then carrying out the procedures of blending, granulating, igniting, sintering, cooling sintered ore, crushing, screening, detecting and the like to obtain a finished product sintered ore. According to the technology, the liquid phase forming temperature in the sintering process can be reduced, the liquid phase composition and generation capacity can be improved, meanwhile, mismatching of the heat transfer front edge speed and the combustion front edge speed is avoided, the problem that the sintering speed is greatly reduced due to increase of the liquid phase amount is effectively solved, and rapid forming of the low-melting-point liquid phase and complete replacement of biomass fuel are promoted. According to the method, the temperature limitation of the existing sintering technology is broken through, the defect of low replacement proportion of biomass fuel is overcome, and the carbon emission in the sintering process is remarkably reduced on the premise of ensuring that the quality index of the sintered mineral product is improved at the same time.

Description

Technical Field

[0001] The invention relates to the field of iron and steel metallurgy, and in particular to an ultra-low temperature sintering method of iron ore with the addition of a prefabricated flux. Background Art

[0002] As the largest steel producer in China, the sintering / pelletizing-blast furnace-converter long process accounts for more than 90% of steel production. Among them, the average proportion of sintered ore entering the furnace is much higher than that of pelletized ore, and the sintering process is still the main source of blast furnace charge. However, the carbon emissions of the sintering process are high, about twice that of the pelletizing process, second only to the blast furnace ironmaking process. At the same time, with the consumption of high-quality iron ore resources, the proportion of low-grade and difficult-to-burn iron ore resources has increased, and the quality indicators of sintered ore products have deteriorated, which further aggravates the problem of high carbon emissions in the sintering process.

[0003] From the perspective of sintering theory, the iron ore sintering process is mainly controlled by liquid phase consolidation, and the amount of liquid phase generated and fluidity are crucial to the consolidation of sintered ore. CN201910591670.8 proposes to replace conventional calcium flux quicklime with pre-prepared flux calcium ferrite to reduce the liquid phase formation temperature during the sintering process and promote the formation of calcium ferrite to improve the strength of the sintered ore and reduce carbon emissions. However, the inventor found in patent CN202210050748.7 that the addition of flux calcium ferrite will cause a decrease in the output of sintered ore, and additional pretreatment steps such as returning ore to inlay or reducing the fuel particle size are required to improve the permeability of the sintering material layer, which further prolongs the process and increases production and equipment costs. In patent CN202310222382.1, similar calcium ferrite flux is used. Although the sintered ore yield and drum strength are slightly improved and solid fuel is reduced, this patent avoids the problem of sintered ore output changes and does not involve output indicators such as sintered ore utilization coefficient. It is meaningless to improve sintered ore strength and reduce carbon emissions during the sintering process at the expense of sintered ore output.

[0004] From the perspective of carbon emission sources, the solid fuels in the sintering process are mainly fossil fuels such as coke powder and anthracite, which are the main sources of CO2 and gaseous pollutants in the sintering process. At present, the CO2 emissions per ton of finished sintered ore are as high as 150-170kg. Reducing the consumption of carbon fossil fuels in the sintering process is the key to reducing carbon emissions. As a renewable clean energy source, biomass fuel has the advantages of good reactivity, low N and S content, wide sources, and carbon neutrality. After replacing carbon fossil fuels in the sintering process, it can promote the reduction of carbon emissions and SO2, NO xHowever, biomass fuel has good reactivity and fast combustion speed. Its large-scale application will aggravate the mismatch between the combustion front speed and the combustion front speed in the sintering process, leading to the deterioration of the quality of sintered minerals. In CN201710900016.1, CN201910957859.4, CN202310891992.0, CN202210778521.4, CN202310565966.9, CN202311643625.5, CN202210548973.3, CN202410455634.X, etc., under the premise of ensuring good sintered mineral quality indicators, the replacement ratio of biomass fuel for conventional fossil fuels such as coke often does not exceed 40%. Even if high-quality biomass fuel with high calorific value is used, and pre-treatment processes such as flue gas circulation, carbonization treatment, and preparation of biomass coke are carried out, the suitable replacement ratio is only increased to 50-60%, which seriously limits the large-scale application of biomass fuel. Summary of the invention

[0005] In view of the above technical problems, the present invention provides an ultra-low temperature sintering method of iron ore with prefabricated flux. On the one hand, the advantages of low melting point and good fluidity of the prefabricated flux are utilized to reduce the liquid phase formation temperature and improve the liquid phase composition and generation capacity; on the other hand, the characteristics of good reactivity and fast combustion speed of biomass fuel are utilized to establish a low-carbon sintering synergistic mechanism of prefabricated flux and biomass fuel, avoid the mismatch between the heat transfer front speed and the combustion front speed, and solve the problem of a significant reduction in sintering speed due to an increase in the liquid phase amount, promote the rapid formation of a low-melting point liquid phase and the complete substitution of biomass fuel, so as to improve the quality indicators of the sintered ore while achieving a significant reduction in carbon emissions during the sintering process.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0007] The present invention first discloses an ultra-low temperature sintering method for iron ore with a prefabricated flux, comprising the following steps:

[0008] S1. Batching: batching the mixed ore, prefabricated flux, quicklime, biomass fuel, coke powder, returned ore and other raw materials according to the corresponding proportion of the ore batching plan;

[0009] 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;

[0010] 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;

[0011] S4, cooling: After sintering, the sintered ore is cooled. When the sintering flue gas temperature is lower than 100°C, unloading begins;

[0012] 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.

[0013] Furthermore, the mixed ore has a total iron content of 59.20wt%, a CaO content of 0.65wt%, a SiO2 content of 3.71wt%, a MgO content of 0.52wt%, an Al2O3 content of 2.57wt%, a burn loss of 5.15wt%, a +8mm content of 6.25wt%, a 5-8mm content of 11.35wt%, a 3-5mm content of 10.28wt%, a 1-3mm content of 25.60wt%, a 0.5-1mm content of 29.82wt%, and a -0.5mm content of 16.70wt%.

[0014] Furthermore, the prefabricated flux has a total iron content of 36.47wt%, a CaO content of 36.12wt%, a SiO2 content of 1.11wt%, a MgO content of 0.15wt%, an Al2O3 content of 0.56wt%, a burn loss of 3.69wt%, a 3-5mm content of 5.35wt%, a 1-3mm content of 10.25wt%, a 0.5-1mm content of 12.30wt%, a -0.5mm content of 72.10wt%, and a melting point of only 1203°C.

[0015] Furthermore, the biomass fuel has a total iron content of 1.35wt%, a CaO content of 2.34wt%, a SiO2 content of 6.94wt%, a MgO content of 0.40wt%, an Al2O3 content of 0.57wt%, a burn loss of 80.52wt%, a +8mm content of 0.50wt%, a 3-5mm content of 3.65wt%, a 3-5mm content of 15.85wt%, a 1-3mm content of 25.32wt%, a 0.5-1mm content of 20.16wt%, a -0.5mm content of 34.52wt%, and a fixed carbon content of 74.47wt%.

[0016] Furthermore, 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%, a burn loss of 83.37wt%, a +8mm content of 0.60wt%, a 3-5mm content of 5.74wt%, a 3-5mm content of 13.99wt%, a 1-3mm content of 31.73wt%, a 0.5-1mm content of 19.16wt%, a -0.5mm content of 28.78wt%, and a fixed carbon content of 80.00wt%.

[0017] Furthermore, the sintered ore has a basicity of 2.0, a mass percentage of mixed ore of 65.34-68.22wt%, a mass percentage of prefabricated flux of 0.00-8.00wt%, a mass percentage of quicklime of 3.48-7.28wt%, a mass percentage of biomass fuel of 0.00-5.30wt%, a mass percentage of coke powder of 0.00-4.50wt%, and a mass percentage of returned ore of 20.00wt%.

[0018] Furthermore, the mixing time is 8 min, the granulation time is 2 min, and the mixer speed is 8 r / min. -1 , filling rate 15%, mixture moisture 7.52~7.98wt%.

[0019] Furthermore, the base material has a mass of 2 kg, a material layer height of 700 mm, an ignition time of 90 s, an ignition temperature of 1050° C., an ignition negative pressure of 6 kPa, and a sintering negative pressure of 10 kPa.

[0020] Furthermore, the cooling negative pressure is 6 kPa.

[0021] Furthermore, the falling height is 2m and the number of falling times is 3 times.

[0022] Compared with the prior art, the advantages of the present invention are:

[0023] (1) The present invention breaks through the temperature limitation of the existing sintering technology and realizes the formation of a low-melting-point liquid phase faster and in greater quantities. At the same time, without adding a pretreatment step, it solves the problem of reduced sintering ore output caused by the addition of prefabricated flux, avoids adding a pretreatment step, reduces production and investment costs, and has broad prospects for industrialization.

[0024] (2) Under the premise of ensuring the quality indicators of sintered minerals, the present invention achieves the complete replacement of fossil fuels such as coke powder by biomass fuels, breaks through the limitation of low replacement ratio of biomass fuels, and promotes further reduction of carbon emissions in the sintering process. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The process flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0026] 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.

[0027] Embodiment 1:

[0028] An ultra-low temperature sintering method for iron ore with a prefabricated flux comprises the following steps:

[0029] The prefabricated flux is 2.00wt%, the biomass fuel is 0.00wt%, and the basicity is 2.0, and the steps include:

[0030] S1. Batching: Batching is performed according to the mass ratio of 67.18wt% of mixed ore, 7.32wt% of quicklime, 4.50wt% of coke powder, and 20.00wt% of returned ore to form a sintering mixture;

[0031] 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 8 minutes, the granulation time is 2 minutes, and the mixer speed is 8 r / min -1 , filling rate 15%, sintering mixture moisture 7.69wt% after granulation;

[0032] 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 placed into the sintering cup, the material layer height is 700mm, and ignition and sintering are carried out, the ignition time is 90s, the ignition temperature is 1050℃, the ignition negative pressure is 6kPa, and the sintering negative pressure is 10kPa;

[0033] 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.

[0034] 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.

[0035] Sinter drum strength 62.82%, utilization coefficient 1.31t·m -2 ·h -1 , yield rate 77.25%, solid fuel consumption 50.06kg / t.

[0036] Embodiment 2:

[0037] An ultra-low temperature sintering method for iron ore with a prefabricated flux comprises the following steps:

[0038] The prefabricated flux is 4.00wt%, the biomass fuel is 0.00wt%, and the basicity is 2.0, and the steps include:

[0039] S1. Batching: Batching is performed according to the mass ratio of 66.10wt% of mixed ore, 5.40wt% of quicklime, 4.50wt% of coke powder, and 20.00wt% of returned ore to form a sintering mixture;

[0040] 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 8 minutes, the granulation time is 2 minutes, and the mixer speed is 8 r / min -1 , filling rate 15%, sintering mixture moisture 7.52wt% after granulation;

[0041] 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 placed into the sintering cup, the material layer height is 700mm, and ignition and sintering are carried out, the ignition time is 90s, the ignition temperature is 1050℃, the ignition negative pressure is 6kPa, and the sintering negative pressure is 10kPa;

[0042] 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.

[0043] 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.

[0044] Sinter drum strength 64.75%, utilization factor 1.25t·m -2 ·h -1 , the yield is 78.96%, and the solid fuel consumption is 45.81kg / t.

[0045] Embodiment 3:

[0046] An ultra-low temperature sintering method for iron ore with a prefabricated flux comprises the following steps:

[0047] The prefabricated flux is 6.00wt%, the biomass fuel is 0.00wt%, and the basicity is 2.0, and the steps include:

[0048] S1. Batching: Batching is performed according to the mass ratio of 65.06wt% of mixed ore, 4.44wt% of quicklime, 4.50wt% of coke powder, and 20.00wt% of returned ore to form a sintering mixture;

[0049] 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 8 minutes, the granulation time is 2 minutes, and the mixer speed is 8 r / min -1 , filling rate 15%, sintering mixture moisture 7.88wt% after granulation;

[0050] 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 placed into the sintering cup, the material layer height is 700mm, and ignition and sintering are carried out, the ignition time is 90s, the ignition temperature is 1050℃, the ignition negative pressure is 6kPa, and the sintering negative pressure is 10kPa;

[0051] 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.

[0052] 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.

[0053] Sinter drum strength 65.36%, utilization coefficient 1.18t·m -2 ·h -1 , yield rate 79.54%, solid fuel consumption 45.32kg / t.

[0054] Embodiment 4:

[0055] An ultra-low temperature sintering method for iron ore with a prefabricated flux comprises the following steps:

[0056] The prefabricated flux is 8.00wt%, the biomass fuel is 0.00wt%, and the basicity is 2.0, and the steps are as follows:

[0057] S1. Batching: Batching is performed according to the mass ratio of 64.02wt% of mixed ore, 3.48wt% of quicklime, 4.50wt% of coke powder, and 20.00wt% of returned ore to form a sintering mixture;

[0058] 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 8 minutes, the granulation time is 2 minutes, and the mixer speed is 8 r / min -1 , filling rate 15%, sintering mixture moisture 7.92wt% after granulation;

[0059] 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 placed into the sintering cup, the material layer height is 700mm, and ignition and sintering are carried out, the ignition time is 90s, the ignition temperature is 1050℃, the ignition negative pressure is 6kPa, and the sintering negative pressure is 10kPa;

[0060] 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.

[0061] 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.

[0062] Sinter drum strength 65.15%, utilization coefficient 1.06t·m -2 ·h -1 , the yield is 81.18%, and the solid fuel consumption is 43.50kg / t.

[0063] Embodiment 5:

[0064] An ultra-low temperature sintering method for iron ore with a prefabricated flux comprises the following steps:

[0065] The prefabricated flux is 4.00wt%, the biomass fuel is 0.90wt%, the replacement ratio of coke powder is 20%, the basicity is 2.0, and the steps are as follows:

[0066] S1. Batching: Batching is performed according to the mass ratio of 66.10wt% of mixed ore, 5.40wt% of quicklime, 3.60wt% of coke powder, and 20.00wt% of returned ore to form a sintering mixture;

[0067] 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 8 minutes, the granulation time is 2 minutes, and the mixer speed is 8 r / min -1 , filling rate 15%, sintering mixture moisture 7.65wt% after granulation;

[0068] 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 placed into the sintering cup, the material layer height is 700mm, and ignition and sintering are carried out, the ignition time is 90s, the ignition temperature is 1050℃, the ignition negative pressure is 6kPa, and the sintering negative pressure is 10kPa;

[0069] 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.

[0070] 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.

[0071] Sinter drum strength 64.82%, utilization coefficient 1.33t·m -2 ·h -1 , the yield rate is 80.06%.

[0072] Embodiment 6:

[0073] An ultra-low temperature sintering method for iron ore with a prefabricated flux comprises the following steps:

[0074] The prefabricated flux is 4.00wt%, the biomass fuel is 1.80wt%, the replacement ratio of coke powder is 40%, the basicity is 2.0, and the following steps are included:

[0075] S1. Batching: Batching is performed according to the mass ratio of 66.10wt% of mixed ore, 5.40wt% of quicklime, 2.70wt% of coke powder, and 20.00wt% of returned ore to form a sintering mixture;

[0076] 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 8 minutes, the granulation time is 2 minutes, and the mixer speed is 8 r / min -1 , filling rate 15%, sintering mixture moisture 7.54wt% after granulation;

[0077] 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 placed into the sintering cup, the material layer height is 700mm, and ignition and sintering are carried out, the ignition time is 90s, the ignition temperature is 1050℃, the ignition negative pressure is 6kPa, and the sintering negative pressure is 10kPa;

[0078] 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.

[0079] 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.

[0080] Sinter drum strength 65.06%, utilization coefficient 1.36t·m -2 ·h -1 , the yield rate is 81.15%.

[0081] Embodiment 7:

[0082] An ultra-low temperature sintering method for iron ore with a prefabricated flux comprises the following steps:

[0083] The prefabricated flux is 4.00wt%, the biomass fuel is 2.70wt%, the replacement ratio of coke powder is 60%, the basicity is 2.0, and the steps are as follows:

[0084] S1. Batching: Batching is performed according to the mass ratio of 66.10wt% of mixed ore, 5.40wt% of quicklime, 1.80wt% of coke powder, and 20.00wt% of returned ore to form a sintering mixture;

[0085] 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 8 minutes, the granulation time is 2 minutes, and the mixer speed is 8 r / min -1 , filling rate 15%, sintering mixture moisture 7.63wt% after granulation;

[0086] 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 placed into the sintering cup, the material layer height is 700mm, and ignition and sintering are carried out, the ignition time is 90s, the ignition temperature is 1050℃, the ignition negative pressure is 6kPa, and the sintering negative pressure is 10kPa;

[0087] 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.

[0088] 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.

[0089] Sinter drum strength 64.25%, utilization factor 1.46t·m -2 ·h -1 , the yield rate is 81.36%.

[0090] Embodiment 8:

[0091] An ultra-low temperature sintering method for iron ore with a prefabricated flux comprises the following steps:

[0092] Prefabricated flux 4.00wt%, biomass fuel 3.60wt%, coke powder replacement ratio 80%, basicity 2.0, including the following steps:

[0093] S1. Batching: Batching is performed according to the mass ratio of 66.10wt% of mixed ore, 5.40wt% of quicklime, 0.90wt% of coke powder, and 20.00wt% of returned ore to form a sintering mixture;

[0094] 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 8 minutes, the granulation time is 2 minutes, and the mixer speed is 8 r / min -1 , filling rate 15%, sintering mixture moisture 7.79wt% after granulation;

[0095] 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 placed into the sintering cup, the material layer height is 700mm, and ignition and sintering are carried out, the ignition time is 90s, the ignition temperature is 1050℃, the ignition negative pressure is 6kPa, and the sintering negative pressure is 10kPa;

[0096] 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.

[0097] 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.

[0098] Sinter drum strength 63.80%, utilization coefficient 1.52t·m -2 ·h -1 , the yield rate is 80.55%.

[0099] Embodiment 9:

[0100] An ultra-low temperature sintering method for iron ore with a prefabricated flux comprises the following steps:

[0101] Prefabricated flux 4.00wt%, biomass fuel 4.50wt%, replacement ratio of coke powder 100%, basicity 2.0, including the following steps:

[0102] S1. Batching: Batching is performed according to the mass ratio of 66.10wt% of mixed ore, 5.40wt% of quicklime, 0.00wt% of coke powder, and 20.00wt% of returned ore to form a sintering mixture;

[0103] 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 8 minutes, the granulation time is 2 minutes, and the mixer speed is 8 r / min -1 , filling rate 15%, sintering mixture moisture 7.81wt% after granulation;

[0104] 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 placed into the sintering cup, the material layer height is 700mm, and ignition and sintering are carried out, the ignition time is 90s, the ignition temperature is 1050℃, the ignition negative pressure is 6kPa, and the sintering negative pressure is 10kPa;

[0105] 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.

[0106] 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.

[0107] Sinter drum strength 63.50%, utilization coefficient 1.58t·m -2 ·h -1 , the yield rate is 79.85%.

[0108] Embodiment 10:

[0109] An ultra-low temperature sintering method for iron ore with a prefabricated flux comprises the following steps:

[0110] Prefabricated flux 4.00wt%, biomass fuel 4.90wt%, replacement ratio of coke powder 100%, basicity 2.0, including the following steps:

[0111] S1. Batching: Batching is performed according to the mass ratio of 65.70wt% of mixed ore, 5.40wt% of quicklime, 0.00wt% of coke powder, and 20.00wt% of returned ore to form a sintering mixture;

[0112] 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 8 minutes, the granulation time is 2 minutes, and the mixer speed is 8 r / min -1 , filling rate 15%, sintering mixture moisture 7.95wt% after granulation;

[0113] 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 placed into the sintering cup, the material layer height is 700mm, and ignition and sintering are carried out, the ignition time is 90s, the ignition temperature is 1050℃, the ignition negative pressure is 6kPa, and the sintering negative pressure is 10kPa;

[0114] 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.

[0115] 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.

[0116] Sinter drum strength 64.20%, utilization factor 1.65t·m -2 ·h -1 , the yield rate is 82.15%.

[0117] Embodiment 11:

[0118] An ultra-low temperature sintering method for iron ore with a prefabricated flux comprises the following steps:

[0119] Prefabricated flux 4.00wt%, biomass fuel 5.30wt%, coke powder replacement ratio 100%, basicity 2.0, including the following steps:

[0120] S1. Batching: Batching is performed according to the mass ratio of 65.34wt% of mixed ore, 5.36wt% of quicklime, 0.00wt% of coke powder, and 20.00wt% of returned ore to form a sintering mixture;

[0121] 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 8 minutes, the granulation time is 2 minutes, and the mixer speed is 8 r / min -1 , filling rate 15%, sintering mixture moisture 7.98wt% after granulation;

[0122] 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 placed into the sintering cup, the material layer height is 700mm, and ignition and sintering are carried out, the ignition time is 90s, the ignition temperature is 1050℃, the ignition negative pressure is 6kPa, and the sintering negative pressure is 10kPa;

[0123] 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.

[0124] 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.

[0125] Sinter drum strength 64.65%, utilization coefficient 1.69t·m -2 ·h -1 , the yield rate is 83.25%.

[0126] From the above data, it can be seen that when 2.00-8.00 wt% prefabricated flux is added without adding biomass fuel (Examples 1-4), the drum strength of sintered ore is 62.82-65.15%, and the utilization coefficient is 1.06-1.31 t·m -2 ·h -1, finished product rate 77.25~81.18%, solid fuel consumption 43.50~50.06kg / t. Compared with comparative example 1, although the sintered ore drum strength and finished product rate are improved, and the solid fuel consumption is reduced, the utilization coefficient is reduced, and the sintered ore output index deteriorates. Based on the relevant results, when the prefabricated flux is 4.00wt%, the overall index of the sintered ore is better. Therefore, under the conditions of 4.00wt% prefabricated flux, 0.90~5.30wt% biomass fuel, and 0~100wt% replacement ratio of coke powder (Examples 5~11), the sintered ore drum strength is 63.50~65.06%, and the utilization coefficient is 1.33~1.69t·m -2 ·h -1 , the yield rate is 79.85-83.25%. Compared with comparative example 1, all indicators of sintered ore are improved. Using the method of the present invention, under the optimal conditions (Example 11), the drum strength of sintered ore increases by 4.60%, an increase of 7.66% year-on-year, the yield rate increases by 7.65%, an increase of 10.12% year-on-year, and the utilization coefficient increases by 0.24t·m -2 ·h -1 , an increase of 16.55% year-on-year, and coke was completely replaced by clean biomass fuel.

[0127] Comparative Example 1:

[0128] An ultra-low temperature sintering method for iron ore with a prefabricated flux comprises the following steps:

[0129] Without adding prefabricated flux and biomass fuel, the basicity is 2.0, including the following steps:

[0130] S1. Batching: Batching is performed according to the mass ratio of 68.22wt% of mixed ore, 7.28wt% of quicklime, 4.50wt% of coke powder, and 20.00wt% of returned ore to form a sintering mixture;

[0131] 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 8 minutes, the granulation time is 2 minutes, and the mixer speed is 8 r / min -1 , filling rate 15%, sintering mixture moisture 7.58wt% after granulation;

[0132] 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 placed into the sintering cup, the material layer height is 700mm, and ignition and sintering are carried out, the ignition time is 90s, the ignition temperature is 1050℃, the ignition negative pressure is 6kPa, and the sintering negative pressure is 10kPa;

[0133] 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.

[0134] 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.

[0135] Sinter drum strength 60.05%, utilization factor 1.45t·m -2 ·h -1 , yield rate 75.60%, solid fuel consumption 51.56kg / t.

[0136] 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 method for ultra-low temperature sintering of iron ore with a prefabricated flux, comprising: S1. Batching: batching the mixed ore, prefabricated flux, quicklime, biomass fuel, coke powder and returned ore according to the corresponding proportion of the ore batching plan; 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; 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; S4, cooling: After sintering, the sintered ore is cooled, and when the sintering flue gas temperature is lower than 100°C, unloading begins; S5. Sintered ore testing: After the S4 sintered ore is dropped, it is screened for whole particles. The drop height is 2m and the number of drops is 3 times. 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 method for ultra-low temperature sintering of iron ore according to claim 1, wherein: The mixed ore has a total iron content of 59.20wt%, a CaO content of 0.65wt%, a SiO2 content of 3.71wt%, a MgO content of 0.52wt%, and an Al2O3 content of 2.57wt%; The mixed ore was burned off by 5.15wt%, of which the particle size of +8mm accounted for 6.25wt%, 5-8mm accounted for 11.35wt%, 3-5mm accounted for 10.28wt%, 1-3mm accounted for 25.60wt%, 0.5-1mm accounted for 29.82wt%, and -0.5mm accounted for 16.70wt%.

3. The method for ultra-low temperature sintering of iron ore according to claim 1, wherein: The prefabricated flux contains 36.47wt% total iron, 36.12wt% CaO, 1.11wt% SiO2, 0.15wt% MgO and 0.56wt% Al2O3; The prefabricated flux is burned 3.69wt%, of which the particle size of 3-5mm accounts for 5.35wt%, 1-3mm accounts for 10.25wt%, 0.5-1mm accounts for 12.30wt%, -0.5mm accounts for 72.10wt%, and the melting point is 1203℃.

4. The method for ultra-low temperature sintering of iron ore according to claim 1, wherein: The biomass fuel contains 1.35wt% total iron, 2.34wt% CaO, 6.94wt% SiO2, 0.40wt% MgO and 0.57wt% Al2O3; The biomass fuel is burned 80.52wt%, of which the particle size of +8mm accounts for 0.50wt%, 3-5mm accounts for 3.65wt%, 3-5mm accounts for 15.85wt%, 1-3mm accounts for 25.32wt%, 0.5-1mm accounts for 20.16wt%, -0.5mm accounts for 34.52wt%, and the fixed carbon content is 74.47wt%.

5. The method for ultra-low temperature sintering of iron ore according to claim 1, wherein: The coke powder contains 1.43wt% total iron, 1.10wt% CaO, 7.22wt% SiO2, 0.26wt% MgO and 4.93wt% Al2O3; The coke powder loss is 83.37wt%, of which the particle size of +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%, -0.5mm accounts for 28.78wt%, and the fixed carbon content is 80.00wt%.

6. The method for ultra-low temperature sintering of iron ore according to claim 1, wherein: The basicity of the sintered ore is 2.

0.

7. The method for ultra-low temperature sintering of iron ore according to claim 1, wherein: In step S1, the mixed ore is 65.34-68.22 parts, the prefabricated flux is 0.00-8.00 parts, the quicklime is 3.48-7.28 parts, the biomass fuel is 0.00-5.30 parts, the coke powder is 0.00-4.50 parts, and the returned ore is 20.00 parts.

8. The method for ultra-low temperature sintering of iron ore according to claim 1, wherein: The mixing time in step S2 is 8 min, the granulation time is 2 min, and the mixer speed is 8 r / min -1 , filling rate 15%, mixture moisture 7.52~7.98wt%.

9. The method for ultra-low temperature sintering of iron 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 90 s, the ignition temperature is 1050° C., the ignition negative pressure is 6 kPa, and the sintering negative pressure is 10 kPa.

10. The method for ultra-low temperature sintering of iron ore according to claim 1, wherein: The cooling negative pressure in step S4 is 6 kPa.

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