Production method for smelting titanium-containing blast furnace slag

Abstract

The invention discloses a production method for smelting titanium-containing blast furnace slag, which comprises the following steps of: S1, enabling molten titanium-containing blast furnace slag to flow into slag tanks from a slag outlet of a blast furnace, and transporting a plurality of slag tanks filled with the titanium-containing blast furnace slag to a slag turning position of a carbonization electric furnace from the slag outlet of the blast furnace; s2, in the process of pouring the titanium-containing blast furnace slag in the plurality of slag tanks into a carbonization electric furnace, adding pre-prepared iron coke into the carbonization electric furnace for smelting; s3, after the concentration of CO gas generated in the smelting process reaches a target state, adding the residual iron coke and continuously smelting; and S4, slag is discharged after smelting is finished, high-pressure water is adopted for directly impacting molten slag in the slag discharging process, water-quenched slag is obtained, the water-quenched slag is crushed for two times of magnetic separation, raw materials containing iron particles and rich in titanium carbide are obtained, the iron-containing particles serve as raw materials of iron coke in the S2 and the S3, and the raw materials rich in titanium carbide serve as raw materials of the titanium dioxide chloride technology. According to the method, the production efficiency of the carbide slag can be improved, enrichment of titanium carbide and cyclic utilization of iron are achieved, and the treatment cost of the tailings is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of titanium extraction from blast furnace slag, and in particular to a production method for smelting titanium-containing blast furnace slag. Background Art

[0002] my country's Panxi region is rich in vanadium-titanium magnetite resources. After the "blast furnace ironmaking" process, about half of the titanium in Panxi vanadium-titanium magnetite enters the blast furnace slag, with a content of 20-25wt% in terms of TiO2. In order to comprehensively recycle the titanium resources in the blast furnace slag and turn waste into treasure, Pansteel independently developed a "high temperature carbonization-low temperature chlorination" titanium extraction process route.

[0003] The main principle of preparing carbide slag by high-temperature carbonization of titanium-containing blast furnace slag is: using titanium-containing blast furnace slag as raw material and conventional metallurgical coke as reducing agent, smelting in an AC electric furnace under high temperature conditions of 1300~1600℃ to obtain molten carbide slag, and using water quenching process to obtain water-quenched slag during the slag discharge process. The water-quenched slag is then dehydrated and ground to obtain finished carbide slag of appropriate particle size. The main smelting reactions are: TiO2+2C = TiC +2CO2TiO2+C = Ti2O3+CO FeO+C=Fe+CO The TiC content in the finished carbide slag produced by the existing technology is generally 10%-15%, and the rest is oxides such as calcium, magnesium, aluminum and silicon. This kind of carbide slag is used in the chloride process to produce titanium dioxide, which produces a large amount of titanium tailings. If these tailings are stored and treated, they will cause environmental pollution, so they need to be harmlessly treated, resulting in a significant increase in process production costs. In addition, the reducing agent used in the existing technology is mainly conventional metallurgical coke, which has the characteristics of high mechanical strength, high strength after reaction, and low reactivity. The coke used for high-temperature carbonization of titanium-containing blast furnace slag focuses on high reactivity and does not require high coke strength. Therefore, there are obvious deficiencies in using conventional metallurgical coke to smelt titanium-containing blast furnace slag.

[0004] In summary, the prior art does not disclose a technology that takes into account both reducing the cost of tailings treatment and improving the efficiency of carburized slag production. It is urgent to develop a production method for smelting titanium-containing blast furnace slag to solve the above-mentioned defects. Summary of the invention

[0005] The main purpose of the present invention is to provide a production method for smelting titanium-containing blast furnace slag to solve the technical problems of how to reduce the production cost of high-carburized slag, achieve the enrichment of titanium carbide and the recycling of iron, and effectively reduce the cost of tailings treatment.

[0006] According to one aspect of the present invention, a production method for smelting titanium-containing blast furnace slag is provided, comprising the following steps: S1, flowing the molten titanium-containing blast furnace slag into a slag pot from a slag outlet of a blast furnace, and transporting a plurality of slag pots filled with the titanium-containing blast furnace slag from the slag outlet of the blast furnace to a slag turning place of a carbonization electric furnace; S2, in the process of pouring titanium-containing blast furnace slag in multiple slag pots into the carbonization electric furnace, adding pre-mixed iron coke into the carbonization electric furnace for smelting; S3, after the CO gas concentration generated during the smelting process reaches the target state, the remaining iron coke is added and the smelting is continued; S4, slag is discharged after smelting. In the slag discharge process, high-pressure water is used to directly impact the molten slag to obtain water-quenched slag. The water-quenched slag is crushed and subjected to two magnetic separations to obtain iron-containing particles and raw materials rich in titanium carbide. The iron-containing particles are used as the raw material for iron coke in S2 and S3, and the raw material rich in titanium carbide is used as the raw material for the titanium dioxide chloride process.

[0007] According to one embodiment of the present invention, in step S1, the mass of titanium-containing blast furnace slag is 50-70t, and the number of slag pots is 3-6 pots.

[0008] According to one embodiment of the present invention, in step S2, the step of adding pre-mixed coke also includes: for two slag pots, the titanium-containing blast furnace slag in each slag pot is poured into the carbonization electric furnace for slag turning, and then a preset amount of pre-mixed coke is added; the titanium-containing blast furnace slag in the third slag pot is poured into the carbonization electric furnace for slag turning, and then the remaining pre-mixed coke is added.

[0009] According to one embodiment of the present invention, in step S3, the target state is that the CO gas concentration reaches above 40% and starts to decrease.

[0010] According to one embodiment of the present invention, in step S2 and step S3, the amount of pre-mixed coke added is 6%-12% of the weight of the multiple slag pots before and after the slag is poured into the carbonization furnace, and the total amount of pre-mixed coke and remaining coke added is 15%-25% of the weight of the multiple slag pots before and after the slag is poured into the carbonization furnace.

[0011] According to one embodiment of the present invention, in step S2 and step S3, the TFe content in the iron coke is 20%-30%.

[0012] According to one embodiment of the present invention, in step S2 and step S3, the particle size of the iron coke is between 200 mesh and 1 mm.

[0013] According to one embodiment of the present invention, in step S3, smelting is continued for 30-60 minutes after the iron coke is completely added.

[0014] According to one embodiment of the present invention, in step S4, the magnetic separation step also includes crushing the water-quenched slag to less than 100 mesh, magnetically separating it under a first magnetic field strength to obtain particle A, grinding particle A to less than 200 mesh, and magnetically separating it under a second magnetic field strength to obtain iron-containing particles and raw materials rich in titanium carbide.

[0015] According to one embodiment of the present invention, the first magnetic field strength is 1500 Gs-2500 Gs, and the second magnetic field strength is 2500 Gs-3000 Gs.

[0016] The present invention adopts ferrocoke as a reducing agent to accelerate the reaction of coke and titanium-containing blast furnace slag and improve the reaction rate. The iron in the ferrocoke can act as a nucleating agent to quickly aggregate TiC generated by reduction, and separate TiC from iron, calcium magnesium aluminum silicon oxide, etc. through magnetic separation, thereby increasing the TiC content in the carbided slag and improving production efficiency. At the same time, the iron separated by magnetic separation can be used to prepare ferrocoke, which can realize the enrichment of titanium carbide and the recycling of iron, greatly reduce the output of titanium-extracting tailings, effectively reduce the cost of tailings treatment, and can be further promoted to other slag smelting industries. DETAILED DESCRIPTION

[0017] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in conjunction with specific embodiments.

[0018] It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are for distinguishing two non-identical entities with the same name or non-identical parameters. It can be seen that "first" and "second" are only for the convenience of expression and should not be understood as limitations on the embodiments of the present invention. The subsequent embodiments will not explain this one by one.

[0019] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0020] Unless otherwise defined, all scientific and technical terms used in the present invention have the same meanings as commonly understood by one of ordinary skill in the art to which the present invention relates.

[0021] In the present invention, the term "TFe" refers to iron including metallic iron and iron compounds, that is, total iron.

[0022] The percentages or % (percent sign) in the present invention are all based on mass percentage unless otherwise specified.

[0023] The content in the present invention refers to mass percentage.

[0024] One or more embodiments of the present invention will be described in detail below.

[0025] The present invention provides a production method for smelting titanium-containing blast furnace slag, comprising the following steps: S1, flowing the molten titanium-containing blast furnace slag into a slag pot from a slag outlet of a blast furnace, and transporting (e.g., by rail) a plurality of (e.g., 3 to 6) slag pots containing the titanium-containing blast furnace slag from the slag outlet of the blast furnace to a slag turning place of a carbonization electric furnace; S2, in the process of pouring the titanium-containing blast furnace slag in the plurality of slag pots into the carbonization electric furnace (for example, through a chute), adding pre-matched iron coke into the carbonization electric furnace for smelting; S3, after the CO gas concentration generated during the smelting process reaches the target state, the remaining iron coke is added and the smelting is continued; S4, slag is discharged after smelting. In the slag discharge process, high-pressure water is used to directly impact the molten slag to obtain water-quenched slag. The water-quenched slag is crushed and subjected to two magnetic separations to obtain iron-containing particles and raw materials rich in titanium carbide. The iron-containing particles are used as the raw material for iron coke in S2 and S3, and the raw material rich in titanium carbide is used as the raw material for the titanium dioxide chloride process.

[0026] In some embodiments, iron coke is a functional coke with high reactivity, in which the iron can act as a nucleating agent, and the TiC solid particles generated by reduction will adhere to these metal iron nuclei to crystallize and grow, which is conducive to the aggregation and growth of TiC and the separation of TiC from oxides such as calcium, magnesium, aluminum and silicon. At the same time, the iron in iron coke can promote the reactivity of coke, accelerate the reaction of coke with titanium-containing blast furnace slag, increase the reaction rate, and improve production efficiency. Therefore, the advantages of iron coke in the smelting of titanium-containing blast furnace slag are obvious.

[0027] The production method of smelting titanium-containing blast furnace slag of the present invention adopts iron coke as a reducing agent to accelerate the reaction of coke and titanium-containing blast furnace slag and improve the carburization reaction rate. The iron in the iron coke can act as a nucleating agent to quickly aggregate TiC generated by reduction, and separate TiC from iron, calcium magnesium aluminum silicon oxide, etc. through magnetic separation, thereby increasing the TiC content in the carburized slag and improving production efficiency. At the same time, the iron separated by magnetic separation can be used to prepare iron coke, which can realize the enrichment of titanium carbide and the recycling of iron. The titanium carbide content is increased by 10%-25% compared with the prior art, which greatly reduces the output of titanium-extracting tailings, effectively reduces the cost of tailings treatment, and can be further promoted to other slag smelting industries.

[0028] In some embodiments, in step S1, the mass of titanium-containing blast furnace slag is 50-70t, and the number of slag pots is 3-6 pots.

[0029] In some embodiments, in step S2, the step of adding pre-mixed coke also includes: for the first two slag pots, the titanium-containing blast furnace slag in each slag pot is poured into the carbonization electric furnace for slag turning, and then a preset amount of pre-mixed coke is added once; the titanium-containing blast furnace slag in the third slag pot is poured into the carbonization electric furnace for slag turning, and then the remaining pre-mixed coke is added.

[0030] In the process of pouring titanium-containing blast furnace slag into the carbonization electric furnace, the present invention pre-allocates part of the iron coke before starting to supply power for smelting. The pre-allocated iron coke is added in the following manner: when the first two slag pots for pouring titanium-containing blast furnace slag into the carbonization electric furnace are turned over, 1 t of iron coke is added after each slag pot is turned over, and the pre-allocated remaining iron coke is added after the third slag pot is turned over. This adding method is conducive to the full mixing of the pre-allocated iron coke with the turned titanium-containing blast furnace slag, effectively promotes the carbonization reaction of the titanium-containing blast furnace slag, improves the reaction efficiency and resource utilization, reduces waste and adverse reactions, and helps to improve the economy and environmental protection of smelting.

[0031] In some embodiments, in step S3, the target state is that the CO gas concentration reaches above 40% and begins to decrease.

[0032] The production method of smelting titanium-containing blast furnace slag of the present invention monitors the CO gas concentration through a flue gas detection system after power transmission and smelting for 40 minutes. When the CO gas concentration reaches more than 40% and begins to decrease, the remaining iron coke is added at a rate of 100kg / min. After the iron coke is completely added, smelting is continued. By monitoring the CO gas concentration to control the timing of adding the iron coke, the reducing agent required for the carbonization reaction, the iron coke, can be replenished in time, which helps to improve the reduction effect. Gradually adding the iron coke after the peak of the CO gas concentration can avoid the reduction of the slag temperature in the furnace and the reduction of the carbonization reaction rate caused by a large amount of one-time addition, which helps to maintain the stability of the smelting process, reduce the risk of slag overflow caused by concentrated reactions in the late stage of smelting, and reduce the occurrence of adverse reactions and safety accidents.

[0033] In some embodiments, in step S2 and step S3, the amount of pre-mixed coke added is 6%-12% of the weight of the multiple slag pots before and after pouring the slag into the carbonization furnace, and the total amount of pre-mixed coke and remaining coke added is 15%-25% of the weight of the multiple slag pots before and after pouring the slag into the carbonization furnace.

[0034] In some embodiments, in step S2 and step S3, the TFe content in the iron coke is 20%-30%, including but not limited to 20%, 23%, 26% or 30%.

[0035] In some embodiments, in step S2 and step S3, the particle size of the iron coke is between 200 mesh and 1 mm.

[0036] The production method of smelting titanium-containing blast furnace slag of the present invention improves the reactivity of iron coke by increasing the iron content in iron coke, which is beneficial to the carbonization reaction of titanium-containing blast furnace slag. At the same time, iron can act as a nucleating agent, and the TiC solid particles generated by reduction will adhere to these metal iron crystal nuclei to crystallize and grow, which is beneficial to the aggregation and growth of TiC and the separation of TiC from oxides such as calcium, magnesium, aluminum and silicon. The TiC content in the carburized slag is increased by 10%-25% compared with the prior art, which effectively improves the production efficiency, recycles the iron coke, reduces the output of titanium-extracting tailings, and effectively reduces the cost of tailings treatment.

[0037] In some embodiments, in step S3, after the iron coke is completely added, smelting is continued for 30-60 minutes, which can be 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes or 60 minutes. During the process of adding the remaining iron coke, power is continuously supplied for smelting. After the iron coke is completely added, slag is discharged for another 30 minutes to 60 minutes. The slag discharge process uses high-pressure water to directly impact the molten slag to obtain water-quenched slag.

[0038] In some embodiments, in step S4, the magnetic separation step also includes crushing the water-quenched slag to less than 100 mesh, magnetically separating it at a first magnetic field strength to obtain particle A, grinding particle A to less than 200 mesh, and magnetically separating it at a second magnetic field strength to obtain iron-containing particles and raw materials rich in titanium carbide.

[0039] The production method of smelting titanium-containing blast furnace slag of the present invention adopts a crushing process to crush the water-quenched slag to less than 100 meshes, and then performs wet magnetic separation under a first magnetic field strength to obtain particles A rich in iron and titanium carbide, and grinds the particles A to less than 200 meshes through a vertical mill process, so that it is more convenient to be magnetically separated under specific magnetic field conditions, and then performs wet magnetic separation under a second magnetic field strength, which can further separate iron-containing particles and raw materials rich in titanium carbide, wherein the iron-containing particles are used as raw materials for making iron coke, and the raw materials rich in titanium carbide are used for a low-temperature chloride titanium dioxide process, that is, iron-containing particles and raw materials rich in titanium carbide that can be recycled are obtained. The output of titanium-extracting tailings is greatly reduced, and the cost of tailings treatment is effectively reduced.

[0040] In some embodiments, the first magnetic field strength is 1500 Gs-2500 Gs, such as 1500 Gs, 2000 Gs or 2500 Gs, and the second magnetic field strength is 2500 Gs-3000 Gs, such as 2500 Gs, 2800 Gs, or 3000 Gs.

[0041] The specific implementation of the present invention is further described below in conjunction with specific embodiments, but the present invention is not limited to the scope of the examples.

[0042] Example 1 This embodiment was carried out in a certain factory. The carbonization furnace was a three-phase AC furnace with a rated power of 30MVA. The molten titanium-containing blast furnace slag (the composition is shown in Table 1) was transported by rail to the slag turning point of the carbonization furnace through a slag tank car, and then the shell was broken by a heavy hammer and added to the carbonization furnace through a chute. The weight of the empty tank and the full tank were weighed by a railway weighing device, and the difference was the weight of the molten titanium-containing blast furnace slag added to the carbonization furnace, and the actual loading amount was 55t. The number of slag turnings this time was 4 tanks. When turning the slag, 1t of iron coke was added to the first two slag tanks after each slag tank was turned over, and 3.5t of iron coke was added after the third slag tank was turned over, and a total of 5.5t of pre-mixed iron coke was added. The iron coke composition is shown in Table 2, where the TFe content is 22%, which is contained in the ash, and the particle size is 200 mesh-1mm.

[0043] After the slag turning, 5.5t of pre-coke was added, and the electric smelting started. The active power of the electric furnace was controlled at 26MW. After smelting for 40 minutes, the CO gas concentration was detected to reach more than 40% and began to decrease. The remaining coke was added. The weight of the remaining coke was 5t, and the adding speed was 100kg / min. After the coke was completely added, smelting continued for another 45 minutes. The active power of the electric furnace was controlled at 28MW, and slag discharge began.

[0044] In the slag discharge process, high-pressure water is used to directly impact the slag to obtain water-quenched slag, which is crushed to less than 100 meshes by a double-roll crushing process, and then wet magnetic separation is performed under a magnetic field strength of 1700Gs to obtain particles rich in metallic iron and titanium carbide. These particles are ground to less than 200 meshes by a vertical mill process, and then wet magnetic separation is performed under a magnetic field strength of 2800Gs to obtain particles rich in metallic iron for the production of iron coke. The remaining particles are particles rich in titanium carbide. The particles rich in titanium carbide are chemically tested, and the TiC content is 24.1%. Compared with the existing technology, the TiC content increases by about 10%. The particles rich in titanium carbide are used to produce titanium dioxide by low-temperature chlorination method, and the output of titanium tailings will be reduced by about 10%-15%.

[0045] The main components of the titanium-containing blast furnace slag in this embodiment are shown in Table 1: Table 1 Main component indexes of titanium-containing blast furnace slag / %

[0046] The industrial analysis composition of the iron coke used in this embodiment is shown in Table 2: Table 2 Industrial analysis composition of iron coke / %

[0047] d: Dry basis.

[0048] The main components of the carburized slag in this embodiment are shown in Table 3: Table 3 Main components of carbonized slag / %

[0049] A person skilled in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the disclosure of the embodiments of the present invention (including the claims) is limited to these examples; under the concept of the embodiments of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and there are many other changes in different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of simplicity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the protection scope of the embodiments of the present invention.

Claims

1. A production method for smelting titanium-containing blast furnace slag, characterized in that: The following steps are involved: S1, flowing the molten titanium-containing blast furnace slag into a slag pot from a slag outlet of a blast furnace, and transporting a plurality of slag pots filled with the titanium-containing blast furnace slag from the slag outlet of the blast furnace to a slag turning place of a carbonization electric furnace; S2, in the process of pouring titanium-containing blast furnace slag in multiple slag pots into the carbonization electric furnace, adding pre-mixed iron coke into the carbonization electric furnace for smelting; S3, after the CO gas concentration generated during the smelting process reaches the target state, the remaining iron coke is added and the smelting is continued; S4, slag is discharged after smelting. In the slag discharge process, high-pressure water is used to directly impact the molten slag to obtain water-quenched slag. The water-quenched slag is crushed and subjected to two magnetic separations to obtain iron-containing particles and raw materials rich in titanium carbide. The iron-containing particles are used as the raw material for iron coke in S2 and S3, and the raw material rich in titanium carbide is used as the raw material for the titanium dioxide chloride process.

2. The method according to claim 1, characterized in that In step S1, the mass of titanium-containing blast furnace slag is 50-70t, and the number of slag pots is 3-6.

3. The method according to claim 1, characterized in that In step S2, the step of adding pre-mixed coke also includes: for the first two slag pots, the titanium-containing blast furnace slag in each slag pot is poured into the carbonization electric furnace for slag turning, and then a preset amount of pre-mixed coke is added; the titanium-containing blast furnace slag in the third slag pot is poured into the carbonization electric furnace for slag turning, and then the remaining pre-mixed coke is added.

4. The method according to claim 1, characterized in that: In step S3, the target state is that the CO gas concentration reaches 40% or more and starts to decrease.

5. The method according to claim 1, characterized in that: In step S2 and step S3, the amount of pre-mixed coke added is 6%-12% of the weight of the multiple slag pots before and after pouring the slag into the carbonization furnace, and the total amount of pre-mixed coke and remaining coke added is 15%-25% of the weight of the multiple slag pots before and after pouring the slag into the carbonization furnace.

6. The method according to claim 1, characterized in that In step S2 and step S3, the TFe content in the iron coke is 20%-30%.

7. The method according to claim 1, characterized in that In step S2 and step S3, the particle size of the iron coke is between 200 mesh and 1 mm.

8. The method according to claim 1, characterized in that: In step S3, smelting is continued for 30-60 minutes after the iron coke is completely added.

9. The method according to claim 1, characterized in that: In step S4, the magnetic separation step also includes crushing the water-quenched slag to less than 100 mesh, magnetically separating it at a first magnetic field strength to obtain particle A, grinding particle A to less than 200 mesh, and magnetically separating it at a second magnetic field strength to obtain iron-containing particles and raw materials rich in titanium carbide.

10. The method according to claim 9, characterized in that The first magnetic field strength is 1500Gs-2500Gs, and the second magnetic field strength is 2500Gs-3000Gs.

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