Blowing-in furnace charge of blast furnace for smelting vanadium titano-magnetite and rapid blowing-in method

Abstract

The invention provides blow-in furnace charge for a vanadium titano-magnetite smelting blast furnace and a blow-in method, and the blow-in furnace charge comprises the following components in percentage by mass: 50-70% of low-titanium vanadium-titanium sinter, 30-50% of natural lump ore and 0-5% of manganese-containing lump ore, the low-titanium vanadium-titanium sintered ore is TFe grade gt; 48% of SiO2 < gt >; 6%, TiO2 1t; 4%, the binary alkalinity is CaO / SiO2gt; 2.0); the natural iron ore is TFe grade gt; 40% of SiO2 < gt >; 20% of MgOgt; 5.0%. The blow-in furnace charge can realize quick blow-in of the schreyerite blast furnace, is beneficial to quick yield reaching and efficiency reaching of the blast furnace and strengthening of smelting of the blast furnace, and has remarkable economic benefits. The content of TiO2 in the furnace slag is gradually increased to 20% or above after the furnace is opened; in the normal material molten iron, the content of C is 4.5%, the content of Si is 0.15%, the content of Ti is 0.20%, the content of V is 0.35%, and the content of Mn is 0.20%.

Description

Technical Field

[0001] The invention belongs to the technical field of blast furnace ironmaking, and in particular relates to a furnace charge for smelting a vanadium-titanium magnetite blast furnace and a rapid furnace opening method. Background Art

[0002] The TiO2 content of the slag from the vanadium-titanium ore smelting in the Panzhihua Iron and Steel blast furnace is as high as 20-23%. When the furnace is opened for large and medium repairs, in order to avoid the over-reduction reaction of TiO2 in the slag to generate low-priced Ti (C, N) due to excessive furnace temperature, which will lead to poor slag performance and difficulty in slag iron discharge, ordinary magnetite block ore without vanadium and titanium is usually used for furnace opening. The main reason is that if the slag contains a high content of (TiO2) when the furnace is opened, the (TiO2) in the slag is easily over-reduced to generate Ti (CN) under the condition of high furnace temperature, which affects the fluidity of the slag and makes it difficult to discharge slag and iron in the early stage of furnace opening. Therefore, since the Panzhihua Iron and Steel blast furnace was put into production, natural magnetite block ore or hematite block ore has been used for furnace opening. As a result, it takes many material changes after the furnace is opened to switch to normal vanadium-titanium ore smelting, and the cycle from furnace opening to production is long. At the same time, ordinary magnetite block ore or hematite block ore is not only difficult to purchase, but also has a high total coke ratio for furnace opening because it is raw ore, which increases the cost of furnace opening. Summary of the invention

[0003] In view of this, the purpose of the present invention is to provide a furnace charge and a rapid furnace opening method for smelting a vanadium-titanium magnetite blast furnace, which can realize rapid furnace opening of the blast furnace, is beneficial to strengthening the smelting of the vanadium-titanium blast furnace; and the furnace opening cost is low.

[0004] The present invention provides a furnace charge for smelting a vanadium-titanium magnetite blast furnace, which comprises, by mass fraction, 50% to 70% of low-titanium vanadium-titanium sintered ore, 30% to 50% of natural iron ore and 0% to 5% of manganese-containing lump ore;

[0005] The low-titanium vanadium-titanium sintered ore has a TFe grade of >48%, SiO2>6%, TiO2<4%, and a binary basicity of CaO / SiO2>2.0;

[0006] The natural iron ore has a TFe grade of >40%, SiO2 of >20%, and MgO of >5.0%.

[0007] The present invention mainly utilizes the good fluidity of low-TiO2 slag when starting the furnace, and adopts "low TiO2 content vanadium-titanium sintered ore + natural lump ore" raw materials to replace the original "whole lump ore + limestone" for starting the furnace, which can realize the rapid opening of the blast furnace, is beneficial to strengthen the smelting of vanadium-titanium ore blast furnace, and has good prospects for promotion and application.

[0008] In the present invention, the manganese-containing lump ore is an iron-manganese lump ore with a TFe content of >20%, a SiO2 content of >20%, and a TMn content of >15%;

[0009] And / or the manganese-containing lump ore is a lean manganese lump ore with a TFe content of <10%, a SiO2 content of <20%, and a TMn content of >18%.

[0010] The present invention also provides a method for quickly starting a blast furnace for smelting vanadium-titanium magnetite, comprising the following steps:

[0011] 65-70% of the volume of the furnace hearth and the lower part of the furnace belly is filled with clean coke, 30-35% of the volume of the upper part of the furnace belly and the furnace waist is filled with empty materials, and the furnace body is filled with empty materials and the furnace charge described in the above technical solution at intervals;

[0012] The normal material includes 50% to 70% low-titanium vanadium-titanium sintered ore, 30% to 50% natural iron ore and 0% to 5% manganese-containing lump ore;

[0013] The low-titanium vanadium-titanium sintered ore has a TFe grade of >48%, SiO2>6%, TiO2<4%, and a binary basicity of CaO / SiO2>2.0;

[0014] The natural iron ore has a TFe grade of >40%, SiO2 of >20%, and MgO of >5.0%.

[0015] The manganese-containing lump ore in the present invention is an iron-manganese lump ore with a TFe content of >20%, a SiO2 content of >20%, and a TMn content of >15%;

[0016] And / or the manganese-containing lump ore is a lean manganese lump ore with a TFe content of <10%, a SiO2 content of <20%, and a TMn content of >18%.

[0017] In a specific embodiment of the present invention, the low-titanium vanadium-titanium sintered ore has a TFe grade of 48.92%, a SiO2 content of 6.98%, and a TiO2 content of 3.83%;

[0018] The natural iron ore is a magnetite ore with a TFe grade of 43.82%, a SiO2 content of 22.92%, and a MgO content of 5.67%;

[0019] The manganese-containing lump ore contains 28.3% TFe, 24.5% SiO2 and 16.5% TMn;

[0020] The lean manganese nugget ore has a TFe content of 5.8%, a SiO2 content of 15.3% and a TMn content of 19.2%.

[0021] The clean coke described in the present invention is coke;

[0022] In terms of mass fraction, the empty material includes 80-92% of coke and 8-12% of limestone.

[0023] In the present invention, the total dry coke ratio of the furnace is 3.0-3.3 t / tFe, and the coke ratio of the furnace charge is 1.20 t / tFe (dry).

[0024] The composition of the pig iron produced by the furnace charge in the present invention is as follows: [Si]=2-3%, [Ti]=0.2-1.0%, [Mn]≤1.3%;

[0025] The binary basicity of the slag is CaO / SiO2=0.95~1.02, TiO2 in the slag is <8%, and the smelting time is 1~2 days.

[0026] After the furnace charge is loaded in the present invention, the charge structure of "50-72% low-titanium and low-titanium vanadium-titanium sintered ore + 0-48% vanadium-titanium pellets + 2-28% natural block ore" is gradually transitioned to normal production materials, and the pig iron [Si] is controlled to be 0.5-2.0%, [Ti] is controlled to be 0.2-1.0%, and TiO2 in the slag is ≤12%; the subsequent charge gradually reduces the proportion of natural block ore, increases the proportion of vanadium-titanium pellets, and controls the TiO2 in the slag to be 15-18%, and enters normal production after 1-2 days of smelting. The present invention uses vanadium-titanium pellets with a TFe grade of 54.63%, a SiO2 content of 3.93%, and a TiO2 content of 9.72%;

[0027] After normal production of the present invention, the charge includes 60% to 40% vanadium-titanium sintered ore, 40% to 60% vanadium-titanium pelletized ore and 0 to 5% natural lump ore; the pig iron [Ti] is controlled to be 0.15 to 0.3%, [Si] is controlled to be 0.1 to 0.2%, and the TiO2 content in the slag is 22 to 25%.

[0028] The invention provides a furnace charge for smelting a vanadium-titanium magnetite blast furnace, which comprises, by mass fraction, 50% to 70% of low-titanium vanadium-titanium sintered ore, 30% to 50% of natural iron ore and 0% to 5% of manganese-containing lump ore; the low-titanium vanadium-titanium sintered ore has a TFe grade of >48%, SiO2>6%, TiO2<4%, and a binary basicity of CaO / SiO2>2.0; the natural iron ore has a TFe grade of >40%, SiO2>20%, and MgO>5.0%. The furnace charge can realize the rapid start-up of a vanadium-titanium ore blast furnace, is conducive to the rapid production and efficiency of the blast furnace, and strengthens the smelting of the blast furnace, and has significant economic benefits. DETAILED DESCRIPTION

[0029] In order to further illustrate the present invention, a furnace charge and a rapid furnace opening method for smelting a vanadium-titanium magnetite blast furnace provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0030] Example

[0031] 65-70% of the volume of the lower part of the furnace hearth and furnace belly is filled with clean coke (coke), 30-35% of the volume of the upper part of the furnace belly and the furnace waist is filled with empty materials (a mixture of coke and limestone with a mass ratio of (88-92): (8-12)), and the furnace body is filled with empty materials and furnace charge at intervals;

[0032] According to the furnace temperature, slag fluidity and blast furnace operation during the furnace smelting, the subsequent material change should gradually increase the TiO2 content and alkalinity of the slag. According to the calculation results of the blast furnace burden, the charge structure changes after the furnace is opened as shown in Table 1, the raw material composition is shown in Table 2, the slag composition is shown in Table 3, and the molten iron composition is shown in Table 4. It is changed to normal material in 3 stages. The specific material change time depends on the blast furnace smelting and furnace conditions.

[0033] Table 1 Blast furnace subsequent material change charge structure after furnace start-up / %

[0034]

[0035]

[0036] Table 2 Main chemical composition of raw materials and slag iron / %

[0037]

[0038] Table 3 Main chemical composition of slag after furnace opening / %

[0039] TFe <![CDATA[SiO2]]> CaO <![CDATA[Al2O3]]> MgO <![CDATA[V2O5]]> <![CDATA[TiO2]]> Slag composition of the starting charge 2.5 33.15 33.64 13.22 10.40 0.12 7.48 Slag composition of subsequent material 2.2 31.44 32.27 12.22 9.67 0.15 11.57 Transition material slag composition 1.9 27.88 29.15 13.05 9.16 0.20 16.66 Normal slag composition 1.5 24.39 25.62 13.36 8.76 0.23 21.67

[0040] Table 4 Main chemical composition of molten iron at different stages after furnace opening / %

[0041] C Si Ti V Mn Composition of hot metal in furnace charge 4.60 2.0 1.5 0.30 0.25 Subsequent material molten iron composition 4.40 1.0 0.8 0.32 0.23 Transition material molten iron composition 4.50 0.40 0.30 0.34 0.22 Normal molten iron composition 4.50 0.15 0.20 0.35 0.20

[0042] It can be seen from Table 4 that with the change of charge structure after furnace opening, the TiO2 content in slag gradually increases, and the Si and Ti contents in molten iron gradually decrease. The use of this method for furnace opening can further reduce the cost of furnace opening, reduce the fluctuation of furnace conditions during the furnace opening and material change process, and realize the rapid opening of the blast furnace. It will play a good role in strengthening the rapid production and efficiency of vanadium-titanium magnetite blast furnace smelting.

[0043] As can be seen from the above embodiments, the present invention provides a furnace charge for smelting a vanadium-titanium magnetite blast furnace, which includes 50% to 70% low-titanium vanadium-titanium sintered ore, 30% to 50% natural iron ore and 0 to 5% manganese-containing lump ore by mass fraction; the low-titanium vanadium-titanium sintered ore has a TFe grade of >48%, SiO2>6%, TiO2<4%, and a binary basicity of CaO / SiO2>2.0; the natural iron ore has a TFe grade of >40%, SiO2>20%, and MgO>5.0%. The furnace charge can realize the rapid start-up of the vanadium-titanium blast furnace, which is conducive to the rapid production and efficiency of the blast furnace and the strengthening of the smelting of the blast furnace, and has significant economic benefits. The experimental results show that after the furnace is opened, the TiO2 content in the normal material slag gradually increases to more than 20%; the C content, Si content, Ti content, V content and Mn content in the normal material molten iron are 4.5%, 0.15%, 0.20%, 0.35% and 0.20% respectively.

[0044] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A furnace charge for smelting a vanadium-titanium magnetite blast furnace, comprising, by mass fraction, 50% to 70% of low-titanium vanadium-titanium sintered ore, 30% to 50% of natural iron ore and 0 to 5% of manganese-containing lump ore; The low-titanium vanadium-titanium sintered ore has a TFe grade of >48%, SiO2>6%, TiO2<4%, and a binary basicity of CaO / SiO2>2.0; The natural iron ore has a TFe grade of >40%, SiO2 of >20%, and MgO of >5.0%.

2. The furnace charge according to claim 1, characterized in that: The manganese-containing lump ore is an iron-manganese lump ore with a TFe content of more than 20%, a SiO2 content of more than 20%, and a TMn content of more than 15%; And / or the manganese-containing lump ore is a lean manganese lump ore with a TFe content of <10%, a SiO2 content of <20%, and a TMn content of >18%.

3. A rapid furnace opening method for smelting vanadium-titanium magnetite blast furnace, comprising the following steps: 65-70% of the volume of the furnace hearth and the lower part of the furnace belly is filled with clean coke, 30-35% of the volume of the upper part of the furnace belly and the furnace waist is filled with empty materials, and the furnace body is filled with empty materials and the furnace charge according to claim 1 at intervals; The furnace charge includes 50% to 70% of low-titanium vanadium-titanium sintered ore, 30% to 50% of natural iron ore and 0% to 5% of manganese-containing lump ore; The low-titanium vanadium-titanium sintered ore has a TFe grade of >48%, SiO2>6%, TiO2<4%, and a binary basicity of CaO / SiO2>2.0; The natural iron ore has a TFe grade of >40%, SiO2 of >20%, and MgO of >5.0%.

4. The rapid furnace opening method according to claim 3, characterized in that: The manganese-containing lump ore is an iron-manganese lump ore with a TFe content of more than 20%, a SiO2 content of more than 20%, and a TMn content of more than 15%; And / or the manganese-containing lump ore is a lean manganese lump ore with a TFe content of <10%, a SiO2 content of <20%, and a TMn content of >18%.

5. The rapid furnace opening method according to claim 3, characterized in that: The net coke is coke; In terms of mass fraction, the empty material includes 88-92% of coke and 8-12% of limestone.

6. The rapid furnace opening method according to claim 3, characterized in that: The total dry coke ratio at furnace start-up is 3.0-3.3t / tFe, and the coke ratio of furnace charge at furnace start-up is 1.20t / tFe (dry).

7. The rapid furnace opening method according to claim 3, characterized in that: Composition of the pig iron produced by the furnace charge: [Si] = 2-3%, [Ti] = 0.2-1.0%, [Mn] ≤ 1.3%; The binary basicity of the slag is CaO / SiO2=0.95~1.02, TiO2 in the slag is <8%, and the smelting time is 1~2 days.

8. The rapid furnace opening method according to claim 3, characterized in that: After the initial furnace charge is loaded, the charge structure of "50-72% low-titanium vanadium-titanium sintered ore + 0-48% vanadium-titanium pellets + 2-28% natural lump ore" is used to gradually transition to normal production materials, controlling pig iron [Si] = 0.5-2.0%, [Ti] = 0.2-1.0%, and TiO2 in slag ≤ 12%; the subsequent charge gradually reduces the proportion of natural lump ore and increases the proportion of vanadium-titanium pellets, and the TiO2 in the slag is controlled at 15-18%. Normal production begins after 1-2 days of smelting.

9. The rapid furnace opening method according to claim 8, characterized in that: After normal production, the charge includes 60% to 40% vanadium-titanium sintered ore, 40% to 60% vanadium-titanium pellets and 0% to 5% natural lump ore; Control the pig iron [Ti] = 0.15 ~ 0.3%, [Si] = 0.1 ~ 0.2%, and the TiO2 content in the slag is 22 ~ 25%.

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