Method for recovering used material particles
The method of crushing, magnetic separation, and density sorting of blast furnace trough refractories addresses the separation challenge, enhancing recycling efficiency and yield by up to 40% through effective categorization based on particle size and density.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- JFE STEEL CORP
- Filing Date
- 2024-11-06
- Publication Date
- 2026-05-19
AI Technical Summary
Existing methods struggle to effectively separate and recycle blast furnace trough refractories due to similar colors and densities of SL and ML materials, leading to low recycling yields, especially for small particle sizes and low-density products.
A method involving crushing, magnetic separation, sieving by particle size, and density separation using an air table to separate blast furnace trough refractories into different categories based on particle size and density, allowing for the recovery of refractory materials.
Enhances recycling efficiency by enabling the recovery of previously considered industrial waste materials, achieving a recycling yield of up to 88% compared to the conventional 48%, with improved purity and reduced impurities.
Smart Images
Figure 2026082159000001_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to a method for recovering used material particles.
Background Art
[0002] In the ironmaking process, the recycling of blast furnace trough refractories that make up the blast furnace trough has been considered. Blast furnace trough refractories are composed of slag line materials (SL materials) and metal line materials (ML materials), and their respective target applications are limited. When disassembling and recovering blast furnace trough refractories after use, slag and metallic iron adhering to the surface are mixed. Therefore, conventionally, they are hardly recycled and are treated as industrial waste.
[0003] As a solution to such problems, Patent Document 1 proposes a method for sorting used blast furnace trough refractories using an air table density separation device.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] In order to recycle blast furnace trough refractories, it is necessary to separate them into three types of components: SL materials, ML materials, and slag after deironing. However, since these materials have very similar colors, it is difficult to industrially use the separation methods used in conventional refractory recycling. In Patent Document 1, the blast furnace trough refractories crushed to a particle size of less than 3 mm cannot be separated by the device, and there is also a problem that for blast furnace trough refractories with a particle size of 3 to 10 mm, the low-density products have a large amount of slag and cannot be recycled.
[0006] This disclosure aims to provide a method for recovering material particles that enable the recycling of refractory materials from blast furnace troughs with small particle size or low density. [Means for solving the problem]
[0007] [1] A method for recovering spent material particles, A recovery step in which material particles are recovered from the blast furnace trough, A crushing step in which the recovered material particles are crushed, A magnetic separation step for separating metallic iron from the crushed material particles, A sieving step in which the material particles after separation of metallic iron are sorted according to particle size, The separation step includes separating the sorted material particles based on the density difference of the constituents, The aforementioned material particles are spent blast furnace trough refractory material. In the aforementioned recovery step, Remove the slag adhering to the surface of the blast furnace trough. The refractory materials of the blast furnace trough are collected by dividing them into two or more categories. Method for recovering used material particles.
[0008] [2] The blast furnace trough refractory material is collected separately from the upstream and downstream of the blast furnace trough. The method for recovering spent material particles according to [1] above, wherein the upstream portion of the blast furnace trough extends from the blast furnace tapping hole to a predetermined position.
[0009] [3] The method for recovering spent material particles according to [2] above, wherein the downstream portion of the blast furnace trough is from the predetermined position to the outlet of the blast furnace trough.
[0010] [4] The material particles include, Slag line material mainly composed of SiC, A metal line material whose main component is Al2O3, Slag containing a large amount of CaO, The aforementioned metallic iron, with Fe as the main component, A method for recovering used material particles as described in any one of the above items [1] to [3].
[0011] [5] The screening step is to distribute the used material particles into those with a particle size of less than 3 mm, those with a particle size of 3 mm or more and less than 6 mm, and those with a particle size of 6 mm or more, and the method for recovering used material particles according to any one of [1] to [4] above.
[0012] [6] The separation step is to separate the used material particles into three density levels, and the method for recovering used material particles according to any one of [1] to [5] above. [Advantages of the Invention]
[0013] According to the present disclosure, it is possible to provide a method for recovering material particles that enables the recycling of small-particle-size or low-density blast furnace trough refractories. [Brief Description of the Drawings]
[0014] [Figure 1] It is a diagram showing an example of a used material particle separation system to which the method for recovering used material particles according to an embodiment of the present disclosure is applied. [Figure 2] It is a diagram showing the location where used blast furnace trough refractories are recovered. [Figure 3] It is a configuration example of a density separation device according to an embodiment of the present disclosure. [Figure 4] It is a graph showing the components of a conventional blast furnace trough refractory, an upstream blast furnace trough refractory, and a downstream blast furnace trough refractory. [Figure 5] It is a graph showing the CaO content rate for each particle size of a conventional blast furnace trough refractory, an upstream blast furnace trough refractory, and a downstream blast furnace trough refractory. [Figure 6] It is a graph showing the component measurement results of the blast furnace trough refractory after density separation. [Figure 7] It is a graph showing the recycling yield in the method according to the conventional example and the present disclosure. <000Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In each drawing, parts having the same configuration or function are denoted by the same reference numerals. In the description of this embodiment, redundant descriptions of the same parts may be omitted or simplified as appropriate.
[0016] Figure 1 shows an example of a spent material particle separation system 1 to which a spent material particle recovery method according to one embodiment of the present disclosure is applied. In one embodiment of the present disclosure, the material particles are blast furnace trough refractories. The spent blast furnace trough refractories include SL material mainly composed of SiC, ML material mainly composed of Al2O3, slag containing a large amount of CaO, and metallic iron mainly composed of Fe.
[0017] The waste material particle separation system 1 comprises a crushing device 10, a magnetic separator 20, a sieving device 30, and a density separator 40.
[0018] The crushing device 10 crushes the recovered used blast furnace trough refractories. The crushing device 10 may be, for example, a hammer crusher, a roll crusher, a jaw crusher, etc. In one embodiment of the present disclosure, the crushing device 10 crushes the used blast furnace trough refractories to a size of 10 mm or less. The blast furnace trough refractories crushed by the crushing device 10 are sent to the magnetic separator 20.
[0019] Figure 2 shows the collection points for used blast furnace trough refractories. The blast furnace trough is a facility that flows molten iron discharged from the blast furnace 50 to the molten iron trough 54 and the inclined pour trough 55. Slag discharged from the blast furnace along with the molten iron is guided to the slag trough 53. The blast furnace trough is equipped with a trough cover 56. In one embodiment of the present disclosure, the blast furnace trough refractories are collected by separating them into surface-adhering slag, upstream blast furnace trough refractories which are refractories used in the upstream blast furnace trough 51, and downstream blast furnace trough refractories which are refractories used in the downstream blast furnace trough 52. Here, the area from the blast furnace tapping hole to a predetermined position is defined as the upstream blast furnace trough 51, and the area from the predetermined position to the blast furnace trough outlet is defined as the downstream blast furnace trough 52. The distance from the blast furnace tapping hole to the predetermined position is not limited to this, but may be, for example, 10 m. The surface slag is treated as industrial waste, while the upstream blast furnace trough refractories and the downstream blast furnace trough refractories are fed separately into the crushing device 10.
[0020] The magnetic separator 20 is installed downstream of the crushing device 10. The magnetic separator 20 separates the blast furnace trough refractory crushed by the crushing device 10 into magnetically attached and non-magnetic materials. The magnetic separator 20 may be, for example, a drum-type magnetic separator, a conveyor magnetic separator, or a suspended magnetic separator. The blast furnace trough refractory separated as magnetic material by the magnetic separator 20 is recycled as metallic iron. The blast furnace trough refractory separated as non-magnetic material by the magnetic separator 20 is sent to the sieving device 30.
[0021] The sieving device 30 is installed downstream of the magnetic separator 20. The sieving device 30 sieves the non-magnetic material particles separated by the magnetic separator 20 into predetermined particle sizes using at least one sieve.
[0022] In one embodiment of the present disclosure, the sieving device 30 comprises two sieves. The sieving device 30, for example, sieves the material particles into those with a particle size of less than 3 mm, those with a particle size of 3 mm or more but less than 6 mm, and those with a particle size of 6 mm or more. The particles with a particle size of less than 3 mm have a low CaO content, which is the main component of slag, and are sent for recycling as ML material. The particles with a particle size of 3 mm or more but less than 6 mm and those with a particle size of 6 mm or more are sent separately to the density separation device 40.
[0023] The density separation device 40 is installed downstream of the sieving device 30. The density separation device 40 separates the material particles sieved by the sieving device 30 according to predetermined densities. The density separation device 40 may be, for example, an air table. An air table is installed at an angle with a table perforated with tiny holes, and separates heavy and light materials by supplying air from below and vibrating the table.
[0024] Figure 3 shows an example of the configuration of a density separation device 40 according to one embodiment of the present disclosure. In Figure 3, white dots represent low-density particles, gray dots represent medium-density particles, and black dots represent high-density particles. In one embodiment of the present disclosure, the density separation device 40 is an air table. The density separation device 40 separates material particles with a particle size of 3 mm or more and less than 6 mm sent from the sieving device 30 into three stages: high density, medium density, and low density, according to the density of the particles. The density separation device 40 also separates material particles with a particle size of 6 mm or more sent from the sieving device 30 into three stages: high density, medium density, and low density, according to the density of the particles.
[0025] High-density material particles, although rich in Al2O3, are recycled as low-grade molten iron trough material because impurities have not been completely removed. Similarly, medium-density material particles, although rich in SiC, are recycled as low-grade ML material because impurities have not been completely removed. Low-density material particles in upstream blast furnace trough refractories are recycled as cover material because they make a lightweight refractory. Low-density material particles in downstream blast furnace trough refractories contain a large amount of CaO and are therefore disposed of as industrial waste.
[0026] By adopting this method, material particles with a particle size of less than 3 mm and refractory materials from the upstream blast furnace trough, which were previously considered industrial waste, can be recycled, enabling high-yield recycling. [Examples]
[0027] The embodiments of this disclosure are described below. However, the embodiments of this disclosure are not limited to the embodiments described below and can be modified at will without departing from the gist of this disclosure.
[0028] Tests were conducted using a blast furnace trough refractory recovery and separation method according to one embodiment of this disclosure, and a conventional blast furnace trough refractory recovery and separation method.
[0029] In the method described herein, cold water was sprayed onto the spent blast furnace trough refractory material to remove the slag adhering to the surface, and the slag was removed using heavy machinery. Subsequently, the section from the blast furnace tap hole to a point 10m in the middle of the trough's total length of approximately 18-20m was designated as the upstream section of the trough, and the section from 10m in the tap hole to the trough outlet was designated as the downstream section of the trough, and the upstream and downstream blast furnace trough refractory materials were recovered, respectively.
[0030] Figure 4 shows the results of comparing the composition of blast furnace trough refractories recovered by a conventional method with those recovered by the method described herein for the upstream and downstream blast furnace troughs. According to the method described herein, compared to conventional blast furnace trough refractories, the CaO content in the upstream blast furnace trough refractories was reduced to 2.3%, about half of the conventional amount, while the SiC content increased. In the downstream blast furnace trough refractories, the Al2O3 content increased. Comparing the upstream and downstream blast furnace trough refractories, it was confirmed that SiC was concentrated in the upstream blast furnace trough refractories, while CaO and Al2O3 were concentrated in the downstream blast furnace trough refractories.
[0031] Next, the blast furnace trough refractories were crushed to a size of 10 mm or less, and metallic iron was separated by magnetic separation. The blast furnace trough refractories were then sieved into sizes of 0-1 mm, 1-2 mm, 2-3 mm, 3-4 mm, 4-5 mm, and 5-10 mm, and the components of each size were measured. Figure 5 shows the CaO content for each particle size of the conventional blast furnace trough refractories, the upstream blast furnace trough refractories, and the downstream blast furnace trough refractories. As shown in Figure 5, compared to the conventional blast furnace trough refractories, the CaO content decreased in the blast furnace trough refractories with particle sizes from 0 to 3 mm, both in the upstream and downstream sections.
[0032] Next, density separation was performed on blast furnace trough refractories with a particle size of 3 mm or larger. The density separation was carried out under different conditions for the upstream and downstream blast furnace trough refractories. Table 1 shows the density separation conditions for the air table, and Figure 6 shows the results of the component measurement of the blast furnace trough refractories after density separation.
[0033] [Table 1]
[0034] As shown in Figure 6, even at a low density, the CaO content in the upstream blast furnace trough refractory material was below the target value of 3.6% for use as ML material, making it recyclable as blast furnace trough cover material.
[0035] Figure 7 shows the recycling yield for a conventional example and the method described herein. As shown in Figure 7, the recycling yield for the conventional example was 48%, while the recycling yield for the method described herein improved to 88%.
[0036] This disclosure is not limited to the embodiments described above. For example, multiple blocks described in the block diagram may be combined, or a single block may be divided. Instead of executing multiple steps described in the flowchart in chronological order as described, they may be executed in parallel or in a different order, depending on the processing capacity of the device performing each step, or as necessary. Other modifications are possible without departing from the spirit of this disclosure.
[0037] Furthermore, in the above-described embodiment, the blast furnace trough refractories were collected by dividing them into two categories: upstream and downstream. However, the number of categories is not limited to these, and they may be collected in any number of categories, as long as there are two or more. For example, the blast furnace trough refractories may be collected by dividing them into three categories: upstream, midstream, and downstream. [Explanation of Symbols]
[0038] 1. Separation system for spent material particles 10 Crushing device 20 Magnetic separator 30 Sieve device 40 Density Separator 50 blast furnace 51 Upstream blast furnace gutter 52 Downstream of the blast furnace culvert 53 Slag gutters 54 Molten iron pit 55. Inclined drain 56 Gutter cover 60 Air Table
Claims
1. A method for recovering used material particles, A recovery step in which material particles are recovered from the blast furnace trough, A crushing step in which the recovered material particles are crushed, A magnetic separation step for separating metallic iron from the crushed material particles, A sieving step in which the material particles after separation of metallic iron are sorted according to particle size, The separation step includes separating the sorted material particles based on the density difference of the constituents, The aforementioned material particles are spent blast furnace trough refractory material. In the aforementioned recovery step, Remove the slag adhering to the surface of the blast furnace trough. The refractory materials of the blast furnace trough are collected by dividing them into two or more categories. Method for recovering used material particles.
2. The refractory material of the blast furnace trough is recovered separately from the upstream and downstream sections of the blast furnace trough. The method for recovering spent material particles according to claim 1, wherein the upstream portion of the blast furnace trough extends from the blast furnace tapping hole to a predetermined position.
3. The method for recovering spent material particles according to claim 2, wherein the downstream portion of the blast furnace trough is from the predetermined position to the outlet of the blast furnace trough.
4. The particles of the aforementioned material include, Slag line material with SiC as the main component, Al ２ O ３ A metal line material whose main component is, Slag containing a large amount of CaO, The aforementioned metallic iron, with Fe as the main component, A method for recovering used material particles according to claim 1.
5. The aforementioned sieving step is A method for recovering used material particles according to claim 1, wherein the material particles are sorted into those with a particle size of less than 3 mm, those with a particle size of 3 mm or more and less than 6 mm, and those with a particle size of 6 mm or more.
6. The separation step is, A method for recovering used material particles according to claim 1, wherein the material particles are separated into three densities.