Low-carbon low-emission type solid fuel for iron ore sintering and preparation method and application of low-carbon low-emission type solid fuel

Abstract

The invention discloses a low-carbon low-emission solid fuel for iron ore sintering and a preparation method and application thereof, and belongs to the technical field of iron ore sintering fuels. The low-carbon low-emission type solid fuel comprises fine-fraction coal-based fuel, an iron-containing material, high-cellulose biomass powder and auxiliary catalysts (vanadium-titanium minerals and nickel-containing minerals), the fine-fraction coal-based fuel which is difficult to recycle is adopted as a main raw material, other auxiliary raw materials are added, and vacuum extrusion forming is carried out to obtain the modified solid fuel. The combustion performance can be obviously improved, so that the material layer heat distribution state in the sintering process is optimized, the sintered mineral product quality index is improved, meanwhile, generation of NOx is restrained, and low-carbon low-emission sintering clean production is achieved from the source.

Description

Technical Field

[0001] The present invention relates to a solid fuel, in particular to a low-carbon and low-emission solid fuel for iron ore sintering, and also relates to a preparation method thereof and an application of the low-carbon and low-emission solid fuel for iron ore sintering in the iron ore sintering process, belonging to the technical field of iron and steel metallurgy fuels. Background Art

[0002] The existing iron and steel production mainly adopts the "blast furnace-converter" method. The sintering process provides more than 70% of the burden for the blast furnace. The production quality indexes of sinter (sintering speed, finished product rate, drum strength and utilization coefficient) are crucial for iron and steel production. As the main source of heat in the sintering process, the combustion performance of solid fuel has a great influence on the heat distribution state in the sintering burden layer, thereby affecting the output, strength and metallurgical properties of sinter. If the particle size of the solid fuel is too small, it will lead to an increase in the content of fine-grained particles after the granulation process, affecting the air permeability and heat transfer efficiency of the sintering burden layer; in addition, the fuel with too small particle size burns too fast during the sintering process, and the highest combustion temperature is relatively low, which will make the thickness of the combustion zone in the burden layer thinner and the highest temperature lower, and the sintering ore-forming conditions are poor. Microscopically, it will lead to more macropores in the sinter and a decrease in the formation amount of calcium ferrite-based bonding phase, which is not conducive to the strength performance and metallurgical properties of the sinter.

[0003] Nitrogen oxides are one of the main flue gas pollutants generated in the sintering process. The process emissions account for about 50% of the total nitrogen oxide emissions in the iron and steel production process, which has a great impact on the ecological environment and human health. More than 90% of the nitrogen oxides emitted in the sintering process come from the conversion of nitrogen-containing compounds or functional groups in the fuel during combustion. At present, the more mature nitrogen oxide treatment technologies are mostly end-treatment technologies, such as the integrated desulfurization and denitrification technology with activated carbon, etc. However, it is necessary to invest in building new equipment, and the cost of activated carbon is relatively high. Therefore, the NOx source emission reduction and process control technologies have gradually been taken seriously by the industry. Existing research shows that the fuel particle size affects the NOx emissions at the source during the sintering process. When the highest combustion temperature of fine-grained solid fuel is relatively low, the oxygen content on the fuel particle surface is relatively high, and NOx is easily generated; when the highest combustion temperature of coarse-grained fuel is relatively high, the surface oxygen content is relatively low, and the combustion speed is relatively slow, and the carbon dissolution loss reaction (C + CO2 → CO) develops, and the CO generation amount increases, which can play a role in reducing NOx. Generally speaking, a relatively high proportion of fine-grained content in the sintering fuel is neither conducive to producing high-quality and high-yield sinter nor conducive to low-carbon and low-emission in the sintering process. It is of great significance to carry out shaping treatment on the sintering fuel to achieve particle size control for improving the production and quality and energy conservation and emission reduction of the sintering process. Summary of the Invention

[0004] Aiming at the technical problems that there is too much fine-grained fuel in sintering fuel, which affects the quality index of sinter and the emission of flue gas pollutants is relatively high, the first object of the present invention is to provide a low-carbon and low-emission solid fuel for iron ore sintering. On the one hand, this fuel has good combustion characteristics, can improve the heat distribution in the sintering material layer, and meet the heat demand during the sintering process. On the other hand, Ni in the auxiliary catalyst can promote the pyrolysis of biomass to produce CH-based reducing agents, and through the catalysis of elements such as V and Ti in the auxiliary catalyst, it can promote the efficient reduction of NOx generated by fuel combustion, realizing pollution reduction and carbon reduction during the sintering process.

[0005] The second object of the present invention is to provide a preparation method of a low-carbon and low-emission solid fuel for iron ore sintering. This method has wide raw material sources, low cost, and simple process, which is conducive to industrial production.

[0006] The third object of the present invention is to provide an application of a low-carbon and low-emission solid fuel in iron ore sintering. This solid fuel can completely replace fossil fuels and be used in the iron ore sintering process. It not only meets the heat demand during the sintering process, improves the heat distribution in the sintering material layer, and improves the quality index of sinter, but also can efficiently inhibit the generation of NO x and achieve low-carbon and low-emission during the sintering process from the source.

[0007] To achieve the above technical objects, the present invention provides a low-carbon and low-emission solid fuel for iron ore sintering, which comprises the following component raw materials: fine-grained coal-based fuel, iron-containing material, high-cellulose biomass powder, and auxiliary catalyst; the auxiliary catalyst comprises vanadium-titanium minerals and nickel-containing minerals.

[0008] The key to the low-carbon and low-emission solid fuel provided by the present invention lies in: using fine-grained coal-based fuel that is difficult to process and utilize during the sintering process as the main raw material, and by adding part of iron-containing materials, high-cellulose biomass powder, and auxiliary catalysts, a fuel with coarser particles is obtained through vacuum extrusion molding. While achieving the quality improvement and modification of the fine-grained fuel to obtain a better sintering fuel, it can also consume some carbon-containing solid waste and iron-containing solid waste resources that are difficult to recycle. In the prior art, the use of fine-grained fuel is harmful to the output and quality indicators of sintered ore and the pollutant emissions in the flue gas. It is necessary to carry out shaping and granulation treatment on the fine-grained fuel. Generally, fine-grained fuel has poor hydrophilicity and is difficult to be shaped directly by pressing. Adding high-cellulose biomass powder can, on the one hand, improve the plasticity of the mixed raw materials, and on the other hand, its surface is relatively rough and has a large frictional resistance, which can be used as a bonding component to bond the raw material particles together. Its high compression ratio can also effectively improve the density of the particles during the forming process. When adding high-cellulose biomass powder, nickel-containing minerals are added at the same time. Nickel-containing minerals can catalyze the biomass to crack and produce CH-based reducing agents, which can effectively inhibit the generation of NOx. To improve the reduction rate of NOx, iron-containing materials and part of vanadium-titanium ore are further introduced into the fine-grained fuel. While consuming some difficult-to-treat iron-containing materials, the introduced elements such as Fe, V, Ti, and Ni have a synergistic catalytic effect on fuel combustion and fuel nitrogen conversion, which helps the fuel to burn efficiently and fully and inhibits the generation of NOx, achieving high-efficiency emission reduction of COx and NOx during the sintering process. In summary, the present invention makes a solid fuel by mixing fine-grained coal-based fuel, iron-containing materials, high-cellulose biomass powder, and auxiliary catalysts. On the one hand, the fine-grained coal-based fuel is prepared into a coarser-grained fuel to improve its combustion performance, thereby optimizing the heat distribution state in the material layer during the sintering process and improving the output and quality indicators of sintered ore. On the other hand, the elements such as Fe, V, Ti, and Ni in the added additives catalyze the oxidation-reduction reaction during the fuel combustion process, and use the CH generated by the biomass to inhibit the generation of NOx, realizing pollution reduction and carbon reduction during the sintering process from the source.

[0009] As a preferred solution, the solid fuel is composed of the following raw materials in mass percentage: 50 - 70% of fine-grained coal-based fuel; 3 - 5% of iron-containing materials; 17 - 40% of high-cellulose biomass powder; 7 - 15% of auxiliary catalysts. When the proportion of iron-containing materials in the solid fuel is too high, it will reduce the strength of the formed solid fuel particles and affect the combustion performance of the solid fuel particles at the same time. While when the proportion of iron-containing materials is too low, it will reduce the catalytic activity for fuel conversion and the emission reduction effect will become worse; if the proportion of high-cellulose biomass powder is too low, it will lead to poor bonding performance, and finally the strength of the formed fuel particles is poor, and at the same time, the inhibitory effect on the generation of NOx becomes worse; if the proportion of high-cellulose biomass powder is too high, it will result in low particle calorific value and too fast combustion, affecting the overall combustion efficiency.

[0010] As a preferred solution, the particle size of the fine-grained coal-based fuel meets the requirement that the mass proportion of the -0.5 mm particle size grade is not less than 80%. As a more preferred solution, the fine-grained coal-based fuel includes at least one of dry coke powder, coal powder, and coke powder. These fine-grained fuels are common in the industry. Due to their relatively fine particle size, they burn quickly and have a relatively low maximum combustion temperature, making it generally difficult to be fully utilized in iron ore sintering.

[0011] As a preferred solution, the high-cellulose biomass powder includes at least one of softwood biomass powder, crop straw powder, bagasse powder, cottonseed hull powder, and coconut shell powder. As a more preferred solution, the particle size of the high-cellulose biomass powder meets the requirement that the mass proportion of the -0.048 mm particle size grade is not less than 80%. The crop straw powder includes, for example, cotton straw powder, wheat straw powder, etc. The introduction of the preferred high-cellulose biomass powder into the solid fuel can improve the plasticity of the raw materials, making it easy to be extruded into shape. At the same time, it has a relatively high compression ratio and a relatively rough surface, and can be used as a binder to bond the coal-based fuel particles that are not easy to form and particles such as iron-containing solid waste, and improve the density, thereby improving the particle strength of the formed solid fuel. During the sintering process, the CH substances generated by the combustion of biomass are good NOx reducers, inhibiting the generation of NOx from the source.

[0012] As a more preferred solution, the specific surface area of the high-cellulose biomass powder should not be less than 1.5 m 2 / g. The high-cellulose biomass powder with a higher specific surface area can contact more materials during the pressing and forming process, thereby increasing the content of the auxiliary catalyst and iron-containing raw materials loaded on its surface, and increasing the probability of the reaction.

[0013] As a preferred solution, the iron-containing material includes at least one of iron-containing dust and specularite. The iron minerals contained in the preferred iron-containing material are prone to solid-phase reactions at high temperatures to form low-melting-point compounds such as calcium ferrite, which have a catalytic effect on the combustion of coal (charcoal), thereby improving the combustion efficiency of the fuel. In addition, calcium ferrite compounds have a catalytic effect on the reduction reaction of CO and NOx.

[0014] As a preferred solution, the particle size of the iron-containing material meets the requirement that the mass proportion of the -0.074 mm particle size grade is not less than 80%. The smaller the particle size grade of the iron-containing material, the better its dispersibility in the solid fuel and the higher its reaction activity.

[0015] As a preferred solution, the auxiliary catalyst is composed of vanadium-titanium-containing minerals and nickel-containing minerals in a mass percentage of 80-95%:5-20%. During the combustion of solid fuel, Ni in the nickel-containing minerals can catalyze the pyrolysis of biomass to produce CH substances, which can play a good role with only a small content; the CH substances are further reduced by NOx under the catalytic action of V and Ti in the vanadium-titanium-containing minerals; if the proportion of vanadium-titanium-containing minerals is too low, the effect of reducing NOx is poor; if the proportion of nickel-containing minerals is too low, it will lead to insufficient CH substances produced by biomass pyrolysis and affect the reduction efficiency. Therefore, when the two are combined in an appropriate proportion, the best synergistic catalytic effect can be achieved.

[0016] As a preferred solution, the content of V2O5 in the vanadium-titanium-containing minerals is not less than 0.3%, and the content of TiO2 is not less than 10%. Specific examples of vanadium-titanium-containing minerals include vanadate and / or vanadium-titanium magnetite. V2O5 and TiO2 are the main catalytic active substances, and when their proportion is low, their catalytic activity will decrease.

[0017] As a preferred solution, the Ni grade in the nickel-containing minerals is not less than 1%. Specific examples of nickel-containing minerals include at least one of laterite nickel ore, pentlandite, and millerite. If the nickel grade is low, its catalytic activity will decrease.

[0018] As a preferred solution, the particle size of the auxiliary catalyst meets the requirement that the mass proportion of the -0.048mm particle size grade is not less than 80%. Controlling the particle size of the auxiliary catalyst within the preferred range is more conducive to the dispersion of the auxiliary catalyst in solid fuel and improves its catalytic activity.

[0019] The particle sizes of the fine-grained fuel, iron-containing material, high-cellulose biomass powder, and auxiliary catalyst of the present invention are controlled within the preferred range. On the one hand, this particle size range is conducive to the full mixing between raw materials, making the components of the formed fuel particles uniform and stable. On the other hand, it is conducive to forming and can improve the overall mechanical strength of the formed fuel particles.

[0020] As a preferred solution, the particle size range of the low-carbon and low-emission solid fuel is 3-8mm. If the particle size of the solid fuel is too small, the combustion speed is fast, the highest combustion temperature is relatively low, and the NOx emission is relatively high. If the particle size is too large, the combustion is slow, which will lead to a thicker combustion zone in the sintered material layer, deteriorate the air permeability, and affect the sinter quality index.

[0021] The present invention also provides a preparation method of a low-carbon and low-emission solid fuel for iron ore sintering. The method is to strongly mix the principles including fine-grained coal-based fuel, iron-containing material, high-cellulose biomass powder, and auxiliary catalyst, and then obtain the product through vacuum extrusion molding.

[0022] As a preferred solution, the process of vacuum extrusion includes pre-pressing and vacuum extrusion; the pre-pressing section is a conical silo with the top of the cone as the discharge port. The feeding tray presses the mixed material into the vacuum chamber at a certain speed to complete pre-pressing. After the vacuum is pumped in the vacuum chamber, the pressing plate extrudes the raw material with a certain pressure and then extrudes and forms it from the discharge hole. The vacuum degree of the vacuum extrusion is <0.5 mbar; the pressure of the vacuum extrusion is 60 - 85 MPa. If the feeding speed is too slow, the pre-pressing effect is poor, affecting the strength of the finally formed fuel particles; if the vacuum degree is insufficient and the extrusion pressure is too small, the formed fuel particles are not dense enough and have poor strength. If the extrusion pressure is too large, the energy consumption of the process increases, but the improvement effect on the strength of the formed particles gradually weakens.

[0023] The present invention also provides an application of a low-carbon and low-emission solid fuel for iron ore sintering, which is used to replace fossil fuels for iron ore sintering.

[0024] More specifically, the low-carbon and low-emission solid fuel can completely or partially replace the existing fossil fuels for iron ore sintering. After proportioning the low-carbon and low-emission solid fuel with iron ore, flux, and return fines, the processes of mixing, granulation, feeding, ignition, and sintering are carried out in sequence to complete the entire sintering process.

[0025] As a more preferred solution, the mass ratio of the low-carbon and low-emission solid fuel is not less than 30% of the total mass of the solid fuel.

[0026] Beneficial effects brought by the technical solution of the present invention compared with the prior art:

[0027] (1) The solid fuel of the present invention uses fine-grained coal-based fuels such as coke breeze, coke powder, and coal powder generated in industrial production as the main raw materials, and obtains coarse-grained fuels with a particle size of 3 - 8 mm through the process of vacuum extrusion molding, improving the fuel combustion sustainability, improving the heat state of the sintering material layer, and improving the quality indexes of sintered ore.

[0028] (2) Iron-containing raw materials and auxiliary catalysts are added to the solid fuel of the present invention. On the one hand, it consumes raw materials such as vanadium-titanium ore, laterite nickel ore, specularite, and iron-containing dust with poor granulation effect and difficult utilization. On the other hand, it catalyzes the reduction process of NOx through elements such as Fe, V, Ti, and Ni, reduces NOx emissions, and realizes source emission reduction in the sintering process.

[0029] (3) High - cellulose biomass powder is added to the solid fuel of the present invention. On the one hand, it improves the plasticity of the mixed raw materials, creating conditions for vacuum extrusion molding. On the other hand, the high - cellulose biomass powder has a relatively high compression ratio, and after extrusion molding, it improves the density of the solid fuel. Thirdly, the surface of the particles of the high - cellulose biomass powder is relatively rough, and there is a large frictional resistance between it and the coal - based fuel particles and iron - containing solid waste particles, which can act as a binder to play a connecting role during the pressing process. In addition, under the catalysis of Ni, the high - cellulose biomass powder generates more CH - type substances during the combustion process, which can be used as a high - quality reducing agent to reduce NOx.

[0030] (4) The vacuum extrusion molding process adopted in the present invention is simple to operate and suitable for industrial production. During the molding process, the vacuum condition is beneficial to eliminating the gaps and air chambers between particles, improving the density of the solid fuel particles after molding, and at the same time, the particle size of the molded fuel can be quickly adjusted according to the actual production situation.

[0031] (5) The present invention makes solid fuel from fine - sized coal - based fuel, iron - containing raw materials, high - cellulose biomass, and auxiliary catalysts. On the one hand, the fine - sized coal - based fuel is prepared into coarse - sized fuel to improve its combustion performance, thereby optimizing the heat distribution state in the material layer during the sintering process and improving the quality index of sintered ore. On the other hand, elements such as Fe, V, Ti, and Ni in the added additives catalyze the oxidation - reduction reaction during the fuel combustion process, and the CH generated by the biomass inhibits the generation of NOx, realizing pollution reduction and carbon reduction during the sintering process from the source; the reduction ratio of solid fuel consumption is 5 - 15%, the reduction ratio of CO emissions is 25 - 50%, and the reduction ratio of NO x emission reduction ratio is 30 - 50%. Specific Embodiments

[0032] For the convenience of understanding the content of the present invention, the following will describe the content of the present invention more comprehensively and meticulously in combination with preferred embodiments, but the protection scope of the claims of the present invention is not limited to the following specific embodiments.

[0033] In the following examples and comparative examples, the V2O5 content in the vanadium - titanium - containing mineral is 0.5%, and the TiO2 content is 15%. The Ni grade in the nickel - containing mineral is 1.8%.

[0034] Example 1

[0035] The fine - sized coal - based fuel of - 0.5mm particle size, iron - containing raw materials, high - cellulose biomass powder, and auxiliary catalysts are proportioned according to the mass percentage of 60%:5%:20%:15%. Among them, the iron - containing raw material is iron - containing dust of - 0.074mm particle size, and the high - cellulose biomass powder is cotton straw powder of - 0.048mm particle size with a mass ratio of 85% (specific surface area is 1.77m 2 / g), the promoter is a mixture of ilmenite with a particle size fraction of -0.048 mm accounting for 83% by mass and laterite nickel ore with a particle size fraction of -0.048 mm accounting for 86% by mass in a mass percentage of 90%:10%. After the above materials are thoroughly mixed by a high-intensity mixer, they are fed into a vacuum extrusion molding device and pressed into particle fuels with a particle size of 3 mm under the conditions of a vacuum degree of 0.3 mbar and a pressure of 80 MPa. The particle fuels are mixed with conventional sintered solid fuels in a mass ratio of 40%:60% to obtain a mixed fuel. Iron ore, quicklime, dolomite, the mixed fuel, and return ore are proportioned in mass percentages of 67.88%, 6.46%, 4.33%, 3.30%, and 18.03%. After mixing and granulation, they are distributed onto a sintering trolley and ignited under the conditions of a temperature of 1050 ± 50 °C and a negative pressure of -6 kPa, with the ignition area accounting for 8% of the material surface. The entire sintering process is completed under a sintering negative pressure of -15 kPa. After sintering, the strength of the obtained fuel particles, sintering indexes, and pollutant emission reduction effects are shown in Table 1.

[0036] Example 2

[0037] The fine-grained coal-based fuel with a particle size fraction of -0.5 mm is proportioned with an iron-containing raw material, high-cellulose biomass powder, and a promoter in mass percentages of 50%:3%:35%:12%. The iron-containing raw material is iron-containing dust with a particle size fraction of -0.074 mm, and the high-cellulose biomass powder is cotton straw powder with a particle size fraction of -0.048 mm accounting for 85% by mass (specific surface area is 1.77 m 2 / g), the promoter is a mixture of ilmenite with a particle size fraction of -0.048 mm accounting for 83% by mass and laterite nickel ore with a particle size fraction of -0.048 mm accounting for 86% by mass in a mass percentage of 80%:20%. After the above materials are thoroughly mixed by a high-intensity mixer, they are fed into a vacuum extrusion molding device and pressed into particle fuels with a particle size of 3 mm under the conditions of a vacuum degree of 0.3 mbar and a pressure of 80 MPa. The particle fuels are mixed with conventional sintered solid fuels in a mass ratio of 50%:50% to obtain a mixed fuel. Iron ore, quicklime, dolomite, the mixed fuel, and return ore are proportioned in mass percentages of 67.88%, 6.46%, 4.33%, 3.30%, and 18.03%. After mixing and granulation, they are distributed onto a sintering trolley and ignited under the conditions of a temperature of 1050 ± 50 °C and a negative pressure of -6 kPa, with the ignition area accounting for 8% of the material surface. The entire sintering process is completed under a sintering negative pressure of -15 kPa. After sintering, the strength of the obtained fuel particles, sintering indexes, and pollutant emission reduction effects are shown in Table 1.

[0038] Example 3

[0039] The fine-grained coal-based fuel of -0.5 mm particle size is proportioned with iron-containing raw materials, high-cellulose biomass powder, and auxiliary catalyst according to the mass percentages of 65%:5%:20%:10%. The iron-containing raw material is iron-containing dust of -0.074 mm particle size, the high-cellulose biomass powder is cotton straw powder of -0.048 mm particle size with a mass percentage of 85% (specific surface area is 1.77 m 2 / g), the auxiliary catalyst is a mixture of vanadium-titanium ore of -0.048 mm particle size with a mass percentage of 83% and laterite nickel ore of -0.048 mm particle size with a mass percentage of 86% according to the mass percentage of 85%:15%. After the above materials are fully mixed by a strong mixer, they are sent to a vacuum extrusion molding device and pressed into particle fuel with a 3 mm particle size under the conditions of a vacuum degree of 0.3 mbar and a pressure of 80 MPa. The particle fuel is mixed with conventional sintered solid fuel according to a mass ratio of 35%:65% to obtain a mixed fuel. Iron ore, quicklime, dolomite, mixed fuel, and return ore are proportioned according to the mass percentages of 67.88%, 6.46%, 4.33%, 3.30%, and 18.03%. After mixing and granulation, they are distributed on a sintering trolley and ignited under the conditions of a temperature of 1050 ± 50 °C and a negative pressure of -6 kPa. The ignition area accounts for 8% of the material surface, and the entire sintering process is completed under a sintering negative pressure of -15 kPa. After sintering, the strength of the obtained fuel particles, sintering indexes, and pollutant emission reduction effects are shown in Table 1.

[0040] Example 4

[0041] The fine-grained coal-based fuel of -0.5 mm particle size is proportioned with iron-containing raw materials, high-cellulose biomass powder, and auxiliary catalyst according to the mass percentages of 67%:3%:20%:10%. The iron-containing raw material is iron-containing dust of -0.074 mm particle size, the high-cellulose biomass powder is cotton straw powder of -0.048 mm particle size with a mass percentage of 85% (specific surface area is 1.77 m 2 / g), the promoter is a mixture of ilmenite with a mass fraction of 83% in the -0.048 mm particle size fraction and laterite nickel ore with a mass fraction of 86% in the -0.048 mm particle size fraction at a mass percentage of 90%:10%. After the above materials are thoroughly mixed by a high-intensity mixer, they are fed into a vacuum extrusion molding device and pressed into particle fuel with a 3 mm particle size under the conditions of a vacuum degree of 0.3 mbar and a pressure of 80 MPa. The particle fuel is mixed with a conventional sintered solid fuel in a mass ratio of 70%:30% to obtain a mixed fuel. Iron ore, quicklime, dolomite, the mixed fuel, and return ore are proportioned by mass percentages of 67.88%, 6.46%, 4.33%, 3.30%, and 18.03%. After mixing and granulation, they are distributed onto a sintering trolley and ignited under the conditions of a temperature of 1050 ± 50 °C and a negative pressure of -6 kPa, with the ignition area covering 8% of the material surface. The entire sintering process is completed under a sintering negative pressure of -15 kPa. After sintering, the strength of the obtained fuel particles, sintering indexes, and pollutant emission reduction effects are shown in Table 1.

[0042] Example 5

[0043] The fine-grained coal-based fuel with a particle size of -0.5 mm is proportioned with an iron-containing raw material, high-cellulose biomass powder, and a promoter according to a mass percentage of 65%:4%:21%:10%. The iron-containing raw material is iron-containing dust with a particle size of -0.074 mm, and the high-cellulose biomass powder is cotton straw powder with a mass fraction of 85% in the -0.048 mm particle size fraction (specific surface area is 1.77 m 2 / g), the promoter is a mixture of ilmenite with a mass fraction of 83% in the -0.048 mm particle size fraction and laterite nickel ore with a mass fraction of 86% in the -0.048 mm particle size fraction at a mass percentage of 80%:20%. After the above materials are thoroughly mixed by a high-intensity mixer, they are fed into a vacuum extrusion molding device and pressed into particle fuel with a 3 mm particle size under the conditions of a vacuum degree of 0.3 mbar and a pressure of 80 MPa. The particle fuel is mixed with a conventional sintered solid fuel in a mass ratio of 100%:0% to obtain a mixed fuel. Iron ore, quicklime, dolomite, the mixed fuel, and return ore are proportioned by mass percentages of 67.88%, 6.46%, 4.33%, 3.30%, and 18.03%. After mixing and granulation, they are distributed onto a sintering trolley and ignited under the conditions of a temperature of 1050 ± 50 °C and a negative pressure of -6 kPa, with the ignition area covering 8% of the material surface. The entire sintering process is completed under a sintering negative pressure of -15 kPa. After sintering, the strength of the obtained fuel particles, sintering indexes, and pollutant emission reduction effects are shown in Table 1.

[0044] Comparative Example 1

[0045] The iron ore, quicklime, dolomite, conventional sintering fuel, and return ore are proportioned by mass percentages of 67.88%, 6.46%, 4.33%, 3.30%, and 18.03%. After mixing and granulation, they are charged onto the sintering pallet. Ignition is carried out under the conditions of a temperature of 1050 ± 50 °C and a negative pressure of -6 kPa, with the ignition area accounting for 8% of the material surface. The entire sintering process is completed under a sintering negative pressure of -15 kPa. After sintering, the fuel particle strength, sintering indexes, and pollutant emission reduction effects are shown in Table 1.

[0046] Comparative Example 2

[0047] The -0.5 mm fine-grained coal-based fuel and the conventional sintering fuel are mixed evenly by a mass percentage of 30% : 70% to obtain a mixed fuel. The iron ore, quicklime, dolomite, mixed fuel, and return ore are proportioned by mass percentages of 67.88%, 6.46%, 4.33%, 3.30%, and 18.03%. After mixing and granulation, they are charged onto the sintering pallet. Ignition is carried out under the conditions of a temperature of 1050 ± 50 °C and a negative pressure of -6 kPa, with the ignition area accounting for 8% of the material surface. The entire sintering process is completed under a sintering negative pressure of -15 kPa. After sintering, the fuel particle strength, sintering indexes, and pollutant emission reduction effects are shown in Table 1.

[0048] Comparative Example 3

[0049] The -0.5 mm fine-grained coal-based fuel, iron-containing raw material, and auxiliary catalyst are proportioned by mass percentages of 70% : 5% : 25%. The iron-containing raw material is iron-containing dust with a particle size of -0.074 mm, and the auxiliary catalyst is a mixture of vanadium-titanium ore with a particle size of -0.048 mm and a mass percentage of 83% and laterite nickel ore with a particle size of -0.048 mm and a mass percentage of 86% by a mass percentage of 90% : 10%. After the above materials are fully mixed by a powerful mixer, they are fed into a vacuum extrusion molding device and pressed under the conditions of a vacuum degree of 0.3 mbar and a pressure of 80 MPa. It is difficult to form under the condition of no high-cellulose biomass.

[0050] Comparative Example 4

[0051] The -0.5 mm fine-grained coal-based fuel, iron-containing raw material, and high-cellulose biomass powder are proportioned by mass percentages of 65% : 5% : 30%. The iron-containing raw material is iron-containing dust with a particle size of -0.074 mm, and the high-cellulose biomass powder is cotton straw powder with a particle size of -0.048 mm and a mass percentage of 85% (specific surface area is 1.77 m 2 / g). After the above materials are fully mixed by a high-strength mixer, they are fed into a vacuum extrusion molding device and pressed into pellet fuels with a particle size of 3 mm under the conditions of a vacuum degree of 0.3 mbar and a pressure of 80 MPa. The pellet fuels are mixed with conventional sintered solid fuels according to a mass ratio of 30%:70% to obtain a mixed fuel. Iron ore, quicklime, dolomite, the mixed fuel, and returned ore are proportioned according to mass percentages of 67.88%, 6.46%, 4.33%, 3.30%, and 18.03%. After mixing and granulation, they are fed onto a sintering trolley. Ignition is carried out under the conditions of a temperature of 1050 ± 50 °C and a negative pressure of -6 kPa, and the surface area of the ignition area accounts for 8%. The entire sintering process is completed under a sintering negative pressure of -15 kPa. After sintering, the strength of the obtained fuel pellets, sintering indexes, and pollutant emission reduction effects are shown in Table 1.

[0052] Comparative Example 5

[0053] The fine-grained coal-based fuel with a particle size of -0.5 mm is proportioned with high-cellulose biomass powder and auxiliary catalyst according to a mass percentage of 50%:35%:15%. Among them, the high-cellulose biomass powder is cotton straw powder with a particle size of -0.048 mm and a mass ratio of 85% (specific surface area is 1.77 m 2 / g), and the auxiliary catalyst is a mixture of vanadium-titanium ore with a particle size of -0.048 mm and a mass ratio of 83% and laterite nickel ore with a particle size of -0.048 mm and a mass ratio of 86% according to a mass percentage of 90%:10%. After the above materials are fully mixed by a high-strength mixer, they are fed into a vacuum extrusion molding device and pressed into pellet fuels with a particle size of 3 mm under the conditions of a vacuum degree of 0.3 mbar and a pressure of 80 MPa. The pellet fuels are mixed with conventional sintered solid fuels according to a mass ratio of 30%:70% to obtain a mixed fuel. Iron ore, quicklime, dolomite, the mixed fuel, and returned ore are proportioned according to mass percentages of 67.88%, 6.46%, 4.33%, 3.30%, and 18.03%. After mixing and granulation, they are fed onto a sintering trolley. Ignition is carried out under the conditions of a temperature of 1050 ± 50 °C and a negative pressure of -6 kPa, and the surface area of the ignition area accounts for 8%. The entire sintering process is completed under a sintering negative pressure of -15 kPa. After sintering, the strength of the obtained fuel pellets, sintering indexes, and pollutant emission reduction effects are shown in Table 1.

[0054] Comparative Example 6

[0055] The fine-grained coal-based fuel with a particle size of -0.5 mm is proportioned with iron-containing raw materials, high-cellulose biomass powder, and auxiliary catalyst according to a mass percentage of 65%:5%:20%:10%. Among them, the iron-containing raw material is iron-containing dust with a particle size of -0.074 mm, and the high-cellulose biomass powder is cotton straw powder with a particle size of -0.048 mm and a mass ratio of 85% (specific surface area is 1.77 m 2 / g), the promoter is ilmenite with a mass fraction of 83% in the -0.048 mm particle size fraction. After the above materials are thoroughly mixed by a high-strength mixer, they are fed into a vacuum extrusion molding device and pressed into granular fuel with a 3 mm particle size under the conditions of a vacuum degree of 0.3 mbar and a pressure of 80 MPa. The granular fuel is mixed with conventional sintered solid fuel according to a mass ratio of 30%:70% to obtain a mixed fuel. Iron ore, quicklime, dolomite, the mixed fuel, and returned ore are proportioned by mass percentages of 67.88%, 6.46%, 4.33%, 3.30%, and 18.03%, respectively. After mixing and granulation, they are distributed onto a sintering trolley and ignited under the conditions of a temperature of 1050±50 °C and a negative pressure of -6 kPa, with the ignition area covering 8% of the material surface. The entire sintering process is completed under a sintering negative pressure of -15 kPa. After sintering, the strength of the obtained fuel particles, sintering indexes, and pollutant emission reduction effects are shown in Table 1.

[0056] Comparative Example 7

[0057] The fine-grained coal-based fuel with a particle size of -0.5 mm, iron-containing raw material, high-cellulose biomass powder, and promoter are proportioned according to mass percentages of 65%:5%:20%:10%. The iron-containing raw material is iron-containing dust with a particle size of -0.074 mm, and the high-cellulose biomass powder is cotton straw powder with a mass fraction of 85% in the -0.048 mm particle size fraction (specific surface area is 1.77 m 2 / g), the promoter is laterite nickel ore with a mass fraction of 86% in the -0.048 mm particle size fraction. After the above materials are thoroughly mixed by a high-strength mixer, they are fed into a vacuum extrusion molding device and pressed into granular fuel with a 3 mm particle size under the conditions of a vacuum degree of 0.3 mbar and a pressure of 80 MPa. The granular fuel is mixed with conventional sintered solid fuel according to a mass ratio of 30%:70% to obtain a mixed fuel. Iron ore, quicklime, dolomite, the mixed fuel, and returned ore are proportioned by mass percentages of 67.88%, 6.46%, 4.33%, 3.30%, and 18.03%, respectively. After mixing and granulation, they are distributed onto a sintering trolley and ignited under the conditions of a temperature of 1050±50 °C and a negative pressure of -6 kPa, with the ignition area covering 8% of the material surface. The entire sintering process is completed under a sintering negative pressure of -15 kPa. After sintering, the strength of the obtained fuel particles, sintering indexes, and pollutant emission reduction effects are shown in Table 1.

[0058] 。

Claims

1. A low-carbon and low-emission solid fuel for iron ore sintering, characterized in that: It contains the following component raw materials: fine-grained coal-based fuel, iron-containing material, high-cellulose biomass powder, and auxiliary catalyst; The auxiliary catalyst contains vanadium-titanium minerals and nickel-containing minerals.

2. The low-carbon and low-emission solid fuel for iron ore sintering according to claim 1, characterized in that: It consists of the following component raw materials by mass percentage: Fine-grained coal-based fuel 50 - 70%; Iron-containing material 3 - 5%; High-cellulose biomass powder 17 - 40%; Auxiliary catalyst 7 - 15%.

3. A low-carbon and low-emission solid fuel for iron ore sintering according to claim 1 or 2, characterized in that: The particle size of the fine-grained coal-based fuel meets the requirement that the mass ratio of the -0.5mm particle size grade is not less than 80%; The fine-grained coal-based fuel includes at least one of dry coke powder, coal powder, and coke powder.

4. A low-carbon and low-emission solid fuel for iron ore sintering according to claim 1 or 2, characterized in that: The high-cellulose biomass powder includes at least one of softwood biomass powder, crop straw powder, bagasse powder, cottonseed hull powder, and coconut shell powder; The particle size of the high-cellulose biomass powder meets the requirement that the mass ratio of the -0.048mm particle size grade is not less than 80%; The specific surface area of the high-cellulose biomass powder is not less than 1.5 m 2 / g; The iron-containing material includes at least one of iron-containing dust and specularite; The particle size of the iron-containing material meets the requirement that the mass ratio of the -0.074mm particle size grade is not less than 80%.

5. A low-carbon and low-emission solid fuel for iron ore sintering according to claim 1 or 2, characterized in that: The auxiliary catalyst is composed of vanadium-titanium minerals and nickel-containing minerals in a mass percentage of 80 - 95%:5 - 20%.

6. A low-carbon and low-emission solid fuel for iron ore sintering according to claim 5, characterized in that: The V2O5 content in the vanadium-titanium minerals is not less than 0.3%, and the TiO2 content is not less than 10%; The Ni grade in the nickel-containing minerals is not less than 1%; The particle size of the auxiliary catalyst meets the requirement that the mass ratio of the -0.048mm particle size grade is not less than 80%.

7. A low-carbon and low-emission solid fuel for iron ore sintering according to claim 1 or 2, characterized in that: The particle size range of the low-carbon and low-emission solid fuel is 3 - 8mm.

8. A preparation method of a low-carbon and low-emission solid fuel for iron ore sintering according to any one of claims 1 to 7, characterized in that: It is obtained by strongly mixing the raw materials including fine-grained coal-based fuel, iron-containing material, high-cellulose biomass powder, and auxiliary catalyst, and then through vacuum extrusion molding.

9. A preparation method of a low-carbon and low-emission solid fuel for iron ore sintering according to claim 8, characterized in that: The process of the vacuum extrusion includes pre-pressing and vacuum extrusion; The vacuum degree of the vacuum extrusion < 0.5 mbar; The pressure of the vacuum extrusion is 60 - 85 MPa.

10. Use of a low-carbon and low-emission solid fuel for iron ore sintering according to any one of claims 1 to 7, characterized in that: It is used to replace fossil fuels for iron ore sintering.