Carbonized slag smelting flue gas comprehensive utilization method

Abstract

This invention provides a method for the comprehensive utilization of flue gas from smelting carbide slag. The method includes: adding solid titanium-containing blast furnace slag and a carbonaceous reducing agent to a pre-reduction furnace; adding the carbonaceous reducing agent and the molten slag from step S10 to a carbide electric furnace for smelting; and water quenching the molten slag. High-temperature flue gas is collected from the pre-reduction furnace, combustible gases are removed by combustion in a secondary combustion chamber, and the combusted flue gas is heat-exchanged through a heat exchanger to obtain flue gas for preliminary drying of the water-quenched slag. This invention proposes a method for the comprehensive utilization of flue gas from smelting carbide slag, recovering the latent heat of the low-CO concentration flue gas generated by the pre-reduction furnace and using it for preliminary drying of the water-quenched slag; and using the high-CO concentration flue gas generated by the carbide electric furnace in a vertical mill system to further dry and grind the water-quenched slag, ensuring that the finished slag meets the particle size and moisture requirements. This invention achieves the rational utilization of flue gas from smelting carbide slag, contributing to the safety and cost control of carbide smelting.

Description

Technical Field

[0001] This invention relates to the field of waste gas treatment technology, and more particularly to the field of high-temperature flue gas treatment technology, specifically to a method for the comprehensive utilization of flue gas from carbonized slag smelting. Background Technology

[0002] In the traditional blast furnace ironmaking-converter steelmaking process, most of the titanium resources from vanadium-titanium magnetite end up in the blast furnace slag, which contains 20%-26% TiO2 and is known as titanium-containing blast furnace slag. To avoid resource waste, it is necessary to recover the metals and recyclables from the titanium-containing blast furnace slag, thus enabling its large-scale utilization.

[0003] The main principle of preparing carbonized slag from titanium-containing blast furnace slag by high-temperature carbonization is as follows: using titanium-containing blast furnace slag as raw material, and anthracite, coke or semi-coke as solid reducing agent, the smelting is carried out under high temperature conditions of 1300-1700℃, and the product is carbonized slag.

[0004] The smelting process of carbonized slag generates a large amount of gas, which contains a large amount of CO. Typically, the smelting process of carbonized slag only recovers flue gas with a higher CO concentration (CO≥30%), while flue gas with a lower CO concentration is burned and released, wasting energy and polluting the environment. In addition, the flue gas generated in the smelting process of carbonized slag has a temperature of 800-1200℃. In actual production, the waste heat of the high-temperature flue gas with a lower CO concentration is not reused, resulting in a huge waste of energy.

[0005] Therefore, to address the above issues, a better method for the comprehensive utilization of flue gas from carbide smelting needs to be proposed to improve the safety and cost control of carbide smelting. Summary of the Invention

[0006] In view of this, the purpose of this invention is to propose an improved method for the comprehensive utilization of flue gas from carbide smelting, so as to improve the safety and cost control of carbide smelting.

[0007] To achieve the above objectives, the present invention provides a method for comprehensive utilization of flue gas from carbonized slag smelting, wherein the method includes the following steps:

[0008] Step S10: Add solid titanium-containing blast furnace slag and carbonaceous reducing agent into the pre-reduction furnace, heat to 1300-1400℃, and smelt for 30-60 minutes.

[0009] In step S20, the carbonaceous reducing agent and the slag from step S10 are added to a carburizing electric furnace for smelting. The temperature is raised to 1600-1700℃ and smelted for 60-90 minutes. Then, the molten slag is water-quenched.

[0010] Step S30: High-temperature flue gas is collected from the pre-reduction furnace, combustible gases are removed by combustion in the secondary combustion chamber, and the flue gas after combustion is heat-exchanged through a heat exchanger to obtain flue gas for preliminary drying treatment of water-quenched slag.

[0011] In some embodiments of the method for comprehensive utilization of flue gas from carbonized slag smelting according to the present invention, the method further includes:

[0012] Step S40: High-temperature flue gas is collected from the carbonization furnace. The high-temperature flue gas undergoes purification processes such as flue cooling, gravity dust removal, and bag dust removal, and is finally stored in a gas holder for use in the vertical mill system to further dry and grind the water-quenched slag.

[0013] In some embodiments of the method for comprehensive utilization of flue gas from carbonized slag smelting according to the present invention, in step S10, the TiO2 content of the solid titanium-containing blast furnace slag is 15-40%.

[0014] In some embodiments of the method for comprehensive utilization of flue gas from carbonized slag smelting according to the present invention, the carbonaceous reducing agent in steps S10 and S20 is at least one of coke powder, anthracite, or semi-coke.

[0015] In some embodiments of the method for comprehensive utilization of flue gas from carbonized slag smelting according to the present invention, the slag described in step S10 flows into the carbonized electric furnace through a chute.

[0016] In some embodiments of the method for comprehensive utilization of flue gas from carbonized slag smelting according to the present invention, the pre-reduction furnace in step S10 is an electric furnace, which uses electricity to provide the required heat.

[0017] In some embodiments of the method for comprehensive utilization of flue gas from carbonized slag smelting according to the present invention, the preliminary drying treatment of water-quenched slag in step S30 reduces the free water content in the water-quenched slag from 30-40% to 15-25%.

[0018] In some embodiments of the method for comprehensive utilization of carbonized slag smelting flue gas according to the present invention, the flue gas in step S40 is used in a vertical mill system to further dry and grind the water-quenched slag, thereby controlling the free water content in the water-quenched slag to below 0.5%.

[0019] In some embodiments of the method for comprehensive utilization of slag smelting flue gas according to the present invention, the flue gas in step S40 is used in a vertical mill system to further dry and grind the water-quenched slag, and the proportion of 100-450 mesh particles reaches 50-80%.

[0020] In some embodiments of the method for comprehensive utilization of flue gas from carbonized slag smelting according to the present invention, the smelting time in step S10 is 50 min.

[0021] This invention offers at least the following beneficial technical effects: It proposes a method for the comprehensive utilization of flue gas from carbonization slag smelting. The low-CO concentration flue gas generated by the pre-reduction furnace is used to recover its latent heat and is then used for the preliminary drying of water-quenched slag. The high-CO concentration flue gas generated by the carbonization electric furnace is used in a vertical mill system for further drying and grinding of the water-quenched slag, ensuring that the finished slag meets the particle size and moisture requirements. This invention achieves the rational utilization of flue gas from carbonization slag smelting, contributing to safety and cost control in carbonization smelting. Attached Figure Description

[0022] 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 only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0023] In the diagram:

[0024] Figure 1 A schematic diagram illustrating the implementation process of the comprehensive utilization method of carbonized slag smelting flue gas according to the present invention is shown. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to specific examples and the accompanying drawings.

[0026] It should be noted that all uses of "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two different entities or different parameters with the same name. Therefore, "first" and "second" are merely for convenience of expression and should not be construed as limiting the embodiments of the present invention. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as other steps or units inherent in a process, method, system, product, or device that includes a series of steps or units.

[0027] Example 1

[0028] A method for comprehensive utilization of flue gas from carbonized slag smelting, such as Figure 1 The diagram shows a schematic flow chart of a method for the comprehensive utilization of flue gas from carbide smelting. The method specifically includes:

[0029] A method for comprehensive utilization of flue gas from carbonized slag smelting includes the following steps:

[0030] Step S10: Add solid titanium-containing blast furnace slag and carbonaceous reducing agent into the pre-reduction furnace, heat to 1300℃, and smelt for 30 minutes;

[0031] In step S20, the carbonaceous reducing agent and the slag from step S10 are added to a carbonization electric furnace for smelting. The temperature is raised to 1600℃ and smelted for 60 minutes. Then, the molten slag is water-quenched.

[0032] Step S30: High-temperature flue gas is collected from the pre-reduction furnace, combustible gases are removed by combustion in the secondary combustion chamber, and the flue gas after combustion is heat-exchanged through a heat exchanger to obtain flue gas for preliminary drying treatment of water-quenched slag.

[0033] Step S40: High-temperature flue gas is collected from the carbonization furnace. The high-temperature flue gas undergoes purification processes such as flue cooling, gravity dust removal, and bag dust removal, and is finally stored in a gas holder for use in the vertical mill system to further dry and grind the water-quenched slag.

[0034] It should be noted that in step S10, the solid titanium-containing blast furnace slag has a TiO2 content of 15%, and the molten slag flows into the carbonization electric furnace through a chute. The carbonaceous reducing agent in steps S10 and S20 is coke powder and anthracite.

[0035] In step S10, the pre-reduction furnace is an electric furnace, which uses electricity to provide the required heat.

[0036] For example, in step S30, the water-quenched slag is subjected to preliminary drying treatment to reduce the free water content in the water-quenched slag from 32% to 15%.

[0037] In this application, the flue gas in step S40 is used in a vertical mill system to further dry and grind the water-quenched slag, controlling the free water content in the water-quenched slag to below 0.5%, and the proportion of 100-450 mesh particles to reach 55%.

[0038] Example 2

[0039] A method for comprehensive utilization of flue gas from carbonized slag smelting, such as Figure 1 The diagram shows a schematic flow chart of a method for the comprehensive utilization of flue gas from carbide smelting. The method specifically includes:

[0040] Step S10: Add solid titanium-containing blast furnace slag and carbonaceous reducing agent into the pre-reduction furnace, heat to 1400℃, and smelt for 40 minutes;

[0041] In step S20, the carbonaceous reducing agent and the slag from step S10 are added to a carbonization electric furnace for smelting. The temperature is raised to 1620°C and smelted for 65 minutes. Then, the molten slag is water-quenched.

[0042] Step S30: High-temperature flue gas is collected from the pre-reduction furnace, combustible gases are removed by combustion in the secondary combustion chamber, and the flue gas after combustion is heat-exchanged through a heat exchanger to obtain flue gas for preliminary drying treatment of water-quenched slag.

[0043] Step S40: High-temperature flue gas is collected from the carbonization furnace. The high-temperature flue gas undergoes purification processes such as flue cooling, gravity dust removal, and bag dust removal, and is finally stored in a gas holder for use in the vertical mill system to further dry and grind the water-quenched slag.

[0044] It should be noted that in step S10, the solid titanium-containing blast furnace slag has a TiO2 content of 18%, and the molten slag flows into the carbonization electric furnace through a chute. In steps S10 and S20, the carbonaceous reducing agent is a mixture of coke powder, anthracite, and semi-coke.

[0045] In step S10, the pre-reduction furnace is an electric furnace, which uses electricity to provide the required heat.

[0046] For example, in step S30, the water-quenched slag is subjected to preliminary drying treatment to reduce the free water content in the water-quenched slag from 36.5% to 22.4%.

[0047] In this application, the flue gas in step S40 is used in a vertical mill system to further dry and grind the water-quenched slag, controlling the free water content in the water-quenched slag to below 0.5%, and the proportion of 100-450 mesh particles to reach 70%.

[0048] Example 3

[0049] A method for comprehensive utilization of flue gas from carbonized slag smelting, such as Figure 1 The diagram shows a schematic flow chart of a method for the comprehensive utilization of flue gas from carbide smelting. The method specifically includes:

[0050] Step S10: Add solid titanium-containing blast furnace slag and carbonaceous reducing agent into the pre-reduction furnace, heat to 1320℃, and smelt for 50 minutes;

[0051] In step S20, the carbonaceous reducing agent and the slag from step S10 are added to a carbonization electric furnace for smelting. The temperature is raised to 1611°C and smelted for 67 minutes. Then, the molten slag is water-quenched.

[0052] Step S30: High-temperature flue gas is collected from the pre-reduction furnace, combustible gases are removed by combustion in the secondary combustion chamber, and the flue gas after combustion is heat-exchanged through a heat exchanger to obtain flue gas for preliminary drying treatment of water-quenched slag.

[0053] Step S40: High-temperature flue gas is collected from the carbonization furnace. The high-temperature flue gas undergoes purification processes such as flue cooling, gravity dust removal, and bag dust removal, and is finally stored in a gas holder for use in the vertical mill system to further dry and grind the water-quenched slag.

[0054] It should be noted that in step S10, the solid titanium-containing blast furnace slag has a TiO2 content of 32%, and the molten slag flows into the carbonization electric furnace through a chute. The carbonaceous reducing agent in steps S10 and S20 is anthracite and semi-coke.

[0055] In step S10, the pre-reduction furnace is an electric furnace, which uses electricity to provide the required heat.

[0056] For example, in step S30, the water-quenched slag is subjected to preliminary drying treatment to reduce the free water content in the water-quenched slag from 36% to 17%.

[0057] In this application, the flue gas in step S40 is used in a vertical mill system to further dry and grind the water-quenched slag, controlling the free water content in the water-quenched slag to below 0.5%, and the proportion of 100-450 mesh particles to reach 30%.

[0058] Example 4

[0059] A method for comprehensive utilization of flue gas from carbonized slag smelting, such as Figure 1 The diagram shows a schematic flow chart of a method for the comprehensive utilization of flue gas from carbide smelting. The method specifically includes:

[0060] Step S10: Add solid titanium-containing blast furnace slag and carbonaceous reducing agent into the pre-reduction furnace, heat to 1390℃, and smelt for 60 minutes;

[0061] In step S20, the carbonaceous reducing agent and the slag from step S10 are added to a carburizing electric furnace for smelting. The temperature is raised to 1685°C and smelted for 77 minutes. Then, the molten slag is water-quenched.

[0062] Step S30: High-temperature flue gas is collected from the pre-reduction furnace, combustible gases are removed by combustion in the secondary combustion chamber, and the flue gas after combustion is heat-exchanged through a heat exchanger to obtain flue gas for preliminary drying treatment of water-quenched slag.

[0063] Step S40: High-temperature flue gas is collected from the carbonization furnace. The high-temperature flue gas undergoes purification processes such as flue cooling, gravity dust removal, and bag dust removal, and is finally stored in a gas holder for use in the vertical mill system to further dry and grind the water-quenched slag.

[0064] It should be noted that in step S10, the solid titanium-containing blast furnace slag has a TiO2 content of 36%, and the molten slag flows into the carbonization electric furnace through a chute. In steps S10 and S20, the carbonaceous reducing agent is a mixture of coke powder and semi-coke.

[0065] In step S10, the pre-reduction furnace is an electric furnace, which uses electricity to provide the required heat.

[0066] For example, in step S30, the water-quenched slag is subjected to preliminary drying treatment to reduce the free water content in the water-quenched slag from 36.3% to 20.3%.

[0067] In this application, the flue gas in step S40 is used in a vertical mill system to further dry and grind the water-quenched slag, controlling the free water content in the water-quenched slag to below 0.5%, and the proportion of 100-450 mesh particles to reach 66%.

[0068] Example 5

[0069] A method for comprehensive utilization of flue gas from carbonized slag smelting, such as Figure 1 The diagram shows a schematic flow chart of a method for the comprehensive utilization of flue gas from carbide smelting. The method specifically includes:

[0070] Step S10: Add solid titanium-containing blast furnace slag and carbonaceous reducing agent into the pre-reduction furnace, heat to 1388℃, and smelt for 44 minutes.

[0071] In step S20, the carbonaceous reducing agent and the slag from step S10 are added to a carbonization electric furnace for smelting. The temperature is raised to 1669°C and smelted for 80 minutes. Then, the molten slag is water-quenched.

[0072] Step S30: High-temperature flue gas is collected from the pre-reduction furnace, combustible gases are removed by combustion in the secondary combustion chamber, and the flue gas after combustion is heat-exchanged through a heat exchanger to obtain flue gas for preliminary drying treatment of water-quenched slag.

[0073] Step S40: High-temperature flue gas is collected from the carbonization furnace. The high-temperature flue gas undergoes purification processes such as flue cooling, gravity dust removal, and bag dust removal, and is finally stored in a gas holder for use in the vertical mill system to further dry and grind the water-quenched slag.

[0074] It should be noted that in step S10, the solid titanium-containing blast furnace slag has a TiO2 content of 34%, and the molten slag flows into the carbonization electric furnace through a chute. In steps S10 and S20, the carbonaceous reducing agent is anthracite.

[0075] In step S10, the pre-reduction furnace is an electric furnace, which uses electricity to provide the required heat.

[0076] For example, in step S30, the water-quenched slag is subjected to preliminary drying treatment to reduce the free water content in the water-quenched slag from 40% to 15%.

[0077] In this application, the flue gas in step S40 is used in a vertical mill system to further dry and grind the water-quenched slag, controlling the free water content in the water-quenched slag to below 0.5%, and the proportion of 100-450 mesh particles to reach 74%.

[0078] This invention proposes a method for the comprehensive utilization of flue gas from carbide smelting. The low-CO concentration flue gas generated by the pre-reduction furnace is used for preliminary drying of water-quenched slag by recovering its latent heat. The higher-CO concentration flue gas generated by the electric carbide furnace is used in a vertical mill system for further drying and grinding of the water-quenched slag, ensuring that the finished slag meets particle size and moisture requirements. This invention achieves the rational utilization of flue gas from carbide smelting, contributing to safety and cost control in carbide smelting. By recovering and utilizing the low-CO concentration flue gas, the problem of resource waste is solved, while simultaneously saving 200-250 kWh / t of electricity consumption per ton of carbide slag.

[0079] The above are exemplary embodiments disclosed in this invention. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments of this invention as defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. Furthermore, although the elements disclosed in the embodiments of this invention may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular number.

[0080] It should be understood that, as used herein, the singular form "a" is intended to include the plural form as well, unless the context clearly supports an exception. It should also be understood that, as used herein, "and / or" refers to any and all possible combinations of one or more of the associatedly listed items. The embodiment numbers disclosed above are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0081] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of different aspects of the invention exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A method for comprehensive utilization of flue gas from carbonized slag smelting, characterized in that, Includes the following steps: Step S10: Add solid titanium-containing blast furnace slag and carbonaceous reducing agent into the pre-reduction furnace, heat to 1300-1400℃, and smelt for 30-60 minutes. In step S20, the carbonaceous reducing agent and the slag from step S10 are added to a carburizing electric furnace for smelting. The temperature is raised to 1600-1700℃ and smelted for 60-90 minutes. Then, the molten slag is water-quenched. Step S30: High-temperature flue gas is collected from the pre-reduction furnace, combustible gases are removed by combustion in the secondary combustion chamber, and the flue gas after combustion is heat-exchanged through a heat exchanger to obtain flue gas for preliminary drying treatment of water-quenched slag, reducing the free water content in the water-quenched slag from 30-40% to 15-25%; Step S40: High-temperature flue gas is collected from the carbonization electric furnace. The high-temperature flue gas undergoes flue cooling, gravity dust removal, and bag filter dust removal purification processes, and is finally stored in a gas holder for use in the vertical mill system to further dry and grind the water-quenched slag, controlling the free water content in the water-quenched slag to below 0.5%.

2. The method according to claim 1, characterized in that, In step S10, the solid titanium-containing blast furnace slag has a TiO2 content of 15-40%.

3. The method according to claim 1 or 2, characterized in that, The carbonaceous reducing agent mentioned in steps S10 and S20 is at least one of coke powder, anthracite, or semi-coke.

4. The method according to claim 1 or 2, characterized in that, The slag mentioned in step S10 flows into the carbonization electric furnace through a chute.

5. The method according to claim 4, characterized in that, The pre-reduction furnace mentioned in step S10 is an electric furnace, which uses electricity to provide the required heat.

6. The method according to claim 5, characterized in that, The flue gas described in step S40 is used in a vertical mill system to further dry and grind the water-quenched slag, with the 100-450 mesh particle size accounting for 50-80%.

7. The method according to claim 3, characterized in that, In step S10, the smelting time is 50 minutes.

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