Method for synergistically agglomerating sintering return mine and hot converter steel slag

Abstract

The invention discloses a method for synergistically agglomerating sintered return mine and hot converter steel slag, and relates to the technical field of ferrous metallurgy. The method has the beneficial effects that the sintering return mine and the hot-state converter steel slag are subjected to collaborative agglomeration, efficient utilization of two solid waste resources is achieved, resource waste is avoided, dependence of steel production on external iron ore and other raw materials is reduced, and by means of mixed agglomeration with the hot-state steel slag, the production efficiency is improved. The problems of more powder, low utilization rate, increased dust removal system burden and the like when the sintering return mine is directly used for the converter are solved, the utilization efficiency of the sintering return mine in the steelmaking process is improved, the complex process of returning the sintering return mine to the sintering process is omitted, the part of the sintering return mine is converted into a short process from a long-process steel production process, and the production cost is reduced. The production efficiency is improved, and the energy consumption and the production cost are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of iron and steel metallurgy, and in particular to a method for collaborative agglomeration of sintered return ore and hot converter slag. Background Art

[0002] Sinter return ore and converter slag are two significant solid wastes in the steel production process. Sinter return ore primarily consists of incompletely burned ore along the sides and surface of the sintering machine car, powder generated after mechanical loads, and fine powder recovered from environmental dust removal that must be returned to the sintering process. Under traditional processes, sinter return ore must be returned to the sintering process, undergoing a complex sintering process before it can be reused in ironmaking. This process is lengthy, energy-intensive, and inefficient.

[0003] During the converter steelmaking process, when excess heat is present, the iron oxides in the sintered return ore can theoretically undergo a reduction reaction with the carbon in the molten steel, absorbing the excess heat and converting the sintered return ore into molten iron in a single step in the converter, shortening the long process. However, using sintered return ore directly in the converter presents a significant problem: it contains a high amount of fines. During converter smelting, the rising gas flow causes a large amount of fines to be extracted by the dust removal system, resulting in extremely low utilization and increasing the burden on the converter's dust removal system.

[0004] Converter slag, a byproduct of converter steelmaking, is rich in elements such as iron, calcium, and silicon. Currently, the main treatment methods for recovering the iron are cooling, crushing, and magnetic separation. This process is complex and the heat energy is not effectively utilized, resulting in energy waste. Therefore, it is imperative to develop an efficient and rational method for the coordinated treatment of sintering return ore and converter slag. Summary of the Invention

[0005] The purpose of the present invention is to address the shortcomings and defects in the prior art and provide a method for collaborative agglomeration of sintered return ore and hot converter slag. The present invention collaboratively agglomerates sintered return ore and hot converter slag, thereby achieving efficient utilization of two solid waste resources, avoiding waste of resources, and reducing the dependence of steel production on external raw materials such as iron ore. Moreover, by mixing with hot slag to form agglomerates, the problems of excessive powder, low utilization rate, and increased burden on the dust removal system when the sintered return ore is directly used in the converter are solved, the utilization efficiency of the sintered return ore in the steelmaking process is improved, and the complicated process of returning the sintered return ore to the sintering process is eliminated, and this part of the sintered return ore is transformed from a long-process steel production process into a short process, thereby improving production efficiency and reducing energy consumption and production costs.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a method for collaborative agglomeration of sintered return ore and hot converter slag, which comprises the following steps: optimizing the original KR desulfurization station silo, leaving one silo empty for loading sintered return ore, and transporting the sintered return ore to the molten iron KR desulfurization station, and adding the sintered return ore to the center of the slag pot through a chute; when collaborative agglomeration is required, the converter does not splash slag to protect the furnace, and the slag is directly discharged to the slag pot to ensure the temperature of the slag; the slag pot filled with hot slag is transported to the molten iron KR processing station; the KR stirring paddle is lowered so that the KR stirring paddle is inserted into the slag pot. The slag pot has a molten pool of 100cm, and then the KR stirring paddle is turned on. The hot steel slag will generate a vortex after stirring. Then the hopper discharger of the sintered return ore hopper is opened and the sintered return ore and hot steel slag are added according to the weight ratio of 1:1. At this time, the sintered return ore is drawn into the steel slag by the vortex, so that the sintered return ore and the steel slag are fully in contact and reacted. During the stirring process, the sintered return ore and the hot steel slag undergo physical and chemical changes at high temperature. The powder in the sintered return ore is gradually wrapped by the steel slag to form a uniform mixed system. At the same time, some iron oxides begin to react with the components in the steel slag to form FeO-CaO-S iO2 composite phase wrapped structure; after the stirring is completed, the slag pot is placed in a designated area for static state to allow the sintered return ore and converter slag to be fully sintered and agglomerated; after the lumps are fully cooled to below 100°C, they are poured out from the slag pot and crushed by a roller crusher; the crushed materials are screened by a 50mm vibrating screen, and the screened materials larger than 50mm are returned to the roller crusher for further crushing, and the screened materials smaller than 50mm are transported by a belt to a 10mm vibrating screen for screening, thereby obtaining the screened materials with a particle size of 10mm-50mm. The oversize material with a particle size of 10mm-50mm is transferred to the high-level hopper of the converter, and the undersize material with a particle size of less than 10mm is returned to the sintering return ore hopper; the obtained 10mm-50mm particle size has a high iron oxide content and suitable alkalinity, and can be directly added as a cold material to the converter steelmaking process. In the early stage of converter steelmaking, the particle is added in time according to the temperature and composition in the converter, and the excess heat is absorbed by the reduction reaction of the iron oxide and carbon in the molten steel, while providing iron source for the steelmaking process, realizing the efficient utilization of solid waste resources and the optimization of the steel production process.

[0007] Furthermore, the lower part of the sintered return ore silo is a silo discharger with a weighing function.

[0008] Furthermore, the use of a dedicated high-temperature resistant slag pot to receive the hot converter slag requires good thermal insulation performance and is covered with an insulation cover during transportation to ensure that the temperature of the slag is not lower than 1400°C when it enters the KR station to maintain the liquid state and activity of the slag.

[0009] Furthermore, the KR processing station has a weighing function, which can first deduct the net weight of the slag pot and then weigh the weight of the hot slag in the slag pot.

[0010] Furthermore, the rotation speed of the KR stirring paddle is controlled at 20 r / min-30 r / min, and the stirring time is 6 min-10 min.

[0011] Furthermore, the standing time is determined according to the ambient temperature and material properties, and is generally 2-4 hours. During the standing time, the chemical reaction inside the material continues to form a block with a certain strength and structure.

[0012] Furthermore, the roller spacing of the roller crusher can be adjusted according to the required particle size.

[0013] Furthermore, the sintered return ore consists of the following chemical components: TFe: 56wt%~58wt%, FeO: 8wt%~10wt%, CaO: 10wt%~13wt%, SiO2: 5wt%~7wt%, MgO: 1.5wt%~1.7wt%, Al2O3: 1.4wt%~1.6wt% and other inevitable impurities.

[0014] Furthermore, the converter slag consists of the following chemical components: TFe: 15wt% to 18wt%, FeO: 14wt% to 20wt%, CaO: 40wt% to 50wt%, SiO2: 18wt% to 25wt%, MgO: 8.0wt% to 10.0wt%, MnO: 4.0wt% to 5.0wt% and other inevitable impurities.

[0015] After adopting the above technical scheme, the beneficial effects of the present invention are as follows: the present invention cooperates with hot converter slag to form blocks, realizes the efficient utilization of two solid waste resources, avoids waste of resources, and reduces the dependence of steel production on external raw materials such as iron ore. Moreover, by mixing with hot steel slag to form blocks, it solves the problems of excessive powder, low utilization rate, and increased burden on dust removal system when sintered return ore is directly used in converter, improves the utilization efficiency of sintered return ore in the steelmaking process, eliminates the complicated process of returning sintered return ore to the sintering process, and transforms this part of sintered return ore from a long process of steel production to a short process, thereby improving production efficiency and reducing energy consumption and production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 It is a schematic flow diagram of the present invention. DETAILED DESCRIPTION

[0018] See Figure 1 As shown, the technical solution adopted in this specific embodiment is: it includes the following steps: S1, optimize the original KR desulfurization station silo, leave one silo empty for loading sintered return ore, and transport the sintered return ore to the molten iron KR desulfurization station. The sintered return ore is added to the center of the slag pot through a chute. The lower part of the sintered return ore silo is a silo discharger with a weighing function.

[0019] S2: When coordinated agglomeration is required, the converter does not splash slag to protect the furnace, and the slag is directly discharged into the slag pot to ensure the temperature of the slag. A dedicated high-temperature resistant slag pot should be used to receive the hot converter slag. The slag pot must have good thermal insulation performance and be covered with an insulation cover during transportation to ensure that the temperature of the slag is not lower than 1400℃ when it enters the KR station to maintain the liquid state and activity of the slag.

[0020] S3, transporting the slag pot filled with hot steel slag to the molten iron KR processing station. The KR processing station has a weighing function. The net weight of the slag pot can be deducted first, and then the weight of the hot steel slag in the slag pot can be weighed.

[0021] S4, lower the KR stirring paddle and insert it into the slag pot molten pool 100cm, then turn on the KR stirring paddle. The hot steel slag will generate a vortex after stirring. Then open the hopper discharger of the sintered return ore hopper and add the sintered return ore and hot steel slag in a weight ratio of 1:1. At this time, the sintered return ore is drawn into the steel slag by the vortex, so that the sintered return ore and steel slag are fully in contact and reacted.

[0022] S5. During the stirring process, the sintered return ore and the hot steel slag undergo physical and chemical changes at high temperatures. The powder in the sintered return ore is gradually wrapped by the steel slag to form a uniform mixed system. At the same time, some iron oxides begin to react with the components in the steel slag to form a FeO-CaO-SiO2 composite phase wrapping structure. The speed of the KR stirring paddle is controlled at 20r / min-30r / min, and the stirring time is 6min-10min.

[0023] S6. After the stirring is completed, the slag pot is placed in a designated area for standing to allow the sintered return ore and converter slag to be fully sintered and agglomerated. The standing time depends on the ambient temperature and material properties and is generally 2-4 hours. During the standing process, the chemical reaction inside the material continues to form a lump with a certain strength and structure.

[0024] S7, after the lumps are sufficiently cooled to below 100° C., they are poured out from the slag pot and crushed by a roller crusher. The roller pitch of the roller crusher can be adjusted according to the required particle size.

[0025] S8, the crushed material is screened through a 50mm vibrating screen, the screened material larger than 50mm is returned to the roller crusher for further crushing, and the screened material smaller than 50mm is transported by a belt to a 10mm vibrating screen for screening, thereby obtaining the screened material with a particle size of 10mm-50mm. The screened material with a particle size of 10mm-50mm is transported to the converter high-level silo, and the screened material smaller than 10mm is returned to the sintering return silo; S9, the obtained 10mm-50mm particle size particles have a high iron oxide content and suitable alkalinity, and can be directly added as cold material in the converter steelmaking process. In the early stage of converter steelmaking, the particles are added in time according to the temperature and composition in the converter, and the reduction reaction of the iron oxides and carbon in the molten steel is used to absorb excess heat, while providing iron source for the steelmaking process, realizing efficient utilization of solid waste resources and optimization of the steel production process.

[0026] More specifically, the sintered return ore is composed of the following chemical components: TFe: 56wt%~58wt%, FeO: 8wt%~10wt%, CaO: 10wt%~13wt%, SiO2: 5wt%~7wt%, MgO: 1.5wt%~1.7wt%, Al2O3: 1.4wt%~1.6wt% and other inevitable impurities.

[0027] More specifically, the converter slag consists of the following chemical components: TFe: 15wt%~18wt%, FeO: 14wt%~20wt%, CaO: 40wt%~50wt%, SiO2: 18wt%~25wt%, MgO: 8.0wt%~10.0wt%, MnO: 4.0wt%~5.0wt% and other inevitable impurities.

[0028] The above description is only used to illustrate the technical solution of the present invention and is not intended to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in this field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for collaborative agglomeration of sintered return ore and hot converter slag, characterized in that: It includes the following steps: S1: The original KR desulfurization station silo was optimized, with one silo left empty for sintered ore. The sintered ore was then transported to the molten iron KR desulfurization station and added to the center of the slag pot through a chute. S2, when coordinated agglomeration is required, the converter does not splash slag to protect the furnace, and the slag is directly discharged into the slag pot to ensure the temperature of the steel slag; S3, transporting the slag pot filled with hot slag to the molten iron KR processing station; S4, lower the KR stirring paddle to insert it into the slag pot 100 cm, then turn on the KR stirring paddle. The hot slag will generate a vortex when stirred. Then open the hopper discharger of the sintered return ore hopper and add the sintered return ore and hot slag in a weight ratio of 1:

1. At this time, the sintered return ore is drawn into the slag by the vortex, so that the sintered return ore and the slag are fully in contact and reacted. During the stirring process, the sintered ore and the hot slag undergo physical and chemical changes at high temperatures. The powder in the sintered ore is gradually wrapped by the slag to form a uniform mixed system. At the same time, some iron oxides begin to react with the components in the slag to form a FeO-CaO-SiO2 composite phase wrapping structure. S6, after the stirring is completed, the slag pot is placed in a designated area for static standing to allow the sintered ore and converter slag to be fully sintered and agglomerated; S7, after the lumps are sufficiently cooled to below 100°C, they are poured out from the slag pot and crushed using a roller crusher; S8, the crushed material is screened through a 50mm vibrating screen, the screened material larger than 50mm is returned to the roller crusher for further crushing, and the screened material smaller than 50mm is transported by a belt to a 10mm vibrating screen for screening, thereby obtaining the screened material with a particle size of 10mm-50mm. The screened material with a particle size of 10mm-50mm is transported to the converter high-level silo, and the screened material smaller than 10mm is returned to the sintering return silo; S9, the obtained 10mm-50mm particle size particles have a high iron oxide content and suitable alkalinity, and can be directly added as cold material in the converter steelmaking process. In the early stage of converter steelmaking, the particles are added in time according to the temperature and composition in the converter, and the reduction reaction of the iron oxides and carbon in the molten steel is used to absorb excess heat, while providing iron source for the steelmaking process, realizing efficient utilization of solid waste resources and optimization of the steel production process.

2. The method for collaborative agglomeration of sintered return ore and hot converter slag according to claim 1, characterized in that: The lower part of the sintered return ore silo in S1 is a silo discharger with a weighing function.

3. The method for collaborative agglomeration of sintered return ore and hot converter slag according to claim 1, characterized in that: In the S2, a special high-temperature resistant slag pot is used to receive the hot converter slag. The slag pot needs to have good thermal insulation performance and is covered with a thermal insulation cover during transportation to ensure that the temperature of the slag is not lower than 1400°C when it enters the KR station to maintain the liquid state and activity of the slag.

4. The method for collaborative agglomeration of sintered return ore and hot converter slag according to claim 1, characterized in that: The KR processing station in S3 has a weighing function, which can first deduct the net weight of the slag pot and then weigh the weight of the hot slag in the slag pot.

5. The method for collaborative agglomeration of sintered return ore and hot converter slag according to claim 1, characterized in that: The rotation speed of the KR stirring paddle in S5 is controlled at 20 r / min-30 r / min, and the stirring time is 6 min-10 min.

6. The method for collaborative agglomeration of sintered return ore and hot converter slag according to claim 1, characterized in that: The standing time in S6 is determined according to the ambient temperature and the material properties, and is generally 2-4 hours. During the standing time, the chemical reaction inside the material continues to form a block with a certain strength and structure.

7. The method for collaborative agglomeration of sintered return ore and hot converter slag according to claim 1, characterized in that: The roller spacing of the roller crusher in S7 can be adjusted according to the required particle size.

8. The method for collaborative agglomeration of sintered return ore and hot converter slag according to claim 1, characterized in that: The sintered ore has the following chemical composition Composition: TFe: 56wt%~58wt%, FeO: 8wt%~10wt%, CaO: 10wt%~13wt%, SiO2: 5wt%~7wt%, MgO: 1.5wt%~1.7wt%, Al2O3: 1.4wt%~1.6wt% and other inevitable impurities.

9. The method for collaborative agglomeration of sintered return ore and hot converter slag according to claim 1, characterized in that: The converter slag has the following chemical composition Composition: TFe: 15wt%~18wt%, FeO: 14wt%~20wt%, CaO: 40wt%~50wt%, SiO2: 18wt%~25wt%, MgO: 8.0wt%~10.0wt%, MnO: 4.0wt%~5.0wt% and other inevitable impurities.

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