A method for recycling converter solid waste

Abstract

This invention provides a method for recycling solid waste from a converter, belonging to the field of converter smelting technology. The method includes: capturing coarse particles from converter exhaust gas; obtaining reusable coarse particles through multi-stage magnetic attraction; recycling the reusable coarse particles into a scrap steel hopper, covering the surface with scrap steel to form a structure with a bottom layer of coarse particles and an upper layer of scrap steel; adding the structure into the converter and performing smelting using a pre-set explosion-proof blowing process. This method recovers high-iron-content (above 65%) coarse particles generated during converter smelting and directly reuses them in the scrap steel + molten iron smelting process, reducing the procurement of raw materials such as iron ore and scrap steel, and significantly improving the economic benefits of enterprises. Direct return to the furnace after magnetic separation reduces intermediate transfer, processing, and re-sintering steps, improving efficiency. Coarse zinc particles in the exhaust gas can be efficiently captured in the high-temperature zone of the converter and enter the dust collector, reducing their accumulation in the ironmaking system, effectively alleviating the problem of increased zinc load in the blast furnace, and extending the blast furnace life.

Description

Technical Field

[0001] This invention relates to the field of converter smelting technology, and in particular to a method for recycling solid waste from converters. Background Technology

[0002] Converter smelting is one of the core processes in steel production. By blowing oxygen into molten iron, decarburization and dephosphorization reactions are achieved, ultimately producing steel. During the smelting process, due to the physicochemical properties and reaction kinetics limitations of the raw materials (such as iron ore and coke), some coarse particles cannot fully participate in the reaction within the furnace. They either settle at the bottom of the furnace due to gravity or are discharged with the exhaust gas. This not only reduces the utilization rate of raw materials but also increases subsequent processing costs. On the other hand, with increasingly stringent environmental policies, steel companies need to balance production efficiency with ultra-low emission requirements. How to efficiently treat converter solid waste and achieve resource utilization has become an urgent problem for the industry.

[0003] Currently, the industry generally uses a combination of wheelbarrow transport and briquetting to solidify coarse particulate materials (mainly unreacted iron ore and coke) generated during converter smelting. Specifically, after the sediment is collected, part of it is transported to the sintering process as sintering raw material, while the other part is directly returned to the steelmaking process for reuse. In addition, a small amount of fine particulate material is captured by a dust removal system and then used for sintering or landfill disposal.

[0004] However, coarse-grained materials, due to their large particle size and low reactivity, are difficult to fully react when directly returned to the smelting or sintering processes; the transportation and briquetting of converter solid waste consumes a large amount of energy and manpower, and environmental compliance costs are high. These problems restrict steel companies from reducing costs, increasing efficiency, and achieving green transformation.

[0005] Therefore, there is an urgent need for a more efficient method for recycling converter solid waste. Summary of the Invention

[0006] In view of this, the present invention provides a method for recycling solid waste from converters, which uses multi-stage magnetic attraction to recover coarse particles for reuse; and designs a blowing process to avoid the risk of explosion during the blowing process.

[0007] Therefore, the present invention provides the following technical solution:

[0008] A method for recycling solid waste from a converter includes:

[0009] Coarse particles in converter exhaust gas are captured and reused through multi-stage magnetic attraction.

[0010] The coarse particles are recycled into the scrap steel bin, and the surface is covered with scrap steel, forming a structure with coarse particles at the bottom and scrap steel on the top.

[0011] The structure is added to the converter, and blowing is carried out using a preset explosion-proof blowing process.

[0012] Furthermore, coarse particles in the waste gas during the converter smelting process are captured by the primary dust removal device in the converter.

[0013] Furthermore, the method of obtaining reusable coarse particles through multi-stage magnetic attraction includes:

[0014] A high-efficiency permanent magnet drum is installed at the dust emission end to perform preliminary separation of coarse particles and obtain preliminary coarse particles;

[0015] The initial coarse particles are transported to the scrap metal storage area via sealed conveyor carts;

[0016] Electromagnetic disk lifting devices are installed in the scrap steel room to perform secondary magnetic separation on the initial coarse particles to improve their purity and obtain reusable coarse particles.

[0017] Furthermore, a crane disk adsorption method is used to recycle coarse particles into the waste steel hopper.

[0018] Furthermore, the preset explosion-proof refining process includes:

[0019] Before starting the blowing process, nitrogen purging at a high lance position is performed for a preset time to disperse the accumulated powder in the furnace.

[0020] Furthermore, the preset explosion-proof refining process also includes:

[0021] During the initial oxygen blowing period, the oxygen flow rate should be controlled at 60% to 70% of the normal flow rate; once the molten iron reaction reaches a stable state, the oxygen flow rate should be restored to full flow.

[0022] During the middle stage of blowing, the oxygen supply intensity of the oxygen lance is increased by 10%-30% compared to the initial stage of blowing, and this oxygen supply intensity is maintained for a preset time during the middle stage of blowing.

[0023] Advantages and positive effects of the present invention:

[0024] This method recovers high-iron-content (over 65%) coarse-particle materials generated during converter smelting and directly reuses them in the scrap steel + molten iron smelting process, which can reduce the amount of raw materials such as iron ore and scrap steel purchased and significantly improve the economic benefits of enterprises.

[0025] In this method, the material is directly returned to the furnace after magnetic separation, which reduces intermediate transfer, processing and re-sintering processes and improves efficiency.

[0026] This method allows coarse zinc particles in the exhaust gas to be efficiently captured in the high-temperature zone of the converter and incorporated into the dust collector, reducing their accumulation in the ironmaking system, effectively alleviating the problem of increased zinc load in the blast furnace, and extending the blast furnace's lifespan. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a flowchart of the converter solid waste recycling method in an embodiment of the present invention. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0030] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0031] This invention provides a method for recycling solid waste from a converter. Coarse particles in the waste gas during the converter smelting process are obtained through two magnetic screenings to obtain recyclable coarse particles. Furthermore, the risk of explosion during the initial blowing is reduced by using nitrogen purging at a high lance position.

[0032] Specific application examples

[0033] S1. Capture coarse particles in the waste gas during converter smelting;

[0034] The primary dust removal device of the converter is used to collect coarse particulate materials in the waste gas during the converter smelting process.

[0035] S2. Due to the large particle size and high iron content (over 65%) of coarse-grained materials, the magnetic separation efficiency is high.

[0036] Therefore, in this embodiment, a high-efficiency permanent magnet drum is installed at the dust emission end to perform preliminary separation of coarse particles and obtain preliminary coarse particles.

[0037] S3. Initial coarse particles are transported to the scrap steel room via sealed conveyor carts to prevent dust from escaping.

[0038] S4. Magnetic separation and reuse of scrap steel;

[0039] Electromagnetic disk lifting devices are installed in the scrap steel room to perform secondary magnetic separation on the initial coarse particles to improve their purity and obtain reusable coarse particles.

[0040] Using a crane disk adsorption method, recycled coarse particles are loaded into the bottom of the scrap steel hopper, and the surface is covered with ordinary scrap steel, forming a loading structure of "bottom coarse particles + top scrap steel".

[0041] S5. Loading method;

[0042] When charging the converter, first add a hopper containing coarse particles of scrap steel, and use the scrap steel covering layer to prevent dust from flying.

[0043] Having coarse particles at the bottom can improve melting efficiency and reduce the risk of splashing.

[0044] S6, Refining process;

[0045] Explosion-proof measures: Since coarse particles are in powder form and easily trigger explosions during the initial blowing process, the following blowing procedure is adopted:

[0046] Before starting the blowing process, nitrogen purging at a high lance position is performed for a preset time to disperse the accumulated powder in the furnace.

[0047] Initially, the oxygen flow rate should be controlled at 60-70% of the normal flow rate, and then restored to full flow rate after the molten iron reaction stabilizes.

[0048] Coarse particles have a high iron content but low sensible heat, so the oxygen supply intensity of the oxygen lance needs to be appropriately increased during the middle stage of blowing.

[0049] The method of this invention proposes to recycle coarse particles as scrap steel by taking measures such as analyzing the raw materials of dust removal ash, conducting batching tests, and tracking the blowing process. By forming a charging structure of "bottom coarse particles + top scrap steel" and improving the blowing process, the method realizes the recycling and reuse of coarse particles and avoids the risk of explosion during blowing.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for recycling solid waste from a converter, characterized in that, include: The process of capturing coarse particles in converter exhaust gas and obtaining reusable coarse particles through multi-stage magnetic attraction includes: installing a high-efficiency permanent magnet drum at the dust removal ash emission end for preliminary separation of coarse particles to obtain preliminary coarse particles; transporting the preliminary coarse particles to the scrap steel room via a sealed conveyor trolley; and setting up an electromagnet lifting device in the scrap steel room to perform secondary magnetic separation on the preliminary coarse particles to improve their purity and obtain reusable coarse particles. The coarse particles are recycled into the scrap steel bin, and the surface is covered with scrap steel, forming a structure with coarse particles at the bottom and scrap steel on the top. The aforementioned structure is added to the converter, and a preset explosion-proof blowing process is used for blowing. The blowing process includes: purging the furnace with nitrogen at a high lance position for a preset time before starting blowing to disperse accumulated dust; controlling the oxygen flow rate to 60% to 70% of the normal flow rate during the predetermined time of starting oxygen blowing; restoring the oxygen flow rate to full flow rate after the molten iron reaction reaches a stable state; and increasing the oxygen supply intensity of the oxygen lance by 10% during the middle stage of blowing compared to the initial stage. 30%, and maintain this oxygen supply intensity for a preset time during the middle of the blowing process.

2. The method for recycling converter solid waste according to claim 1, characterized in that, Coarse particles in the exhaust gas during the converter smelting process are captured by the primary dust removal device in the converter.

3. The method for recycling converter solid waste according to claim 1, characterized in that, The coarse particles are recycled into the waste steel hopper using a crane disk adsorption method.

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