Smelting method for all-vanadium-titanium magnetite pellets in oxygen blast furnace and burden structure therefor

Abstract

A burden structure for smelting of all-vanadium-titanium magnetite pellets in an oxygen blast furnace and a smelting method for all-vanadium-titanium magnetite pellets in an oxygen blast furnace, said method using the burden structure. The burden structure is completely composed of vanadium-titanium magnetite pellets, and comprises the following components: TFe: 51.0-58.0 wt%, SiO2: 3.0-5.0 wt%, CaO: 0.4-5.0 wt%, MgO: 2.0-4.2 wt%, Al2O3: 2.0-4.0 wt%, TiO2: 8.0-11.0 wt%, and V2O5: 0.50-0.80 wt%. The burden structure and the smelting method for all-vanadium-titanium magnetite pellets in an oxygen blast furnace provided in the present invention can achieve smelting of all-vanadium-titanium magnetite pellets, improve the comprehensive utilization rate of vanadium-titanium magnetite, and reduce energy consumption and emissions of carbon dioxide and other pollutants.

Description

Vanadium-titanium magnetite pellet smelting method of oxygen blast furnace and burden structure thereof

[0001] The present application claims priority to the Chinese patent application No. 202410585912.3, filed on May 11, 2024, and entitled "Vanadium-titanium magnetite pellet smelting method of oxygen blast furnace and burden structure thereof", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application belongs to the field of vanadium-titanium magnetite blast furnace smelting, and specifically relates to a burden structure for vanadium-titanium magnetite pellet smelting of an oxygen blast furnace and a vanadium-titanium magnetite pellet smelting method of an oxygen blast furnace using the burden structure. BACKGROUND

[0003] Vanadium-titanium magnetite is a composite iron ore mainly composed of iron, titanium and vanadium elements, and has very high comprehensive utilization value. The proven reserves in Panxi region are 939 million tons, and the predicted reserves are 117.75 million tons, accounting for about 1 / 5 of the total reserves of various iron ores in China and 1 / 4 of the world's vanadium-titanium magnetite reserves. The reserves of vanadium and titanium account for 87% and 94.3% of the proven reserves in China, respectively, ranking third and first in the world.

[0004] As an important iron ore resource in China, vanadium-titanium magnetite pellet smelting is the ultimate goal of vanadium-titanium magnetite blast furnace smelting, which can improve the comprehensive utilization rate of vanadium-titanium magnetite and reduce energy consumption and emissions of carbon dioxide and other pollutants. However, due to the high TiO2 content in the blast furnace slag produced by vanadium-titanium magnetite smelting, Ti(C,N) is formed with carbonaceous reducing agents such as coke, which will deteriorate the fluidity of the slag and affect the operation of the blast furnace. If a full-oxygen blast furnace is used, 100% O2 is blown into the blast furnace without N2, which can greatly reduce the generation of Ti(C,N) and achieve full vanadium-titanium magnetite blast furnace smelting. However, if full vanadium-titanium magnetite is used, the TiO2 content in the slag will increase from the current 22-23% to more than 35%. If the existing slag making system remains unchanged, the metallurgical properties of the slag will deteriorate, the melting point of the slag will rise significantly, and the blast furnace production cannot be carried out.

[0005] Therefore, how to solve the problem of slag metallurgical property deterioration is an urgent problem to be solved for realizing full vanadium-titanium magnetite pellet smelting. SUMMARY

[0006] To solve the above problems, the present application provides a burden structure that can realize full vanadium-titanium magnetite pellet smelting and a full vanadium-titanium magnetite pellet smelting method.

[0007] To achieve the above purpose, the present application adopts the following technical solutions:

[0008] According to a first aspect of the present application, a burden structure for oxygen blast furnace smelting of vanadium titanomagnetite pellets is provided, which is entirely composed of vanadium titanomagnetite pellets and contains the following components: TFe: 51.0-58.0wt%, SiO2: 3.0-5.0wt%, CaO: 0.4-5.0wt%; MgO: 2.0-4.2wt%, Al2O3: 2.0-4.0wt%, TiO2: 8.0-11.0wt%, V2O5: 0.50-0.80wt%.

[0009] According to an embodiment of the present application, the vanadium titanomagnetite pellets are made of vanadium titanomagnetite concentrate with the following components: TFe: 54.0-60.0wt%, Al2O3: 3.0-5.0wt%, SiO2: 2.0-4.0wt%, CaO: 0-0.5wt%, MgO: 2.0-5.0wt%, TiO2: 8.0-12.0wt%, V2O5: 0.5-0.7wt%.

[0010] According to an embodiment of the present application, the vanadium titanomagnetite pellets are made of vanadium titanomagnetite concentrate with the following components: TFe: 54.0-60.0wt%, Al2O3: 3.0-5.0wt%, SiO2: 2.0-4.0wt%, CaO: 0-0.5wt%, MgO: 2.0-5.0wt%, TiO2: 8.0-12.0wt%, V2O5: 0.5-0.7wt%.

[0011] According to an embodiment of the present application, the burden structure is composed of one or more kinds of vanadium titanomagnetite pellets.

[0012] According to a second aspect of the present application, a method for oxygen blast furnace smelting of vanadium titanomagnetite pellets is provided, which uses the burden structure according to the first aspect of the present application.

[0013] According to an embodiment of the present application, the smelting method controls the slag basicity to be between 0.20-0.65.

[0014] According to an embodiment of the present application, the smelting method controls the slag composition to be TiO2: 35.0-46.0wt%, Al2O3: 14.0-18.0wt%, MgO: 9.0-15.0wt%, SiO2: 18.0-24.0wt%, CaO: 2.0-18.0wt%.

[0015] According to an embodiment of the present application, the smelting method controls the slag basicity by adjusting the basicity of the vanadium titanomagnetite pellets according to the content of TiO2, Al2O3 and MgO in the vanadium titanomagnetite pellets.

[0016] According to an embodiment of the present application, when the content of TiO2 in the slag composition is 35-38wt% and the content of Al2O3 is 14-18wt%, the following conditions are ensured:

[0017] When the MgO content is 9-11wt%, the slag basicity is controlled between 0.45-0.65;

[0018] When the MgO content is 11-13wt%, the slag basicity is controlled between 0.35-0.55;

[0019] When the MgO content is 13-15wt%, the slag basicity is controlled between 0.20-0.40;

[0020] When the TiO2 content is 38-42wt% and the Al2O3 content is 14-18wt% in the slag composition of the slag, the following conditions are ensured:

[0021] When the MgO content is 9-11wt%, the slag basicity is controlled between 0.40-0.60;

[0022] When the MgO content is 11-13wt%, the slag basicity is controlled between 0.30-0.50;

[0023] When the MgO content is 13-15wt%, the slag basicity is controlled between 0.25-0.45;

[0024] When the TiO2 content is 42-46wt% and the Al2O3 content is 14-18wt% in the slag composition of the slag, the following conditions are ensured:

[0025] When the MgO content is 9-11wt%, the slag basicity is controlled between 0.35-0.55;

[0026] When the MgO content is 11-13wt%, the slag basicity is controlled between 0.25-0.45;

[0027] When the MgO content is 13-15wt%, the slag basicity is controlled between 0.30-0.50.

[0028] According to one embodiment of the present application, the smelting method employs full oxygen for blast furnace smelting.

[0029] By employing the technical solution described above, the present application has at least the following beneficial effects:

[0030] The charge structure and the oxygen blast furnace full vanadium-titanium ore pellet smelting method provided by the present application can realize full vanadium-titanium ore pellet smelting, thereby improving the comprehensive utilization rate of vanadium-titanium magnetite and reducing energy consumption and reducing carbon dioxide and other pollutant gas emissions. BRIEF DESCRIPTION OF DRAWINGS

[0031] Fig. 1 is a viscosity-melting temperature curve measured for the titanium-containing blast furnace slag of Example 1;

[0032] Figure 2 is a measured viscosity-meltability temperature curve of the titanium-containing blast furnace slag of Example 2. DETAILED DESCRIPTION

[0033] In order to make the objectives, technical solutions, and advantages of the present application clearer, further detailed description of the present application will be given below in conjunction with specific examples. It should be understood that the specific examples described herein are only used to explain the present application and should not be used to limit the present application.

[0034] According to the need, specific embodiments of the present application are disclosed in the specification of the present application; however, it should be understood that the embodiments disclosed herein are only examples of the present application which can be implemented in various alternative forms. In the following description, a plurality of operating parameters and components are described in a plurality of embodiments conceived. These specific parameters and components are only used as examples in the specification and do not mean limitation.

[0035] As mentioned in the background section, global smelting of vanadium titano-magnetite is the ultimate goal of the blast furnace smelting of vanadium titano-magnetite, which can improve the comprehensive utilization rate of vanadium titano-magnetite and reduce energy consumption and reduce carbon dioxide and other pollutant gas emissions. For this purpose, according to the first aspect of the present application, a burden structure for oxygen blast furnace global smelting of vanadium titano-magnetite is provided, which is entirely composed of vanadium titano-magnetite pellets, the main components of which are shown in Table 1.

[0036] Table 1 Main component range of vanadium titano-magnetite pellets (wt%)

[0037] When global smelting of vanadium titano-magnetite pellets is carried out using the burden structure provided by the present application, the blast furnace slag produced by smelting has a suitable liquidus temperature range and viscosity range, which meets the requirements of the blast furnace smelting process for the metallurgical properties of the blast furnace slag.

[0038] In some embodiments, the vanadium titano-magnetite pellets are made of vanadium titano-magnetite concentrate containing the following components: TFe: 54.0-60.0wt%, Al2O3: 3.0-5.0wt%, SiO2: 2.0-4.0wt%, CaO: 0-0.5wt%, MgO: 2.0-5.0wt%, TiO2: 8.0-12.0wt%, V2O5: 0.5-0.7wt%.

[0039] In some embodiments, the vanadium titanomagnetite pellets are made from the vanadium titanomagnetite concentrate described above by adding an appropriate amount of calcareous flux, magnesian flux or a substance containing calcium oxide and magnesium oxide after high-temperature calcination. Specifically, a whole sample analysis can be performed on the composition of the vanadium titanomagnetite concentrate, and then based on the composition requirements of the vanadium titanomagnetite pellets, an appropriate amount of calcareous flux, magnesian flux or a substance containing calcium oxide and magnesium oxide after high-temperature calcination is added to the vanadium titanomagnetite concentrate, and then roasting and balling are performed to obtain vanadium titanomagnetite pellets with the desired composition. The calcareous flux can be one or a mixture of several of the following: quicklime, slaked lime, calcium carbonate and other calcium oxide raw materials or substances that can obtain calcium oxide after calcination; the magnesian flux can be one or a mixture of several of the following: light-burned magnesium oxide, high-purity magnesia and other magnesium oxide raw materials or substances that can obtain magnesium oxide after calcination, such as magnesium hydroxide, magnesium carbonate and basic magnesium carbonate; and the substance containing calcium oxide and magnesium oxide after high-temperature calcination can be, for example, dolomite.

[0040] In some embodiments, the burden structure is composed of one or more types of vanadium titanomagnetite pellets. In other words, the burden structure described in the present application can only contain one type of vanadium titanomagnetite pellet, in which case the composition of the burden structure is the composition of the vanadium titanomagnetite pellet; alternatively, the burden structure described in the present application can contain multiple types of vanadium titanomagnetite pellets with different compositions, in which case the composition of the burden structure is the average composition of the multiple types of vanadium titanomagnetite pellets.

[0041] In some embodiments, the vanadium titanomagnetite pellets have an alkalinity within 0.1 to 1.1. The vanadium titanomagnetite pellets with such an alkalinity range can make the blast furnace slag produced during smelting have a suitable liquidus temperature range and viscosity range, meeting the requirements of the blast furnace smelting process in terms of the metallurgical properties of the blast furnace slag.

[0042] According to a second aspect of the present application, there is provided an oxygen blast furnace full vanadium titanomagnetite pellet smelting method using the burden structure of the first aspect of the present application.

[0043] In some embodiments, the alkalinity of the slag during smelting is controlled to be between 0.20 and 0.65. Using the burden structure provided in the present application, a high-titanium slag system with a TiO2 content of 35wt% or more is obtained after smelting. Due to the high TiO2 content, the alkalinity needs to be greatly adjusted to obtain a low liquidus temperature range, thereby obtaining a lower blast furnace operating temperature. The TiO2 content in the existing titanium-containing blast furnace slag is between 20wt% and 23wt%, and the alkalinity is usually controlled to be between 1.0 and 1.2. In the present application, in order to ensure that the high-titanium slag system can be smelted in the blast furnace, the slag alkalinity needs to be controlled to be between 0.20 and 0.65.

[0044] In some embodiments, the composition of the high-titanium slag system is shown in Table 2. The composition of the slag has a low liquidus temperature, and can obtain a suitable operating temperature of the blast furnace during full vanadium titanomagnetite pellet smelting.

[0045] Table 2 Main components of high titanium slag system (wt%)

[0046] In some embodiments, in order to more accurately control the appropriate slag liquidus temperature, the basicity of the vanadium-titanium ore pellets needs to be adjusted according to the TiO2, Al2O3, and MgO content in the vanadium-titanium ore pellets.

[0047] In some embodiments, preferably, in order to more accurately control the appropriate slag liquidus temperature, the slag basicity control mode is as follows:

[0048] When TiO2= 35-38wt%, Al2O3= 14-18wt%, the following needs to be ensured:

[0049] 1) When MgO = about 9-11wt%, R2(CaO / SiO2) should be controlled between 0.45-0.65;

[0050] 2) When MgO = about 11-13wt%, R2(CaO / SiO2) should be controlled between 0.35-0.55;

[0051] 3) When MgO = about 13-15wt%, R2(CaO / SiO2) should be controlled between 0.20-0.40;

[0052] When TiO2= 38-42wt%, Al2O3= 14-18wt%, the following needs to be ensured:

[0053] 1) When MgO = about 9-11wt%, R2(CaO / SiO2) should be controlled between 0.40-0.60;

[0054] 2) When MgO = about 11-13wt%, R2(CaO / SiO2) should be controlled between 0.30-0.50;

[0055] 3) When MgO = about 13-15wt%, R2(CaO / SiO2) should be controlled between 0.25-0.45;

[0056] When TiO2= 42-46wt%, Al2O3= 14-18wt%, the following needs to be ensured:

[0057] 1) When MgO = about 9-11wt%, R2(CaO / SiO2) should be controlled between 0.35-0.55;

[0058] 2) When MgO = about 11-13wt%, R2(CaO / SiO2) should be controlled between 0.25-0.45;

[0059] 3) When MgO = about 13-15wt%, R2(CaO / SiO2) should be controlled between 0.30-0.50.

[0060] R2 refers to binary basicity represented by CaO / SiO2.

[0061] In some embodiments, the smelting process employs top-oxygen for blast furnace smelting. Since the TiO2 content in the slag is higher than the TiO2 content in the current blast furnace slag of vanadium-titanium magnetite smelting (about 20-23wt%), the present application uses top-oxygen blast furnace smelting, pure oxygen is blown into the tuyere, and the blast furnace smelting temperature is controlled to be comparable to the current blast furnace smelting temperature. Since the gas blown into the tuyere does not contain N2, the generation of TiN can be greatly reduced when smelting total vanadium-titanium magnetite in the blast furnace. By comparing the drop experiments of global briquettes under top-oxygen conditions in the blast furnace with the drop experiments of the existing charge structure under the current blast furnace atmosphere conditions, it can be seen that the generation amount of TiC+TiN only slightly increases. This shows that by top-oxygen blast furnace smelting, Ti(C,N) in the blast furnace can be maintained at a level comparable to the existing blast furnace, and total vanadium-titanium magnetite smelting can be realized.

[0062] The present application will be specifically described below through specific examples.

[0063] Example 1:

[0064] Vanadium-titanium magnetite concentrate with main components as shown in Table 3 was used.

[0065] Table 3 Main components of vanadium-titanium magnetite concentrate (wt%)

[0066] Vanadium-titanium ore pellets were prepared after adding 2.3% calcium carbonate and 2% bentonite, and the main components of the pellets are shown in Table 4.

[0067] Table 4 Main components of vanadium-titanium ore pellets (wt%)

[0068] Using the vanadium-titanium ore pellets, 100% vanadium-titanium ore pellets were smelted into the blast furnace, and the blast furnace slag composition and liquidus temperature are shown in Table 5 (V2O5 content is not more than 1.0%, which is ignored).

[0069] Table 5 Composition of titanium-containing blast furnace slag (wt%) and liquidus temperature value (℃)

[0070] The product obtained by calcining the analytically pure chemical reagent at 870℃ for more than 2h after dehydration was used as the initial raw material, the slag was prepared according to the components in Table 5, and the slag was fully melted at 1500℃. The viscosity-melting temperature test experiment was carried out by using a high-temperature melt physical property tester and a rotation method, and the test results are shown in Figure 1.

[0071] As shown in Fig. 1, the slag melting temperature (inflection point temperature of viscosity sharply increasing) gradually decreases under the composition, and the viscosity of the slag under the condition of 1410℃ or above is 0.5 Pa·s, which can meet the production of blast furnace.

[0072] Example 2:

[0073] The vanadium-titanium magnetite concentrate was used, and the main components are shown in Table 6.

[0074] Table 6 Main components of vanadium-titanium magnetite concentrate (wt%)

[0075] The vanadium-titanium ore pellets were prepared by adding 2.7% calcium carbonate and 2% bentonite, and the main components of the pellets are shown in Table 7.

[0076] Table 7 Main components of vanadium-titanium ore pellets (wt%)

[0077] The vanadium-titanium ore pellets were used, and 100% vanadium-titanium ore pellets were smelted into the blast furnace, and the slag composition and liquidus temperature are shown in Table 8 (V2O5 content is not more than 1.0%, which is ignored).

[0078] Table 8 Slag composition (wt%) and liquidus temperature value (℃) of blast furnace containing titanium

[0079] The product obtained by calcining the analytical pure chemical reagent at 870℃ for more than 2h was used as the initial raw material, and the slag was prepared according to the components in Table 8, and the slag was fully melted at 1500℃. The viscosity-melting temperature test experiment was carried out by using a high-temperature melt physical property tester and a rotation method, and the test results are shown in Fig. 2.

[0080] As shown in Fig. 2, the slag melting temperature (inflection point temperature of viscosity sharply increasing) gradually decreases under the composition, and the viscosity of the slag under the condition of 1420℃ or above is 0.5 Pa·s, which can meet the production of blast furnace.

[0081] Finally, it should be noted that the above-described embodiments are part of the embodiments of the present application, not all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

Claims

1. A burden structure for oxygen blast furnace smelting of vanadium titanomagnetite pellets, characterized in that, The furnace charge structure is entirely composed of vanadium titanomagnetite pellets, and contains the following components: TFe: 51.0-58.0wt%, SiO2: 3.0-5.0wt%, CaO: 0.4-5.0wt%; MgO: 2.0-4.2wt%, Al2O3: 2.0-4.0wt%, TiO2: 8.0-11.0wt%, V2O5: 0.50-0.80wt%.

2. A burden structure for the smelting of vanadium titano-magnetite pellets in an oxygen blast furnace according to claim 1, characterized in that, The vanadium titanomagnetite pellets are made of vanadium titanomagnetite concentrate with the following components: TFe: 54.0-60.0wt%, Al2O3: 3.0-5.0wt%, SiO2: 2.0-4.0wt%, CaO: 0-0.5wt%, MgO: 2.0-5.0wt%, TiO2: 8.0-12.0wt%, V2O5: 0.5-0.7wt%.

3. The burden structure for the smelting of vanadium titano-magnetite pellets in an oxygen blast furnace according to claim 2, characterized in that, The vanadium titanomagnetite pellets are made of vanadium titanomagnetite concentrate with the following components: TFe: 54.0-60.0wt%, Al2O3: 3.0-5.0wt%, SiO2: 2.0-4.0wt%, CaO: 0-0.5wt%, MgO: 2.0-5.0wt%, TiO2: 8.0-12.0wt%, V2O5: 0.5-0.7wt%.

4. The burden structure for the oxygen blast furnace smelting of vanadium titano-magnetite pellets according to claim 1, characterized in that, The furnace charge structure is composed of one or more kinds of vanadium titanomagnetite pellets.

5. A method for smelting vanadium titano-magnetite pellets in an oxygen blast furnace, characterized by, The furnace charge structure according to any one of the preceding claims.

6. The oxygen blast vanadium titanomagnetite pellet smelting method according to claim 5, characterized in that, The slag basicity is controlled to be between 0.20 and 0.

65.

7. The oxygen blast vanadium titanomagnetite pellet smelting method according to claim 6, characterized in that, The slag composition is controlled to have TiO2 content of 35.0-46.0wt%, Al2O3 content of 14.0-18.0wt%, MgO content of 9.0-15.0wt%, SiO2 content of 18.0-24.0wt%, and CaO content of 2.0-18.0wt%.

8. The oxygen blast vanadium titanomagnetite pellet smelting method according to claim 7, characterized in that, The slag basicity is controlled by adjusting the basicity of the vanadium titanomagnetite pellets according to the contents of TiO2, Al2O3 and MgO in the vanadium titanomagnetite pellets.

9. The oxygen blast furnace full-carbon vanadium titanomagnetite pellet smelting method according to claim 7, characterized in that, when the TiO2 content in the slag composition is 35-38wt% and the Al2O3 content is 14-18wt%, the following conditions are ensured: when the MgO content is 9-11wt%, the slag basicity is controlled to be between 0.45 and 0.65; when the MgO content is 11-13wt%, the slag basicity is controlled to be between 0.35 and 0.55; when the MgO content is 13-15wt%, the slag basicity is controlled to be between 0.20 and 0.40; when the TiO2 content in the slag composition is 38-42wt% and the Al2O3 content is 14-18wt%, the following conditions are ensured: when the MgO content is 9-11wt%, the slag basicity is controlled to be between 0.40 and 0.60; when the MgO content is 11-13wt%, the slag basicity is controlled to be between 0.30 and 0.50; when the MgO content is 13-15wt%, the slag basicity is controlled to be between 0.25 and 0.45; when the TiO2 content in the slag composition is 42-46wt% and the Al2O3 content is 14-18wt%, the following conditions are ensured: when the MgO content is 9-11wt%, the slag basicity is controlled to be between 0.35 and 0.55; when the MgO content is 11-13wt%, the slag basicity is controlled to be between 0.25 and 0.45; The slag basicity is controlled between 0.30 and 0.50 when the MgO content is between 13 and 15 wt%.

10. The oxygen blast vanadium titanomagnetite pellet smelting method according to claim 5, characterized in that, The blast furnace is smelted using pure oxygen.

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