Method for preparing reducing agent from acid-soluble titanium slag electric furnace fly ash and reduction method of vanadium titano-magnetite hydrometallurgy electric furnace

Abstract

The invention provides a method for preparing a reducing agent from acid-soluble titanium slag electric furnace fly ash, which comprises the following steps: S1) crushing a coal type with the fluidity of 10-10000 ddpm, and humidifying to obtain a basic coal type; and S2) mixing the basic coal type, the biomass and the acid-soluble titanium slag electric furnace fly ash, and coking to obtain the reducing agent. According to the reducing agent prepared in the invention, the acid-soluble titanium slag electric furnace fly ash is combined with the biomass, so that the iron oxide is quickly reduced, and meanwhile, the iron oxide is also a raw material for ironmaking, so that the yield of pig iron is increased; the biomass can replace part of coking coal, so that carbon emission can be reduced; furthermore, titanium dioxide in the acid-soluble titanium slag electric furnace fly ash enters the melt separation slag, the content of titanium dioxide in the slag is increased, recycling is facilitated, and the method has great application and popularization value.

Description

Technical Field

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

[0002] The new process of direct reduction of vanadium-titanium magnetite in hydrogen metallurgical gas-based vertical furnace and electric furnace smelting can get rid of the dependence on coking coal resources, reduce energy consumption, and improve the recovery rate of vanadium and titanium, providing a new process method for the efficient and clean comprehensive utilization of vanadium-titanium magnetite resources. In the hydrogen metallurgical gas-based vertical furnace, the iron of vanadium-titanium magnetite is reduced to metallic iron, and its metallization rate is normally about 80-90%. The reduced metallic iron and unreduced iron oxides and titanium oxides all enter the electric furnace and are reduced and separated by the dual effects of carbon-containing substances and temperature. In the reduction electric furnace smelting process, the overall reduction efficiency of ordinary pure carbonaceous reducing agents such as coke is low due to the low reactivity and is non-renewable, which is not conducive to carbon reduction and emission reduction. Therefore, the selection of reducing agent is particularly important.

[0003] The annual output of acid-soluble titanium slag electric furnace dust is about hundreds of thousands of tons, and the transportation and storage costs are expensive and easy to cause pollution. At the same time, acid-soluble titanium slag electric furnace dust contains a large amount of iron oxides and titanium dioxide, which has great recycling value, but acid-soluble titanium slag electric furnace dust has not been effectively reused. In addition, biomass such as poplar trees are renewable energy sources with huge annual output, and have great potential for producing high-quality reducing agents. Therefore, how to prepare a combination of acid-soluble titanium slag electric furnace dust and biomass can achieve recycling while actually solving the problem of low reactivity of reducing agents in vanadium-titanium magnetite hydrogen metallurgy electric furnaces, which is of great significance for vanadium-titanium magnetite hydrogen metallurgy. Summary of the invention

[0004] The technical problem solved by the present invention is to provide a method for preparing a reducing agent using acid-soluble titanium slag electric furnace dust. The preparation method provided in the present application can produce a highly reactive reducing agent required for hydrogen metallurgical electric furnace smelting of vanadium-titanium magnetite, 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 a reducing agent using acid-soluble titanium slag electric furnace dust, comprising the following steps:

[0006] S1) crushing the coal with a fluidity of 10 to 10000 ddpm and adjusting the humidity to obtain a basic coal;

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

[0008] Preferably, among the basic coal types, the addition amount of coal type A with a fluidity of 100-2000ddpm is 30-50wt%, the addition amount of coal type B with a fluidity of 10-1000ddpm is 10-30wt%, and the addition amount of coal type C with a fluidity of 2000-10000ddpm is 20-60wt%.

[0009] Preferably, the preparation of the basic coal is specifically as follows:

[0010] Coal type A, coal type B, and coal type C are crushed and humidified respectively, and the conditioned coal type A, coal type B, and coal type C are mixed to obtain a basic coal type.

[0011] 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%, and the moisture content of the coal type C after moisture adjustment is 9-10%.

[0012] 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%.

[0013] Preferably, in step S2), the bulk density of the mixed material is 0.5-0.7 t / m 3 .

[0014] Preferably, in step S2), based on the total amount of the basic coal, the biomass and the acid-soluble titanium slag electric furnace dust ash, the content of the acid-soluble titanium slag electric furnace dust ash is 3-10wt%, the content of the biomass is 1-10wt%, and the remainder is the basic coal.

[0015] Preferably, the coking process is specifically:

[0016] The mixed mixture is heated to 400-600°C at a heating rate of 10-15°C / min, and then heated to 800-1000°C at a heating rate of 20-25°C / min, and kept at a constant temperature for 3-4 hours.

[0017] Preferably, the biomass has a moisture content of 3-6 wt%, a volatile content of 60-90%, a fixed carbon content of 10-20 wt%, and an ash content of 3-10 wt%.

[0018] The present application also provides a reduction method of vanadium-titanium magnetite in a hydrogen metallurgical electric furnace, comprising the following steps:

[0019] The iron oxides in the vanadium-titanium magnetite that cannot be reduced in the hydrogen metallurgical gas-based vertical furnace are reacted under the action of a reducing agent in a subsequent electric furnace;

[0020] The reducing agent is the reducing agent prepared by the method described.

[0021] The present application provides a method for preparing a reducing agent using acid-soluble titanium slag electric furnace dust ash, which first crushes coal with a fluidity of 10 to 10,000 ddpm and then adjusts the humidity to obtain a basic coal; then the basic coal, biomass and acid-soluble titanium slag electric furnace dust ash are mixed and coked to obtain a reducing agent for a vanadium-titanium magnetite hydrogen metallurgical electric furnace; in the present application, a reducing agent for a hydrogen metallurgical electric furnace is prepared by mixing the basic coal, acid-soluble titanium slag electric furnace dust ash and biomass, and the resulting reducing agent has high reactivity. At the same time, the iron oxide in the acid-soluble titanium slag electric furnace dust ash serves as a reduction reaction catalyst and is also a raw material for ironmaking, which helps to increase pig iron production; biomass can replace part of coking coal, and neutral carbon can replace the carbon in coking coal, which helps to reduce carbon emissions; further, titanium dioxide in the acid-soluble titanium slag electric furnace dust ash enters the molten slag, thereby increasing the content of titanium dioxide in the slag for easy recycling. 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 demand for recycling and reusing acid-soluble titanium slag electric furnace dust in the prior art and the demand for high reactivity of reducing agents for vanadium-titanium magnetite hydrogen metallurgical electric furnaces, the present application provides a method for preparing a reducing agent using acid-soluble titanium slag electric furnace dust, which uses acid-soluble titanium slag electric furnace dust and biomass as additives for the reducing agent. The reducing agent produced has high reactivity and is green and low-carbon, increases the output of pig iron, can be used for vanadium-titanium magnetite electric furnace smelting, and realizes the recycling of titanium dioxide. Specifically, the embodiment of the present invention discloses a method for preparing a reducing agent using acid-soluble titanium slag electric furnace dust, comprising the following steps:

[0024] S1) crushing the coal with a fluidity of 10 to 10000 ddpm and adjusting the humidity to obtain a basic coal;

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

[0026] In the method for preparing the reducing agent, the present application first crushes the coal with a fluidity of 10 to 10000 ddpm and then adjusts the humidity to obtain the basic coal; in this process, the basic coal includes coal A with a fluidity of 100 to 2000 ddpm, coal B with a fluidity of 10 to 1000 ddpm, and coal C with a fluidity of 2000 to 10000 ddpm; specifically, the fluidity of the coal A is 120 to 1800 ddpm, the fluidity of the coal B is 100 to 800 ddpm, and the fluidity of the coal C is 3500 to 6000 ddpm. The 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 then affect the quality of the reducing agent (strength after reaction), and if the reducing agent has no strength, its particle size range cannot be controlled.

[0027] Among them, the addition amount of coal type A with a fluidity of 100-2000ddpm is 30-50wt%, the addition amount of coal type B with a fluidity of 10-1000ddpm is 10-30wt%, and the addition amount of coal type C with a fluidity of 2000-10000ddpm is 20-60wt%. Specifically, the addition amount of coal type A with a fluidity of 1000-2000ddpm is 40-45wt%, the addition amount of coal type B with a fluidity of 10-1000ddpm is 15-25wt%, and the addition amount of coal type C with a fluidity of 2000-10000ddpm is 25-50wt%. The overlapping values ​​of the above fluidity, for example, 100-2000ddpm specifically means greater than or equal to 100ddpm and less than or equal to 2000ddpm, 10-1000ddpm specifically means greater than or equal to 10ddpm and less than or equal to 1000ddpm, and 2000-10000ddpm specifically means greater than 2000ddpm and less than or equal to 10000ddpm.

[0028] In the present application, the coal type A, the coal type B and the coal type C can be selected from coal types familiar to those skilled in the art according to the above-mentioned fluidity range. For example, they can be independently selected from one or more of main coking coal, 1 / 3 coking coal and fat coal.

[0029] Furthermore, the preparation of the basic coal species described in this application is specifically as follows:

[0030] Coal type A, coal type B, and coal type C are crushed and humidified respectively, and the conditioned coal type A, coal type B, and coal type C are mixed to obtain a basic coal type.

[0031] 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, and C. The moisture content of the humidified coal type A is 9-10%, the moisture content of the humidified coal type B is 9-10%, and the moisture content of the humidified coal type C is 9-10%.

[0032] After obtaining the basic coal, the present application mixes it with biomass and acid-soluble titanium slag electric furnace dust ash and then cokes it to obtain a reducing agent. In this process, based on the total mass of the basic coal, the biomass and the acid-soluble titanium slag electric furnace dust ash, the content of the acid-soluble titanium slag electric furnace dust ash is 3-10wt%, the content of the biomass is 1-10wt%, and the balance is the basic coal; specifically, the content of the acid-soluble titanium slag electric furnace dust ash is 5-8wt%, and the content of the biomass is 3-8wt%; for example, the content of the acid-soluble titanium slag electric furnace dust ash in the present application is 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt% or 10wt%, and the content of the biomass is 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt% or 10wt%.

[0033] 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 reactivity of the carbonaceous reducing agent and accelerate the reaction process. At the same time, the iron oxide is also the raw material of the vanadium-titanium magnetite hydrogen metallurgical electric furnace, which helps to increase the output of pig iron; and titanium dioxide enters the slag through the smelting furnace, and the titanium dioxide can be recycled through the selective carbonization-chlorination of the slag. The biomass is used to provide a carbon source to replace carbon and improve the reactivity of carbon; the water content of the biomass is 3-6wt%, the volatile content is 60-90%, the fixed carbon is 10-20wt%, and the ash content is 3-10wt%; specifically, the water content of the biomass is 4-5wt%, the volatile content is 64-88%, the fixed carbon is 15-18wt%, and the ash content is 5-9wt%.

[0034] According to the present invention, the bulk density of the mixture of the basic coal, the biomass and the acid-soluble titanium slag electric furnace dust is 0.5-0.7 t / m 3 Specifically, the bulk density is 0.55-0.6 t / m 3 ; The bulk density may affect the reaction intensity of the reducing agent.

[0035] The present application finally performs coking to obtain a reducing agent, and the coking is specifically as follows:

[0036] The mixed mixture is heated to 400-600°C at a heating rate of 10-15°C / min, and then heated to 800-1000°C at a heating rate of 20-25°C / min, and kept at a constant temperature for 3-4 hours.

[0037] More specifically, the coking is:

[0038] The mixed mixture is heated to 450-500°C at a heating rate of 12-13°C / min, and then heated to 850-900°C at a heating rate of 22-23°C / min, and maintained at a constant temperature for 3.5-4h.

[0039] The present application also provides a reduction method of vanadium-titanium magnetite in a hydrogen metallurgical electric furnace, comprising the following steps:

[0040] The iron oxides in the vanadium-titanium magnetite that cannot be reduced in the hydrogen metallurgical gas-based vertical furnace are reacted under the action of a reducing agent in a subsequent electric furnace;

[0041] The reducing agent is the reducing agent prepared by the method described above.

[0042] In order to further understand the present invention, the method for preparing a reducing agent 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.

[0043] Example 1

[0044] Select coking coal, 1 / 3 coking coal and fat coal with different fluidities, and the specific industrial analysis and fluidity are shown in Table 1, wherein the fluidity of coking coal is 1587ddpm, the fluidity of 1 / 3 coking coal is 135ddpm, and the fluidity of fat coal is 6078ddpm. The above three types of coal are crushed respectively as basic coals; the basic coals are humidified respectively to control the moisture content at 9%; the three basic coals are mixed in a mixer, and the mixing ratio of the three types of coal is: main coking coal-40wt%, 1 / 3 coking coal-30wt%, fat coal-30wt%, to obtain a mixed coal;

[0045] Acid-soluble titanium slag electric furnace dust (the main components are shown in Table 2) and biomass (the main components are shown in Table 3) are selected as additives, dried, and then mixed with mixed coal in a mixer, and then put into a coking reactor for tamping. The amount of acid-soluble titanium slag electric furnace dust is 5wt%, the amount of biomass is 7wt%, and the bulk density of the mixture of coal, acid-soluble titanium slag electric furnace dust and biomass in the coking reactor is 0.6t / m 3 ;

[0046] The mixed material was first heated to 500°C at a heating rate of 10°C / min, the coking reactor was placed in the center of the coke oven, and then heated to 900°C at 20°C / min, the coking constant temperature time was 3h, and then the coking reactor was taken out and cooled at room temperature to obtain a vanadium-titanium magnetite hydrogen metallurgical electric furnace reducing agent. The performance and structural indicators of the obtained reducing agent are shown in Table 4;

[0047] Table 1 Industrial analysis and thermoplastic characteristics of coal types

[0048]

[0049] Note: ad: air dried basis; daf: dry ash-free basis; d: dry basis.

[0050] Table 2 Main component index data of acid-soluble titanium slag electric furnace dust removal ash / wt%

[0051] <![CDATA[TiO2]]> FeO <![CDATA[Fe2O3]]> C 32.99 28.14 11.63 3.09

[0052] Table 3 Main component index data of biomass / wt%

[0053] <![CDATA[Moisture ad > <![CDATA[Volatile matter d > <![CDATA[Fixed carbon d > <![CDATA[Ash d > 4.29 84.48 15.52 5.79

[0054] Table 4 Performance structure index data table of reducing agent

[0055] Reactivity / % Strength after reaction / % <![CDATA[Specific surface area m 2 ·g -1 > 43.9 28.6％ 52.68

[0056] It can be seen from Table 4 that the reactivity of the reducing agent reaches 43.9%, which is 13.9% higher than the reactivity of primary coke (30%, GB / T 1996-2017).

[0057] Example 2

[0058] Select coking coal, 1 / 3 coking coal and fat coal of different fluidity (specific industrial analysis and fluidity are shown in Table 1), wherein the fluidity of coking coal is 1206ddpm, the fluidity of 1 / 3 coking coal is 128ddpm, and the fluidity of fat coal is 3582ddpm, and the above three types of coal are crushed respectively as basic coal types; the basic coal types are humidified respectively to control the moisture content at 9%; the three basic coal types are mixed in a mixer, and the mixing ratio of the three types of coal is: main coking coal-45wt%, 1 / 3 coking coal-30wt%, fat coal-25wt%, to obtain a mixed coal type;

[0059] Acid-soluble titanium slag electric furnace dust (the main components are shown in Table 2) and biomass (the main components are shown in Table 3) are selected as additives, dried, and then mixed with 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 is 6wt%, the amount of biomass added is 5wt%, and the bulk density of the mixture of coal, acid-soluble titanium slag electric furnace dust and biomass in the coking reactor is 0.55t / m 3 ;

[0060] The mixed material was first heated to 500°C at a heating rate of 10°C / min, the coking reactor was placed in the center of the coke oven, and then heated to 900°C at a rate of 20°C / min, the coking constant temperature time was 3.5h, and then the coking reactor was taken out and cooled at room temperature to obtain a vanadium-titanium magnetite hydrogen metallurgical electric furnace reducing agent. The performance and structural indicators of the obtained reducing agent are shown in Table 5;

[0061] Table 5 Performance structure index data table of reducing agent

[0062] Reactivity / % Strength after reaction / % <![CDATA[Specific surface area m 2 ·g -1 > 39.4 32.1％ 43.15

[0063] It can be seen from Table 5 that the reactivity of the reducing agent reaches 39.4%, which is 9.4% higher than the reactivity of primary coke (30%, GB / T 1996-2017).

[0064] 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.

[0065] 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 a reducing agent using acid-soluble titanium slag electric furnace dust, comprising the following steps: S1) crushing the coal with a fluidity of 10 to 10000 ddpm and adjusting the humidity to obtain a basic coal; S2) mixing the basic coal, biomass and acid-soluble titanium slag electric furnace dust ash and then coking to obtain a reducing agent.

2. The method according to claim 1, characterized in that: Among the basic coal types, the addition amount of coal type A with a fluidity of 100-2000ddpm is 30-50wt%, the addition amount of coal type B with a fluidity of 10-1000ddpm is 10-30wt%, and the addition amount of coal type C with a fluidity of 2000-10000ddpm is 20-60wt%.

3. The method according to claim 1, characterized in that The preparation of the basic coal is specifically as follows: Coal type A, coal type B, and coal type C are crushed and humidified respectively, and the conditioned coal type A, coal type B, and coal type C are mixed to obtain a basic coal type.

4. The method according to claim 3, characterized in that 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%, and the moisture content of the coal type C after moisture adjustment is 9-10%.

5. 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%.

6. The method according to claim 1, characterized in that In step S2), the bulk density of the mixed material is 0.5-0.7 t / m 3 .

7. The method according to claim 1, characterized in that In step S2), based on the total amount of the basic coal, the biomass and the acid-soluble titanium slag electric furnace dust ash, the content of the acid-soluble titanium slag electric furnace dust ash is 3-10wt%, the content of the biomass is 1-10wt%, and the remainder is the basic coal.

8. The method according to claim 1, characterized in that The coking process is specifically as follows: The mixed mixture is heated to 400-600°C at a heating rate of 10-15°C / min, and then heated to 800-1000°C at a heating rate of 20-25°C / min, and kept at a constant temperature for 3-4 hours.

9. The method according to claim 1, characterized in that: The biomass has a moisture content of 3-6 wt%, a volatile content of 60-90%, a fixed carbon content of 10-20 wt%, and an ash content of 3-10 wt%.

10. A reduction method of vanadium-titanium magnetite in a hydrogen metallurgical electric furnace, comprising the following steps: The iron oxides in the vanadium-titanium magnetite that cannot be reduced in the hydrogen metallurgical gas-based vertical furnace are reacted under the action of a reducing agent in a subsequent electric furnace; The reducing agent is a reducing agent prepared by the method according to any one of claims 1 to 9.

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