Pollution-reducing and carbon-reducing solid fuel as well as preparation method and application thereof

Abstract

The invention relates to a pollution-reducing and carbon-reducing solid fuel as well as a preparation method and application thereof, and belongs to the technical field of ferrous metallurgy fuels. The solid fuel comprises the following raw materials in parts by weight: 70-85 parts of fine fraction fuel, 10-15 parts of iron-containing solid waste, 5-10 parts of a calcium-based additive and 5-10 parts of a composite organic binder. Fine-grained fuel is adopted as a main raw material, and an auxiliary reagent is added, so that the fine-grained fuel is bonded and granulated, and modification and quality improvement are realized. The catalytic effect of iron elements in the iron-containing solid waste and active calcium oxide in the calcium-containing solid waste on fuel combustion and fuel nitrogen conversion is utilized, and efficient and sufficient combustion of fuel is promoted. The high-quality CH reducing agent provided by the composite organic binder can efficiently inhibit generation of NOx, so that pollution reduction and carbon reduction in the sintering process are realized from the source.

Description

Technical Field

[0001] The present application relates to the field of steel metallurgical fuels, and in particular to a pollution-reducing and carbon-reducing solid fuel and a preparation method and application thereof. Background Art

[0002] As the first high-temperature process in steel production, the sintering process provides more than 75% of the iron-containing charge for the blast furnace. The quality characteristics and usage methods of sintering fuel directly affect its combustion behavior in the sintering bed, thereby affecting the efficiency of the sintering process and the quality of the final product. For example, too large or too small fuel particle size may affect the permeability and uniformity of the bed, and may even lead to inconsistent heat transfer. With the increase of fuel particle size, the combustion efficiency and sintering indicators (the overall trend of sintering speed, yield, barrel strength and utilization coefficient) show a trend of first increasing and then decreasing. The crushing and screening of fuel can produce fuel with appropriate particle size, but it will inevitably produce a large amount of fine-grained fuel. The addition of fine-grained fuel (-1mm) will increase the content of small particles after the mixed granulation process, resulting in the deterioration of the granulation effect of the mixture, which is not conducive to the permeability and heat transfer of the sintering material layer; from the perspective of microstructure, the increase in the proportion of fine-grained fuel will increase the number of macropores in sintering and reduce the number of calcium-iron phases, which is not conducive to the strength and metallurgical properties of the sintered ore.

[0003] The steel industry is the main source of nitrogen oxide emissions, of which the nitrogen oxides produced during the sintering process account for about 50% of the total nitrogen oxide emissions. Nitrogen in solid fuels is easily released during pyrolysis and combustion, and the nitrogen oxides produced account for 94.59% of the total nitrogen oxides in sintering flue gas. Combined with advanced tail gas denitrification technology, improving fuel quality and combustion efficiency can fundamentally and effectively reduce nitrogen oxide emissions. The efficient use of solid fuels during sintering is an important way to achieve pollution reduction and carbon reduction in the steel industry. The addition of fine-grained fuels is harmful to the output, quality indicators and pollutant emissions of sintered ore. The molding and pelletizing of fine-grained fuels is of great significance for energy conservation, emission reduction and energy consumption reduction. Summary of the invention

[0004] The present application provides a pollution-reducing and carbon-reducing solid fuel and a preparation method and application thereof, in order to solve the following technical problem: how to achieve pollution reduction and carbon reduction in the sintering process of fine-grained fuel.

[0005] In the first aspect, the present application provides a pollution-reducing and carbon-reducing solid fuel. The raw materials of the solid fuel include, by weight: 70 to 85 parts of fine-grained fuel, 10 to 15 parts of iron-containing solid waste, 5 to 10 parts of calcium-based additives and 5 to 10 parts of composite organic binder.

[0006] Optionally, the fine-grained fuel is at least one of fine-grained coal powder, fine-grained coke powder, and activated carbon powder; the fine-grained fuel is of -1mm particle size, wherein the mass of the fine-grained fuel of -0.5mm particle size is not less than 70% of the total mass of the fine-grained fuel.

[0007] Optionally, the iron-containing solid waste is at least one of dust removal ash, converter mud, and gas ash; the mass of the iron-containing solid waste with a particle size of -0.074 mm is not less than 90% of the total mass of the iron-containing solid waste.

[0008] Optionally, the calcium-based additive is at least one of quicklime, limestone, and steel slag; the mass of the calcium-based additive with a particle size of -0.074 mm is not less than 90% of the total mass of the calcium-based additive.

[0009] Optionally, the composite organic binder is composed of an organic binder and biomass powder; the mass m1 of the organic binder and the mass m2 of the biomass powder satisfy the relationship: m1:m2=(0-60):(40-100).

[0010] Optionally, the organic binder is at least one of sodium carboxymethyl cellulose, molasses, humic acid, and sodium starch.

[0011] Optionally, the biomass powder is at least one of sawdust, crop straw, bagasse, and rice husk; the mass of the biomass powder with a particle size of -0.074 mm is not less than 95% of the total mass of the biomass powder.

[0012] Optionally, the particle size of the solid fuel is 2 mm to 4 mm.

[0013] In a second aspect, the present application provides a method for preparing the pollution-reducing and carbon-reducing solid fuel described in the first aspect, the method comprising:

[0014] Mixing the fine-grained fuel, the iron-containing solid waste, the calcium-based additive and the composite organic binder according to the weight parts to obtain a mixture;

[0015] The mixture is pressed and molded in a low temperature environment to obtain a solid fuel.

[0016] Optionally, the temperature of the low-temperature pressing is 100°C to 150°C.

[0017] In a third aspect, the present application provides an application of the pollution-reducing and carbon-reducing solid fuel described in the first aspect, wherein the solid fuel is used for iron ore sintering.

[0018] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0019] The present application provides a pollution-reducing and carbon-reducing solid fuel. The raw materials of the solid fuel include, by weight: 70 to 85 parts of fine-grained fuel, 10 to 15 parts of iron-containing solid waste, 5 to 10 parts of calcium-based additives, and 5 to 10 parts of composite organic binders. Fine-grained fuel is used as the main raw material, and auxiliary reagents are added to make the fine-grained fuel bonded into particles to achieve modification and quality improvement. The catalytic effect of the iron element in the iron-containing solid waste and the active calcium oxide in the calcium-containing solid waste on fuel combustion and fuel nitrogen conversion is utilized to promote efficient and complete combustion of the fuel. The high-quality CH-based reducing agent provided by the composite organic binder can effectively inhibit NO x The generation of carbon dioxide can be reduced, thereby reducing pollution and carbon emissions in the sintering process from the source. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0022] Figure 1 A schematic flow chart of a method for preparing a pollution-reducing and carbon-reducing solid fuel provided in an embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0024] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a rigid limitation on the scope of the present application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within the range; for example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which applies regardless of the range; in addition, whenever a numerical range is indicated in this document, it is meant to include any cited numbers (fractions or integers) within the indicated range.

[0025] In this document, the terms including "including" and "including" mean "including but not limited to". Relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone; where A and B can be singular or plural. "At least one" means one or more, and "plurality" means two or more; "at least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items; for example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple. "Parts" such as parts by weight and parts by mass indicate the proportional relationship between the components. In the proportional relationship involved in this article, the parameters that need to be described by proportion should be understood as the first term of the proportional formula in the order of description, and the proportional numbers should be understood as the second term of the proportional formula. For example, if the weight ratio of substance A, substance B and substance C is 1:2:3, then substance A, substance B and substance C should correspond to the proportional numbers in the proportional formula in the order of description, that is, the weight of substance A: the weight of substance B: the weight of substance C = 1:2:3.

[0026] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this article can be purchased from the market or prepared by existing methods.

[0027] In the first aspect, the present application provides a pollution-reducing and carbon-reducing solid fuel. The raw materials of the solid fuel include, by weight: 70 to 85 parts of fine-grained fuel, 10 to 15 parts of iron-containing solid waste, 5 to 10 parts of calcium-based additives and 5 to 10 parts of composite organic binder.

[0028] The embodiments of the present application use cheap and readily available fine-grained fuel as the main raw material, and make it bonded into granules by adding auxiliary reagents, and achieve modification and quality improvement to obtain high-quality granular fuel that can better meet the needs of iron ore sintering. The use of fine-grained fuel in the prior art is harmful to the sintered ore output, quality indicators and pollutant emissions in the flue gas. It is necessary to shape and granulate the fine-grained fuel, but fine-grained fuel generally has poor hydrophilicity and is difficult to shape by direct pressing. The addition of a composite organic binder can combine with the surface of the fine-grained fuel to form a large amount of gel and various forms of crystal structures on its surface to produce a bridging effect (or bridging, bridging, etc.) to make the fine-grained fuel particles bonded to each other, thereby shortening the distance between particles after simple pressing, which is conducive to forming a stronger bonding layer to improve the strength of the molded fuel particles. At the same time, the composite organic binder can be NO formed by the oxidation of fuel nitrogen. x Provide high-quality CH reducing agents and efficiently inhibit NO x However, the composite organic binder has a high viscosity, a low degree of dispersion in the mixed material, and poor fluidity, which leads to some gaps inside the molded fuel particles. On the basis of adding a composite organic binder, iron-containing solid waste and calcium-based additives are also introduced. The addition of the two can make the solid fuel particle structure more compact, reduce the breakage rate of the molded fuel particles, and improve the wear resistance. At the same time, it can absorb the iron-containing solid waste and calcium-containing solid waste generated by some steel companies. In particular, the iron element in the iron-containing solid waste and the active calcium oxide in the calcium-containing solid waste can be used to catalyze the combustion of fuel and the conversion of fuel nitrogen, which is conducive to the efficient and full combustion of the fuel and NO x The suppression of CO generation during the sintering process x 、NO x The embodiment of the present application combines fine-grained fuel with iron-containing solid waste, calcium-based additives, and composite organic binders to make solid fuel. On the one hand, it meets the heat demand of the sintering process and improves the strength and metallurgical properties of the sintered ore. On the other hand, it utilizes the catalytic and reduction effects of Fe, Ca, CH and other components to achieve efficient and clean combustion of the fuel and significantly inhibit NO x The generation of solid waste and calcium-based additives can reduce pollution and carbon emissions in the sintering process from the source. When the proportion of iron-containing solid waste and calcium-based additives exceeds the specified weight range, the strength of the molded fuel particles will be significantly reduced, and the original structure of the molded fuel particles will also be changed; when the proportion of composite organic binder exceeds the specified weight range, the powder will be too viscous, resulting in difficulty in molding, and at the same time reducing the basic properties of the pellet fuel, such as combustion efficiency and calorific value.

[0029] In some embodiments, the fine-grained fuel is at least one of fine-grained coal powder, fine-grained coke powder, and activated carbon powder; the fine-grained fuel is of -1 mm particle size, wherein the mass of the fine-grained fuel of -0.5 mm particle size is not less than 70% of the total mass of the fine-grained fuel.

[0030] These fine-grained fuels are common in the industry and are generally difficult to be fully utilized in iron ore sintering. Activated carbon powder can be waste activated carbon powder generated by the activated carbon desulfurization and denitrification process of steel enterprises.

[0031] The particle size control of the fine-grained fuel helps to fully burn and evenly distribute it during the sintering process. Full combustion can reduce the emission of unburned carbon and reduce the carbon emission during the sintering process. Exemplarily, the mass of the fine-grained fuel of -0.5 mm particle size can be 70%, 75%, 80%, 85%, 90%, 95%, etc. of the total mass of the fine-grained fuel.

[0032] In some embodiments, the iron-containing solid waste is at least one of dust removal ash, converter mud, and gas ash; the mass of the iron-containing solid waste with a particle size of -0.074 mm is not less than 90% of the total mass of the iron-containing solid waste.

[0033] The main substances in the iron-containing solid waste will undergo solid-phase reaction at high temperature to generate calcium ferrites and may form a liquid phase. These substances have a catalytic effect on coal (charcoal) combustion, thereby improving the combustion efficiency of the fuel, and will also act as a catalyst to promote the reduction of NO by CO. Among them, the mechanism of calcium ferrite catalyzing CO to reduce NO is: CO is first adsorbed on the active site of calcium ferrite before NO, and this part of calcium ferrite is preferentially reduced by CO, and the resulting reduction reaction product contains low-valent FeO and Fe, while NO is preferentially adsorbed on the Fe surface before CO and oxidizes it, while it is reduced to N2.

[0034] As one of the raw materials for iron ore sintering, iron-containing solid waste can reduce the dependence on new iron ore resources. The particle size control of iron-containing solid waste helps its uniform distribution and full reaction during the sintering process, reducing the emission of unreacted solid waste. Exemplarily, the mass of the iron-containing solid waste with a particle size of -0.074 mm can be 90%, 91%, 92%, 93%, 94%, 95%, etc. of the total mass of the iron-containing solid waste.

[0035] In some embodiments, the calcium-based additive is at least one of quicklime, limestone, and steel slag; the mass of the calcium-based additive with a particle size of -0.074 mm is not less than 90% of the total mass of the calcium-based additive.

[0036] The calcium-based additive mainly provides active calcium oxide, so substances containing calcium oxide or that can produce active calcium oxide at high temperatures theoretically meet the requirements. The addition of calcium-based additives helps to adjust the pH during the sintering process, promote the melting and bonding of iron ore powder, and thus improve the quality of sintered ore. Calcium-based additives can also react with harmful elements such as sulfur and phosphorus during the sintering process to generate stable compounds, reducing the emission of these harmful elements in sintered ore and exhaust gas. Exemplarily, the mass of the calcium-based additive at a particle size of -0.074 mm can be 90%, 91%, 92%, 93%, 94%, 95%, etc. of the total mass of the calcium-based additive.

[0037] In some embodiments, the composite organic binder is composed of an organic binder and biomass powder; the mass m1 of the organic binder and the mass m2 of the biomass powder satisfy the relationship: m1:m2=(0-60):(40-100).

[0038] The addition of composite organic binder improves the formability and strength of solid fuel, enabling it to maintain a stable shape and size during the sintering process.

[0039] In some embodiments, the organic binder is at least one of sodium carboxymethyl cellulose, molasses, humic acid, and sodium starch.

[0040] In some embodiments, the biomass powder is at least one of sawdust, crop straw, bagasse, and rice husk; the mass of the biomass powder with a particle size of -0.074 mm is not less than 95% of the total mass of the biomass powder.

[0041] The addition of biomass powder not only increases the combustibility of solid fuel, but also provides an additional carbon source for it, which helps to reduce the solid fuel consumption during sintering. Exemplarily, the mass of the biomass powder with a particle size of -0.074 mm can be 95%, 95.5%, 96%, 96.5%, 97%, 97.5%, etc. of the total mass of the biomass powder.

[0042] C and H in organic binders and biomass powder will compete with N for oxygen, so the presence of C, CO, H, and OH in the combustion system will reduce NO x Based on the softening and bonding effect of cellulose and hemicellulose in biomass during the hot pressing process, it can be used as a binder alone or together with an organic binder to bind fine fuel particles into pellet fuel with a certain strength. In addition, biomass and organic binders can be used to remove NO formed by oxidation of fuel nitrogen. x Provide high-quality CH reducing agents and efficiently inhibit NO x Generation of.

[0043] The particle size of the fine-grained fuel, iron-containing solid waste, calcium-based additives and composite organic binder in the embodiments of the present application is controlled within a preferred range. On the one hand, it is beneficial to granulation and improve the mechanical strength of the solid fuel. On the other hand, it is beneficial to sufficient contact between the raw materials and improve the combustion performance of the fuel.

[0044] In some embodiments, the particle size of the solid fuel is 2 mm to 4 mm.

[0045] As the particle size of the fuel increases, the sintering speed, yield rate, drum strength and utilization coefficient generally show a trend of first increasing and then decreasing, and when the particle size of the fuel is 2mm to 4mm, all indicators are better. For example, the particle size of the solid fuel can be 2mm, 2.5mm, 3mm, 3.5mm, 4mm, etc.

[0046] Figure 1 A schematic flow chart of a method for preparing a pollution-reducing and carbon-reducing solid fuel provided in an embodiment of the present application.

[0047] See also Figure 1 In a second aspect, the present application provides a method for preparing the pollution-reducing and carbon-reducing solid fuel described in the first aspect, the method comprising:

[0048] S1. Mixing the fine-grained fuel, the iron-containing solid waste, the calcium-based additive and the composite organic binder according to the weight parts to obtain a mixture;

[0049] S2. In a low temperature environment, pressing the mixture into a shape to obtain a solid fuel.

[0050] In some embodiments, the temperature of the low temperature pressing is 100°C to 150°C.

[0051] The heat can come from the waste heat of hot exhaust gas in the low temperature section of the sintering process. Properly increasing the temperature can promote the formation of particle structure, improve product performance, and increase production efficiency, but when the temperature is higher than 150°C, the raw materials may undergo chemical changes or phase changes. Pressing at a temperature of 100°C to 150°C helps to maintain the structural integrity of the fuel particles on the one hand, and on the other hand, using the waste heat of hot exhaust gas can save energy and reduce production costs. Exemplarily, the temperature of low-temperature pressing can be 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, etc.

[0052] Based on a general inventive concept, the present application provides an application of the pollution-reducing and carbon-reducing solid fuel described in any one of the above embodiments, wherein the solid fuel is used for iron ore sintering.

[0053] The present application is further described below in conjunction with specific embodiments. The experimental methods in the following embodiments that do not specify specific conditions are usually measured in accordance with national standards / industry standards; if there are no corresponding national standards / industry standards, they are measured in accordance with common international standards, conventional conditions, or conditions recommended by the manufacturer.

[0054] Example 1

[0055] The fine-grained fuel with a particle size of -0.5mm is mixed with iron-containing solid waste, calcium-based additives, and composite organic binders in a weight ratio of 75:10:5:10, wherein the iron-containing solid waste is dust ash with a particle size of -0.074mm, the calcium-based additive is quicklime with a particle size of -0.074mm, and the composite organic binder is a mixture of molasses and sawdust with a particle size of -0.074mm in a mass ratio of 60:40. After the above materials are fully mixed in a strong mixer, they are sent to The solid fuel is put into the molding equipment at 120℃ and pressed into a solid fuel with a particle size of 3mm. The obtained solid fuel is mixed with iron ore, dolomite, quicklime and return ore in a mass ratio of 3.12:75.96:2.32:6.52:12.18. After mixing and granulation, it is distributed to the sintering trolley and ignited at a temperature of 1050±50℃ and a negative pressure of -5kPa. The material surface in the ignition area accounts for 8.5%, and the entire sintering process is completed under a sintering negative pressure of -14kPa.

[0056] Example 2

[0057] The fine-grained fuel with a particle size of -0.5 mm is mixed with iron-containing solid waste, calcium-based additives, and composite organic binders in a weight ratio of 75:13:7:5, wherein the iron-containing solid waste is dust ash with a particle size of -0.074 mm, the calcium-based additive is quicklime with a particle size of -0.074 mm, and the composite organic binder is a mixture of molasses and sawdust with a particle size of -0.074 mm in a mass ratio of 60:40. After the above materials are fully mixed in a powerful mixer, they are sent into The molding equipment presses the solid fuel with a particle size of 3mm at 120°C. The obtained solid fuel is mixed with iron ore, dolomite, quicklime and return ore in a mass ratio of 3.12:75.96:2.32%:6.52:12.18. After mixing and granulation, it is distributed to the sintering trolley and ignited at a temperature of 1050±50°C and a negative pressure of -5kPa. The material surface in the ignition area accounts for 8.5%, and the entire sintering process is completed under a sintering negative pressure of -14kPa.

[0058] Example 3

[0059] The fine-grained fuel with a particle size of -0.5 mm is mixed with iron-containing solid waste, calcium-based additives, and composite organic binders in a weight ratio of 75:13:7:5, wherein the iron-containing solid waste is dust ash with a particle size of -0.074 mm, the calcium-based additive is quicklime with a particle size of -0.074 mm, and the composite organic binder is a mixture of molasses and sawdust with a particle size of -0.074 mm in a mass ratio of 30:70. After the above materials are fully mixed in a powerful mixer, they are sent into The molding equipment presses the solid fuel with a particle size of 3mm at 120°C. The obtained solid fuel is mixed with iron ore, dolomite, quicklime and return ore in a mass ratio of 3.12:75.96:2.32:6.52:12.18. After mixing and granulation, it is distributed to the sintering trolley and ignited at a temperature of 1050±50°C and a negative pressure of -5kPa. The material surface in the ignition area accounts for 8.5%, and the entire sintering process is completed under a sintering negative pressure of -14kPa.

[0060] Comparative Example 1

[0061] Fine-grained fuel with a particle size of -0.5 mm is mixed with iron ore, dolomite, quicklime and return ore in a mass ratio of 3.12:75.96:2.32:6.52:12.18, and distributed into a sintering trolley after mixing and granulation. It is ignited at a temperature of 1050±50°C and a negative pressure of -5kPa. The material surface in the ignition area accounts for 8.5%, and the entire sintering process is completed under a sintering negative pressure of -14kPa.

[0062] Comparative Example 2

[0063] The fine-grained fuel of -0.5mm particle size is fed into the molding equipment and pressed at low temperature. In the absence of additives, the fine-grained fuel is difficult to bond and mold, has a high breakage rate, and has extremely low strength.

[0064] Comparative Example 3

[0065] The fine-grained fuel with a particle size of -0.5mm is mixed with iron-containing solid waste and a composite organic binder in a weight ratio of 75:15:10, wherein the iron-containing solid waste is dust ash with a particle size of -0.074mm, and the composite organic binder is a mixture of molasses and sawdust with a particle size of -0.074mm in a mass ratio of 30:70. After the above materials are fully mixed in a strong mixer, they are sent to a molding device and pressed into a solid fuel with a particle size of 3mm at 120°C. The obtained solid fuel is mixed with iron ore, dolomite, quicklime and return ore in a mass ratio of 3.12:75.96:2.32:6.52:12.18, and after mixing and granulation, they are distributed in a sintering trolley, ignited at a temperature of 1050±50°C and a negative pressure of -5kPa, with the material surface in the ignition area accounting for 8.5%, and the entire sintering process is completed under a sintering negative pressure of -14kPa.

[0066] Comparative Example 4

[0067] The fine-grained fuel with a particle size of -0.5mm is mixed with a calcium-based additive and a composite organic binder in a weight ratio of 75:15:10, wherein the calcium-based additive is quicklime with a particle size of -0.074mm, and the composite organic binder is a mixture of molasses and sawdust with a particle size of -0.074mm in a mass ratio of 30%:70%. After the above materials are fully mixed in a strong mixer, they are sent to a molding device and pressed into a solid fuel with a particle size of 3mm at 120°C. The obtained solid fuel is mixed with iron ore, dolomite, quicklime and return ore in a mass ratio of 3.12:75.96:2.32:6.52:12.18, and after mixing and granulation, they are distributed in a sintering trolley, ignited at a temperature of 1050±50°C and a negative pressure of -5kPa, the material surface in the ignition area accounts for 8.5%, and the entire sintering process is completed under a sintering negative pressure of -14kPa.

[0068] Comparative Example 5

[0069] The fine-grained fuel with a particle size of -0.5mm and the composite organic binder are mixed in a weight ratio of 75:25, wherein the composite organic binder is a mixture of molasses and sawdust with a particle size of -0.074mm in a mass ratio of 30:70. After the above materials are fully mixed in a strong mixer, they are sent to a molding device and pressed into a solid fuel with a particle size of 3mm at 120°C. The obtained solid fuel is mixed with iron ore, dolomite, quicklime and return ore in a mass ratio of 3.12:75.96:2.32:6.52:12.18, and after mixing and granulation, they are distributed in a sintering trolley, ignited at a temperature of 1050±50°C and a negative pressure of -5kPa, the material surface in the ignition area accounts for 8.5%, and the entire sintering process is completed under a sintering negative pressure of -14kPa.

[0070] Comparative Example 6

[0071] The fine-grained fuel with a particle size of -0.5mm and the iron-containing solid waste are mixed in a weight ratio of 75:25, wherein the iron-containing solid waste is dust ash with a particle size of -0.074mm. The above materials are fully mixed in a strong mixer and then sent to a molding device to be pressed into a solid fuel with a particle size of 3mm at 120°C. The obtained solid fuel is mixed with iron ore, dolomite, quicklime and return ore in a mass ratio of 3.12:75.96:2.32:6.52:12.18, and after mixing and granulation, they are distributed to the sintering trolley and ignited at a temperature of 1050±50°C and a negative pressure of -5kPa. The material surface in the ignition area accounts for 8.5%, and the entire sintering process is completed under a sintering negative pressure of -14kPa.

[0072] Comparative Example 7

[0073] The fine-grained fuel with a particle size of -0.5mm and the calcium-based additive are mixed in a weight ratio of 75:25, wherein the calcium-based additive is quicklime with a particle size of -0.074mm. The above materials are fully mixed in a strong mixer and then sent to a molding device to be pressed into a solid fuel with a particle size of 3mm at 120°C. The obtained solid fuel is mixed with iron ore, dolomite, quicklime and return ore in a mass ratio of 3.12:75.96:2.32:6.52:12.18, and after mixing and granulation, they are distributed in a sintering trolley and ignited at a temperature of 1050±50°C and a negative pressure of -5kPa. The material surface in the ignition area accounts for 8.5%, and the entire sintering process is completed under a sintering negative pressure of -14kPa.

[0074] After sintering, the sintering indicators and pollutant emission reduction effects of Examples 1 to 3 and Comparative Examples 1 and 3 to 7 are shown in Table 1:

[0075] Table 1 Sintering indicators and pollutant emission reduction effects

[0076]

[0077] It can be seen from Table 1 that the solid fuel consumption of the embodiment is reduced and the pollutant emission reduction effect is better.

[0078] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0079] The preparation method of the pollution-reducing and carbon-reducing solid fuel provided by the embodiment of the present invention is simple, has a wide source of raw materials, is low in cost, and is conducive to industrial production.

[0080] The pollution-reducing and carbon-reducing solid fuel provided by the embodiment of the present invention has good sustainability during the combustion process, meets the requirements of sintering, and realizes the value-added utilization of fine-grained fuel.

[0081] 3. Efficient resource utilization and environmental friendliness: It realizes the resource utilization of iron-containing solid waste and calcium-containing solid waste, reduces solid waste emissions; reduces pollutant emissions during the sintering process, and has positive significance for environmental protection.

[0082] The above is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. It will be apparent to those skilled in the art that various modifications to these embodiments are possible, and the general principles defined in the present application can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown in the present application, but will conform to the widest scope consistent with the principles and novel features applied for by the present application.

Claims

1. A pollution-reducing and carbon-reducing solid fuel, wherein the raw materials of the solid fuel include, by weight: 70 to 85 parts of fine-grained fuel, 10 to 15 parts of iron-containing solid waste, 5 to 10 parts of calcium-based additives and 5 to 10 parts of composite organic binder.

2. The solid fuel according to claim 1, characterized in that The fine-grained fuel is at least one of fine-grained coal powder, fine-grained coke powder, and activated carbon powder; and / or, The fine-grained fuel has a particle size of -1 mm, wherein the mass of the fine-grained fuel with a particle size of -0.5 mm is not less than 70% of the total mass of the fine-grained fuel.

3. The solid fuel according to claim 1, characterized in that The iron-containing solid waste is at least one of dust removal ash, converter mud and gas ash; and / or, The mass of the iron-containing solid waste with a particle size of -0.074 mm is not less than 90% of the total mass of the iron-containing solid waste.

4. The solid fuel according to claim 1, characterized in that The calcium-based additive is at least one of quicklime, limestone and steel slag; and / or, The mass of the calcium-based additive with a particle size of -0.074 mm is not less than 90% of the total mass of the calcium-based additive.

5. The solid fuel according to claim 1, characterized in that The composite organic binder is composed of an organic binder and biomass powder; the mass m1 of the organic binder and the mass m2 of the biomass powder satisfy the relationship: m1:m2=(0-60):(40-100).

6. The solid fuel according to claim 5, characterized in that The organic binder is at least one of sodium carboxymethyl cellulose, molasses, humic acid, and sodium starch; and / or, The biomass powder is at least one of sawdust, crop straw, bagasse, and rice husk; and / or, The mass of the biomass powder with a particle size of -0.074 mm is not less than 95% of the total mass of the biomass powder.

7. The solid fuel according to claim 1, characterized in that The particle size of the solid fuel is 2 mm to 4 mm.

8. A method for preparing the solid fuel according to any one of claims 1 to 7, the method comprising: Mixing the fine-grained fuel, the iron-containing solid waste, the calcium-based additive and the composite organic binder according to the weight parts to obtain a mixture; The mixture is pressed and molded in a low temperature environment to obtain a solid fuel.

9. The method according to claim 8, characterized in that The temperature of the low temperature pressing is 100°C to 150°C.

10. Use of the solid fuel according to any one of claims 1 to 7, wherein the solid fuel is used for iron ore sintering.

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