Recycling method of high-temperature flue gas in carbonization titanium extraction process

Abstract

The invention discloses a recycling method of high-temperature flue gas in a carbonization titanium extraction process, which comprises the following steps of: 1, performing heat exchange on the high-temperature flue gas generated in a smelting process and a mixture in a feeding pipeline through a heat exchange system, cooling the high-temperature flue gas to form cooled flue gas, and preheating the mixture; 2, mixing the cooled flue gas with nitrogen, and pressurizing to form mixed gas; 3, in the deslagging process, the TiC-containing hot melting slag is subjected to air quenching through mixed gas, and the hot melting slag is decomposed into particles uniform in size; and fourthly, high-temperature flue gas generated in the air quenching process is reused in the heat exchange system in the first step to be recycled. The method disclosed by the invention can effectively reduce the smelting power consumption of carbon-containing blast furnace slag smelting, improve the energy utilization rate and reduce the production cost. And meanwhile, cooling flue gas is used as a gas source, so that the whole air quenching process can keep a reducing atmosphere, the carbon reduction effect can be achieved, and cyclic utilization of the smelting flue gas is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of titanium extraction from blast furnace slag, and in particular to a method for recycling high-temperature flue gas in a titanium extraction process by carburization. Background Art

[0002] Panxi vanadium-titanium magnetite is a famous multi-metallic symbiotic ore in my country, rich in strategic resources such as iron, titanium, vanadium, chromium, cobalt, nickel, copper, and manganese. At present, the proven reserves of TiO2 are nearly 900 million tons, accounting for 90.54% of my country's titanium resource reserves and 35.17% of the world's titanium resource reserves, ranking first in China and third in the world. The content of TiO2 in the original ore of Panxi vanadium-titanium magnetite is about 10%. After the original ore is beneficiated, about 47% of the titanium enters the titanium concentrate, and nearly 53% of the titanium enters the iron concentrate. After the iron concentrate is smelted in a blast furnace, all the titanium resources in it enter the blast furnace slag, forming a titanium-containing blast furnace slag with a titanium content (calculated as TiO2) of 20-26%, also known as high-titanium blast furnace slag. Since Panzhihua Iron and Steel was put into production, the titanium-containing blast furnace slag produced by blast furnace ironmaking has reached tens of millions of tons, and is still increasing at a rate of about 3 million tons per year. It is a unique artificial secondary titanium resource in my country. In order to make use of this valuable resource, relevant scientific research and production units at home and abroad have carried out scientific and technological public relations on the extraction and utilization of titanium resources in Panzhihua Iron and Steel's high-titanium blast furnace slag since the 1970s. At present, Panzhihua Iron and Steel has mastered the technology of using AC electric furnace to smelt titanium-containing blast furnace slag with carbon. Through the reaction TiO2+C→TiC+CO, TiO2 in titanium-containing blast furnace slag can be converted into TiC.

[0003] However, in the existing electric furnace carbon smelting titanium-containing blast furnace slag to extract titanium, the smelting process will produce a large amount of high-temperature flue gas. If the high-temperature flue gas can be utilized, the smelting power consumption of titanium-containing blast furnace slag carbon smelting can be effectively reduced, the energy utilization rate can be improved, the production cost can be reduced, and it has great industrial application value.

[0004] Based on this, the existing technology still needs to be improved. Summary of the invention

[0005] In order to solve the above technical problems, an embodiment of the present invention proposes a method for recycling high-temperature flue gas in a titanium carbide extraction process, so as to solve the problem of utilizing a large amount of high-temperature flue gas generated in the above titanium carbide extraction smelting process.

[0006] In order to solve the above technical problems, some embodiments of the present invention disclose a method for recycling high-temperature flue gas in a titanium carbide extraction process, comprising the following steps: Step 1: exchanging heat between the high-temperature flue gas generated during the smelting process and the mixture in the feed pipeline through a heat exchange system, so that the high-temperature flue gas is cooled to form cooling flue gas, and the mixture is preheated; Step 2: mixing the cooling flue gas with nitrogen and pressurizing it to form a mixed gas; Step 3: During the slag discharge process, the hot molten slag containing TiC is quenched by air using the mixed gas to decompose the hot molten slag into particles of uniform size; Step 4: The high-temperature flue gas generated during the wind quenching process is recycled into the heat exchange system of step 1 for cyclic use.

[0007] In some embodiments, the high-temperature flue gas includes CO and CO2, wherein, by volume percentage, the CO content is 40% to 65%, and the CO2 content is 3% to 6%.

[0008] In some embodiments, after the wind quenching process, the particle size of the hot slag is 1-3 mm.

[0009] In some embodiments, the mixture includes titanium-containing blast furnace slag solid powder and coke powder.

[0010] In some embodiments, the particle size of the titanium-containing blast furnace slag solid powder is 2-30 mm, and the mass percentage of fixed carbon in the coke powder is not less than 75%.

[0011] In some embodiments, the temperature of the high temperature flue gas is 750°C to 1150°C.

[0012] In some embodiments, the temperature of the cooled flue gas is no greater than 55°C.

[0013] In some embodiments, in step 1, the preheating temperature is 150°C to 300°C.

[0014] In some embodiments, in step 2, the temperature of the mixed gas is no greater than 35°C.

[0015] In some embodiments, in step 2, the pressure of the mixed gas is 0.5-0.9 MPa.

[0016] By adopting the above technical solution, the present invention has at least the following beneficial effects: The present invention provides a method for recycling high-temperature flue gas in a carbonization titanium extraction process. The method utilizes the high sensible heat characteristics of a large amount of hot flue gas generated during the smelting process of titanium-containing blast furnace slag with carbon to preheat the mixture of solid powder and coke powder of titanium-containing blast furnace slag; the mixed gas formed by mixing the cooling flue gas with nitrogen and pressurizing it after heat exchange can be used to quench the hot molten slag containing TiC during the slag discharge process, so that the hot molten slag is decomposed into particles of uniform size, which is convenient for later use; the high-temperature flue gas generated during the air quenching process can be reused in the heat exchange procedure for recycling. The present invention can effectively reduce the smelting power consumption of titanium-containing blast furnace slag with carbon smelting, improve energy utilization, and reduce production costs. At the same time, using cooling flue gas as a gas source can not only keep the reducing atmosphere in the entire air quenching process, but also play a role in carbon reduction, thereby realizing the recycling of smelting flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0018] Figure 1 The present invention is a flow chart of a method for recycling high-temperature flue gas in a titanium carbide extraction process disclosed in some embodiments of the present invention. DETAILED DESCRIPTION

[0019] The following is a further detailed description of the embodiments of the present disclosure in conjunction with the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to exemplarily illustrate the principles of the present disclosure, but cannot be used to limit the scope of the present disclosure. The present disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

[0020] The present disclosure provides these embodiments to make the present disclosure thorough and complete, and to fully express the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the parts and steps, the composition of the materials, the numerical expressions and the numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary, and not as limiting.

[0021] It should be noted that, in the description of the present disclosure, unless otherwise specified, the meaning of "multiple" is greater than or equal to two; the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicating the orientation or positional relationship, are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present disclosure. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0022] In addition, the words "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts. "Vertical" does not mean vertical in the strict sense, but is within the tolerance range. "Parallel" does not mean parallel in the strict sense, but is within the tolerance range. "Include" or "comprising" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements.

[0023] It should also be noted that in the description of the present disclosure, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to the specific circumstances. When a specific device is described as being located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device.

[0024] All terms used in the present disclosure have the same meanings as those understood by those of ordinary skill in the art to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries, for example, should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined as such herein.

[0025] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0026] like Figure 1 As shown, some embodiments of the present invention disclose a method for recycling high-temperature flue gas in a titanium carbide extraction process, comprising the following steps: Step 1: The high-temperature flue gas generated during the smelting process is heat exchanged with the mixture in the feed pipe through a heat exchange system to cool the high-temperature flue gas to form cooling flue gas, and the mixture is preheated. Specifically, the mixture includes titanium-containing blast furnace slag solid powder and coke powder, wherein the particle size of the titanium-containing blast furnace slag solid powder is 2~30mm, and the mass percentage of fixed carbon in the coke powder is not less than 75%. Generally, the reaction of the smelting process is TiO2+C→TiC+CO, and the TiO2 of the titanium-containing blast furnace slag is converted into TiC. The high-temperature flue gas generated during the reaction has the characteristics of high sensible heat, and the temperature is 750℃~1150℃. The mixture can be preheated to 150℃~300℃, reducing the power consumption of the later smelting. After heat exchange, the high-temperature flue gas is cooled to form cooling flue gas with a temperature not greater than 55℃, which is prepared for the wind quenching in step 3. Specifically, the temperature of the cooling flue gas can be controlled by adjusting the intake volume of the high-temperature flue gas.

[0027] Step 2: Mix the cooling flue gas and nitrogen and pressurize them to form a mixed gas; wherein the temperature of the mixed gas is not greater than 35°C and the pressure is 0.5-0.9 MPa. Specifically, the temperature of the mixed gas can be controlled by adjusting the ratio of nitrogen.

[0028] Step 3: During the slag discharge process, the hot molten slag containing TiC is quenched by air using the mixed gas, so that the hot molten slag is decomposed into particles with a uniform size distribution of 1 to 3 mm. Specifically, during the slag discharge process, the slag flow is large in the early stage and small in the later stage, and the decomposition particle size of the hot molten slag containing TiC can be ensured by adjusting the pressure of the mixed gas.

[0029] Step 4: The high-temperature flue gas generated during the wind quenching process is recycled into the heat exchange system of step 1 for cyclic use.

[0030] Generally, high-temperature flue gas includes CO and CO2, wherein the CO content is 40-65% and the CO2 content is 3%-6% by volume. The cooling flue gas formed after the high-temperature flue gas is cooled can be used as the gas source for wind quenching, wherein the CO gas can ensure that the entire wind quenching process maintains a reducing atmosphere, preventing TiC from being exposed to the air and oxidized to TiO2. CO2 can react with the free carbon in the hot slag during wind quenching to produce CO2+C→CO, thereby reducing carbon and further increasing TiC. In this embodiment, the cooling flue gas is used as the gas source, which can not only maintain the reducing atmosphere during the entire wind quenching process, but also reduce carbon, thereby realizing the recycling of smelting flue gas.

[0031] The method for recycling high-temperature flue gas in the carbonization titanium extraction process disclosed in the above-mentioned embodiment utilizes the high sensible heat property of a large amount of hot flue gas generated during the smelting process of titanium-containing blast furnace slag with carbon to preheat the mixture of solid powder and coke powder of titanium-containing blast furnace slag; the mixed gas formed by mixing the cooling flue gas with nitrogen and pressurizing it after the heat exchange can be used to quench the hot molten slag containing TiC during the slag discharge process, so that the hot molten slag is decomposed into particles of uniform size, which is convenient for later use; the high-temperature flue gas generated during the air quenching process can be reused in the heat exchange procedure for recycling. The present invention can effectively reduce the smelting power consumption of titanium-containing blast furnace slag with carbon smelting, improve energy utilization, and reduce production costs. At the same time, using cooling flue gas as the gas source can not only keep the reducing atmosphere in the entire air quenching process, but also play a role in carbon reduction, thereby realizing the recycling of smelting flue gas.

[0032] The following describes it in conjunction with specific embodiments.

[0033] Example 1 like Figure 1 A method for recycling high-temperature flue gas in a titanium carbide extraction process shown includes: The high-temperature flue gas with a temperature of 750°C generated during the smelting process is heat exchanged with the mixture in the feed pipe (including titanium-containing blast furnace slag solid powder and coke powder, wherein the particle size of the titanium-containing blast furnace slag solid powder is 2mm, and the mass percentage of fixed carbon in the coke powder is 75%), and the mixture is preheated to 150°C, and the intake amount of the high-temperature flue gas during the heat exchange process is controlled to cool it down to form a cooling flue gas at 45°C; the cooling flue gas is mixed with nitrogen and pressurized to form a mixed gas with a pressure of 0.5~0.9MPa, and the temperature of the mixed gas reaches 35°C by adjusting the nitrogen ratio; during the slag discharge process, the pressure value of the mixed gas is adjusted according to the size of the slag flow rate, so that the hot molten slag containing TiC is decomposed into uniform particles with a particle size of 1~3mm. In this embodiment, the high-temperature flue gas includes CO and CO2, wherein the CO content is 40% and the CO2 content is 6% by volume.

[0034] Example 2 like Figure 1 A method for recycling high-temperature flue gas in a titanium carbide extraction process shown includes: The high-temperature flue gas with a temperature of 850°C generated during the smelting process is heat exchanged with the mixture in the feed pipe (including titanium-containing blast furnace slag solid powder and coke powder, wherein the particle size of the titanium-containing blast furnace slag solid powder is 10mm, and the mass percentage of fixed carbon in the coke powder is 80%), and the mixture is preheated to 200°C. By controlling the intake amount of the high-temperature flue gas during the heat exchange process, the temperature is reduced to form a cooling flue gas of 50°C; the cooling flue gas is mixed with nitrogen and pressurized to form a mixed gas with a pressure of 0.5~0.9MPa, and the temperature of the mixed gas reaches 30°C by adjusting the nitrogen ratio; during the slag discharge process, the pressure value of the mixed gas is adjusted according to the size of the slag flow rate, so that the hot molten slag containing TiC is decomposed into uniform particles with a particle size of 1~3mm. In this embodiment, the high-temperature flue gas includes CO and CO2, wherein the CO content is 50% and the CO2 content is 4% by volume.

[0035] Example 3 like Figure 1 A method for recycling high-temperature flue gas in a titanium carbide extraction process shown includes: The high-temperature flue gas with a temperature of 1150°C generated during the smelting process is heat exchanged with the mixture in the feed pipe (including titanium-containing blast furnace slag solid powder and coke powder, wherein the particle size of the titanium-containing blast furnace slag solid powder is 30mm, and the mass percentage of fixed carbon in the coke powder is 85%), and the mixture is preheated to 300°C. By controlling the intake amount of the high-temperature flue gas during the heat exchange process, the temperature is reduced to form a cooling flue gas of 55°C; the cooling flue gas is mixed with nitrogen and pressurized to form a mixed gas with a pressure of 0.5~0.9MPa, and the temperature of the mixed gas is adjusted to 25°C by adjusting the nitrogen ratio; during the slag discharge process, according to the size of the slag flow, the pressure value of the mixed gas is adjusted to decompose the hot molten slag containing TiC into uniform particles with a particle size of 1~3mm. In this embodiment, the high-temperature flue gas includes CO and CO2, wherein, by volume percentage: the CO content is 65% and the CO2 content is 3%.

[0036] In summary, the method for recycling high-temperature flue gas in a carburization titanium extraction process disclosed in an embodiment of the present invention utilizes the high sensible heat characteristic of a large amount of hot flue gas generated during the smelting process of titanium-containing blast furnace slag with carbon to preheat the mixture of solid powder and coke powder of titanium-containing blast furnace slag; the mixed gas formed by mixing the cooling flue gas with nitrogen and pressurizing it after heat exchange can be used to quench the hot molten slag containing TiC during the slag discharge process, so that the hot molten slag is decomposed into particles of uniform size, which is convenient for later use; the high-temperature flue gas generated during the air quenching process can be reused in the heat exchange procedure for recycling. The present invention can effectively reduce the smelting power consumption of titanium-containing blast furnace slag with carbon smelting, improve energy utilization, and reduce production costs. At the same time, using cooling flue gas as a gas source can not only keep the reducing atmosphere in the entire air quenching process, but also play a role in carbon reduction, thereby realizing the recycling of smelting flue gas.

[0037] So far, various embodiments of the present disclosure have been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed here.

[0038] Although some specific embodiments of the present disclosure have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. It should be understood by those skilled in the art that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present disclosure. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict.

Claims

1. A method for recycling high-temperature flue gas in a titanium carbide extraction process, characterized in that: The following steps are involved: Step 1: exchanging heat between the high-temperature flue gas generated during the smelting process and the mixture in the feed pipeline through a heat exchange system, so that the high-temperature flue gas is cooled to form cooling flue gas, and the mixture is preheated; Step 2: mixing the cooling flue gas with nitrogen and pressurizing it to form a mixed gas; Step 3: During the slag discharge process, the hot molten slag containing TiC is quenched by air using the mixed gas to decompose the hot molten slag into particles of uniform size; Step 4: The high-temperature flue gas generated during the wind quenching process is recycled into the heat exchange system of step 1 for cyclic use.

2. The method for recycling high temperature flue gas in the titanium carbide extraction process according to claim 1, characterized in that: The high-temperature flue gas includes CO and CO2, wherein, by volume percentage, the CO content is 40-65%, and the CO2 content is 3%-6%.

3. The method for recycling high temperature flue gas in the titanium carbide extraction process according to claim 1, characterized in that: After the wind quenching process, the particle size of the hot slag is 1-3 mm.

4. The method for recycling high temperature flue gas in the titanium carbide extraction process according to claim 1, characterized in that: The mixture includes titanium-containing blast furnace slag solid powder and coke powder.

5. The method for recycling high temperature flue gas in the titanium carbide extraction process according to claim 4, characterized in that: The particle size of the titanium-containing blast furnace slag solid powder is 2-30 mm, and the mass percentage of fixed carbon in the coke powder is not less than 75%.

6. The method for recycling high temperature flue gas in the titanium carbide extraction process according to claim 1, characterized in that: The temperature of the high-temperature flue gas is 750°C to 1150°C.

7. The method for recycling high temperature flue gas in the titanium carbide extraction process according to claim 1, characterized in that: The temperature of the cooling flue gas is not greater than 55°C.

8. The method for recycling high temperature flue gas in the titanium carbide extraction process according to claim 1, characterized in that: In step 1, the preheating temperature is 150°C to 300°C.

9. The method for recycling high temperature flue gas in the titanium carbide extraction process according to claim 1, characterized in that: In step 2, the temperature of the mixed gas is no greater than 35°C.

10. The method for recycling high temperature flue gas in the titanium carbide extraction process according to claim 1, characterized in that: In step 2, the pressure of the mixed gas is 0.5-0.9 MPa.

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