Process for improving vanadium recovery rate of blast furnace

Abstract

The invention relates to the technical field of steel smelting, in particular to a process for improving the blast furnace vanadium recovery rate. Comprising the following steps that a, vanadium-titanium pellets and sintered ore are selected; b, the vanadium-titanium pellets and the sintered ore are fed into a blast furnace to be smelted; c, in the blast furnace smelting process, adjusting the alkalinity of blast furnace slag, the magnesium-aluminum ratio and the physical heat and chemical heat of molten iron; and d, the molten iron with the high vanadium content is separated out, and follow-up treatment is conducted to extract a vanadium product. According to the process, the vanadium recovery rate of the blast furnace is remarkably increased by accurately controlling the vanadium input amount of the raw material entering the furnace and key parameters such as physical heat and chemical heat of molten iron. The process not only improves the reduction thermodynamic and dynamic conditions of vanadium, but also reduces the blast furnace slag amount and the loss of vanadium in the blast furnace slag, thereby greatly improving the recovery rate of vanadium.

Description

Technical Field

[0001] The invention relates to the technical field of steel smelting, in particular to a process for improving the recovery rate of vanadium in a blast furnace. Background Art

[0002] In the process of steelmaking, vanadium, as an important microalloying element, plays a significant role in improving the performance of steel. At present, the technical difficulties in improving the vanadium recovery rate of blast furnaces are mainly concentrated in the selection of raw materials, optimization of blast furnace operating parameters and slag treatment. However, the vanadium recovery rate of blast furnaces in existing processes is generally low, which affects the vanadium resource utilization efficiency and economic benefits of the entire production process. Summary of the invention

[0003] In order to solve the defects in the prior art, the present invention provides a process for improving the recovery rate of vanadium in a blast furnace. The process achieves a significant improvement in the recovery rate of vanadium in a blast furnace by accurately controlling the amount of vanadium input into the furnace raw material and key parameters such as the physical heat and chemical heat of molten iron. The process not only improves the reduction thermodynamics and kinetic conditions of vanadium, but also reduces the amount of blast furnace slag and the loss of vanadium in the blast furnace slag, thereby greatly improving the recovery rate of vanadium.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] The present invention provides a process for improving the recovery rate of vanadium in a blast furnace, comprising the following steps:

[0006] a. Select vanadium-titanium pellets and sintered ore;

[0007] b. Sending vanadium-titanium pellets and sintered ore into a blast furnace for smelting;

[0008] c. During the blast furnace smelting process, adjust the blast furnace slag basicity, magnesium-aluminum ratio and the physical and chemical heat of molten iron;

[0009] d. Separate the molten iron with higher vanadium content and carry out subsequent treatment to extract vanadium products.

[0010] Preferably, the vanadium input amount in the blast furnace raw material is below 5.0 kg / tFe, the physical heat of the molten iron is controlled so that the proportion of furnaces above 1450°C is not less than 80%; and the [Si+Ti] content in the molten iron is controlled at 0.25% to 0.40%.

[0011] Preferably, the vanadium input amount in the blast furnace raw material is 5.0-5.5 kg / tFe, the physical heat of the molten iron is controlled so that the proportion of furnaces above 1450°C is not less than 80%; and the [Si+Ti] content in the molten iron is controlled at 0.30%-0.40%.

[0012] Preferably, the vanadium input amount in the blast furnace raw material is above 5.5 kg / tFe, the physical heat of the molten iron is controlled at 1450-1470°C; and the [Si+Ti] content in the molten iron is controlled at 0.35%-0.45%.

[0013] More preferably, the theoretical combustion temperature is controlled at 2250-2350°C.

[0014] Preferably, the basicity of the blast furnace slag is 1.18±0.05, and the magnesium-aluminum ratio should be controlled at 0.7.

[0015] Preferably, the selection criteria for the vanadium-titanium pellets are: selecting pellets with a stable dry component grade ≥53.5%, a FeO mass content ≤2%, a V2O5 mass content ≥0.66%, a TiO2 mass content of 9.0-10.0%, and a compressive strength ≥1800N.

[0016] Preferably, the ore blending principle of the sintered ore is: select sintered ore grade ≥48%, TiO2 mass content controlled to 3.8-4.8%, FeO mass content to 8.0-9.0%, V2O5 mass content ≥0.35%, low-temperature reduction pulverization rate +3.15≥55%, and sintered ore binary basicity to 2.45-2.65.

[0017] Preferably, the total proportion of pellets entering the furnace in step b is 50%.

[0018] The beneficial effects of the present invention are:

[0019] In the present invention, as the amount of vanadium input into the blast furnace increases, the vanadium recovery rate also increases, and vice versa, indicating that the amount of vanadium input is one of the most important factors affecting the vanadium recovery rate. From the perspective of the kinetics of vanadium reduction, the increase in the amount of vanadium input improves the kinetic conditions of the vanadium reduction reaction, increases the vanadium oxide reaction interface, improves the mass transfer conditions, increases the vanadium reduction reaction rate, and the generated vanadium single substance can be infinitely miscible with molten iron, which is more conducive to the occurrence of the vanadium reduction reaction.

[0020] In the present invention, increasing the temperature is beneficial to the reduction of vanadium oxides. There are two ways to measure the furnace temperature during blast furnace smelting, one is the physical heat of molten iron, and the other is the chemical heat, that is, the [Si+Ti] content in the molten iron. The present invention specifically regulates the physical heat and chemical heat of molten iron according to the blast furnace vanadium input amount in three stages to achieve the maximum blast furnace vanadium recovery rate. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the technical solution of the invention, the present invention is further described in detail below in conjunction with specific implementation methods.

[0022] Example 1

[0023] This embodiment provides a process for improving the recovery rate of vanadium in a blast furnace, comprising the following steps:

[0024] (1) Raw material preparation:

[0025] Selection of vanadium-titanium pellets: select self-produced pellets with a stable dry content of ≥55%, FeO mass content ≤1.5%, V2O5 mass content ≥0.66%, TiO2 mass content 9.0-10.0%, and compressive strength ≥2200N; select purchased pellets with a stable dry content of ≥53.5%, FeO mass content ≤2%, V2O5 mass content ≥0.66%, TiO2 mass content 9.0-10.0%, and compressive strength ≥1800N;

[0026] Sintering ore blending principle: select sintering ore grade ≥48%, TiO2 control mass content 3.8~4.8%, FeO mass content 8.0~9.0%, V2O5 mass content ≥0.35%, low temperature reduction pulverization rate +3.15≥55%, sintering ore binary basicity 2.45~2.65;

[0027] Ratio of pellets entering the furnace: The total ratio of pellets entering the furnace is 50% (35% self-produced pellets + 15% purchased pellets).

[0028] Select and prepare qualified vanadium-titanium pellets and sintered ore according to the above technical parameters.

[0029] (2) Blast furnace smelting: The above raw materials are added into a blast furnace, the vanadium input amount in the blast furnace raw materials is controlled to be below 5.0 kg / tFe, and the blast furnace operating parameters such as air volume, material speed, etc. are controlled in a conventional manner in the art to keep the blast furnace running smoothly.

[0030] (3) Treatment of molten iron and slag: During the smelting process, the blast furnace slag basicity is adjusted to 1.18±0.05, the magnesium-aluminum ratio should be controlled at 0.7; the molten iron physical heat is controlled so that the number of furnaces above 1450°C accounts for no less than 80%; the [Si+Ti] content in the molten iron is controlled to 0.25%-0.40%, and the monthly average is above 0.35%. This can promote the reduction of vanadium and reduce the loss of vanadium in the blast furnace slag.

[0031] (4) Collection of vanadium products: Separate the molten iron with a higher vanadium content from the molten iron and perform subsequent processing to extract the vanadium product.

[0032] When the vanadium input in high-vanadium smelting is below 5.0g / tFe, the vanadium recovery rate is significantly proportional to the [Si+Ti] content in the molten iron, that is, as the [Si+Ti] content in the molten iron increases, the vanadium recovery rate increases, but it is difficult to increase the vanadium recovery rate to more than 75%. When the vanadium recovery rate reaches more than 73%, the monthly average value of the [Si+Ti] content in the molten iron is required to be above 0.35%. Since increasing the [Si+Ti] content in the molten iron usually requires increasing fuel consumption, the impact of fuel consumption and vanadium recovery rate on the comprehensive cost of ironmaking should be comprehensively considered during the low-vanadium smelting process, and a reasonable [Si+Ti] content should be selected.

[0033] Example 2

[0034] Same as Example 1, except that:

[0035] Step (2) blast furnace smelting: controlling the vanadium input amount in the blast furnace raw material to be 5.0-5.5 kg / tFe;

[0036] Step (3) Treatment of molten iron and slag: Control the physical heat of the molten iron so that the proportion of furnaces with a temperature above 1450°C is not less than 80%; control the [Si+Ti] content in the molten iron to be between 0.30% and 0.40%, with a monthly average of not less than 0.35%.

[0037] When the vanadium input is 5.0-5.5 kg / tFe, the vanadium recovery rate is significantly proportional to the [Si+Ti] content in the molten iron, that is, as the [Si+Ti] content in the molten iron increases, the vanadium recovery rate increases. If the vanadium recovery rate is above 73%, the monthly average value of the [Si+Ti] content in the molten iron should not be less than 0.38%.

[0038] Example 3

[0039] Same as Example 1, except that:

[0040] Step (2) blast furnace smelting: controlling the vanadium input amount in the blast furnace raw material to be above 5.5 kg / tFe, based on the principle of stable and smooth operation of the blast furnace;

[0041] Step (3) Treatment of molten iron and slag: Control the physical heat of the molten iron at 1450-1470°C; control the [Si+Ti] content in the molten iron at 0.35%-0.45%, and control the theoretical combustion temperature at 2250-2350°C through operations such as oxygen enrichment, wind temperature, coal injection, and humidification.

[0042] When the vanadium input is above 5.5kg / tFe, the vanadium recovery rate is not greatly affected by the amount of [Si+Ti] in the molten iron, and basically remains above 73%. In this case, the smelting focus should be on ensuring the smooth operation of the blast furnace and reducing fuel consumption.

[0043] The above are only preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A process for improving the recovery rate of vanadium in a blast furnace, characterized in that: The following steps are involved: a. Select vanadium-titanium pellets and sintered ore; b. Sending vanadium-titanium pellets and sintered ore into a blast furnace for smelting; c. During the blast furnace smelting process, adjust the blast furnace slag basicity, magnesium-aluminum ratio and the physical and chemical heat of molten iron; d. Separate the molten iron with higher vanadium content and carry out subsequent treatment to extract vanadium products.

2. The process for improving the recovery rate of vanadium in a blast furnace according to claim 1, characterized in that: The vanadium input amount in the blast furnace raw material is below 5.0kg / tFe, the physical heat of the molten iron is controlled so that the number of furnaces above 1450°C accounts for no less than 80%, and the [Si+Ti] content in the molten iron is controlled to be between 0.25% and 0.40%.

3. The process for improving the vanadium recovery rate of a blast furnace according to claim 1, characterized in that: The amount of vanadium input in the blast furnace raw material is below 5.0-5.5 kg / tFe, the physical heat of the molten iron is controlled so that the proportion of furnaces above 1450°C is not less than 80%, and the [Si+Ti] content in the molten iron is controlled to be 0.30%-0.40%.

4. The process for improving the recovery rate of vanadium in a blast furnace according to claim 1, characterized in that: The amount of vanadium input into the blast furnace raw material is above 5.5 kg / tFe, the physical heat of the molten iron is controlled at 1450-1470° C., and the [Si+Ti] content in the molten iron is controlled at 0.35%-0.45%.

5. The process for improving the recovery rate of vanadium in a blast furnace according to claim 4, characterized in that: The theoretical combustion temperature is controlled at 2250 ~ 2350℃.

6. The process for improving the recovery rate of vanadium in a blast furnace according to any one of claims 1 to 5, characterized in that: The basicity of the blast furnace slag is 1.18±0.05, and the magnesium-aluminum ratio should be controlled at 0.

7.

7. The process for improving the recovery rate of vanadium in a blast furnace according to claim 1, characterized in that: The selection criteria of the vanadium-titanium pellets are: selecting pellets with a stable dry component grade of ≥53.5%, a FeO mass content of ≤2%, a V2O5 mass content of ≥0.66%, a TiO2 mass content of 9.0-10.0%, and a compressive strength of ≥1800N.

8. The process for improving the recovery rate of vanadium in a blast furnace according to claim 1, characterized in that: The ore blending principle of the sintered ore is: select the sintered ore grade ≥48%, control the TiO2 mass content to 3.8-4.8%, the FeO mass content to 8.0-9.0%, the V2O5 mass content to ≥0.35%, the low-temperature reduction pulverization rate +3.15≥55%, and the binary basicity of the sintered ore to 2.45-2.

65.

9. The process for improving the recovery rate of vanadium in a blast furnace according to claim 1, characterized in that: In the step b, the total pellet ratio entering the furnace is 50%.