Coal-based reduction-melt separation-electric furnace re-reduction-converter blowing smelting method

Abstract

The invention provides a coal-based reduction-melt separation-electric furnace re-reduction-converter blowing smelting method, and belongs to the technical field of comprehensive utilization of vanadium titano-magnetite. According to the method, iron, titanium and vanadium resources in the vanadium titano-magnetite are recycled in a stepped manner by adopting a method of coal-based direct reduction, primary melt separation, secondary melt separation and converter blowing smelting of the vanadium titano-magnetite. And low-carbon molten steel, semi-steel, vanadium slag and high-titanium slag are prepared respectively, and high-valued utilization of iron, vanadium and titanium in the vanadium titano-magnetite is achieved. Due to the fact that hot charging enters the electric furnace, electric furnace melting separation power consumption can be reduced, in the second melting separation process, petroleum coke and titanium ore are added into the ferrovanadium titanium slag for secondary deep selective reduction, separation can be effectively carried out, and therefore qualified products are produced.

Description

Technical Field

[0001] The invention belongs to the technical field of comprehensive utilization of vanadium-titanium magnetite, and in particular relates to a method of coal-based reduction-smelting-electric furnace re-reduction-converter blowing. Background Art

[0002] The reserves of vanadium-titanium magnetite rank third among my country's iron ore resources. It is mainly composed of iron, vanadium and titanium, and contains a variety of valuable elements such as cobalt, chromium, nickel, gallium and scandium, with a very high comprehensive utilization value. It is widely used in aerospace, batteries, medicine, optics, chemistry and other fields. Titanium has good high-temperature resistance, low-temperature resistance, strong acid resistance, strong alkali resistance, high strength and low density. It is widely used in aerospace, military, automobile, medicine and other fields. In recent years, with the rapid development of the national economy, my country's steel industry has developed very rapidly, greatly increasing my country's demand for iron ore resources. my country has rich reserves of iron ore resources, but the lack of high-quality iron ore resources and the low utilization rate of complex and difficult-to-select iron ore have caused my country's dependence on imported iron ore to increase year by year. Therefore, it has become an urgent task to efficiently develop complex and difficult-to-select iron ore and alleviate my country's dependence on imported iron ore.

[0003] At present, blast furnace method and non-blast furnace method are mainly used to process vanadium-titanium magnetite concentrate, among which the non-blast furnace method mainly includes pre-reduction-electric furnace method, reduction-grinding method and sodium vanadium extraction-pre-reduction-electric furnace method. The blast furnace method also has the disadvantages of long process flow, high infrastructure investment, large environmental pollution and high production capacity consumption. The pre-reduction-electric furnace smelting process in the non-blast furnace method has problems such as high overall energy consumption, high operation difficulty and vanadium-titanium recovery rate not reaching the expected target, which limits its industrialization. Sodium vanadium extraction-pre-reduction-electric furnace method, but the process requires a large amount of sodium agent, and the residual sodium salt will also cause the pellets to expand and pulverize during the reduction process. Moreover, the leaching time of pellets for vanadium extraction after sodium roasting is long, the energy consumption is high, and the vanadium concentration of the leachate is low. Direct use for vanadium precipitation will produce a large amount of vanadium precipitation wastewater, which pollutes the environment and also limits its industrial application. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method of coal-based reduction-smelting-electric furnace re-reduction-converter blowing, which adopts the method of coal-based direct reduction of vanadium-titanium magnetite, primary smelting and secondary smelting, and converter blowing to stepwise recover the iron, titanium and vanadium resources in vanadium-titanium magnetite.

[0005] A method of coal-based reduction-smelting-electric furnace re-reduction-converter blowing, comprising the following steps:

[0006] Step 1: The vanadium-titanium magnetite is coarsely crushed with a jaw crusher to a particle size of 20-40 mm, and then the coarsely crushed material is crushed and ground with a high-pressure roller mill, and the ground ore and coal powder are granulated according to the ratio;

[0007] Step 2: After granulation, coal-based reduction roasting is carried out, the roasting temperature is 750-850°C, and the roasting time is 40-60min; the roasted metallized particles are put into a melting furnace in a hot state for a melting, and the pre-reduced vanadium-titanium magnetite is melted at high temperature without adding flux and reducing agent to form molten steel and liquid vanadium-titanium slag, which are released separately, and the molten steel is cooled to form a product;

[0008] Step 3: transporting the melted liquid vanadium-titanium slag to a high-temperature granulator for high-temperature centrifugal granulation with petroleum coke and titanium ore;

[0009] Step 4: The material after high-temperature granulation enters the insulation tank for insulation; the insulation tank is connected to the discharge pipe of the ore-fired electric furnace, and the insulated material is evenly distributed according to the material surface in the ore-fired electric furnace, and the secondary strong reduction melting is carried out in the ore-fired electric furnace to produce high-titanium slag and high-vanadium pig iron;

[0010] Step 5: The high-vanadium pig iron released from the electric furnace is blown in a converter to produce semi-steel and vanadium slag.

[0011] Furthermore, the main components of the vanadium-titanium magnetite described in step 1 are TFe content of 45-48.03wt%, V2O5 content of 0.25-0.37wt%, SiO2 content of 1.1-1.52wt%, Al2O3 content of 2.5-3.15wt%, S content of 0-0.011wt%, P content of 0-0.015wt%; Ca content of 0-0.043wt%, and Mg content of 0.5-0.84wt%.

[0012] Furthermore, the particle size of the ore after grinding in step 1 is -2mm 100%, -1mm 80%.

[0013] Furthermore, the ratio in step 1 is: the coal powder accounts for 5-7% of the mass ratio of the ground ore.

[0014] Furthermore, the melting temperature of the first melting in step 2 is between 1550-1700° C., and the melting time is 40-80 min.

[0015] Furthermore, the petroleum coke in step 3 accounts for 10-15% by mass of the liquid vanadium-titanium slag after smelting; and the titanium ore accounts for 18-25% by mass of the liquid vanadium-titanium slag after smelting.

[0016] Furthermore, the insulation temperature in step 4 is 900-1000°C.

[0017] Furthermore, in the secondary strong reduction smelting described in step 4, the smelting temperature is 1650-1800° C., and the smelting time is 1.5-2 h.

[0018] Furthermore, the V2O5 in the vanadium slag obtained in step 5 is greater than 16%.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The smelting method of vanadium-titanium magnetite provided by the present invention adopts the method of coal-based direct reduction of vanadium-titanium magnetite, primary smelting and secondary smelting, and converter blowing, and the iron, titanium and vanadium resources in vanadium-titanium magnetite are recovered in stages, and low-carbon molten steel, semi-steel, vanadium slag and high-titanium slag are prepared respectively, so as to realize the high-value utilization of iron, vanadium and titanium in vanadium-titanium magnetite. Because it is hot-charged into the electric furnace, the power consumption of the electric furnace smelting can be reduced. In the second smelting, the iron-vanadium-titanium slag is added with petroleum coke and titanium ore for secondary deep selective reduction, which can effectively separate and thus produce qualified products. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention is a flow chart of a method of coal-based reduction-smelting-electric furnace re-reduction-converter blowing. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the embodiments.

[0023] Example 1

[0024] A method of coal-based reduction-smelting-electric furnace re-reduction-converter blowing, comprising the following steps:

[0025] Step 1: The vanadium-titanium magnetite is coarsely crushed by a jaw crusher (particle size 20 mm), and then the coarsely crushed material is crushed and ground by a high-pressure roller mill (particle size -2mm 100%, -1mm 80%); the ground ore is granulated with coal powder (5% by mass), and the main components of the vanadium-titanium magnetite are TFe content of 48.03wt%, V2O5 content of 0.37wt%, SiO2 content of 1.52wt%, Al2O3 content of 3.15wt%, S content of 0.011wt%, P content of 0.015wt%; Ca content of 0.043wt%, Mg content of 0.84wt%;

[0026] Step 2: After granulation, coal-based reduction roasting (roasting temperature 750°C) is carried out, and the roasted metallized particles are put into a melting furnace for melting in a hot state. The pre-reduced vanadium-titanium magnetite is melted at high temperature without adding flux and reducing agent to form molten steel and liquid vanadium-titanium slag, which are released separately. The molten steel is cooled to form a product, wherein the melting temperature of the electric furnace is between 1550°C and the melting time is 40min;

[0027] Step 3: The liquid vanadium-titanium slag after melting is transported to a high-temperature granulator for high-temperature centrifugal granulation with petroleum coke (10% by mass) and titanium ore (18% by mass);

[0028] Step 4: the material after high-temperature granulation enters the insulation tank for insulation; the insulation tank is connected to the discharge pipe of the ore-fired electric furnace, the insulated material is evenly distributed according to the material surface in the ore-fired electric furnace, and the secondary strong reduction melting is carried out through the ore-fired electric furnace, wherein the melting temperature is 1650°C, the melting time is 1.5h, and high-titanium slag (product) and high-vanadium pig iron are produced;

[0029] Step 5: The high-vanadium pig iron released from the electric furnace is blown in a converter to produce semi-steel and vanadium slag (vanadium slag with V2O5 16.2%).

[0030] Example 2

[0031] A method of coal-based reduction-smelting-electric furnace re-reduction-converter blowing, comprising the following steps:

[0032] Step 1: The vanadium-titanium magnetite is coarsely crushed by a jaw crusher (particle size 20 mm), and then the coarsely crushed material is crushed and ground by a high-pressure roller mill (particle size -2mm 100%, -1mm 80%); the ground ore is granulated with coal powder (6% by mass), and the main components of the vanadium-titanium magnetite are TFe content of 47.03wt%, V2O5 content of 0.35wt%, SiO2 content of 1.5wt%, Al2O3 content of 3wt%, S content of 0.01wt%, P content of 0.01wt%; Ca content of 0.04wt%, Mg content of 0.8wt%;

[0033] Step 2: After granulation, coal-based reduction roasting (roasting temperature 770°C) is carried out, and the roasted metallized particles are put into a melting furnace for melting in a hot state. The pre-reduced vanadium-titanium magnetite is melted at high temperature without adding flux and reducing agent to form molten steel and liquid vanadium-titanium slag, which are released separately. The molten steel is cooled to form a product, wherein the melting temperature of the electric furnace is between 1600°C and the melting time is 40min;

[0034] Step 3: The liquid vanadium-titanium slag after melting is transported to a high-temperature granulator for high-temperature centrifugal granulation with petroleum coke (11% by mass) and titanium ore (19% by mass);

[0035] Step 4: the material after high-temperature granulation enters the insulation tank for insulation; the insulation tank is connected to the discharge pipe of the ore-fired electric furnace, the insulated material is evenly distributed according to the material surface in the ore-fired electric furnace, and the secondary strong reduction melting is carried out through the ore-fired electric furnace, wherein the melting temperature is 1700°C, the melting time is 1.5h, and high-titanium slag (product) and high-vanadium pig iron are produced;

[0036] Step 5: The high-vanadium pig iron released from the electric furnace is blown in a converter to produce semi-steel and vanadium slag (vanadium slag with V2O5 16.5%).

[0037] Example 3

[0038] A method of coal-based reduction-smelting-electric furnace re-reduction-converter blowing, comprising the following steps:

[0039] Step 1: The vanadium-titanium magnetite is coarsely crushed by a jaw crusher (particle size 20 mm), and then the coarsely crushed material is crushed and ground by a high-pressure roller mill (particle size -2mm 100%, -1mm 80%); the ground ore is granulated with coal powder (7% by mass), and the main components of the vanadium-titanium magnetite are TFe content of 48wt%, V2O5 content of 0.37wt%, SiO2 content of 1.49wt%, Al2O3 content of 3.12wt%, S content of 0.01wt%, P content of 0.014wt%; Ca content of 0.042wt%, and Mg content of 0.83wt%;

[0040] Step 2: After granulation, coal-based reduction roasting (roasting temperature 770°C) is carried out, and the roasted metallized particles are put into a melting furnace in a hot state for a melting. The pre-reduced vanadium-titanium magnetite is melted at high temperature without adding flux and reducing agent to form molten steel and liquid vanadium-titanium slag, which are released separately. The molten steel is cooled to form a product, wherein the melting temperature of the electric furnace is between 1600°C and the melting time is 50min;

[0041] Step 3: The liquid vanadium-titanium slag after melting is transported to a high-temperature granulator for high-temperature centrifugal granulation with petroleum coke (11.5% by mass) and titanium ore (18.5% by mass);

[0042] Step 4: the material after high-temperature granulation enters the insulation tank for insulation; the insulation tank is connected to the discharge pipe of the ore-fired electric furnace, the insulated material is evenly distributed according to the material surface in the ore-fired electric furnace, and the secondary strong reduction melting is carried out through the ore-fired electric furnace, wherein the melting temperature is 1700°C, the melting time is 1.5h, and high-titanium slag (product) and high-vanadium pig iron are produced;

[0043] Step 5: The high-vanadium pig iron released from the electric furnace is blown in a converter to produce semi-steel and vanadium slag (vanadium slag with V2O5 16.3%).

[0044] Example 4

[0045] A method of coal-based reduction-smelting-electric furnace re-reduction-converter blowing, comprising the following steps:

[0046] Step 1: The vanadium-titanium magnetite is coarsely crushed by a jaw crusher (particle size 20 mm), and then the coarsely crushed material is crushed and ground by a high-pressure roller mill (particle size -2mm 100%, -1mm 80%); the ground ore is granulated with coal powder (7% by mass), and the main components of the vanadium-titanium magnetite are TFe content of 47.9wt%, V2O5 content of 0.36wt%, SiO2 content of 1.51wt%, Al2O3 content of 3.14wt%, S content of 0.009wt%, P content of 0.013wt%; Ca content of 0.041wt%, and Mg content of 0.79wt%;

[0047] Step 2: After granulation, coal-based reduction roasting (roasting temperature 800°C) is carried out, and the roasted metallized particles are put into a melting furnace for melting in a hot state. The pre-reduced vanadium-titanium magnetite is melted at high temperature without adding flux and reducing agent to form molten steel and liquid vanadium-titanium slag, which are released separately. The molten steel is cooled to form a product, wherein the melting temperature of the electric furnace is between 1650°C and the melting time is 60min;

[0048] Step 3: The liquid vanadium-titanium slag after melting is transported to a high-temperature granulator for high-temperature centrifugal granulation with petroleum coke (12% by mass) and titanium ore (19% by mass);

[0049] Step 4: the material after high-temperature granulation enters the insulation tank for insulation; the insulation tank is connected to the discharge pipe of the ore-fired electric furnace, the insulated material is evenly distributed according to the material surface in the ore-fired electric furnace, and the secondary strong reduction melting is carried out through the ore-fired electric furnace, wherein the melting temperature is 1750°C, the melting time is 1.5h, and high-titanium slag (product) and high-vanadium pig iron are produced;

[0050] Step 5: The high-vanadium pig iron released from the electric furnace is blown in a converter to produce semi-steel and vanadium slag (vanadium slag containing 17% V2O5).

[0051] Example 5

[0052] A method of coal-based reduction-smelting-electric furnace re-reduction-converter blowing, comprising the following steps:

[0053] Step 1: The vanadium-titanium magnetite is coarsely crushed by a jaw crusher (particle size 20 mm), and then the coarsely crushed material is crushed and ground by a high-pressure roller mill (particle size -2mm 100%, -1mm 80%); the ground ore is granulated with coal powder (7% by mass), and the main components of the vanadium-titanium magnetite are TFe content of 47.5wt%, V2O5 content of 0.33wt%, SiO2 content of 1.45wt%, Al2O3 content of 3.01wt%, S content of 0.01wt%, P content of 0.013wt%; Ca content of 0.039wt%, and Mg content of 0.83wt%;

[0054] Step 2: After granulation, coal-based reduction roasting (roasting temperature 850°C) is carried out, and the roasted metallized particles are put into a melting furnace for melting in a hot state. The pre-reduced vanadium-titanium magnetite is melted at high temperature without adding flux and reducing agent to form molten steel and liquid vanadium-titanium slag, which are released separately. The molten steel is cooled to form a product, wherein the melting temperature of the electric furnace is between 1650°C and the melting time is 50min;

[0055] Step 3: The liquid vanadium-titanium slag after melting is transported to a high-temperature granulator for high-temperature centrifugal granulation with petroleum coke (12.5% ​​by mass) and titanium ore (20% by mass);

[0056] Step 4: the material after high-temperature granulation enters the insulation tank for insulation; the insulation tank is connected to the discharge pipe of the ore-fired electric furnace, the insulated material is evenly distributed according to the material surface in the ore-fired electric furnace, and the secondary strong reduction melting is carried out through the ore-fired electric furnace, wherein the melting temperature is 1700°C, the melting time is 1.5h, and high-titanium slag (product) and high-vanadium pig iron are produced;

[0057] Step 5: The high-vanadium pig iron released from the electric furnace is blown in a converter to produce semi-steel and vanadium slag (vanadium slag with V2O5 16.7%).

[0058] See the table below for detailed data:

[0059] Element analysis table of primary slag (%)

[0060]

[0061] Element analysis table of primary molten steel (%)

[0062] Fe V You Yes S P C 95.6 0.01 0.84 0.26 0.12 0.01 0.92

[0063] Secondary melting slag element analysis table (%)

[0064]

[0065] Secondary melting semi-steel element analysis table (%)

[0066] Fe V You Yes S P C 93 1.88 0.84 1.26 0.12 0.01 1.92

Claims

1. A method of coal-based reduction-smelting-electric furnace re-reduction-converter blowing, characterized in that: The following steps are involved: Step 1: The vanadium-titanium magnetite is coarsely crushed with a jaw crusher to a particle size of 20-40 mm, and then the coarsely crushed material is crushed and ground with a high-pressure roller mill, and the ground ore and coal powder are granulated according to the ratio; Step 2: After granulation, coal-based reduction roasting is carried out, the roasting temperature is 750-850°C, and the roasting time is 40-60min; the roasted metallized particles are put into a melting furnace in a hot state for a melting, and the pre-reduced vanadium-titanium magnetite is melted at high temperature without adding flux and reducing agent to form molten steel and liquid vanadium-titanium slag, which are released separately, and the molten steel is cooled to form a product; Step 3: transporting the melted liquid vanadium-titanium slag to a high-temperature granulator for high-temperature centrifugal granulation with petroleum coke and titanium ore; Step 4: The material after high-temperature granulation enters the insulation tank for insulation; the insulation tank is connected to the discharge pipe of the ore-fired electric furnace, and the insulated material is evenly distributed according to the material surface in the ore-fired electric furnace, and the secondary strong reduction melting is carried out in the ore-fired electric furnace to produce high-titanium slag and high-vanadium pig iron; Step 5: The high-vanadium pig iron released from the electric furnace is blown in a converter to produce semi-steel and vanadium slag.

2. The method of coal-based reduction-melting-electric furnace re-reduction-converter blowing according to claim 1, characterized in that: The main components of the vanadium-titanium magnetite described in step 1 are TFe content of 45-48.03wt%, V2O5 content of 0.25-0.37wt%, SiO2 content of 1.1-1.52wt%, Al2O3 content of 2.5-3.15wt%, S content of 0-0.011wt%, P content of 0-0.015wt%; Ca content of 0-0.043wt%, and Mg content of 0.5-0.84wt%.

3. The method of coal-based reduction-melting-electric furnace re-reduction-converter blowing according to claim 1, characterized in that: The particle size of the ore after grinding in step 1 is -2mm 100%, -1mm 80%.

4. The method of coal-based reduction-melting-electric furnace re-reduction-converter blowing according to claim 1, characterized in that: The proportion in step 1 is: coal powder accounts for 5-7% of the mass ratio of the ground ore.

5. The method of coal-based reduction-melting-electric furnace re-reduction-converter blowing according to claim 1, characterized in that: The melting temperature of the first melting in step 2 is between 1550-1700° C., and the melting time is 40-80 min.

6. The method of coal-based reduction-melting-electric furnace re-reduction-converter blowing according to claim 1, characterized in that: The petroleum coke in step 3 accounts for 10-15% by mass of the liquid vanadium-titanium slag after melting; the titanium ore accounts for 18-25% by mass of the liquid vanadium-titanium slag after melting.

7. The method of coal-based reduction-melting-electric furnace re-reduction-converter blowing according to claim 1, characterized in that: The insulation temperature in step 4 is 900-1000°C.

8. The method of coal-based reduction-melting-electric furnace re-reduction-converter blowing according to claim 1, characterized in that: The melting temperature in the secondary strong reduction melting described in step 4 is 1650-1800° C., and the melting time is 1.5-2 h.

9. The method of coal-based reduction-melting-electric furnace re-reduction-converter blowing according to claim 1, characterized in that: The V2O5 in the vanadium slag obtained in step 5 is greater than 16%.

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