Method for preparing low-vanadium alloy material from vanadium-containing converter steel slag

Abstract

The application discloses a method for preparing low-vanadium alloy material from vanadium-containing converter steel slag, and relates to the field of comprehensive utilization of vanadium-containing steel slag. The vanadium-containing converter steel slag is classified and magnetically selected, two different materials are obtained, and two kinds of different composition pellets are prepared. The layered placement is realized during furnace charging, the material permeability is increased, the spitting and large boiling caused by the large production of CO and CO2 in the molten liquid reduction process is greatly eliminated, and the safety is enhanced. The layered pellet setting enables the liquid phase reduction, internal reduction of the pellet and external reduction to be simultaneously performed, and the energy consumption is greatly reduced. The raw material cost is low in the whole process, and the purchase is convenient. The yield of iron and vanadium in the vanadium-containing converter steel slag reaches 90% and 80%, the effect is remarkable, the purpose of changing solid waste into treasure is achieved, and the market demand for vanadium-containing alloy additives is greatly met.

Description

Technical Field

[0001] This invention relates to the field of comprehensive utilization of vanadium-containing steel slag, specifically to a method for preparing low-vanadium alloy materials from vanadium-containing converter steel slag. Background Technology

[0002] Conventional utilization of vanadium-containing steel slag involves pretreatment using methods such as hot quenching, air quenching, and water quenching, followed by thermodynamic activation to revitalize the slag and use it as a raw material for cement, floor tiles, and building materials. However, this method fails to utilize the extraction of valuable elements from the steel slag, resulting in significant resource waste. Summary of the Invention

[0003] To address the aforementioned shortcomings of existing technologies, this invention provides a simple method for preparing low-vanadium alloy materials from vanadium-containing converter steel slag, which yields high vanadium and iron content.

[0004] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0005] A method for preparing low-vanadium alloy materials from vanadium-containing converter steel slag is provided, comprising the following steps:

[0006] S1: Vanadium-containing converter steel slag is crushed to 50-100 mesh and obtained by magnetic separation to obtain material one and material two; material one includes: TFe and Fe3O4; material two includes: Fe2O3 and feldspar, etc.

[0007] S2: Material 1 is mixed evenly with carbon powder, silica and fluorite and then granulated to obtain pellet 1; Material 2 is mixed evenly with carbon powder, silica and fluorite and then granulated to obtain pellet 2;

[0008] S3: Place scrap iron and scrap steel in the electric arc furnace below the electrodes to form an arc-starting layer. The particle size of the scrap iron and scrap steel is no more than 5cm.

[0009] S4: Pellet 1 and Pellet 2 are laid evenly from bottom to top above the arc-starting layer to obtain smelting layer 1 and smelting layer 2; the graphite electrode of the electric arc furnace is inserted from top to bottom through smelting layer 2 and smelting layer 1 into the arc-starting layer, with the bottom end of the graphite electrode located in the middle of the arc-starting layer;

[0010] S5: Adjust the power of the electric arc furnace to start the arc, and melt at 1600~1700℃ for 1.0~2.5h;

[0011] S6: After smelting, slag is removed from the slag removal port, and low-vanadium alloy melt is discharged from the tapping port and poured into a mold to cool, thus obtaining the low-vanadium alloy.

[0012] Furthermore, the carbon powder is one or more of coke, semi-coke, petroleum coke powder, and fly ash, and has a carbon content of not less than 80%, a volatile matter content of not more than 5%, and a particle size of 50 to 100 mesh.

[0013] The silica has a SiO2 content of not less than 85% and a particle size of 50-100 mesh.

[0014] Fluorite has a CaF2 content of not less than 90% and a particle size of 50-100 mesh.

[0015] Furthermore, the ratio of material one to carbon powder, silica and fluorite is 100:10-25:10-25:2-6.

[0016] Furthermore, the ratio of material two to carbon powder, silica and fluorite is 100:14-35:15-30:1-5.

[0017] Furthermore, the diameters of both pellet one and pellet two are 3–5 cm.

[0018] Furthermore, a carbon block layer is laid above the second smelting layer. The carbon block particle size of the carbon block layer is 1-5 cm, and the ratio of carbon block to material one is 1-5:100.

[0019] Furthermore, in step S6, the slag is discharged using a guide channel, and water is sprayed onto the molten slag at the middle of the guide channel to form water-quenched slag. After drying, the water-quenched slag is ball-milled to obtain active building materials.

[0020] Furthermore, in step S6, after removing the slag, ferrosilicon and aluminum granules are added to the electric arc furnace, with the ratio of ferrosilicon, aluminum granules and material one being 1-4:1-3:100; after adding ferrosilicon and aluminum granules, the furnace is stirred using a graphite stirring rod to dephosphorize and deoxidize the low-vanadium alloy.

[0021] Furthermore, during continuous production, 12.5% ​​to 20% of the low-vanadium alloy melt in the electric arc furnace is retained to replace scrap iron and scrap steel as the starting layer for the next melting.

[0022] The beneficial effects of this invention are as follows:

[0023] 1. This invention employs graded magnetic separation of vanadium-containing converter steel slag to obtain two different materials and prepare two types of pellets with different compositions. When charging the furnace, these pellets are placed in layers, increasing the permeability of the materials and greatly eliminating splashing and boiling caused by the large amount of CO and CO2 generated during the molten metal reduction process, thus enhancing safety.

[0024] 2. The layered pellet configuration allows for simultaneous liquid-phase reduction, internal pellet reduction, and external reduction, significantly reducing energy consumption.

[0025] 3. Using scrap steel and scrap iron as arc-starting and arc-initiating materials solves the problem that steel slag is non-conductive and cannot generate an arc, thus broadening the range of electric arc furnaces for melting converter steel slag. It also allows for the adjustment of low-vanadium alloy composition based on the use of scrap steel and scrap iron.

[0026] 4. The molten slag is drawn out through a slag remover and a guide trough, and then water-quenched and ball-milled to obtain active building materials that meet the requirements for cement and floor brick preparation, thus achieving full utilization of converter steel slag resources.

[0027] 5. The entire process has low raw material costs and is easy to purchase; moreover, the recovery rate of iron and vanadium in vanadium-containing converter steel slag reaches 90% and 80% respectively, which is very effective and achieves the goal of turning solid waste into treasure, greatly satisfying the market demand for vanadium-containing alloy additives. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the process for preparing low-vanadium alloys according to the present invention. Detailed Implementation

[0029] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0030] Vanadium-containing steel slag was obtained by blast furnace smelting and converter steelmaking processes on vanadium-titanium magnetite. Its main components are shown in Table 1.

[0031] Table 1

[0032] Product Name TFe <![CDATA[V2O5]]> CaO MnO <![CDATA[SiO2]]> <![CDATA[Al2O3]]> MgO P S content% 23.55 1.41 28.48 1.43 12.97 2.46 9.60 0.843 0.091

[0033] Example 1

[0034] according to Figure 1 The method shown in the diagram prepares low-vanadium alloys, and the specific steps include the following:

[0035] S1: Vanadium-containing converter steel slag is crushed to 50-100 mesh and obtained by magnetic separation to obtain material one and material two; material one includes: TFe and Fe3O4; material two includes: Fe2O3 and feldspar, etc.

[0036] S2: After uniformly mixing material one with toner, silica, and fluorite, granulate and press to obtain pellets with a diameter of 3-5 cm; the ratio of material one to toner, silica, and fluorite in pellet one is 100:10:16:3; in specific implementations, the ratio of material one to toner can also be 100:13, 100:16, 100:19, 100:22, or 100:25; the ratio of material one to silica can also be 100:10, 100:13, 100:19, 100:22, or 100:25; the ratio of material one to fluorite can also be 100:3, 100:4, 100:5, or 100:6.

[0037] Material II is mixed evenly with toner, silica, and fluorite, then granulated and pressed to obtain pellets II with a diameter of 3-5 cm. The ratio of material II to toner, silica, and fluorite in pellet II is 100:15:20:2. In specific implementations, the ratio of material II to toner can also be 100:20, 100:23, 100:26, 100:29, 100:32, or 100:35; the ratio of material II to silica can also be 100:15, 100:17, 100:19, 100:21, 100:23, or 100:25; and the ratio of material II to fluorite can also be 100:1, 100:3, 100:4, or 100:5.

[0038] In specific implementation, the carbon powder shall be one or more of coke, semi-coke, petroleum coke powder, and fly ash, with a carbon content of not less than 80%, volatile matter of not more than 5%, and a particle size of 50-100 mesh; the silica shall have a SiO2 content of not less than 85% and a particle size of 50-100 mesh; and the fluorite shall have a CaF2 content of not less than 90% and a particle size of 50-100 mesh.

[0039] S3: Place scrap iron and scrap steel pieces under the electrodes in the electric arc furnace to form an arc-starting layer. The particle size of the scrap iron and scrap steel should not exceed 5cm. In practice, the thickness of the arc-starting layer is set to 30cm to facilitate arc starting at the junction of the electrodes later.

[0040] S4: Pellet 1 and Pellet 2 are evenly laid from bottom to top above the arc-starting layer to obtain smelting layer 1 and smelting layer 2; a carbon block layer is also laid above smelting layer 2. The carbon block particle size of the carbon block layer is 1-5cm, and the ratio of carbon block to material 1 is 3:100. In specific implementation, the ratio of carbon block to material 1 can also be 1:100, 2:100, 4:100 or 5:100. The carbon block layer is used to reduce splashing after the furnace charge melts and to isolate air to prevent excessive reaction of iron oxide, vanadium oxide, and carbon oxide; the graphite electrode of the electric arc furnace is inserted from top to bottom through smelting layer 2 and smelting layer 1 into the arc-starting layer, and the bottom end of the graphite electrode is located in the middle of the arc-starting layer;

[0041] S5: Adjust the power of the electric arc furnace to start the arc, and melt at 1700℃ for 2 hours;

[0042] S6: After smelting, the slag is removed from the slag removal port and discharged through the guide channel. Water is sprayed onto the molten slag in the middle of the guide channel to form water-quenched slag. After drying, the water-quenched slag is ball-milled to obtain 60-100 mesh active building materials, which are used to make building products such as cement and floor bricks.

[0043] Next, ferrosilicon and aluminum granules are added to the electric arc furnace. The ratio of ferrosilicon, aluminum granules, and material one is 2:2:100. In practice, the ratio of ferrosilicon to material one can also be 1:100, 3:100, or 4:100; the ratio of aluminum granules to material one can also be 1:100 or 3:100. After adding the ferrosilicon and aluminum granules, the furnace is stirred using a graphite stirring rod to dephosphorize and deoxidize the low-vanadium alloy. After stirring, the molten low-vanadium alloy is discharged from the tap hole and poured into a mold for cooling to obtain the low-vanadium alloy.

[0044] By replacing scrap iron and scrap steel with 20% low-vanadium alloy melt in the electric arc furnace as the starting layer for the next melting, cyclic melting and low-vanadium alloy preparation can be achieved.

[0045] Chemical analysis was performed on the low-vanadium alloy obtained from the first three smelting cycles, and the yields of pig iron and vanadium were measured to be 90.2% and 84.5%, respectively.

[0046] Example 2

[0047] Pellet 1 was prepared with a ratio of material 1 to carbon powder, silica, and fluorite of 100:15:18:3; Pellet 2 was prepared with a ratio of material 2 to carbon powder, silica, and fluorite of 100:18:22:2. The electric arc furnace melting temperature was set at 1650℃, and the melting time was 1.5 hours. All other conditions were the same as in Example 1. The low-vanadium alloy obtained from the first three cyclic melting processes was chemically analyzed, and the yields of pig iron and vanadium were measured to be 85.6% and 74.6%, respectively.

[0048] Example 3

[0049] Pellet 1 was prepared with a ratio of material 1 to carbon powder, silica, and fluorite of 100:10:19:3; Pellet 2 was prepared with a ratio of material 2 to carbon powder, silica, and fluorite of 100:15:25:2; the electric arc furnace melting temperature was set at 1650℃, and the melting time was 1.5 hours. All other conditions were the same as in Example 1. The low-vanadium alloy obtained from the first three cyclic melting processes was chemically analyzed, and the yields of pig iron and vanadium were measured to be 92.3% and 85.1%, respectively.

[0050] Example 4

[0051] Pellet 1 was prepared with a ratio of material 1 to carbon powder, silica, and fluorite of 100:10:25:3; Pellet 2 was prepared with a ratio of material 2 to carbon powder, silica, and fluorite of 100:14:30:2. The electric arc furnace melting temperature was set at 1600℃, and the melting time was 1.5 hours. All other conditions were the same as in Example 1. The low-vanadium alloy obtained from the first three cyclic melting processes was chemically analyzed, and the yields of pig iron and vanadium were measured to be 91.3% and 65.7%, respectively.

[0052] In summary, the method of this invention can successfully prepare low-vanadium alloys from vanadium-containing converter steel slag. The entire process involves low raw material costs and is easy to procure. Furthermore, the iron recovery rate from the vanadium-containing converter steel slag is consistently higher than 85%, with a maximum of 92.3%; the vanadium recovery rate is consistently higher than 65%, with a maximum of 85.1%. The alloy recovery effect of converter steel slag is significant, achieving the goal of turning solid waste into treasure and greatly satisfying the market demand for vanadium-containing alloy additives.

Claims

1. A method for preparing low-vanadium alloy materials from vanadium-containing converter steel slag, characterized in that, Includes the following steps: S1: Vanadium-containing converter steel slag is crushed to 50-100 mesh and obtained by magnetic separation to obtain material one and material two; wherein, material one includes: TFe and Fe3O4; material two includes: Fe2O3 and feldspar. S2: Material 1 is mixed evenly with carbon powder, silica and fluorite and then granulated to obtain pellet 1; Material 2 is mixed evenly with carbon powder, silica and fluorite and then granulated to obtain pellet 2; S3: Place scrap iron and scrap steel in the electric arc furnace below the electrodes to form an arc-starting layer, wherein the particle size of the scrap iron and scrap steel is no greater than 5cm. S4: Pellet 1 and Pellet 2 are laid evenly from bottom to top above the arc-starting layer to obtain smelting layer 1 and smelting layer 2; the graphite electrode of the electric arc furnace is inserted from top to bottom through smelting layer 2 and smelting layer 1 into the arc-starting layer, with the bottom end of the graphite electrode located in the middle of the arc-starting layer; S5: Adjust the power of the electric arc furnace to start the arc, and melt at 1600~1700℃ for 1.0~2.5h; S6: After smelting, slag is removed from the slag removal port, and low-vanadium alloy melt is discharged from the tapping port and poured into a mold to cool, thus obtaining the low-vanadium alloy.

2. The method for preparing low-vanadium alloy materials from vanadium-containing converter steel slag according to claim 1, characterized in that, The carbon powder is one or more of coke, semi-coke, petroleum coke powder, and fly ash, with a carbon content of not less than 80%, a volatile matter content of not more than 5%, and a particle size of 50-100 mesh. The silica has an SiO2 content of not less than 85% and a particle size of 50-100 mesh. The fluorite has a CaF2 content of not less than 90% and a particle size of 50-100 mesh.

3. The method for preparing low-vanadium alloy materials from vanadium-containing converter steel slag according to claim 1, characterized in that, The ratio of the material to carbon powder, silica and fluorite is 100:10~25:10~25:2~6.

4. The method for preparing low-vanadium alloy materials from vanadium-containing converter steel slag according to claim 1, characterized in that, The ratio of material 2 to carbon powder, silica and fluorite is 100:14~35:15~30:1~5.

5. The method for preparing low-vanadium alloy materials from vanadium-containing converter steel slag according to claim 1, characterized in that, Both pellet one and pellet two have a diameter of 3-5 cm.

6. The method for preparing low-vanadium alloy materials from vanadium-containing converter steel slag according to claim 1, characterized in that, A carbon block layer is also laid above the second smelting layer. The carbon block particle size of the carbon block layer is 1~5cm, and the ratio of carbon block to material one is 1~5:

100.

7. The method for preparing low-vanadium alloy materials from vanadium-containing converter steel slag according to claim 1, characterized in that, In step S6, the slag is discharged using a guide channel, and water is sprayed onto the molten slag at the middle of the guide channel to form water-quenched slag. After drying, the water-quenched slag is ball-milled to obtain active building materials.

8. The method for preparing low-vanadium alloy materials from vanadium-containing converter steel slag according to claim 1, characterized in that, In step S6, after removing the slag, ferrosilicon and aluminum granules are added to the electric arc furnace. The ratio of ferrosilicon, aluminum granules and material one is 1~4:1~3:

100. After adding ferrosilicon and aluminum granules, the furnace is stirred with a graphite stirring rod to remove phosphorus and deoxidize the low vanadium alloy.

9. The method for preparing low-vanadium alloy materials from vanadium-containing converter steel slag according to claim 1, characterized in that, During continuous production, 12.5% ​​to 20% of the low-vanadium alloy melt in the electric arc furnace is retained to replace scrap iron and scrap steel as the starting layer for the next melting.

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