A method for reducing particle size segregation in a multi-stage flat lay of a mixed material

Abstract

The present application belongs to the technical field of sintering mixed material batching, and relates to a method for reducing particle size segregation of mixed material in a multi-stage flat laying manner. According to the required batching ratio, each kind of material is divided into 3-4 stages according to particle size, the first stage is for the material with the largest particle size and the most segregation, the second stage is for the dust removal ash with fine particle size and large dust, and the third and fourth stages are for the material with uniform particle size. Before taking the material, the head and tail cutting operation is implemented, and the mixed material in this area is returned to the top of the new pile. The present application adopts the segmented flat laying manner, solves the particle size segregation, adds the dust removal ash in the second stage, and solves the problem of dust diffusion. Each bin can be used alternately, solving the problem of the number of bins. At the same time, small materials can be added in a certain stage, realizing the recycling of iron-containing resources.

Description

Technical Field

[0001] This invention belongs to the field of sintering and homogenizing material batching technology, specifically relating to a method for reducing particle size segregation through multi-stage flat spreading of homogenized materials. Background Technology

[0002] Sinter production is a crucial step in iron and steel metallurgical production. The rationality of the sinter blend ratio not only affects the yield and quality of sinter but also significantly impacts its final cost. To achieve uniform blending, a silo distribution method is typically used, where individual materials are poured into different silos according to a set ratio to ensure simultaneous addition of each material during the distribution process. However, due to the scarcity of ore resources, the large volume and variety of iron ore used have led to a continuous increase in the number of silos required. Furthermore, the significant particle size differences between different material types mean that simultaneous addition of various materials can easily cause particle segregation, with particles larger than 8mm tending to accumulate at the edges of the stockpile.

[0003] Meanwhile, with the recycling of carbonaceous solid waste, various dust collector ash particles are added to the mixing materials. Due to the fine particle size of the dust collector ash, dust is generated during the spreading and direct extraction processes, failing to meet environmental protection requirements. Currently, many enterprises adopt multi-span, multi-stacking layouts to improve the uniformity of the mixing materials and reduce particle segregation. These layouts occupy a large area, and the renovated steel plants, due to their compact layout and scarce land resources, cannot meet the land requirements. In addition, due to the small quantity of on-site solid waste such as iron oxide scale, it is not possible to achieve full-process mixing.

[0004] Chinese invention patent application CN 113388733 A discloses a method for controlling the fluctuation of the composition of a homogenized material. This method divides the homogenized material into five stable material layer intervals and uses a tiered material ratio method for stockpiling. Material flow control is only applied during the batching process, which does not increase the homogenization of the homogenized material and avoids the waste of ore resources caused by tailings. The article "Research on the Hybridization and Batching Technology of SiO2 and TFe by Shougang Jingtang et al." (Sintering and Pelletizing, 2017, No. 4, pp. 35-39) uses the BLOCK method. This method imposes too many restrictions on material types and ratios, and the minimum ratio is greater than 1%, which cannot meet the requirements for adding small amounts of different materials. Summary of the Invention

[0005] To address the problems of existing methods for reducing particle size segregation in mixed materials, such as the need for a large number of silos, the presence of large particles at the edges, the large area required for material storage, severe dust generation, and difficulty in adding small material types, the present invention aims to provide a method for reducing particle size segregation through multi-stage flat laying of mixed materials.

[0006] The technical solution adopted by this invention to solve its technical problem is: a method for reducing particle size segregation by multi-stage flat spreading of mixed materials. According to the production requirements, each material is divided into 3-4 stages according to particle size. The first stage is filled with the material with the largest particle size and the most prone to segregation; the second stage is filled with the fine particle size and dust that generates a lot of dust; the third and fourth stages are filled with materials with uniform particle size; before taking out the material, the head and tail are trimmed, and the mixed material in this area is returned to the top of the new pile.

[0007] Furthermore, each material is classified into five grades according to particle size: >8mm, 5-8mm, 3-5mm, 1-3mm, and <1mm.

[0008] Furthermore, the specific steps are as follows:

[0009] (1) After the new stockpile is opened, the first stage of feeding is poor, with more than 30% of the particles > 8mm. For materials with a large proportion of large particles, the material flow rate should be controlled to ≤ 800t / h, and the number of layers should be controlled to 100-120.

[0010] (2) The second stage is to add fine carbonaceous solid waste with a particle size of <1mm and a proportion of more than 20%, and control the material flow rate to 1050-1200t / h and the number of layers to 15-20.

[0011] (3) The third stage is to add materials with uniform particle size and good material properties, with 1-8mm accounting for more than 85%, and control the material flow rate to 1500-1600t / h and the number of layers to 190-220.

[0012] (4) Head and tail materials shall be trimmed.

[0013] (5) Head material handling: After the sealing of the pile is completed, the reclaimer starts to take the head material, starting from the bottom edge of the head of the pile and taking it 17-19m towards the tail. At this time, the tip of the material advances forward 3.9-5.2m, and the head material is returned to the new pile of this pile.

[0014] (6) Tail material disposal: Tail material disposal is divided into two parts, one part is transition material and the other part is dead material pile; the outermost edge of the tail of the pile is fixed as a dead material pile 16.5-18.5m towards the head. This pile is fixed and not removed, which serves as a retaining wall and reduces the segregation of the tail material; 4-8m towards the head, 2000-4000 tons is the "transition material" area. The mixed material in this area is returned to the top of the new pile.

[0015] Furthermore, the carbonaceous solid waste in step (2) is one or more of the following: coking dust, sintering dust, blast furnace rotary dust, and steelmaking fine ash.

[0016] Furthermore, when the proportion of 3-5mm particles in the feed is greater than 50%, a fourth stage of addition is added, in which the feed with the most uniform particle size is added.

[0017] Furthermore, each material in each section must be added evenly throughout the entire process. When switching between spare bins, a delay operation is used to ensure that the "joints" of the same material are aligned. The delay time is equal to the distance between the two bins and the belt speed.

[0018] Furthermore, enhance the matching between the stockpile flow rate and the walking and spreading of the blending stockpile: V 逆 / V 顺 =V 带 / (V 带 -2V 顺 ), where V 顺 V is the forward speed of the mixing and stacking machine. 逆 V is the reverse speed of the mixing and stacking machine. 带 This refers to the belt running speed.

[0019] The present invention has the following beneficial effects:

[0020] 1. This invention adopts a segmented flat-laying method, which adds materials in stages according to the particle size of the material. Each silo can be used in rotation, thus solving the problem of the number of silos.

[0021] 2. This invention classifies various materials according to particle size, spreading large particles evenly at the bottom of the material pile, which solves the problem of edge distribution of materials with a particle size greater than 8mm and reduces particle size segregation.

[0022] 3. In the second stage, the present invention adds fine-grained, lightweight carbonaceous solid waste such as coking dust, sintering dust, blast furnace rotary dust, and steelmaking fine ash with a particle size of <1mm accounting for more than 20%, which solves the problem of dust dispersion during the material handling process.

[0023] 4. The present invention features segmented flat paving, which can adopt a two-span, two-pile layout, replacing the multi-span, multi-pile model of newly built steel plants, and greatly reducing the land area occupied by the mixing yard.

[0024] 5. Since the amount of iron oxide scale, miscellaneous ores and other materials in steel plants is small and the proportion is small, it is difficult to achieve uniform addition. This invention adopts a multi-stage flat laying method, which can add small types of materials at a certain stage, ensuring their uniform addition and realizing the recycling of iron-containing resources.

[0025] 6. The present invention performs head and tail trimming operations on the head and tail materials and spreads them flat on the top of the material pile, which solves the problem of head material segregation. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the cross-section of the mixed material in Example 1.

[0027] Figure 2 This is a schematic diagram of the head material taking out in Example 1.

[0028] Figure 3 This is a schematic diagram of material removal at the tail end in Example 1. Detailed Implementation

[0029] The following are specific embodiments of the present invention, which further describe the technical solution of the present invention. However, the scope of protection of the present invention is not limited to these embodiments. All changes or equivalent substitutions that do not depart from the concept of the present invention are included within the scope of protection of the present invention.

[0030] According to the production requirements, each material type will be divided into five grades based on particle size: >8mm, 5-8mm, 3-5mm, 1-3mm, and <1mm. Each material type will be added in 3-4 stages according to particle size. After the new stockpile is opened, the first stage will be added with poor material properties, with particles >8mm accounting for more than 30% and a large proportion of large particles. The material flow rate will be controlled at ≤800t / h, and the number of layers will be controlled at 100-120. The second stage will be added with fine particles, with <1mm accounting for more than 20% and lightweight carbonaceous solid waste. The carbonaceous solid waste is one or more mixtures of coking dust, sintering dust, blast furnace rotary dust, and steelmaking fine ash. The material flow rate is controlled at 1050-1200 t / h, and the number of layers is controlled at 15-20. The third stage adds materials with uniform particle size and good material properties, with 1-8mm particles accounting for more than 85%, and the material flow rate is controlled at 1500-1600 t / h, with the number of layers controlled at 190-220. When the proportion of 3-5mm particles in the material is >50%, a fourth stage is added, adding the material with the most uniform particle size. Before material removal, the head and tail of the material are trimmed.

[0031] Head material handling: After the sealing of the pile is completed, the reclaimer begins to remove the head material, starting from the bottom edge of the head of the pile and moving towards the tail for 17-19m. At this time, the tip of the material advances forward 3.9-5.2m, and the head material is returned to the new pile of this pile.

[0032] Tail material handling: Tail material handling is divided into two parts: one is transition material and the other is dead material pile; the outermost edge of the tail of the pile is fixed as a dead material pile 16.5-18.5m towards the head. This pile is fixed and not removed, serving as a retaining wall and reducing tail material segregation; 4-8m towards the head, 2000-4000 tons is the "transition material" zone. The mixed material in this zone is returned to the top of the new pile.

[0033] Example 1

[0034] According to the production requirements, the particle size of materials such as Lunan fine powder, Yangdi powder, Lingang fine powder, iron oxide scale, and dust collector ash are divided into five grades: >8mm, 5-8mm, 3-5mm, 1-3mm, and <1mm.

[0035] like Figure 1As shown, after the new stockpile is opened, the first stage has poor feedability, with more than 30% of the particles being >8mm. For materials with a large proportion of large particles, the feed flow rate should be controlled at ≤800t / h, and the number of layers should be controlled at 120.

[0036] The second stage adds fine-grained, lightweight carbonaceous solid wastes, such as coking dust, sintering dust, blast furnace rotary dust, and steelmaking fine ash, with a particle size of <1mm accounting for more than 20%. The material flow rate is controlled at 1150t / h, and the number of layers is controlled at 19.

[0037] The third stage adds materials with uniform particle size and good material properties, with 1-8mm accounting for more than 85%, controlling the material flow rate to 1570t / h and the number of layers to 215.

[0038] The fourth stage adds materials with a particle size of 3-5mm accounting for more than 50%, controls the material flow rate at 1500t / h, and controls the number of layers at 41.

[0039] Each material in each section must be added evenly throughout the process. When switching between spare bins, a delay operation is used to ensure that the "joints" of the same material are aligned. The delay time is equal to the distance between the two bins and the belt speed.

[0040] Headstock handling: After the stockpile is sealed, the reclaimer begins removing the headstock, starting from the westernmost bottom edge of the stockpile and moving 17.5m eastward. At this point, the tip of the stockpile has advanced 4m. Figure 2 As shown. The head stock is returned to the new pile in this pile.

[0041] Tail material handling: Tail material handling is divided into two parts: one is transition material, and the other is dead material stockpile, such as... Figure 3 As shown. 17m west of the outermost edge of the eastern side of the stockpile, a fixed dead stockpile is maintained and not removed, serving as a retaining wall and reducing material segregation at the tail end. 8m further west, approximately 4000 tons, is the "transitional material" zone, where the mixed material returns to the top of the new stockpile.

[0042] Example 2

[0043] According to the production requirements, the particle size of materials such as Roy Mountain powder, Brazilian Cara powder, Australian refined powder, iron oxide scale, and dust collector ash are divided into five grades: >8mm, 5-8mm, 3-5mm, 1-3mm, and <1mm.

[0044] After the new stockpile is opened, the first stage of feeding is poor, with more than 30% of the material having a particle size > 8mm. For materials with a large proportion of large particles, the material flow rate should be controlled to ≤ 800t / h, and the number of layers should be controlled to 110.

[0045] The second stage adds fine-grained, lightweight carbonaceous solid wastes, such as coking dust, sintering dust, blast furnace rotary dust, and steelmaking fine ash, with a particle size of <1mm accounting for more than 20%. The material flow rate is controlled at 1100t / h, and the number of layers is controlled at 20.

[0046] The third stage of addition consists of materials with uniform particle size and good material properties, with 1-8mm accounting for more than 85%, controlling the material flow rate at 1550t / h and the number of layers at 216.

[0047] Each material in each section must be added evenly throughout the process. When switching between spare bins, a delay operation is used to ensure that the "joints" of the same material are aligned. The delay time is equal to the distance between the two bins and the belt speed.

[0048] Headstock handling: After the stockpile is sealed, the reclaimer begins to remove the headstock, starting from the westernmost bottom edge of the stockpile and moving 18.5m eastward. At this point, the tip of the headstock has advanced 5m. The headstock is then returned to the new stockpile on the same site.

[0049] Tailstock disposal: Tailstock disposal is divided into two parts: a transitional stockpile and a dead stockpile. 18m west of the easternmost edge of the bottom of the stockpile, a fixed dead stockpile is maintained and not removed, serving as a retaining wall and reducing tailstock segregation. 4.5m further west, approximately 2250 tons, is the "transitional stockpile" area. The mixture in this area is returned to the top of the new stockpile.

[0050] This invention is not limited to the above-described embodiments. Anyone should know that any structural changes made under the guidance of this invention, and any technical solutions that are the same as or similar to this invention, fall within the protection scope of this invention.

[0051] The technologies, shapes, and structures not described in detail in this invention are all known technologies.

Claims

1. A method for reducing particle size segregation through multi-stage flat spreading of a mixed material, characterized in that, According to the production requirements, the materials are divided into 3-4 sections according to particle size. The first section contains the materials with the largest particle size and the most prone to segregation; the second section contains the fine particles and dust that generate a lot of dust. The third and fourth sections are mixed with uniformly sized materials; before taking out the materials, the head and tail are trimmed, and the mixture in this area is returned to the top of the new pile.

2. The method for reducing particle size segregation through multi-stage flat spreading of the mixed material as described in claim 1, characterized in that, The materials are classified into five grades according to particle size: >8mm, 5-8mm, 3-5mm, 1-3mm, and <1mm.

3. The method for reducing particle size segregation through multi-stage flat spreading of the mixed material as described in claim 1 or 2, characterized in that, The specific steps are as follows: (1) After the new stockpile is opened, the first stage of feeding is poor, with more than 30% of the particles > 8mm. For materials with a large proportion of large particles, the material flow rate should be controlled to ≤ 800t / h, and the number of layers should be controlled to 100-120. (2) The second stage is to add fine carbonaceous solid waste with a particle size of <1mm and a proportion of more than 20%, and control the material flow rate to 1050-1200t / h and the number of layers to 15-20. (3) The third stage is to add materials with uniform particle size and good material properties, with 1-8mm accounting for more than 85%, and control the material flow rate to 1500-1600t / h and the number of layers to 190-220. (4) Head and tail materials shall be trimmed. (5) Head material handling: After the sealing of the pile is completed, the reclaimer starts to take the head material, starting from the bottom edge of the head of the pile and taking it 17-19m towards the tail. At this time, the tip of the material advances forward 3.9-5.2m, and the head material is returned to the new pile of this pile. (6) Tail material disposal: Tail material disposal is divided into two parts, one part is transition material and the other part is dead material pile; the outermost edge of the tail of the pile is fixed as a dead material pile 16.5-18.5m towards the head. This pile is fixed and not removed, which serves as a retaining wall and reduces the segregation of the tail material; 4-8m towards the head, 2000-4000 tons is the "transition material" area. The mixed material in this area is returned to the top of the new pile.

4. The method for reducing particle size segregation through multi-stage flat spreading of the mixed material as described in claim 3, characterized in that, The carbon-containing solid waste in step (2) is one or a mixture of coking dust, sintering dust, blast furnace rotary dust, and steelmaking fine ash.

5. The method for reducing particle size segregation through multi-stage flat spreading of the mixed material as described in claim 3, characterized in that, When the proportion of 3-5mm particles in the feed is greater than 50%, a fourth stage of addition is added to mix the feed with the most uniform particle size.

6. The method for reducing particle size segregation through multi-stage flat spreading of the mixed material as described in claim 3, characterized in that, Each material in each section must be added evenly throughout the process. When switching between spare bins, a delay operation is used to ensure that the "joints" of the same material are aligned. The delay time is equal to the distance between the two bins and the belt speed.

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