All-solid waste high-alkalinity sintered ore and preparation method thereof

Abstract

The invention relates to all-solid-waste high-alkalinity sintered ore and a preparation method, and belongs to the technical field of sintering. The sintered ore comprises the following raw materials in parts by weight: 65-75 parts of high-iron solid waste, 8-13 parts of high-carbon solid waste, 10-15 parts of high-calcium solid waste and 8-12 parts of water. Complementation is realized by mixing different solid waste types, the iron source is provided by the high-iron solid waste, the fuel is replaced by the high-carbon solid waste, the alkalinity is adjusted by the high-calcium solid waste, the prepared sintered ore can meet the steelmaking requirement, and the comprehensive utilization rate of the metallurgical solid waste is greatly increased.

Description

Technical Field

[0001] This application relates to the field of sintering technology, and particularly relates to a fully solid waste high-alkalinity sintered ore and a preparation method thereof. Background Art

[0002] In the process of iron and steel metallurgy, a large amount of solid waste will be generated in processes such as coking, sintering, pelletizing, ironmaking, steelmaking, and rolling. The solid waste mainly includes metallurgical dust sludge, metallurgical slag, waste refractories, etc. Among them, the production points of metallurgical dust sludge solid waste are numerous and the components are complex. The output per ton of steel is about 60 - 70 kg. Some of the dust sludge can be recycled in sintering, and most of it is sold externally. With the improvement of the quality requirements of sintered ore for blast furnaces, the requirements for raw material alkali metals in sintering are also getting higher and higher, and the external sales ratio will continue to increase.

[0003] With the increasingly strict requirements of national environmental protection laws, local governments and all sectors of society have gradually begun to require that iron and steel enterprises should not simply sell solid waste externally, allowing solid waste that may cause pollution to flow into society. Instead, they hope that iron and steel enterprises will eliminate pollution sources within the enterprise, that is, "iron and steel solid waste does not leave the factory". "Iron and steel solid waste does not leave the factory" can not only prompt steel mills to make the most use of solid waste resources but also ensure that the local environment is not threatened by potential pollution from external solid waste. Metallurgical solid waste mainly includes elements such as Fe, C, Ca, and Mg. According to the element ratio, it can be divided into high-iron solid waste, high-carbon solid waste, high-calcium solid waste, etc., such as steelmaking dust removal ash, scale, ironmaking dust removal ash, coking dust removal ash, ironmaking raw material ash, steel slag powder, and slag iron powder. In addition to being recycled in the main process, the treatment methods mainly include rotary hearth furnace, rotary kiln, and flue gas melting furnace technologies, but they all have certain limitations, and the equipment occupies a large area and requires a large investment. Summary of the Invention

[0004] This application provides a fully solid waste high-alkalinity sintered ore and a preparation method thereof to solve the following technical problem: how to improve the utilization rate of metallurgical solid waste.

[0005] In a first aspect, an embodiment of this application provides a fully solid waste high-alkalinity sintered ore. In parts by weight, the raw materials of the sintered ore include: 65 - 75 parts of high-iron solid waste, 8 - 13 parts of high-carbon solid waste, 10 - 15 parts of high-calcium solid waste, and 8 - 12 parts of water.

[0006] Optionally, the high-iron solid waste is at least two of steelmaking dust removal ash, LT ash, dried OG sludge, scale, and ironmaking dust removal ash. The particle size of the high-iron solid waste ≤ 3 mm. In terms of mass fraction, the TFe content of the high-iron solid waste ≥ 60%.

[0007] Optionally, the high-carbon solid waste is at least two of coking dust removal ash, ironmaking raw material ash, and gas gravity ash. The particle size of the high-carbon solid waste ≤ 3 mm. In terms of mass fraction, the fixed carbon content of the high-carbon solid waste ≥ 30%.

[0008] Optionally, the high-calcium solid waste is at least two of white lime sleeve kiln dust, slag steel powder, slag iron powder, and refining slag. The particle size of the high-calcium solid waste is ≤ 10 mm, and in terms of mass fraction, the calcium oxide content of the high-calcium solid waste is ≥ 50%.

[0009] Optionally, the sintered ore satisfies at least one of the following properties:

[0010] The drum index > 80%;

[0011] The binary basicity is 3.5 - 4.5;

[0012] In terms of mass fraction, the TFe content ≥ 55%;

[0013] In terms of mass fraction, the calcium ferrite content is 30% - 40%.

[0014] Optionally, the particle size of the sintered ore is 15 mm - 45 mm.

[0015] In a second aspect, an embodiment of the present application provides a method for preparing the sintered ore described in the first aspect. The method includes:

[0016] Mix the high-iron solid waste, the high-carbon solid waste, the high-calcium solid waste, and the water according to the weight parts to obtain a first mixture;

[0017] Granulate the first mixture to obtain a second mixture;

[0018] Perform feeding, ignition, and sintering on the second mixture in sequence to obtain a hot-state all-solid waste high-alkalinity sintered ore;

[0019] Cool, crush, and screen the hot-state all-solid waste high-alkalinity sintered ore in sequence to obtain a finished all-solid waste high-alkalinity sintered ore.

[0020] Optionally, the mass of the second mixture with a particle size less than 3 mm is 30% - 40% of the total mass of the second mixture, the mass of the second mixture with a particle size of 3 mm - 5 mm is 20% - 30% of the total mass of the second mixture, and the mass of the second mixture with a particle size greater than 5 mm is 30% - 40% of the total mass of the second mixture.

[0021] Optionally, the thickness of the feeding is 800 mm - 850 mm.

[0022] Optionally, the temperature of the sintering is 1150°C - 1250°C, and the vertical sintering speed of the sintering is 22 mm / min - 28 mm / min.

[0023] The above technical solutions provided by the embodiments of the present application have the following advantages compared with the prior art:

[0024] The present application provides a fully solid waste high-alkalinity sintered ore. In parts by weight, the raw materials of the sintered ore include: 65 to 75 parts of high-iron solid waste, 8 to 13 parts of high-carbon solid waste, 10 to 15 parts of high-calcium solid waste, and 8 to 12 parts of water. By mixing different types of solid waste to achieve complementarity, the high-iron solid waste provides an iron source, the high-carbon solid waste replaces fuel, and the high-calcium solid waste adjusts the alkalinity. The prepared sintered ore can meet the requirements of steelmaking, and the comprehensive utilization rate of metallurgical solid waste is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings herein are incorporated into and constitute a part of this specification, showing embodiments consistent with the present application, and together with the specification are used to explain the principles of the present application.

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 It is a schematic flow chart of a method for preparing a fully solid waste high-alkalinity sintered ore provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present application.

[0029] The various embodiments of the present application may exist 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 construed 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 individual values within that 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., and individual numbers within that range, such as 1, 2, 3, 4, 5, and 6, regardless of the range; additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0030] In this text, terms including "comprising" and the like mean "including but not limited to". Relative 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 and indicates that there can be three relationships. For example, A and / or B can represent the cases of A existing alone, A and B existing simultaneously, and B existing alone; where A and B can be singular or plural. "At least one" means one or more, and "a plurality" means two or more; "at least one kind", "at least one of the following items" or similar expressions refer to any combination of these items, including any combination of single items or plural items; for example, "at least one of a, b, or c", or, "at least one of a, b, and c" can both represent: a, b, c, a-b (that is, a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or plural respectively. The "parts representation method" such as parts by weight and parts by mass represents the proportional relationship between each component. In the proportional relationships involved in this text, the parameters that need to be described by the ratio should be understood as the antecedents of the ratio formula in the order of description, and the ratio numbers should be understood as the consequents of the ratio formula. For example, if the mass ratio of substance A, substance B, and substance C is 1:2:3, then substance A, substance B, and substance C should correspond one by one with the ratio numbers in the ratio formula in the order of description, that is, the mass of substance A: the mass of substance B: the mass of substance C = 1:2:3.

[0031] Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment, etc. used in this text can be obtained through market purchase or can be prepared by existing methods.

[0032] In a first aspect, an embodiment of the present application provides a fully solid waste high-alkalinity sintered ore. Calculated by weight, the raw materials of the sintered ore include: 65 parts to 75 parts of high-iron solid waste, 8 parts to 13 parts of high-carbon solid waste, 10 parts to 15 parts of high-calcium solid waste, and 8 parts to 12 parts of water.

[0033] The high-iron solid waste is used as the main iron source of the sintered ore, and the weight part range of the high-iron solid waste is between 65 parts and 75 parts. The setting of this range aims to ensure that the sintered ore has sufficient iron content to meet the iron element requirements in the steelmaking process. At the same time, the utilization of high-iron solid waste also helps to reduce the mining of natural iron ore and achieve the recycling of resources. Exemplarily, the weight parts of the high-iron solid waste can be 65 parts, 67 parts, 69 parts, 71 parts, 73 parts, 75 parts, etc.

[0034] As an energy source in the sintering process, the high-carbon solid waste has a weight fraction range between 8 parts and 13 parts. This weight fraction of high-carbon solid waste can meet the heat demand in the sintering process, causing partial melting and agglomeration of mineral particles in the mixture, thereby improving the strength of the sinter. In addition, the utilization of high-carbon solid waste also reduces the dependence on traditional high-cost fuels such as coke, further reducing production costs. Exemplarily, the weight fraction of high-carbon solid waste can be 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, etc.

[0035] As a flux for the sinter, the high-calcium solid waste has a weight fraction range between 10 parts and 15 parts. This weight fraction range helps to promote the formation of liquid phase and optimize the mineral phase, increasing the calcium ferrite ratio and drum strength of the sinter. At the same time, the utilization of high-calcium solid waste also reduces the use of traditional fluxes such as lime, which is beneficial to environmental protection. Exemplarily, the weight fraction of high-calcium solid waste can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, etc.

[0036] As a wetting agent and regulator in the sintering process, water has a weight fraction range between 8 parts and 12 parts, which helps to form small balls of fine-grained materials through capillary force and surface tension, enhancing the binding force between particles and reducing raw material segregation. In addition, it can also play a role in regulating the temperature distribution and combustion efficiency, improving the output and quality of the sinter. Exemplarily, the weight fraction of water can be 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, etc.

[0037] This application realizes the recycling of resources and the goal of energy conservation and emission reduction by reasonably utilizing metallurgical solid wastes such as high-iron solid waste, high-carbon solid waste, and high-calcium solid waste. This not only helps to reduce environmental pollution, but also reduces production costs and improves the economic benefits of enterprises.

[0038] In some embodiments, the high-iron solid waste is at least two of steelmaking dedusting ash, LT ash, dried OG sludge, scale, and ironmaking dedusting ash. The particle size of the high-iron solid waste ≤ 3 mm, and in terms of mass fraction, the TFe content of the high-iron solid waste ≥ 60%.

[0039] The high-iron solid wastes adopted in the embodiments of the present application are at least two of steelmaking dedusting ash, LT ash, dried OG sludge, mill scale, and ironmaking dedusting ash. These solid wastes all come from the iron and steel metallurgy process and contain rich iron elements, making them ideal raw materials for preparing high-alkali sinter. To ensure the uniform distribution and good pelletizing effect of the high-iron solid wastes during the sintering process, the embodiments of the present application put forward clear requirements for the particle size of the high-iron solid wastes, that is, the particle size needs to be ≤ 3 mm. The setting of this particle size range helps the full mixing of the high-iron solid wastes with other raw materials, improving the density and strength of the sinter. At the same time, the particle size of ≤ 3 mm can also increase the contact area between the high-iron solid wastes and the sintering atmosphere, which is beneficial to the formation of the bonding phase. In terms of mass fraction, the content of iron element (TFe) in the high-iron solid wastes required by the embodiments of the present application is ≥ 60%. This requirement for the iron content ensures the sufficient supply of iron element in the sinter, improving the grade of the sinter and the recovery rate of iron element in the steelmaking process. At the same time, this requirement for the iron content of the high-iron solid wastes also helps to reduce the usage amount of natural iron ore, further reducing the production cost and environmental burden. Exemplarily, the TFe content of the high-iron solid wastes can be 60%, 61%, 62%, 63%, 64%, 65%, etc.

[0040] In some embodiments, the high-carbon solid wastes are at least two of coking dedusting ash, ironmaking raw material ash, and gas gravity ash. The particle size of the high-carbon solid wastes is ≤ 3 mm. In terms of mass fraction, the fixed carbon content of the high-carbon solid wastes is ≥ 30%.

[0041] The high-carbon solid wastes involved in the embodiments of the present application mainly include coking dust, iron-making raw material ash, and gas gravity ash. These solid wastes all originate from the steel metallurgy and coking processes, contain rich carbon elements, and are indispensable fuels in the sintering process. In practical applications, at least two of them can be selected for mixed use according to the supply situation of raw materials, cost, and required carbon content to achieve the best sintering effect and sintered ore performance. To ensure the uniform distribution and effective heat supply of high-carbon solid wastes in the sintering process, the embodiments of the present application put forward clear requirements for the particle size of high-carbon solid wastes, that is, the particle size needs to be ≤ 3 mm. The setting of this particle size range helps the full mixing of high-carbon solid wastes with other raw materials, improving the uniformity and air permeability of the sintering material. At the same time, the particle size of ≤ 3 mm can also increase the contact area between high-carbon solid wastes and the sintering atmosphere, promoting the full combustion of carbon elements. In terms of mass fraction, the content of fixed carbon in the high-carbon solid wastes required by the embodiments of the present application needs to be ≥ 30%. Fixed carbon is an important index to measure the calorific value of high-carbon solid wastes. The higher its content, the stronger the combustion heat release ability of high-carbon solid wastes. In the sintering process, a fixed carbon content of ≥ 30% can ensure the generation of sufficient bonding phase in the sintered ore, improving the drum strength and finished product rate of the sintered ore. At the same time, high-carbon solid wastes with a fixed carbon content of ≥ 30% can also reduce the dependence on traditional high-cost raw materials such as coke, further reducing production costs and environmental burdens. Exemplarily, the fixed carbon content of high-carbon solid wastes can be 30%, 31%, 32%, 33%, 34%, 35%, etc.

[0042] In some embodiments, the high-calcium solid waste is at least two of white lime sleeve kiln dust, steel slag powder, iron slag powder, and refining slag. The particle size of the high-calcium solid waste is ≤ 10 mm. In terms of mass fraction, the calcium oxide content of the high-calcium solid waste is ≥ 50%.

[0043] The high-calcium solid wastes involved in the embodiments of the present application mainly include dust from lime sleeve kiln, slag steel powder, slag iron powder and refining slag. These solid wastes all come from the iron and steel metallurgy process, contain rich calcium elements, and are ideal fluxes for preparing high-alkali sinter. In practical applications, at least two of them can be selected and mixed according to the supply situation of raw materials, cost and required calcium content to achieve the best liquid phase generation amount. To ensure the uniform distribution and effective melting of high-calcium solid wastes during sintering, the embodiments of the present application put forward clear requirements for the particle size of high-calcium solid wastes, that is, the particle size needs to be ≤ 10 mm. The setting of this particle size range helps the full mixing of high-calcium solid wastes with other raw materials, improving the uniformity and air permeability of the sintering material. At the same time, the particle size of ≤ 10 mm can also increase the contact area between high-calcium solid wastes and the sintering atmosphere, promoting the full melting of calcium elements and the formation of calcium ferrite. In terms of mass fraction, the calcium oxide content in the high-calcium solid wastes required by the embodiments of the present application needs to be ≥ 50%. Calcium oxide is an important index to measure the fluxing ability of high-calcium solid wastes. The higher its content, the stronger the fluxing ability of high-calcium solid wastes. During sintering, a calcium oxide content of ≥ 50% can ensure that the sinter has a high alkalinity, thereby increasing the proportion of calcium ferrite and drum strength of the sinter. At the same time, high-calcium solid wastes with a calcium oxide content of ≥ 50% can also reduce the usage amount of traditional fluxes such as lime, further reducing production costs and environmental burdens. Exemplarily, the calcium oxide content of high-calcium solid wastes can be 50%, 51%, 52%, 53%, 54%, 55%, etc.

[0044] In some embodiments, the sinter satisfies at least one of the following properties:

[0045] Drum index > 80%;

[0046] Binary basicity is 3.5 - 4.5;

[0047] In terms of mass fraction, the TFe content ≥ 55%;

[0048] In terms of mass fraction, the calcium ferrite content is 30% - 40%.

[0049] The drum index is an important index to measure the anti-breakage ability of the sinter. The drum index of the all-solid waste high-alkali sinter prepared in the embodiments of the present application is greater than 80%. This means that the sinter can maintain a high integrity when subjected to external force impact, is not easily broken, and avoids generating a large amount of powder during the transfer process, affecting the batching and feeding.

[0050] The binary basicity is an important indicator for measuring the content of basic oxides in sinter. It is expressed by the ratio of CaO / SiO2. The binary basicity of the all-solid waste high-basicity sinter prepared in the embodiments of the present application is between 3.5 and 4.5. The binary basicity within this range helps to form a stable sinter structure, increase the proportion of calcium ferrite and drum strength of the sinter. At the same time, the binary basicity between 3.5 and 4.5 can also promote the dephosphorization reaction during the steelmaking process and improve the quality of molten steel.

[0051] The content of TFe (total iron) is an important indicator for measuring the iron element content in sinter. The TFe content of the all-solid waste high-basicity sinter prepared in the embodiments of the present application is ≥55%. This content means that the sinter is rich in iron elements, which helps to improve the recovery rate of iron elements during the steelmaking process and reduce production costs.

[0052] Calcium ferrite is an important mineral phase in sinter and has an important influence on the metallurgical properties of sinter. The calcium ferrite content of the all-solid waste high-basicity sinter prepared in the embodiments of the present application is between 30% and 40%. This content helps to improve the drum strength of the sinter and is also beneficial to the dephosphorization reaction during the steelmaking process.

[0053] In some embodiments, the particle size of the sinter is 15mm - 45mm.

[0054] The particle size requirement of the all-solid waste high-basicity sinter prepared in the embodiments of the present application is between 15mm and 45mm. The particle size within this range helps to ensure the rapid melting and dephosphorization efficiency of the sinter in the steelmaking furnace, improve the steelmaking efficiency and the quality of molten steel. When the particle size is less than 15mm, it is easily carried away by the dust removal system during the batching process. When the particle size is greater than 45mm, the melting speed slows down after batching, affecting the steelmaking blowing time. Exemplarily, the particle size of the sinter can be 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, etc.

[0055] Figure 1 It is a schematic flow chart of a preparation method of an all-solid waste high-basicity sinter provided by the embodiments of the present application.

[0056] Please refer to Figure 1 , Second, the embodiments of the present application provide a preparation method of the sinter described in the first aspect, and the method includes:

[0057] S1. According to the weight parts, mix the high-iron solid waste, the high-carbon solid waste, the high-calcium solid waste and the water to obtain a first mixture;

[0058] S2. Granulate the first mixture to obtain a second mixture;

[0059] In some embodiments, the mass of the second mixture with a particle size less than 3 mm is 30% - 40% of the total mass of the second mixture, the mass of the second mixture with a particle size of 3 mm - 5 mm is 20% - 30% of the total mass of the second mixture, and the mass of the second mixture with a particle size greater than 5 mm is 30% - 40% of the total mass of the second mixture.

[0060] A reasonable particle size distribution helps to improve the gas permeability and uniformity of the sinter, and promotes gas exchange and heat transfer during the sintering process. At the same time, raw materials with different particle sizes can form a stable skeleton structure during the sintering process, improving the strength and anti-crushing properties of the sinter. In addition, a reasonable particle size distribution can also optimize the pore structure of the sinter, improving the rapid slag formation and dephosphorization efficiency of the sinter.

[0061] The second mixture with a particle size less than 3 mm helps to increase the specific surface area of the sintering material and improve the reaction rate during the sintering process. In the embodiments of the present application, the mass of the second mixture with a particle size less than 3 mm accounts for 30% - 40% of the total mass of the second mixture. The mass ratio within this range can ensure that there is enough fine-grained material in the sintering material, promoting gas exchange and heat transfer during the sintering process.

[0062] The second mixture with a particle size of 3 mm - 5 mm can both maintain good gas permeability and provide a certain skeleton support effect. In the embodiments of the present application, the mass of the second mixture with a particle size of 3 mm - 5 mm accounts for 20% - 30% of the total mass of the second mixture. The mass ratio within this range helps to form a stable sinter structure, improving the strength and yield of the sinter.

[0063] The second mixture with a particle size greater than 5 mm mainly plays a role in skeleton support and increasing the density of the sinter. In the embodiments of the present application, the mass of the second mixture with a particle size greater than 5 mm accounts for 30% - 40% of the total mass of the second mixture. The mass ratio within this range can ensure that there is enough coarse-grained material in the sinter, improving the drum strength of the sinter.

[0064] S3. Sequentially perform feeding, ignition, and sintering on the second mixture to obtain a hot-state fully solid waste high-alkali sinter.

[0065] In some embodiments, the thickness of the feeding is 800 mm - 850 mm.

[0066] A reasonable cloth thickness helps to optimize the air permeability of the sintering material, enabling air to smoothly pass through the material layer and providing sufficient oxygen for combustion and reactions during the sintering process. This helps to increase the sintering rate and the quality of the sinter. The reasonable setting of the cloth thickness can also ensure the uniform transfer of heat in the sintering material layer, which helps to avoid local overheating or overcooling, thereby improving the uniformity and quality stability of the sinter. In the embodiments of the present application, the cloth thickness of the all-solid-waste high-alkali sinter is set between 800 mm and 850 mm. This range of cloth thickness is designed to ensure that gas can uniformly and efficiently penetrate the material layer during the sintering process, achieving sufficient combustion and reactions. Exemplarily, the thickness of the cloth can be 800 mm, 810 mm, 820 mm, 830 mm, 840 mm, 850 mm, etc.

[0067] In some embodiments, the temperature of the sintering is 1150°C to 1250°C, and the vertical sintering speed of the sintering is 22 mm / min to 28 mm / min.

[0068] In the embodiments of the present application, the sintering temperature of the all-solid-waste high-alkali sinter is set between 1150°C and 1250°C. Within this temperature range, the minerals in the raw materials can be fully melted and reacted to form a stable sinter structure. At the same time, the sintering temperature of 1150°C to 1250°C can also ensure that sufficient bonding phase is generated in the sinter, improving the drum strength of the sinter. Exemplarily, the sintering temperature can be 1150°C, 1170°C, 1190°C, 1210°C, 1230°C, 1250°C, etc.

[0069] The vertical sintering speed refers to the sintering speed of the sintering material layer in the vertical direction. In the embodiments of the present application, the vertical sintering speed of the all-solid-waste high-alkali sinter is set between 22 mm / min and 28 mm / min. The selection of this speed range is designed to ensure that the sintering process can proceed smoothly and efficiently. Within this speed range, the sintering material layer can be fully preheated, melted, and solidified to form high-quality sinter. Exemplarily, the vertical sintering speed of the sintering can be 22 mm / min, 23 mm / min, 24 mm / min, 25 mm / min, 26 mm / min, 27 mm / min, 28 mm / min, etc.

[0070] S4. Cool, crush, and screen the hot all-solid-waste high-alkali sinter in sequence to obtain the finished all-solid-waste high-alkali sinter.

[0071] The embodiments of this application use metallurgical solid wastes containing iron, carbon, and calcium as raw materials, and prepare a fully solid-waste high-alkalinity sintered ore through processes such as mixing, sintering, cooling, and crushing. It can be used as a steelmaking cooling and dephosphorizing agent, and can be realized by using the existing equipment in the sintering process, with little impact on the flue gas desulfurization system in the sintering process. It realizes the collaborative resource utilization of various types of metallurgical solid wastes such as those containing iron, carbon, and calcium, gives full play to the utilization of valuable elements in each raw material, reduces the use of resources such as natural iron ore, lime, and coke, reduces energy consumption, and significantly reduces the production raw material cost. It also reduces the carbon dioxide emissions during iron ore mining and lime and coke production. The prepared high-alkalinity sintered ore can meet the requirements of steelmaking cooling and dephosphorization.

[0072] The preparation product of the preparation method of this fully solid-waste high-alkalinity sintered ore is the above-mentioned fully solid-waste high-alkalinity sintered ore. Since the preparation method of this fully solid-waste high-alkalinity sintered ore adopts some or all of the technical solutions of the embodiments of the fully solid-waste high-alkalinity sintered ore, it at least has all the beneficial effects brought by the technical solutions of the embodiments of the fully solid-waste high-alkalinity sintered ore, which will not be elaborated one by one here.

[0073] The following combines specific embodiments to further elaborate this application. For the experimental methods without specific conditions noted in the following embodiments, they are usually determined in accordance with national standards / industry standards; if there are no corresponding national standards / industry standards, they are carried out in accordance with general international standards, conventional conditions, or the conditions recommended by the manufacturer.

[0074] Example 1:

[0075] A fully solid-waste high-alkalinity sintered ore, in parts by weight, includes the following components: 65 parts of high-iron solid waste, 8 parts of high-carbon solid waste, 15 parts of high-calcium solid waste, and 12 parts of water. The high-iron solid waste includes steelmaking dust, LT ash, dried OG sludge, and scale, with a particle size ≤ 3 mm and a total iron content of 65%; the high-carbon solid waste includes coking dust, ironmaking raw material ash, and gas gravity ash, with a particle size ≤ 3 mm and a fixed carbon content of 33%; the high-calcium solid waste includes white lime sleeve kiln dust and slag steel powder, with a particle size ≤ 10 mm and a calcium oxide content of 54%.

[0076] A preparation method of a fully solid-waste high-alkalinity sintered ore specifically includes: mixing the high-iron solid waste, the high-carbon solid waste, the high-calcium solid waste, and the water according to the above parts by weight to obtain a first mixture; granulating the first mixture to obtain a second mixture; sequentially carrying out feeding, ignition, and sintering on the second mixture to obtain a hot fully solid-waste high-alkalinity sintered ore; sequentially carrying out cooling, crushing, and screening on the hot fully solid-waste high-alkalinity sintered ore to obtain a finished fully solid-waste high-alkalinity sintered ore.

[0077] The proportion of the second mixture with a particle size less than 3 mm is 38%, the proportion with a particle size of 3 mm - 5 mm is 28%, and the proportion with a particle size greater than 5 mm is 34%; the cloth thickness is 800 mm; the sintering temperature is 1150 °C, and the vertical sintering speed is 22 mm / min.

[0078] Example 2

[0079] Comparing Example 2 with Example 1, the differences between Example 2 and Example 1 are as follows:

[0080] By weight, the all-solid-waste high-alkalinity sinter includes the following components: 69 parts of high-iron solid waste, 13 parts of high-carbon solid waste, 10 parts of high-calcium solid waste, and 8 parts of water. The high-iron solid waste includes steelmaking dust, LT ash, mill scale, and ironmaking dust, with a particle size ≤ 3 mm and a total iron content of 63%; the high-carbon solid waste includes coking dust, ironmaking raw material ash, and gas gravity ash, with a particle size ≤ 3 mm and a fixed carbon content of 32%; the high-calcium solid waste includes white lime shaft kiln dust, slag iron powder, and refining slag, with a particle size ≤ 10 mm and a calcium content (calculated as calcium oxide) of 53%.

[0081] The proportion of the second mixture with a particle size less than 3 mm is 36%, the proportion with a particle size of 3 mm - 5 mm is 26%, and the proportion with a particle size greater than 5 mm is 38%; the cloth thickness is 850 mm; the sintering temperature is 1250 °C, and the vertical sintering speed is 28 mm / min.

[0082] Example 3

[0083] Comparing Example 3 with Example 1, the differences between Example 3 and Example 1 are as follows:

[0084] By weight, the all-solid-waste high-alkalinity sinter includes the following components: 75 parts of high-iron solid waste, 11 parts of high-carbon solid waste, 13 parts of high-calcium solid waste, and 11 parts of water. The high-iron solid waste includes steelmaking dust, LT ash, mill scale, and ironmaking dust, with a particle size ≤ 3 mm and a total iron content of 65%; the high-carbon solid waste includes coking dust, ironmaking raw material ash, and gas gravity ash, with a particle size ≤ 3 mm and a fixed carbon content of 34%; the high-calcium solid waste includes white lime shaft kiln dust, slag iron powder, and refining slag, with a particle size ≤ 10 mm and a calcium content (calculated as calcium oxide) of 52%.

[0085] The proportion of the second mixture with a particle size less than 3 mm is 37%, the proportion with a particle size of 3 mm - 5 mm is 27%, and the proportion with a particle size greater than 5 mm is 36%; the cloth thickness is 830 mm; the sintering temperature is 1200 °C, and the vertical sintering speed is 25 mm / min.

[0086] Comparative Example 1

[0087] Comparing Comparative Example 1 with Example 1, the differences between Comparative Example 1 and Example 1 are as follows:

[0088] On a parts-by-weight basis, the all-solid waste high-alkalinity sinter includes the following components: 78 parts of high-iron solid waste, 4 parts of high-carbon solid waste, 6 parts of high-calcium solid waste, and 12 parts of water.

[0089] Comparative Example 2

[0090] Comparing Comparative Example 2 with Example 1, the differences between Comparative Example 2 and Example 1 are as follows:

[0091] On a parts-by-weight basis, the all-solid waste high-alkalinity sinter includes the following components: 55 parts of high-iron solid waste, 15 parts of high-carbon solid waste, 16 parts of high-calcium solid waste, and 14 parts of water.

[0092] Perform performance tests on the all-solid waste high-alkalinity sinter obtained in the examples and comparative examples according to the standard requirements. The test results are shown in Table 1.

[0093] Method for determining the drum index: Take 20 kg of the finished sinter, load it into the drum, rotate it at a speed of 25 revolutions per minute for 4 minutes, and then pour the sample onto a mechanical sieve with a 5-mm square hole and sieve it back and forth 10 times. The percentage of the sample weighing more than 5 mm on the sieve is the drum index. Method for testing the binary alkalinity: Use X-ray fluorescence spectroscopy to detect the mass percentage of calcium oxide and silicon dioxide in the material. The TFe content reflects the iron grade of the sinter and is detected by the titration method after reduction with titanium trichloride. The calcium ferrite content is observed and counted by the structural morphology of the ore microscope.

[0094] Table 1

[0095] Group Drum index (%) Binary basicity TFe content (%) Calcium ferrite content (%) Example 1 82.4 4.4 56.8 38 Example 2 88.7 3.6 60.4 32 Example 3 86.1 4.0 62.3 34 Comparative Example 1 54 2.6 67.3 14 Comparative Example 2 47 5.0 51.1 28

[0096] As can be seen from Table 1, the drum indexes of the all-solid waste high-alkalinity sinter provided in the examples all reach more than 80%, the TFe content reaches more than 55%, the binary alkalinity is in the range of 3.5 - 4.5, and the calcium ferrite content reaches 30% - 40%, which can be used as a dephosphorizing agent for steelmaking. In Comparative Example 1, the proportion of carbon-containing solid waste added is too small to provide enough heat. In addition, the alkalinity is low, and both make it impossible to form enough calcium ferrite bonding phase, resulting in a significant decrease in the drum strength of the sinter. In Comparative Example 2, the proportion of calcium-containing solid waste added is too large, the alkalinity increases significantly, and the excessive flux is not completely reacted, resulting in a loose structure of the sinter and a significant reduction in the drum strength.

[0097] One or more technical solutions in the embodiments of the present invention at least further have the following technical effects or advantages:

[0098] During the preparation process of the sinter in the embodiments of the present invention, the impact on the sintering flue gas desulfurization system is small, which is beneficial to reducing the emission of harmful gases such as sulfur dioxide.

[0099] By reducing the use of resources such as natural iron ore, lime, and coke in the embodiments of the present invention, it helps to reduce carbon emissions and achieve green production.

[0100] The embodiments of the present invention directly utilize the existing sintering machine equipment without adding new devices, reducing the transformation cost.

[0101] The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art. 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 claimed in the present application.

Claims

1. A fully solid waste high-alkalinity sinter, by weight, the raw materials of the sinter include: 65 to 75 parts of high-iron solid waste, 8 to 13 parts of high-carbon solid waste, 10 to 15 parts of high-calcium solid waste, and 8 to 12 parts of water.

2. The sintered ore according to claim 1, characterized in that, The high-iron solid waste is at least two of steelmaking dedusting ash, LT ash, dried OG sludge, scale, and ironmaking dedusting ash. The particle size of the high-iron solid waste is ≤ 3 mm. In terms of mass fraction, the TFe content of the high-iron solid waste is ≥ 60%.

3. The sintered ore according to claim 1, characterized in that, The high-carbon solid waste is at least two of coking dedusting ash, ironmaking raw material ash, and gas gravity ash. The particle size of the high-carbon solid waste is ≤ 3 mm. In terms of mass fraction, the fixed carbon content of the high-carbon solid waste is ≥ 30%.

4. The sintered ore according to claim 1, wherein, The high-calcium solid waste is at least two of white lime shaft kiln dedusting ash, steel slag powder, slag iron powder, and refining slag. The particle size of the high-calcium solid waste is ≤ 10 mm. In terms of mass fraction, the calcium oxide content of the high-calcium solid waste is ≥ 50%.

5. The sintered ore according to claim 1, wherein, The sintered ore meets at least one of the following properties: The drum index > 80%; The binary basicity is 3.5 to 4.5; In terms of mass fraction, the TFe content is ≥ 55%; In terms of mass fraction, the calcium ferrite content is 30% to 40%.

6. The sintered ore according to claim 1, wherein, The particle size of the sintered ore is 15 mm to 45 mm.

7. A method for preparing sintered ore according to any one of claims 1 to 6, characterized in that The method includes: Mix the high-iron solid waste, the high-carbon solid waste, the high-calcium solid waste, and the water according to the above weight parts to obtain a first mixture. Granulate the first mixture to obtain a second mixture. Charge, ignite, and sinter the second mixture in sequence to obtain a hot-state fully solid waste high-alkalinity sintered ore. Cool, crush, and screen the hot-state fully solid waste high-alkalinity sintered ore in sequence to obtain a finished fully solid waste high-alkalinity sintered ore.

8. The method according to claim 7, wherein The mass of the second mixture with a particle size less than 3 mm is 30% to 40% of the total mass of the second mixture. The mass of the second mixture with a particle size of 3 mm to 5 mm is 20% to 30% of the total mass of the second mixture. The mass of the second mixture with a particle size greater than 5 mm is 30% to 40% of the total mass of the second mixture.

9. The method according to claim 7, characterized in that, The thickness of the charging is 800 mm to 850 mm.

10. The method according to claim 7, characterized in that The sintering temperature is 1150 °C to 1250 °C, and the vertical sintering speed of the sintering is 22 mm / min to 28 mm / min.

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