Method for preparing coke from acid-soluble titanium slag electric furnace fly ash and blast furnace smelting method of vanadium titano-magnetite

Abstract

The invention provides a method for preparing coke by using acid-soluble titanium slag electric furnace fly ash, which comprises the following steps: S1) crushing a coal type of which the fluidity is less than 5000ddpm, and humidifying to obtain a basic coal type; and S2) mixing the basic coal type with the acid-soluble titanium slag electric furnace fly ash, and coking to obtain coke. According to the coke prepared in the invention, the acid-soluble titanium slag electric furnace fly ash is introduced, so that the ability of Buddaler reaction is improved, and meanwhile, iron oxide in the acid-soluble titanium slag electric furnace fly ash is also a raw material for blast furnace ironmaking, so that the yield of blast furnace pig iron is improved; the titanium dioxide has the capability of passivating the coke, so that the strength of the coke in the blast furnace after reaction can be maintained, and the effect of stabilizing the framework of the coke blast furnace can be realized; furthermore, part of the titanium dioxide is reduced into titanium carbonitride, and the rest of the titanium dioxide enters blast furnace slag for schreyerite smelting, so that recycling of the titanium dioxide can be realized, secondary efficient utilization of the fly ash is realized, and the method has great popularization and application values.

Description

Technical Field

[0001] The invention relates to the technical field of iron and steel metallurgy, in particular to a method for preparing coke by utilizing acid-soluble titanium slag electric furnace dust removal ash and a method for smelting vanadium-titanium magnetite in a blast furnace. Background Art

[0002] At present, 90% of the world's iron production comes from blast furnace ironmaking. Compared with existing non-blast furnace ironmaking technologies, blast furnace ironmaking has the characteristics of good technical and economic indicators, simple process, large production volume and low energy consumption. It is predicted that blast furnace ironmaking will still be the main iron production process in the future. Coke, as an indispensable raw material for blast furnace ironmaking, plays the role of providing heat source, coke, carburizing agent and starting column skeleton in the blast furnace. Therefore, the performance of coke is of great significance to the blast furnace coke ratio, production efficiency, molten iron quality and economic benefits in blast furnace ironmaking. With the development of large-scale blast furnaces and coal injection technology, the coal ratio is constantly increasing, and the coke load in the blast furnace is heavier, so the requirements for the metallurgical properties of coke are becoming more and more stringent. With the shortage of high-quality coking coal resources, how to use existing resources and solid waste materials to smelt the coke required for blast furnaces is of great significance.

[0003] The annual output of acid-soluble titanium slag electric furnace dust is about hundreds of thousands of tons. The transportation and storage costs are expensive and easy to cause pollution. However, the acid-soluble titanium slag electric furnace dust has not been effectively recycled and reused. How to use the acid-soluble titanium slag electric furnace dust to prepare the coke required for the vanadium-titanium ore smelting blast furnace is of great significance to ensure the quality of the coke and realize the utilization of the acid-soluble titanium slag electric furnace dust. Summary of the invention

[0004] The technical problem solved by the present invention is to provide a method for preparing coke using acid-soluble titanium slag electric furnace dust. The coke prepared in this application can be used for blast furnace smelting of vanadium-titanium magnetite, has certain reactivity, and realizes the reuse of acid-soluble titanium slag electric furnace dust.

[0005] In view of this, the present application provides a method for preparing coke using acid-soluble titanium slag electric furnace dust, comprising the following steps:

[0006] S1) crushing the coal with fluidity less than 5000 ddpm and adjusting the humidity to obtain the basic coal;

[0007] S2) mixing the basic coal and the acid-soluble titanium slag electric furnace dust ash and then coking to obtain coke.

[0008] Preferably, the basic coal types include: coal type A with a fluidity of 1000-2000ddpm, coal type B with a fluidity of 10-1000ddpm, coal type C with a fluidity of 2000-5000ddpm, and coal type D with a fluidity less than 10ddpm.

[0009] Preferably, the addition amount of coal type A with a fluidity of 1000-2000ddpm is 20-40wt%, the addition amount of coal type B with a fluidity of 10-1000ddpm is 30-50wt%, the addition amount of coal type C with a fluidity of 2000-5000ddpm is 10-30wt%, and the addition amount of coal type D with a fluidity less than 10ddpm is 0-10%.

[0010] Preferably, the preparation of the basic coal is specifically as follows:

[0011] Coal type A, coal type B, coal type C and coal type D are crushed and humidified respectively, and the conditioned coal type A, coal type B, coal type C and coal type D are mixed to obtain a basic coal type.

[0012] Preferably, the moisture content of the coal type A after moisture adjustment is 9-10%, the moisture content of the coal type B after moisture adjustment is 9-10%, the moisture content of the coal type C after moisture adjustment is 9-10%, and the moisture content of the coal type D after moisture adjustment is 9-10%.

[0013] Preferably, the content of TiO2 in the acid-soluble titanium slag electric furnace dust is 20-40wt%, the content of FeO is 20-35wt%, and the content of Fe2O3 is 5-15wt%.

[0014] Preferably, in step S2), the bulk density of the mixed material after mixing is 0.7-0.9 t / m 3 .

[0015] Preferably, in step S2), based on the total amount of the basic coal and the acid-soluble titanium slag electric furnace dust ash, the content of the acid-soluble titanium slag electric furnace dust ash is 1-7wt%, and the remainder is the basic coal.

[0016] Preferably, the coking process is specifically:

[0017] The mixed material is heated to 700-900°C at a heating rate of 5-15°C / min, and then heated to 1000-1050°C at a heating rate of 15-25°C / min, and kept at a constant temperature for 7-8 hours.

[0018] The present application also provides a method for smelting vanadium-titanium magnetite in a blast furnace, comprising:

[0019] The vanadium-titanium magnetite charge and coke are added from the top of the blast furnace, and heat exchange is carried out with the ascending high-temperature coal gas. The iron-containing charge is indirectly reduced and directly reduced with the high-temperature coal gas and the hot coke, respectively, to form high-temperature molten slag iron.

[0020] The coke is coke prepared by the method described.

[0021] The present application provides a method for preparing coke by using acid-soluble titanium slag electric furnace dust ash, which comprises the following steps: firstly, crushing a coal with a fluidity of less than 5000 ddpm and then adjusting the humidity to obtain a basic coal; then, mixing the basic coal with the acid-soluble titanium slag electric furnace dust ash and then coking to obtain the coke; in the present application, the basic coal is mixed with the acid-soluble titanium slag electric furnace dust ash to prepare the coke, and the obtained coke has a certain reactivity for blast furnace smelting of vanadium-titanium magnetite, which helps to improve the ability of the Boudoir reaction; at the same time, the iron oxide in the acid-soluble titanium slag electric furnace dust ash is also a raw material for blast furnace ironmaking, which helps to improve the output of pig iron in the blast furnace; titanium dioxide has the ability to passivate coke, which helps to maintain the strength of the coke in the blast furnace after the reaction, and stabilizes the blast furnace skeleton effect of the coke; further, in addition to partially reducing the titanium dioxide to titanium carbonitride, the rest enters the blast furnace slag from the vanadium-titanium ore smelting, and the titanium dioxide can be recycled by reprocessing the titanium-containing blast furnace slag, thereby realizing the secondary and efficient utilization of the dust ash. DETAILED DESCRIPTION

[0022] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0023] In view of the need for recycling and reusing acid-soluble titanium slag electric furnace dust in the prior art and the need for high reactivity of coke used in blast furnace smelting of vanadium-titanium magnetite, the present application provides a method for preparing coke using acid-soluble titanium slag electric furnace dust, which uses acid-soluble titanium slag electric furnace dust as an additive for preparing coke. The prepared coke has certain reactivity and is green and low-carbon, increases the output of pig iron, and realizes the recycling of titanium dioxide. Specifically, an embodiment of the present invention discloses a method for preparing coke using acid-soluble titanium slag electric furnace dust, comprising the following steps:

[0024] S1) crushing the coal with fluidity less than 5000 ddpm and adjusting the humidity to obtain the basic coal;

[0025] S2) mixing the basic coal and the acid-soluble titanium slag electric furnace dust ash and then coking to obtain coke.

[0026] In the method for preparing coke, the present application first crushes the coal with fluidity less than 5000 ddpm and then adjusts the humidity to obtain the basic coal; in this process, in the present application, the basic coal includes: coal A with fluidity of 1000-2000 ddpm, coal B with fluidity of 10-1000 ddpm, coal C with fluidity of 2000-5000 ddpm, and coal D with fluidity less than 10 ddpm; more specifically, the fluidity of coal A is 1200-1800 ddpm, the fluidity of coal B is 120-800 ddpm, the fluidity of coal C is 2500-3500 ddpm, and the fluidity of coal D is 0-8 ddpm. Fluidity is a side reflection of the colloid content in the coal, which can directly affect the bonding effect in the thermoplastic range of the coking process, and thus affect the quality of coke.

[0027] Specifically, the addition amount of coal type A with a fluidity of 1000-2000ddpm is 20-40wt%, the addition amount of coal type B with a fluidity of 10-1000ddpm is 30-50wt%, the addition amount of coal type C with a fluidity of 2000-5000ddpm is 10-30wt%, and the addition amount of coal type D with a fluidity less than 10ddpm is 0-10%; more specifically, the addition amount of coal type A with a fluidity of 1000-2000ddpm is 30-35wt%, the addition amount of coal type B with a fluidity of 10-1000ddpm is 35-40wt%, the addition amount of coal type C with a fluidity of 2000-5000ddpm is 15-20wt%, and the addition amount of coal type D with a fluidity less than 10ddpm is 5-8%.

[0028] The overlapping values ​​of the above fluidity, for example, 1000-2000ddpm specifically means greater than or equal to 1000ddpm and less than or equal to 2000ddpm, 10-1000ddpm specifically means greater than or equal to 10ddpm and less than 1000ddpm, and 2000-5000ddpm specifically means greater than 2000ddpm and less than or equal to 5000ddpm.

[0029] In the present application, the coal types A, B, C and D can be selected from coal types well known to those skilled in the art according to the above-mentioned range of fluidity. For example, they can be independently selected from one or more of main coking coal, 1 / 3 coking coal, fat coal and lean coal. For example, the coal type A can be selected from main coking coal, the coal type B can be selected from 1 / 3 coking coal, the coal type C can be selected from fat coal, and the coal type D can be selected from lean coal. The main coking coal, the 1 / 3 coking coal, the fat coal and the lean coal are coal types well known to those skilled in the art, and the present application has no particular restrictions on their sources.

[0030] Furthermore, the addition amount of main coking coal with a fluidity of 1200-1800ddpm is 30-35wt%, the addition amount of 1 / 3 coking coal with a fluidity of 120-800ddpm is 35-40wt%, the addition amount of fat coal with a fluidity of 2500-3500ddpm is 15-20wt%, and the addition amount of lean coal with a fluidity of 0-8ddpm is 5-8%.

[0031] Furthermore, the preparation of the basic coal species described in this application is specifically as follows:

[0032] Coal types A, B, C and D are crushed and humidified respectively, and the conditioned coal type A, 1 / 3 of the conditioned coal type B, the conditioned coal type C and the conditioned coal type D are mixed to obtain the basic coal type.

[0033] In the above-mentioned basic coal preparation process, the crushing is specifically carried out in a manner well known to those skilled in the art, and there is no particular limitation in this application. The moisture adjustment can be performed by directly adding water to the coal types A, B, C and D. The moisture content of the conditioned coal type A is 9-10%, the moisture content of the conditioned coal type B is 9-10%, the moisture content of the conditioned coal type C is 9-10%, and the moisture content of the conditioned coal type D is 9-10%.

[0034] After obtaining the basic coal, the present application mixes it with the acid-soluble titanium slag electric furnace dust ash and then cokes it to obtain coke. In this process, based on the total mass of the basic coal and the acid-soluble titanium slag electric furnace dust ash, the content of the acid-soluble titanium slag electric furnace dust ash is 1-7wt%, and the balance is the basic coal; specifically, the content of the acid-soluble titanium slag electric furnace dust ash is 3-6wt%; for example, the content of the acid-soluble titanium slag electric furnace dust ash in the present application is 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%.

[0035] In the present application, there is no special restriction on the source of the acid-soluble titanium slag electric furnace dust ash. Preferably, the content of TiO2 in the acid-soluble titanium slag electric furnace dust ash is 20-40wt%, the content of FeO is 20-35wt%, and the content of Fe2O3 is 5-15wt%; specifically, the content of TiO2 in the acid-soluble titanium slag electric furnace dust ash is 25-35wt%, the content of FeO is 23-32wt%, and the content of Fe2O3 is 8-13wt%; more specifically, the content of TiO2 in the acid-soluble titanium slag electric furnace dust ash is 28-32wt%, the content of FeO is 25-28wt%, and the content of Fe2O3 is 9-11wt%. The iron oxide in the acid-soluble titanium slag electric furnace dust removal ash can catalyze the gasification reactivity of coke, which helps to improve the ability of Boudouard reaction in the blast furnace. At the same time, the iron oxide is also a raw material for blast furnace ironmaking, which helps to increase the output of pig iron in the blast furnace. Titanium dioxide has the ability to passivate coke, which helps to maintain the strength of coke after reaction in the blast furnace and stabilize the blast furnace skeleton effect of coke. At the same time, in addition to partially reducing titanium dioxide to titanium carbonitride, the rest enters the blast furnace slag of vanadium-titanium ore smelting. The titanium dioxide can be recycled by reprocessing the titanium-containing blast furnace slag.

[0036] According to the present invention, the bulk density of the mixture of the base coal and the acid-soluble titanium slag electric furnace dust is 0.7-0.9 t / m 3 Specifically, the bulk density is 0.7t / m 3 , 0.8t / m 3 , 0.9t / m 3 ; The bulk density can affect the reaction intensity of the coke.

[0037] The present application finally performs coking to obtain coke, and the coking is specifically as follows:

[0038] The mixed material is heated to 700-900°C at a heating rate of 5-15°C / min, and then heated to 1000-1050°C at a heating rate of 15-25°C / min, and kept at a constant temperature for 7-8 hours.

[0039] More specifically, the coking is:

[0040] The mixed material was heated to 800°C at a heating rate of 10°C / min, and then heated to 1050°C at a heating rate of 20°C / min, and kept at this temperature for 8 hours.

[0041] The present application also provides a method for smelting vanadium-titanium magnetite in a blast furnace, comprising:

[0042] The vanadium-titanium magnetite charge and coke are added from the top of the blast furnace, and heat exchange is carried out with the ascending high-temperature coal gas, and the iron-containing charge is indirectly reduced and directly reduced with the high-temperature coal gas and the hot coke respectively to form high-temperature molten slag iron. The coke is the coke prepared by the above-mentioned method.

[0043] In order to further understand the present invention, the method for preparing coke using acid-soluble titanium slag electric furnace dust ash provided by the present invention is described in detail below in conjunction with embodiments. The protection scope of the present invention is not limited by the following embodiments.

[0044] Example 1

[0045] Select coking coal, 1 / 3 coking coal, fat coal and lean coal of different fluidity (specific industrial analysis and thermoplastic characteristics are shown in Table 1), wherein the fluidity of coking coal is 1206ddpm, the fluidity of 1 / 3 coking coal is 128ddpm, the fluidity of fat coal is 3582ddpm, and the fluidity of lean coal is 0ddpm, and the above four types of coal are crushed respectively; the above four types of coal are humidified respectively, and the moisture content is controlled at 9%; the four types of coal are mixed in a mixer, and the mixing ratio of the four types of coal is: main coking coal-30%, 1 / 3 coking coal-40%, fat coal-20%, lean coal-10%, to obtain mixed coal;

[0046] Acid-soluble titanium slag electric furnace dust (the main components are shown in Table 2) was selected as a coke preparation additive, dried, and then mixed with the mixed coal in a mixer, and then put into a coking reactor for tamping. The amount of acid-soluble titanium slag electric furnace dust added was 3%, and the bulk density of the mixture of coal and acid-soluble titanium slag electric furnace dust in the coking reactor was 0.8 t / m 3 ;

[0047] The temperature of the mixed material was raised to 800°C at a heating rate of 10°C / min, and the coking reactor was placed in the center of the coke oven, and then the temperature was raised to 1050°C at a rate of 20°C / min. The coking constant temperature time was 8h, and then the coking reactor was taken out and cooled at room temperature to obtain acid-soluble titanium slag electric furnace dust removal ash to prepare coke for blast furnace smelting vanadium titanium magnetite. The performance indicators of the obtained coke are shown in Table 3;

[0048] Table 1 Industrial analysis and thermoplastic characteristics of coal types

[0049]

[0050] ad: air dry basis; daf: dry ash-free basis; d: dry basis

[0051] Table 2 Main component index data of acid-soluble titanium slag electric furnace dust removal ash / %

[0052] <![CDATA[TiO2]]> FeO <![CDATA[Fe2O3]]> C 34.41 30.69 8.81 3.74

[0053] Table 3 Performance index data table of coke prepared in this example

[0054] Reactivity / % Strength after reaction / % 26.24 61.16

[0055] As can be seen from Table 3, the performance indicators of the coke prepared in this embodiment are better than those of first-class metallurgical coke (coke reactivity ≤ 30%, strength after reaction ≥ 60%), and meet the requirements of blast furnace production.

[0056] Example 2

[0057] Select coking coal, 1 / 3 coking coal, fat coal and lean coal of different fluidity (specific industrial analysis and thermoplastic characteristics are shown in Table 1), wherein the fluidity of coking coal is 1206ddpm, the fluidity of 1 / 3 coking coal is 128ddpm, the fluidity of fat coal is 3582ddpm, and the fluidity of lean coal is 0ddpm, and the above four types of coal are crushed respectively; the above four types of coal are humidified respectively, and the moisture content is controlled at 10%; the four types of coal are mixed in a mixer, and the mixing ratio of the four types of coal is: main coking coal-35%, 1 / 3 coking coal-50%, fat coal-10%, lean coal-5%, to obtain mixed coal;

[0058] Acid-soluble titanium slag electric furnace dust (the main components are shown in Table 2) was selected as a coke preparation additive, dried, and then mixed with the mixed coal in a mixer, and then put into a coking reactor for tamping. The amount of acid-soluble titanium slag electric furnace dust added was 1%, and the bulk density of the mixture of coal and acid-soluble titanium slag electric furnace dust in the coking reactor was 0.9 t / m 3 ;

[0059] The temperature of the mixed material was raised to 800°C at a heating rate of 10°C / min, and the coking reactor was placed in the center of the coke oven. The temperature was then raised to 1050°C at a rate of 20°C / min, and the coking temperature was kept constant for 8 hours. The coking reactor was then taken out and cooled at room temperature to obtain acid-soluble titanium slag electric furnace dust removal ash to prepare coke for blast furnace smelting vanadium-titanium magnetite. The performance indicators of the obtained coke are shown in Table 4.

[0060] Table 4 Performance index data table of coke prepared in this example

[0061] Reactivity / % Strength after reaction / % 24.19 63.28

[0062] It can be seen from Table 4 that the performance indicators of the coke prepared in this embodiment are better than those of first-class metallurgical coke (coke reactivity ≤ 30%, strength after reaction ≥ 60%), and meet the requirements of blast furnace production.

[0063] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0064] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing coke using acid-soluble titanium slag electric furnace dust, comprising the following steps: S1) crushing the coal with fluidity less than 5000 ddpm and adjusting the humidity to obtain the basic coal; S2) mixing the basic coal and the acid-soluble titanium slag electric furnace dust ash and then coking to obtain coke.

2. The method according to claim 1, characterized in that: The basic coal types include: coal type A with a fluidity of 1000-2000 ddpm, coal type B with a fluidity of 10-1000 ddpm, coal type C with a fluidity of 2000-5000 ddpm, and coal type D with a fluidity less than 10 ddpm.

3. The method according to claim 1 or 2, characterized in that: The addition amount of coal type A with fluidity of 1000-2000ddpm is 20-40wt%, the addition amount of coal type B with fluidity of 10-1000ddpm is 30-50wt%, the addition amount of coal type C with fluidity of 2000-5000ddpm is 10-30wt%, and the addition amount of coal type D with fluidity less than 10ddpm is 0-10%.

4. The method according to claim 3, characterized in that The preparation of the basic coal is specifically as follows: Coal type A, coal type B, coal type C and coal type D are crushed and humidified respectively, and the humidified coal type A, coal type B, coal type C and coal type D are mixed to obtain the basic coal type.

5. The method according to claim 4, characterized in that The moisture content of the humidified coal type A is 9-10%, the moisture content of the humidified coal type B is 9-10%, the moisture content of the humidified coal type C is 9-10%, and the moisture content of the humidified coal type D is 9-10%.

6. The method according to claim 1, characterized in that The acid-soluble titanium slag electric furnace dust removal ash has a TiO2 content of 20-40wt%, a FeO content of 20-35wt%, and a Fe2O3 content of 5-15wt%.

7. The method according to claim 1, characterized in that In step S2), the bulk density of the mixed material is 0.7-0.9 t / m 3 .

8. The method according to claim 1, characterized in that In step S2), based on the total amount of the basic coal and the acid-soluble titanium slag electric furnace dust ash, the content of the acid-soluble titanium slag electric furnace dust ash is 1-7wt%, and the remainder is the basic coal.

9. The method according to claim 1, characterized in that: The coking process is specifically as follows: The mixed material is heated to 700-900°C at a heating rate of 5-15°C / min, and then heated to 1000-1050°C at a heating rate of 15-25°C / min, and kept at a constant temperature for 7-8 hours.

10. A method for smelting vanadium-titanium magnetite in a blast furnace, comprising: The vanadium-titanium magnetite charge and coke are added from the top of the blast furnace, and heat exchange is carried out with the ascending high-temperature coal gas. The iron-containing charge is indirectly reduced and directly reduced with the high-temperature coal gas and the hot coke, respectively, to form high-temperature molten slag iron. The coke is coke prepared by the method according to any one of claims 1 to 9.

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