Method for preparing sintered ore through long-process multi-element solid waste resource cyclic utilization

Abstract

The invention relates to the technical field of solid waste recycling, in particular to a method for preparing sintered ore through long-process multi-element solid waste resource cyclic utilization. The method comprises the following steps: uniformly mixing fly ash, iron oxide powder and sludge according to a certain proportion to obtain metallurgical dust sludge; metallurgy dust and mud and iron ore powder are blended according to a certain proportion, mixed evenly and piled, and evenly-mixed ore is obtained; the uniformly mixed ore, the steel slag tailings, the oxide scale, the dust-removed coke powder, the flux and the return ore are mixed according to a certain proportion, water is added, the mixture is uniformly mixed and granulated to obtain a sintering mixture, and the sintering ore is obtained through material distribution, ignition, sintering, crushing and cooling. According to the method, various solid wastes containing iron, calcium and carbon generated in the steel smelting and rolling process serve as sintering raw materials to be put into production again through process reconstruction, and resource recycling of solid waste resources in enterprises is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste resource utilization, and particularly relates to a method for recycling and preparing sinter ore from long-process multi-component solid waste resources. Background Art

[0002] A large amount of iron-containing, calcium-containing, and carbon-containing waste is generated during the iron and steel smelting and rolling processes, including various process and environmental dusts, gas ash (mud), water treatment sludge, steel slag, scale, and dust coke powder and other solid waste resources. These resources can be returned to the production process due to their high iron, calcium, or carbon content, and used as sintering raw materials to produce sinter ore, and then remelted to obtain hot metal, realizing resource recycling.

[0003] The return of metallurgical solid waste resources to sintering for preparing sinter ore has been applied in different forms and degrees in the iron and steel industry, including the return of steel slag to sintering, the return and utilization of rolling scale to sintering, etc. However, there are few applications of simultaneously using iron-containing, carbon-containing, and calcium-containing solid wastes in sintering production under certain proportions and addition methods, and there is no reported technology on how to rationally use metallurgical solid waste to both maximize the recovery of metallurgical solid waste resources and effectively improve the quality of sinter ore.

[0004] The patent "Method for Preparing Sinter Ore by Using Rolling Scale and Sinter Ore Prepared Thereby" with the application number 201910502677.8 describes a method for preparing sinter ore by using rolling scale and the prepared sinter ore. The method includes raw material batching according to the following mass percentage content: rolling scale 1% - 5%, iron ore powder A 10% - 25%, iron ore powder B 8% - 30%, iron ore powder C 0% - 15%, iron concentrate D 15 - 35%, steel slag powder 2.0% - 5.0%, limestone 4.0% - 8.0%, dolomite 3.0% - 6.0%, quicklime 1.0% - 3.5%, coke powder 2.0% - 7.0%, and return ore 8.0% - 13.0%; granulating the raw materials after adding water to obtain a mixture; and sintering the mixture to obtain sinter ore. This method only designs the ratio and method for using rolling scale to prepare sinter ore, without considering the raw material ratio and production process of simultaneously returning multiple solid waste resources to sintering for utilization.

[0005] The patent "A Method for Preparing Sintered Ore from Steel Slag Tailings after Extracting CaO" with the application number 202211566756.3 is characterized in that it describes a method for preparing sintered ore from steel slag tailings after extracting CaO. The raw materials are proportioned according to the following mass percentages: 0% - 8% of steel slag tailings, 35% - 55% of iron concentrate A, 30% - 55% of iron ore powder B, 3% - 20% of iron ore powder C, 1.0% - 8.0% of scale, 2.0% - 8.0% of limestone, 1.0% - 5.0% of quicklime, 2.0% - 8.0% of coke powder, and 5.0% - 20.0% of blast furnace return ore; the raw materials are mixed with water and granulated to obtain a mixed material; the mixed material is sintered to obtain sintered ore. This invention only designs the proportioning and method for using steel slag tailings after extracting CaO to prepare sintered ore, without considering the raw material proportioning and production process for simultaneously recycling multiple solid waste resources in sintering.

[0006] The patent "A Method for Preparing Sintered Ore from Converter Steel Slag Tailings" with the application number 202310742413.6 includes preparing raw materials: the raw materials include iron materials and batching. Among them, the iron materials, by mass percentage, include: 40 - 50% of low-silicon high-grade iron concentrate, 30 - 40% of Australian MAC powder, and 10 - 20% of Australian FMG mixed powder; the batching, calculated based on the mass of the iron materials, includes: 2 - 3% of steel slag tailings in the iron materials, 3 - 4% of dolomite powder in the iron materials, 7 - 9% of limestone in the iron materials, and 5 - 6% of coke powder in the iron materials; the iron materials and the batching are mixed and granulated in a granulator to obtain mixed granules; the time control for the granulation process is 4 - 6 minutes; the mixed granules are loaded into a sintering device through a feeding device and undergo the processes of ignition, sintering, and cooling by a sintering machine, and finally sintered ore is obtained. This invention's solution only designs the proportioning and method for using converter steel slag tailings to prepare sintered ore, without considering the raw material proportioning and production process for simultaneously recycling multiple solid waste resources in sintering.

[0007] The patent "A Method for Recycling Converter Steel Slag Tailings in Sintering" with the application number 202310695439.X is characterized by describing a method for recycling converter steel slag tailings in sintering. The steel slag tailings with a particle size range of 0 - 10 mm are air-dried for 5 - 10 days to reduce their moisture content to less than 7%; the air-dried steel slag tailings are further screened into two particle size grades of >5 mm and <5 mm steel slag tailings; the <5 mm steel slag tailings are dried to a moisture content of less than 2% and sent to a ball mill to be ground into <3 mm steel slag tailings. After magnetic separation, <3 mm non-magnetic steel slag tailings are obtained and mixed evenly with biomass fuel in a mass ratio of (18 - 20):1; the obtained >5 mm steel slag tailings, the non-magnetic steel slag tailings mixture obtained in step (3), the homogenized ore, sintering flux, return ore, and fuel are fully mixed in proportion to obtain a sintering mixture for producing sintered ore. This invention only designs a method for using converter steel slag tailings to prepare sintered ore and mainly proposes a processing technology for using steel slag tailings as raw materials for sintered ore, without considering the raw material ratio and production process of simultaneously recycling multiple solid waste resources in sintering.

[0008] The patent "A Method for Treating Iron-Containing Solid Waste by Sintering Process" with the application number 202010874739.0 is characterized by describing a method for treating iron-containing solid waste by sintering process. The raw materials are proportioned according to the following mass percentages: 2% - 4% of steel slag magnetic separation concentrate, 40% - 50% of iron concentrate A, 40% - 45% of iron ore powder B, 6% - 12% of iron ore powder C, 3.5% - 8.5% of limestone, 0% - 4% of light-burned dolomite, 1.5% - 2.5% of serpentine, 3.0% - 4.5% of quicklime, and 4.5% - 6.0% of coke powder; the raw materials are mixed with water to make pellets to obtain a mixture; the mixture is fed, ignited, and sintered to obtain sintered ore. This invention mainly proposes a method for treating iron-containing solid waste by sintering process, and specifically only targets this kind of solid waste as steel slag magnetic separation concentrate, without considering the raw material ratio and production process of simultaneously recycling multiple solid waste resources in sintering.

[0009] The patent "A Process for Solid Waste Pelletizing and Its High-Efficiency Sintering Method" with the application number 202110051392.4 is characterized in that it describes a process for solid waste pelletizing and its high-efficiency sintering method. Using waste magnesium oxide powder, iron-containing solid waste and binder as raw materials, solid waste pellets are prepared after batching, surface modification and pelletizing. Then, using the solid waste pellets and the mineral mixture prepared by the mixed granulation process as the sintering raw materials, after mixing, they are successively subjected to feeding, ignition and sintering, cooling and sizing screening to obtain the finished sintered ore. The binder is prepared from waste magnesium oxide sludge, municipal sludge, first quicklime and corn starch. The waste magnesium oxide powder and waste magnesium oxide sludge are magnesium oxide waste. This invention mainly proposes a binder obtained by uniformly mixing waste magnesium oxide sludge, municipal sludge, first quicklime and corn starch to improve the pelletizing effect, and mixes it with iron-containing solid waste for pelletizing. Moreover, this invention only targets iron-containing solid waste, and the iron-containing solid waste includes 0-20wt% of blast furnace tap slag, 0-10wt% of raw material ash, 25-45wt% of sinter machine tail dust, 15-35wt% of finished product ash, 5-15wt% of ore storage tank ash, 0-1wt% of sinter main electrostatic precipitator ash and 0-10wt% of rotary hearth furnace fine powder. It does not include iron-containing solid wastes such as steel slag, scale and water treatment sludge.

[0010] After retrieval, the current patent technical solutions for using metallurgical solid waste to prepare sintered ore mainly focus on iron-containing solid waste and steel slag tailings, and target single varieties or specified varieties. In practical applications, different types of solid waste, especially iron-containing, calcium-containing and carbon-containing solid waste, can be used to prepare sintered ore. However, due to the different sources, particle size distributions, moisture contents, fluidities, etc. of different solid wastes, different blending methods and blending ratios need to be selected according to the characteristics of the solid waste to ensure the mixing effect of the raw materials, the air permeability of the sintering material layer and the quality of the sintered ore, so as to realize the utilization of solid waste resources while preparing high-quality sintered ore for blast furnace use. Summary of the Invention

[0011] To solve the problems in the prior art, the object of the present invention is to provide a method for recycling and preparing sinter ore from long-process multi-component solid waste resources. The present invention aims at solid waste resources containing iron, calcium, and carbon generated in the iron and steel smelting and rolling processes, including various process and environmental dusts, gas ash (mud), water treatment sludge, steel slag, scale, and dust coke powder. According to the characteristics of various solid waste components, particle sizes, moisture contents, fluidities, etc., after targeted pretreatment, the iron-containing dust removed from each process, recycled iron oxide powder, and iron-containing sludge are mixed in a certain proportion and used as an iron-containing raw material to participate in the mixing and stacking to obtain a mixed ore, which is then returned to sintering for utilization; the steel slag generated in the steelmaking process is crushed, magnetic separated, and screened to obtain tail slag with a particle size of less than 5 mm, which is returned to sintering to replace the flux for utilization; the scale generated in hot rolling is returned to sintering to replace iron ore powder for batching; the dust coke powder generated in the coking process is returned to sintering to replace fuel for utilization; various solid wastes are used as sintering raw materials in a certain proportion by adopting a reasonable batching and mixing method to produce sinter ore, realizing the utilization of solid waste resources while preparing high-quality sinter ore for blast furnace use.

[0012] To achieve the above object, the present invention is realized through the following technical solutions:

[0013] The present invention provides a method for recycling and preparing sinter ore from long-process multi-component solid waste resources, including the following steps:

[0014] (1) Mix dust removed, iron oxide powder, and sludge in a certain proportion and mix them evenly to obtain metallurgical dust sludge;

[0015] (2) Mix the metallurgical dust sludge and iron ore powder in a certain proportion, mix them evenly, and stack them to obtain a mixed ore;

[0016] (3) Mix the mixed ore, steel slag tail slag, scale, dust coke powder, flux, and returned ore in a certain proportion, add water, mix, and granulate to obtain a sintering mixture, and obtain sinter ore through feeding, ignition, sintering, crushing, and cooling.

[0017] In the above technical solution, an overall method for recycling and preparing sinter ore from long-process multi-component solid waste resources is provided, covering the complete process of making metallurgical dust sludge from dust removed, iron oxide powder, and sludge, then making a mixed ore with iron ore powder, and finally making a sintering mixture with various materials and sintering. Integrating multiple solid waste treatment links to form a coherent preparation process provides a clear path for the application of solid waste in sinter ore production. Realize the recycling of solid waste resources, reduce solid waste emissions, open up new raw material sources for sinter ore production, and reduce the dependence on primary resources.

[0018] As a further optimized solution of the present invention, in step (1), the mass ratios of dust removed, iron oxide powder, and sludge in the metallurgical dust sludge are 75-85%, 0-5%, and 10-25% respectively.

[0019] In the above technical solution, the mass proportion of each component in the metallurgical dust and sludge is clarified, the composition of the metallurgical dust and sludge is accurately controlled, the properties of the metallurgical dust and sludge are ensured to be stable, the quality stability of the subsequent blended ore and sinter is improved, the quality of the sinter is made more stable, and it is beneficial to the stable operation of blast furnace production.

[0020] As a further optimized solution of the present invention, the dust removal ash includes the dust removal ash from the blending yard, sintering dust removal ash, blast furnace dust removal ash and converter dust removal ash, the iron oxide powder includes cold rolling acid regeneration iron oxide powder, and the sludge includes converter sludge and hot rolling sludge; wherein, the mass proportions of the dust removal ash from the blending yard, sintering dust removal ash, blast furnace dust removal ash and converter dust removal ash in the metallurgical dust and sludge are 15-25%, 20-40%, 35-50%, 0-10% respectively, and the mass proportions of converter sludge and hot rolling sludge in the metallurgical dust and sludge are 75-100%, 0-25% respectively.

[0021] In the above technical solution, the specific types of the dust removal ash, iron oxide powder and sludge are refined, the solid wastes from different sources are separately treated and utilized, the characteristics of different solid wastes are fully exerted, the utilization rate of solid wastes is improved, the coordinated utilization of multiple solid wastes is realized, and the resource utilization efficiency is enhanced.

[0022] As a further optimized solution of the present invention, the main chemical components of the dust removal ash from the blending yard include: TFe 45.0-60.0%, FeO 0.1-0.5%, CaO 1.0-6.1%, SiO2 2.0-5.8%, MgO 0.5-1.5%, Al2O3 1.5-3.0%, P 0.05-0.15%, S 0.1-0.5%, K2O 0.05-0.10%, Na2O 0.10-0.25%, Zn 0-0.1%; the proportion of particles smaller than 1 mm is greater than 95%, and the moisture content is lower than 1%;

[0023] The sintering dust removal ash does not include the dust removal ash from the sintering machine head, and its main chemical components include: TFe 47.0-50.0%, FeO 5.0-10.0%, CaO 3.0-4.0%, SiO2 5.0-6.0%, MgO 0.6-1.3%, Al2O3 1.5-2.0%, P 0.05-0.15%, S 0.3-0.5%, K2O 0.40-0.60%, Na2O 0.05-0.15%, Zn 0.3-0.5%; the proportion of particles smaller than 1 mm is greater than 95%, and the moisture content is lower than 1%;

[0024] The blast furnace dust removal ash includes bunker dust removal ash, blast furnace gravity dust removal ash, and tapping yard dust removal ash, excluding blast furnace bag filter dust. Its main chemical components include: TFe 35.0 - 65.0%, FeO 3.0 - 11.0%, CaO 0.5 - 4.5%, SiO2 3.0 - 7.0%, MgO 0.1 - 1.1%, Al2O3 0.5 - 2.5%, P 0.10 - 0.20%, S 0.1 - 0.5%, K2O 0.50 - 1.0%, Na2O 0.40 - 1.0%, Zn 0.1 - 1.0%; the proportion of particles smaller than 1 mm is greater than 95%, and the moisture content is lower than 1%;

[0025] The main chemical components of the converter dust removal ash include: TFe 30.0 - 65.0%, FeO 5.0 - 15.0%, CaO 1.0 - 20.0%, SiO2 2.0 - 8.0%, MgO 1.0 - 7.0%, Al2O3 0.3 - 2.5%, P 0 - 0.10%, S 0.05 - 0.7%, K2O 0.05 - 1.0%, Na2O 0.04 - 0.30%, Zn 0.04 - 1.0%; the proportion of particles smaller than 1 mm is greater than 95%, and the moisture content is lower than 1%;

[0026] The main chemical components of the cold rolling acid regeneration iron oxide powder include: TFe 60.0 - 69.0%, FeO 0.05 - 0.50%, CaO 0.01 - 0.05%, SiO2 0.03 - 0.08%, MgO 0 - 0.1%, Al2O3 0.01 - 0.60%, P 0 - 0.10%, S 0 - 0.10%, K2O 0 - 0.1%, Na2O 0 - 0.10%, Zn 0 - 0.10%; the proportion of particles smaller than 0.075 mm is greater than 95%, and the moisture content is lower than 1%;

[0027] The converter sludge is dehydrated, and the moisture content does not exceed 50%. Its main chemical components include: TFe 55.0 - 65.0%, FeO 10.0 - 20.0%, CaO 8.0 - 12.0%, SiO2 1.0 - 2.0%, MgO 3.0 - 5.0%, Al2O3 0.3 - 1.0%, P 0 - 0.10%, S 0 - 0.10%, K2O 0 - 0.10%, Na2O 0.10 - 0.50%, Zn 0.10 - 1.0%;

[0028] The hot-rolled sludge is dehydrated and has a moisture content of no more than 50%. Its main chemical components include: TFe 60.0 - 65.0%, FeO 15.0 - 30.0%, CaO 3.0 - 5.0%, SiO2 1.0 - 2.0%, MgO 0.5 - 1.0%, Al2O3 0 - 0.5%, P 0 - 0.10%, S 0 - 0.10%, K2O 0 - 0.10%, Na2O 0 - 0.10%, Zn 0 - 0.2%.

[0029] In the above technical solution, the detailed chemical components, particle sizes, and moisture contents of each raw material are given, providing a basis for raw material selection and treatment, facilitating the optimization of process parameters according to the characteristics of the raw materials, ensuring the adaptability of the raw materials, improving the quality of the sintering mixture, and further enhancing the quality of the sinter.

[0030] As a further optimized solution of the present invention, in step (1), the metallurgical dust sludge has a moisture content of 5 - 8%, and its main chemical components include: TFe 40.0 - 50.0%, FeO 5.0 - 10.0%, CaO 5.0 - 8.0%, SiO2 5.0 - 8.0%, MgO 1.0 - 2.0%, Al2O3 1.0 - 3.0%, P 0 - 0.10%, S 0.10 - 0.50%, K2O 0.1 - 0.50%, Na2O 0.10 - 0.50%, Zn 0 - 0.5%.

[0031] In the above technical solution, the moisture content and chemical components of the metallurgical dust sludge are defined, ensuring the quality of the metallurgical dust sludge, laying a foundation for the stability of the quality of the subsequent blended ore and sinter, improving the stability of the sinter quality, and enhancing the stability of blast furnace production.

[0032] As a further optimized solution of the present invention, in step (2), the iron ore powder includes iron ore powder A, iron ore powder B, iron ore powder C, iron ore powder D, and iron concentrate E. The mass ratios of various raw materials in the blended ore are respectively: metallurgical dust sludge 2 - 8%, iron ore powder A 20 - 50%, iron ore powder B 15 - 40%, iron ore powder C 3 - 6%, iron ore powder D 5 - 15%, iron concentrate E 5 - 15%;

[0033] The main chemical components of the iron ore powder A include: TFe 56.0 - 59.0%, FeO 0.05 - 0.50%, CaO 0.01 - 0.10%, SiO2 4.5 - 7.0%, MgO 0.01 - 0.05%, Al2O3 1.5 - 3.5%, P 0.01 - 0.10%, S 0 - 0.05%, K2O 0.01 - 0.10%, Na2O 0.01 - 0.10%, Zn 0 - 0.10%;

[0034] The main chemical components of the iron ore powder B include: TFe 60.0 - 65.0%, FeO 0.10 - 0.40%, CaO 0.01 - 0.10%, SiO2 4.5 - 5.5%, MgO 0.03 - 0.08%, Al2O3 2.0 - 3.0%, P 0.05 - 0.10%, S 0.01 - 0.05%, K2O 0.01 - 0.10%, Na2O 0.01 - 0.10%, Zn 0 - 0.10%;

[0035] The main chemical components of the iron ore powder C include: TFe 57.0 - 60.0%, FeO 0.01 - 0.10%, CaO 0.01 - 0.10%, SiO2 10.0 - 12.5%, MgO 0.01 - 0.05%, Al2O3 1.0 - 2.0%, P 0.05 - 0.10%, S 0 - 0.05%, K2O 0.01 - 0.10%, Na2O 0.01 - 0.10%, Zn 0 - 0.10%;

[0036] The main chemical components of the iron ore powder D include: TFe 62.0 - 67.0%, FeO 0.10 - 0.50%, CaO 0.01 - 0.10%, SiO2 2.0 - 4.0%, MgO 0.01 - 0.05%, Al2O3 1.0 - 3.0%, P 0.03 - 0.10%, S 0.01 - 0.05%, K2O 0.01 - 0.10%, Na2O 0.01 - 0.10%, Zn 0 - 0.10%;

[0037] The main chemical components of the iron concentrate E include: TFe 65.0 - 68.0%, FeO 10 - 25%, CaO 0.05 - 0.10%, SiO2 7.0 - 10.0%, MgO 0.15 - 0.25%, Al2O3 0.4 - 0.6%, P 0.01 - 0.05%, S 0.05 - 0.50%, K2O 0.01 - 0.10%, Na2O 0.01 - 0.10%, Zn 0 - 0.10%.

[0038] In the above technical solution, determine the mass ratio of each raw material in the blended ore, the types and components of the iron ore powder, optimize the blending of the blended ore, ensure the uniformity of the quality of the blended ore, meet the requirements of the sintering process, improve the quality of the sintered ore, and reduce the production cost.

[0039] As a further optimized solution of the present invention, in step (3), the steel slag tailings include the steel slag obtained by crushing, magnetic separation and powder screening of the steel slag generated from converter / electric furnace steelmaking, and do not include the steel slag generated during the process of hot metal desulfurization and molten steel refining; the scale is the scale generated in the hot rolling process; the dedusted coke powder is the dedusted coke powder generated in the coking process.

[0040] In the above technical solution, the sources of steel slag tailings, mill scale, and dedusting coke powder are clarified to ensure the quality and consistency of raw materials, facilitate production management and quality control, improve the quality stability of sinter, and enhance production efficiency.

[0041] As a further optimized solution of the present invention, the particle size of the steel slag tailings is less than 5 mm, and its main chemical components include: TFe 15 - 25%, MFe 0 - 2.0%, FeO 5.0 - 10.0%, CaO 35 - 50%, SiO2 10.0 - 15.0%, MgO 5.0 - 7.0%, Al2O3 1.0 - 3.0%, P 0.1 - 1.5%, S 0.10 - 0.30%, K2O 0.01 - 0.10%, Na2O 0.01 - 0.10%, Zn 0 - 0.10%;

[0042] The main chemical components of the mill scale include: TFe 67.0 - 74.0%, FeO 35.0 - 65.0%, SiO2 0.5 - 4.0%, Al2O3 0.3 - 1.2%, P 0.01 - 0.06%, S 0.01 - 0.02%, K2O 0 - 0.02%, Na2O 0.01 - 0.20%, Zn 0 - 0.10%; the proportion of particles less than 10 mm is not less than 90%, and the moisture content does not exceed 8%;

[0043] In the dedusting coke powder, the proportion of particles less than 0.15 mm is not less than 90%, and the fixed carbon content is not less than 80%.

[0044] In the above technical solution, the particle size, composition and other indexes of steel slag tailings, mill scale, and dedusting coke powder are specified to ensure that the raw materials meet the sintering requirements, improve the performance of sintering mixture, improve the efficiency and quality of the sintering process, and improve the strength, particle size distribution and metallurgical properties of sinter.

[0045] As a further optimized solution of the present invention, in step (3), the flux includes quicklime, limestone, and dolomite, wherein the mass ratio of the mixed ore is 50 - 65%, the mass ratio of the steel slag tailings is 1 - 3%, the mass ratio of the mill scale is 1 - 3%, the mass ratio of the dedusting coke powder is 3.5 - 4.5%, the mass ratio of the quicklime powder is 3 - 4%, the mass ratio of the limestone powder is 3 - 5%, the mass ratio of the dolomite powder is 4.5 - 5.5%, and the mass ratio of the return ore is 15 - 30%.

[0046] In the above technical solution, the mass ratio of each material in the sintering mixture is given, the batching of the sintering mixture is optimized, the comprehensive performance of the sintering mixture is ensured to be good, the requirements of the sintering process and blast furnace production are met, the quality of sinter is improved, and the production cost is reduced.

[0047] As a further optimized solution of the present invention, in step (3), the ignition time is 1.5 - 4.0 min, the ignition negative pressure is 6.5 - 8.5 KPa, the sintering exhaust negative pressure is 10 - 16 KPa, and the material layer thickness is 650 mm; the sintered ore has TFe of 57.0 - 58.0%, an average particle size of 21.0 - 22.0 mm, an alkalinity of 2.0 - 2.2, a drum index ≥ 80%, RDI +3.15 ≥ 65%, and RI ≥ 80%.

[0048] In the above technical solution, the sintering process parameters and the sintered ore quality indexes are set, the sintering process and the product quality are strictly controlled, so as to ensure the stable quality of the sintered ore, meet the requirements of blast furnace production, improve the blast furnace production efficiency, reduce the production cost, and enhance the enterprise competitiveness.

[0049] The present invention provides a method for recycling and preparing sintered ore aiming at the problem of solid waste resource utilization in long-process iron and steel enterprises, and its technical features bring various beneficial effects:

[0050] 1. Through process reengineering, various iron-containing, calcium-containing, and carbon-containing solid wastes generated in the iron and steel smelting and rolling processes, such as various dusts, sludges, steel slags, scale, and dust coke powder, are subjected to targeted pretreatment and then re-input into production as sintering raw materials, realizing the resource recycling of solid wastes within the enterprise. This not only reduces the emissions and treatment costs of solid wastes, but also effectively utilizes these wastes, improves the resource utilization rate, and conforms to the concept of sustainable development.

[0051] 2. For different types of solid wastes, a classification treatment method is adopted, and the functional characteristics of the iron and steel production process are reasonably utilized. Different types of solid wastes such as slag, dust, and sludge are respectively returned to sintering for utilization through pretreatment such as pre-mixing, crushing, magnetic separation, and screening. For example, the steel slag generated in the steelmaking process is crushed, magnetically separated, and screened to obtain tail slag below 5 mm and returned to sintering to replace the flux. This treatment method can improve the particle size distribution and physical and chemical properties of the solid waste, making it more suitable as a sintering raw material, thus ensuring the granulation effect and air permeability of the sintering mixture, and being beneficial to improving the efficiency and quality of the sintering process.

[0052] 3. Through reasonable raw material ratio design, the proportions of various raw materials such as solid wastes, iron ore powder, flux, and fuel are precisely controlled, and the sintering process is strictly controlled, such as parameters such as ignition time, ignition negative pressure, sintering exhaust negative pressure, and material layer thickness, so as to ensure the quality of the prepared sintered ore. Specifically, the TFe content of the sintered ore is stably at 57.0 - 58.0%, the average particle size is 21.0 - 22.0 mm, the alkalinity is 2.0 - 2.2, the drum index ≥ 80%, RDI + 3.15 ≥ 65%, and RI ≥ 80%. These indexes indicate that the sintered ore has good strength, particle size distribution, and metallurgical properties, can meet the requirements of blast furnace production, and provides a guarantee for the stable and smooth operation and high-efficiency production of the blast furnace.

[0053] 4. The present invention makes extensive use of solid waste resources, reduces the dependence on new resources such as iron ore, and lowers the raw material procurement cost. At the same time, it reduces solid waste emissions and the cost of solid waste treatment, showing significant economic benefits. From an environmental perspective, it reduces the pollution of the environment by solid waste and the land resources occupied by waste stacking, which is of positive significance for environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a process flow diagram for preparing sinter ore by recycling multi-component solid waste resources in a long process flow of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0055] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the preferred implementation solutions of the present invention will be described below in conjunction with specific embodiments. However, it should be understood that the drawings are only for illustrative purposes and cannot be construed as a limitation to this patent.

[0056] Please refer to Figure 1 , a method for recycling multi-component solid waste resources to prepare sinter ore in a long process flow steel enterprise, which includes the following steps:

[0057] The dedusting ash from the blending yard, sintering dedusting ash, blast furnace dedusting ash, converter dedusting ash, and oxidized iron powder from cold rolling acid regeneration are respectively transported to the dedusting ash bin by tank trucks; the converter sludge and hot rolling sludge are respectively transported to the sludge pond by dump trucks; the dedusting ash and sludge are proportionally mixed and added to a high-strength mixer to be evenly mixed to obtain a metallurgical dust sludge, which is mixed with iron ore powder to obtain a blended ore. The steel slag produced by converter / electric furnace steelmaking is screened after being crushed and magnetic separated to obtain steel slag tailings; the above-mentioned blended ore, steel slag tailings, oxidized iron scale generated in the hot rolling process, dedusting coke powder generated in the coking process, flux, and return ore are proportionally mixed, and granulated by adding water and mixing to obtain a sintering mixture, and sinter ore is obtained through feeding, ignition, sintering, crushing, and cooling.

[0058] Example 1:

[0059] The metallurgical dust sludge solid waste is proportionally mixed according to Table 5, and after being evenly mixed by strong mixing, it is proportionally mixed with iron ore powder and iron concentrate according to the ratio in Table 6, and a blended ore is obtained by mixing and piling. The blended ore is proportionally mixed with quicklime, limestone powder, dolomite powder, return ore, steel slag tailings, oxidized iron scale, pulverized coal, and dedusting coke powder according to the ratio in Table 7, and granulated by adding water and mixing to obtain a sintering mixture. The sintering mixture is fed, ignited, sintered, cooled, and crushed to obtain sinter ore. The ignition time is 2.0 min, the ignition negative pressure is 7.5 KPa, the sintering exhaust negative pressure is 14 KPa, the bed thickness is 650 mm, and the composition and properties of the sinter ore are shown in Table 8.

[0060] Example 2:

[0061] The metallurgical dust and sludge solid waste is proportioned according to Table 5, and after being strongly mixed and homogenized, it is proportioned with iron ore powder and iron concentrate according to the proportion in Table 6, and then mixed and piled to obtain the homogenized ore. The homogenized ore is proportioned with quicklime, limestone powder, dolomite powder, return ore, steel slag tailings, mill scale, pulverized coal, and dust removal coke powder according to the proportion in Table 7, and water is added and mixed to granulate to obtain the sintering mixture. The sintering mixture is subjected to feeding, ignition, sintering, cooling and crushing to obtain sintered ore. The ignition time is 2.8 min, the ignition negative pressure is 7.8 KPa, the sintering exhaust negative pressure is 13.5 KPa, the material layer thickness is 650 mm, and the composition and properties of the sintered ore are shown in Table 8.

[0062] Example 3:

[0063] The metallurgical dust and sludge solid waste is proportioned according to Table 5, and after being strongly mixed and homogenized, it is proportioned with iron ore powder and iron concentrate according to the proportion in Table 6, and then mixed and piled to obtain the homogenized ore. The homogenized ore is proportioned with quicklime, limestone powder, dolomite powder, return ore, steel slag tailings, mill scale, pulverized coal, and dust removal coke powder according to the proportion in Table 7, and water is added and mixed to granulate to obtain the sintering mixture. The sintering mixture is subjected to feeding, ignition, sintering, cooling and crushing to obtain sintered ore. The ignition time is 3 min, the ignition negative pressure is 7.5 KPa, the sintering exhaust negative pressure is 13 KPa, the material layer thickness is 650 mm, and the composition and properties of the sintered ore are shown in Table 8.

[0064] Comparative example:

[0065] Iron ore powder A, iron ore powder B, iron ore powder C, iron ore powder D, and iron concentrate E are proportioned according to the proportion in Table 6, and then mixed and piled to obtain the homogenized ore. The homogenized ore is proportioned with quicklime, limestone powder, dolomite powder, return ore, and pulverized coal according to the proportion in Table 7, and water is added and mixed to granulate to obtain the sintering mixture. The sintering mixture is subjected to feeding, ignition, sintering, cooling and crushing to obtain sintered ore. The ignition time is 2.5 min, the ignition negative pressure is 7.1 KPa, the sintering exhaust negative pressure is 12 KPa, the material layer thickness is 650 mm, and the composition and properties of the sintered ore are shown in Table 8.

[0066] The chemical compositions, particle sizes and moisture contents of the various raw materials used in the comparative example and the examples are shown in Tables 1, 2, 3 and 4 respectively.

[0067] Table 1 Proportion and chemical composition of various iron-containing raw materials in the homogenized ore, %

[0068] Table 2 Composition and particle size of fluxes and fuels, %

[0069]

[0070] Table 3 Composition of metallurgical dust and sludge solid waste, %

[0071]

[0072]

[0073] Table 4 Composition and particle size of steel slag tailings, %

[0074]

[0075] Table 5 Mixing ratios of various dust removal ashes and sludges in metallurgical dust sludge, %

[0076]

[0077]

[0078] Table 6 Mixing ratios of various iron-bearing materials in blended ore, %

[0079] Implementation situation Metallurgical dust and sludge Iron ore powder A Iron ore powder B Iron ore powder C Iron ore powder D Iron concentrate E Comparative example 0 45.0 35.0 4.0 10.0 6.0 Example 1 2.5 40.0 36.5 5.0 10.5 5.5 Example 2 5.0 40.0 32.0 5.0 11.5 6.5 Example 3 7.5 35.0 33.0 5.5 12.0 7.0

[0080] Table 7 Mixing ratios of various materials in sintering mixture, %

[0081]

[0082] Table 8 Composition and properties of sinter

[0083] By comparing the composition and property data of the sinter in the examples and comparative examples, it can be seen that the sinter prepared from solid waste in the examples performs well in various indicators and is superior to the comparative examples. This proves that the method of the present invention can effectively utilize solid waste to prepare high-quality sinter that meets the requirements of blast furnaces, realizing the resource utilization of solid waste and ensuring the quality of sinter.

[0084] The present invention has been described in detail above in conjunction with the embodiments. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A method for preparing sinter ore by recycling multiple solid wastes in a long process, characterized in that, The steps include: (1) Dust removal ash, iron oxide powder and sludge are mixed uniformly according to a certain ratio to obtain metallurgical dust sludge; (2) mixing metallurgical dust and iron ore powder in a certain proportion to form a pile to obtain a mixed ore; (3) Mixing the mixed ore, steel slag tailings, iron oxide scale, dust removal coke powder, flux and return ore in a certain proportion, adding water to mix and granulate to obtain a sintering mixture, and then obtaining sintered ore through distribution, ignition, sintering, crushing and cooling.

2. The method for preparing sinter ore by recycling multiple solid wastes in a long process according to claim 1, characterized in that, In step (1), the mass proportions of dust removal ash, iron oxide powder and sludge in the metallurgical dust and sludge are 75-85%, 0-5% and 10-25% respectively.

3. The method for preparing sinter ore by recycling multiple solid wastes in a long process according to claim 1 or 2, characterized in that The dust removal ash includes dust removal ash from a mixed material field, dust removal ash from sintering, dust removal ash from a blast furnace and dust removal ash from a converter; the iron oxide powder includes cold-rolled acid-regenerated iron oxide powder; and the sludge includes converter sludge and hot-rolled sludge; wherein the mass proportions of dust removal ash from a mixed material field, dust removal ash from sintering, dust removal ash from a blast furnace and dust removal ash from a converter in the dust removal ash are 15-25%, 20-40%, 35-50% and 0-10% respectively, and the mass proportions of converter sludge and hot-rolled sludge in the sludge are 75-100% and 0-25% respectively.

4. The method for preparing sintered ore by recycling multiple solid waste resources in a long process according to claim 3, characterized in that: The main chemical components of the dust removal ash in the mixing material field include: TFe 45.0-60.0%, FeO 0.1-0.5%, CaO1.0-6.1%, SiO2 2.0-5.8%, MgO 0.5-1.5%, Al2O3 1.5-3.0%, P 0.05-0.15%, S0.1-0.5%, K2O 0.05-0.10%, Na2O 0.10-0.25%, Zn 0-0.1%; the particle size is less than 1mm, accounting for more than 95%, and the moisture content is less than 1%; The sintering dust removal ash does not contain sintering machine head dust removal ash, and its main chemical components include: TFe 47.0-50.0%, FeO5.0-10.0%, CaO 3.0-4.0%, SiO2 5.0-6.0%, MgO 0.6-1.3%, Al2O3 1.5-2.0%, P0.05-0.15%, S 0.3-0.5%, K2O 0.40-0.60%, Na2O 0.05-0.15%, Zn 0.3-0.5%; the particle size is less than 1mm, accounting for more than 95%, and the moisture content is less than 1%; The blast furnace dust removal ash includes bunker dust removal ash, blast furnace gravity dust removal ash and tapping yard dust removal ash, excluding blast furnace bag filter dust. Its main chemical components include: TFe 35.0 - 65.0%, FeO 3.0 - 11.0%, CaO 0.5 - 4.5%, SiO2 3.0 - 7.0%, MgO 0.1 - 1.1%, Al2O3 0.5 - 2.5%, P 0.10 - 0.20%, S 0.1 - 0.5%, K2O 0.50 - 1.0%, Na2O 0.40 - 1.0%, Zn 0.1 - 1.0%; the proportion of particles smaller than 1 mm is greater than 95%, and the moisture content is lower than 1%; The converter dust removal ash's main chemical components include: TFe 30.0 - 65.0%, FeO 5.0 - 15.0%, CaO 1.0 - 20.0%, SiO2 2.0 - 8.0%, MgO 1.0 - 7.0%, Al2O3 0.3 - 2.5%, P 0 - 0.10%, S 0.05 - 0.7%, K2O 0.05 - 1.0%, Na2O 0.04 - 0.30%, Zn 0.04 - 1.0%; the proportion of particles smaller than 1 mm is greater than 95%, and the moisture content is lower than 1%; The main chemical components of the cold rolling acid regeneration iron oxide powder include: TFe 60.0 - 69.0%, FeO 0.05 - 0.50%, CaO 0.01 - 0.05%, SiO2 0.03 - 0.08%, MgO 0 - 0.1%, Al2O3 0.01 - 0.60%, P 0 - 0.10%, S 0 - 0.10%, K2O 0 - 0.1%, Na2O 0 - 0.10%, Zn 0 - 0.10%; the proportion of particles smaller than 0.075 mm is greater than 95%, and the moisture content is lower than 1%; The converter sludge is dehydrated, and the moisture content does not exceed 50%. Its main chemical components include: TFe 55.0 - 65.0%, FeO 10.0 - 20.0%, CaO 8.0 - 12.0%, SiO2 1.0 - 2.0%, MgO 3.0 - 5.0%, Al2O3 0.3 - 1.0%, P 0 - 0.10%, S 0 - 0.10%, K2O 0 - 0.10%, Na2O 0.10 - 0.50%, Zn 0.10 - 1.0%; The hot rolling sludge is dehydrated, and the moisture content does not exceed 50%. Its main chemical components include: TFe 60.0 - 65.0%, FeO 15.0 - 30.0%, CaO 3.0 - 5.0%, SiO2 1.0 - 2.0%, MgO 0.5 - 1.0%, Al2O3 0 - 0.5%, P 0 - 0.10%, S 0 - 0.10%, K2O 0 - 0.10%, Na2O 0 - 0.10%, Zn 0 - 0.2%.

5. The method for preparing sinter ore by long-process multi-solid waste resource recycling according to claim 3, characterized in that, In step (1), the moisture content of the metallurgical dust and sludge is 5-8%, and its main chemical components include: TFe 40.0-50.0%, FeO 5.0-10.0%, CaO 5.0-8.0%, SiO2 5.0-8.0%, MgO 1.0-2.0%, Al2O3 1.0-3.0%, P 0-0.10%, S 0.10-0.50%, K2O 0.1-0.50%, Na2O 0.10-0.50%, Zn 0-0.5%.

6. The method for preparing sinter ore by long-process multi-solid waste resource recycling according to claim 1, characterized in that, In step (2), the iron ore powder includes iron ore powder A, iron ore powder B, iron ore powder C, iron ore powder D, and iron concentrate E. The mass ratios of various raw materials in the blended ore are as follows: metallurgical dust and sludge 2-8%, iron ore powder A 20-50%, iron ore powder B 15-40%, iron ore powder C 3-6%, iron ore powder D 5-15%, and iron concentrate E 5-15%; The main chemical components of the iron ore powder A include: TFe 56.0-59.0%, FeO 0.05-0.50%, CaO 0.01-0.10%, SiO2 4.5-7.0%, MgO 0.01-0.05%, Al2O3 1.5-3.5%, P 0.01-0.10%, S 0-0.05%, K2O 0.01-0.10%, Na2O 0.01-0.10%, Zn 0-0.10%; The main chemical components of the iron ore powder B include: TFe 60.0-65.0%, FeO 0.10-0.40%, CaO 0.01-0.10%, SiO2 4.5-5.5%, MgO 0.03-0.08%, Al2O3 2.0-3.0%, P 0.05-0.10%, S 0.01-0.05%, K2O 0.01-0.10%, Na2O 0.01-0.10%, Zn 0-0.10%; The main chemical components of the iron ore powder C include: TFe 57.0-60.0%, FeO 0.01-0.10%, CaO 0.01-0.10%, SiO2 10.0-12.5%, MgO 0.01-0.05%, Al2O3 1.0-2.0%, P 0.05-0.10%, S 0-0.05%, K2O 0.01-0.10%, Na2O 0.01-0.10%, Zn 0-0.10%; The main chemical components of the iron ore powder D include: TFe 62.0-67.0%, FeO 0.10-0.50%, CaO 0.01-0.10%, SiO2 2.0-4.0%, MgO 0.01-0.05%, Al2O3 1.0-3.0%, P 0.03-0.10%, S 0.01-0.05%, K2O 0.01-0.10%, Na2O 0.01-0.10%, Zn 0-0.10%; The main chemical components of the iron concentrate E include: TFe 65.0 - 68.0%, FeO 10 - 25%, CaO 0.05 - 0.10%, SiO2 7.0 - 10.0%, MgO 0.15 - 0.25%, Al2O3 0.4 - 0.6%, P 0.01 - 0.05%, S 0.05 - 0.50%, K2O 0.01 - 0.10%, Na2O 0.01 - 0.10%, Zn 0 - 0.10%.

7. The method for preparing sinter ore by recycling multiple solid wastes in a long process according to claim 1, characterized in that, In step (3), the steel slag tailings include the steel slag obtained by crushing, magnetic separation, and screening of the steel slag generated from converter / electric furnace steelmaking, excluding the steel slag generated during the hot metal desulfurization and molten steel refining processes; the scale is the scale generated in the hot rolling process; the dedusting coke powder is the dedusting coke powder generated in the coking process.

8. The method for preparing sinter ore by recycling multiple solid wastes in a long process according to claim 7, characterized in that, The particle size of the steel slag tailings is less than 5 mm, and its main chemical components include: TFe 15 - 25%, MFe 0 - 2.0%, FeO 5.0 - 10.0%, CaO 35 - 50%, SiO2 10.0 - 15.0%, MgO 5.0 - 7.0%, Al2O3 1.0 - 3.0%, P 0.1 - 1.5%, S 0.10 - 0.30%, K2O 0.01 - 0.10%, Na2O 0.01 - 0.10%, Zn 0 - 0.10%; The main chemical components of the scale include: TFe 67.0 - 74.0%, FeO 35.0 - 65.0%, SiO2 0.5 - 4.0%, Al2O3 0.3 - 1.2%, P 0.01 - 0.06%, S 0.01 - 0.02%, K2O 0 - 0.02%, Na2O 0.01 - 0.20%, Zn 0 - 0.10%; the proportion of particles with a particle size less than 10 mm is not less than 90%, and the moisture content does not exceed 8%; In the dedusting coke powder, the proportion of particles with a particle size less than 0.15 mm is not less than 90%, and the fixed carbon content is not less than 80%.

9. The method for preparing sinter ore by recycling multiple solid wastes in a long process according to claim 1, characterized in that, In step (3), the fluxes include quicklime, limestone, and dolomite, among which the mass proportion of the blended ore is 50 - 65%, the mass proportion of the steel slag tailings is 1 - 3%, the mass proportion of the scale is 1 - 3%, the mass proportion of the dedusting coke powder is 3.5 - 4.5%, the mass proportion of the quicklime powder is 3 - 4%, the mass proportion of the limestone powder is 3 - 5%, the mass proportion of the dolomite powder is 4.5 - 5.5%, and the mass proportion of the return ore is 15 - 30%.

10. The method for preparing sinter ore by recycling multiple solid wastes in a long process according to claim 1, characterized in that In step (3), the ignition time is 1.5 - 4.0 min, the ignition negative pressure is 6.5 - 8.5 KPa, the sintering exhaust negative pressure is 10 - 16 KPa, and the material layer thickness is 650 mm; the sintered ore has TFe of 57.0 - 58.0%, an average particle size of 21.0 - 22.0 mm, an alkalinity of 2.0 - 2.2, a drum index of ≥ 80%, RDI +3.15 ≥ 65%, and RI ≥ 80%.

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