Comprehensive utilization method of vanadium-containing shale, vanadium-containing steel slag and vanadium-titanium magnetite concentrate

Abstract

The invention discloses a comprehensive utilization method of vanadium-containing shale, vanadium-containing steel slag and vanadium-titanium magnetite concentrate, which comprises the following steps: (1) finely grinding vanadium-containing shale raw ore, vanadium-containing steel slag and vanadium-titanium magnetite concentrate to preset fineness, uniformly mixing the finely ground vanadium-containing shale, vanadium-titanium magnetite concentrate and an additive according to a set proportion, pelletizing the obtained mixture, and drying to obtain vanadium-containing shale pellets; green pellets are obtained; (2) the green pellets are sequentially subjected to drying, preheating and oxidizing roasting, and pre-oxidized pellets are obtained; (3) the pre-oxidized pellets are subjected to reduction treatment, and pre-reduced pellets are obtained; and (4) the pre-reduced pellets and a reducing agent are added into an electric furnace for reduction smelting, and vanadium-containing molten iron and titanium-containing slag are obtained through separation. According to the method, comprehensive utilization of the vanadium-containing shale, the vanadium-containing steel slag and the vanadium-titanium magnetite concentrate is achieved, the resource utilization rate is increased, and resource waste is reduced. The pre-oxidation-pre-reduction-reduction process is adopted, the vanadium-containing shale, the vanadium-containing steel slag and the vanadium-titanium magnetite concentrate are effectively treated, the technological process is simple, operation is convenient, and the production cost is reduced. According to the method, vanadium, titanium and iron elements are effectively extracted, environmental pollution is reduced, and the requirement of sustainable development is met.

Description

Technical Field

[0001] The present invention belongs to the field of comprehensive utilization of vanadium and titanium resources, and relates to a comprehensive utilization method of vanadium-containing shale, vanadium-containing steel slag and vanadium-titanium magnetite concentrate. Background Art

[0002] Improving the comprehensive utilization level of my country's vanadium-titanium magnetite resources is of great significance to the development of my country's steel and vanadium-titanium industries.

[0003] At present in the treatment process for vanadium-titanium magnetite concentrate, non-blast furnace process all can be realized all-vanadium-titanium ore smelting, and iron, vanadium, titanium recovery rate are high, and in blast furnace smelting, coke not only provides smelting required temperature as reductive agent but also as fuel, causes reduction potential in the blast furnace to be stronger.When smelting vanadium-titanium magnetite, the coke zone is in carbon excess state always, easily causes titanium oxide overreduction in the slag to generate high melting point materials such as titanium carbonitride, makes slag become sticky, poor fluidity, slag is difficult to go out, and iron band is many in the slag, and iron loss is high.In order to suppress the reduction of this regional titanium oxide, blast furnace process has adopted the TiO2 that adds common ore to reduce in the slag Content, and then reduce TiO Activity, to reach and suppress titanium oxide overreduction, reduce titanium carbonitride and generate, guarantee that slag-iron separation and smelt the purpose of going along, but adding common iron ore has reduced TiO2 in the blast furnace slag Content, TiO2 in the blast furnace titanium-containing slag of production Low content (TiO Massfraction about 20%~25%) can't economic recycling, only can reclaim iron and vanadium.

[0004] Vanadium ores rarely exist independently in nature; the vast majority occur as paragenetic or associated minerals, primarily vanadium-titanium magnetite and anthracite. Since the national ban on vanadium extraction from anthracite due to environmental concerns, vanadium has become primarily derived from vanadium-titanium magnetite. The vanadium-titanium magnetite in the Panxi region contains approximately 0.3% vanadium dioxide (V2O5), theoretically suitable for direct vanadium extraction. However, in practice, due to cost constraints, few companies directly utilize vanadium-titanium magnetite for vanadium extraction. Most companies utilize an indirect method to recover vanadium from vanadium-titanium magnetite, first smelting the vanadium-containing hot metal into vanadium-bearing hot metal, which is then used for vanadium extraction. Whether extracting vanadium from the hot metal through atomization or converters, a significant amount of residual vanadium oxidizes into the slag, forming vanadium-bearing steel slag containing 1% to 4% V2O5.

[0005] Vanadium-bearing shale, vanadium-bearing steel slag, and vanadium-titanium magnetite concentrate are important vanadium resources. Currently, the utilization of vanadium-bearing shale primarily focuses on extracting vanadium alone, while the processing of vanadium-titanium magnetite concentrate often focuses on separating vanadium from titanium and other elements, failing to fully achieve the synergistic extraction of multiple elements. Furthermore, existing processing methods suffer from complex process flows, low element recovery rates, high energy consumption, and environmental pollution. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method for the comprehensive utilization of vanadium-containing shale, vanadium-containing steel slag and vanadium-titanium magnetite concentrate, so as to achieve efficient extraction and comprehensive utilization of valuable elements in vanadium-titanium resources while reducing energy consumption and environmental pollution.

[0007] The present invention provides the following technical solution: a method for comprehensive utilization of vanadium-containing shale, vanadium-containing steel slag and vanadium-titanium magnetite concentrate, comprising the following steps:

[0008] (1) grinding vanadium-containing shale ore, vanadium-containing steel slag, and vanadium-titanium magnetite concentrate to a predetermined fineness, mixing the finely ground vanadium-containing shale, vanadium-titanium magnetite concentrate, and additives in a set proportion, and pelletizing the resulting mixture to obtain green balls;

[0009] (2) drying, preheating, and oxidatively roasting the green pellets obtained in step (1) to obtain pre-oxidized pellets;

[0010] (3) subjecting the pre-oxidized pellets obtained in step (2) to a reduction treatment to obtain pre-reduced pellets;

[0011] (4) adding the pre-reduced pellets and the reducing agent obtained in step (3) into an electric furnace for reduction smelting, and separating to obtain vanadium-containing molten iron and titanium-containing slag.

[0012] Preferably, in step (1), the vanadium-containing shale ore, vanadium-containing steel slag, and vanadium-titanium magnetite concentrate are crushed and finely ground to a particle size of less than -200 mesh ≥80%.

[0013] More preferably, the fine grinding treatment method includes one or more combinations of damp grinding, high pressure roller grinding, and vertical grinding, and the mass ratio of the vanadium-containing shale, vanadium-containing steel slag and vanadium-titanium magnetite concentrate is (5-30):(5-10):(60-90).

[0014] Preferably, in step (1), the additives are calcium flux and magnesium flux, and the particle size of the additives is -200 mesh ≥ 80%;

[0015] The calcium flux includes one or more of limestone, dolomite, slaked lime, quicklime and high calcium slag, and the amount thereof added is adjusted according to the CaO / SiO2 mass ratio in the mixture of 0.2 to 1.5;

[0016] The magnesia flux comprises one or more of dolomite, magnesite, magnesium silicate, serpentine and magnesia slag, and the added amount thereof is adjusted to a mass fraction of MgO in the mixture of 1 to 5%.

[0017] Preferably, in step (1), the particle size of the green balls is 8 mm to 20 mm, the drop strength of the green balls is greater than 3.0 times / (0.5 m·ball), and the compressive strength is greater than 10 N / ball.

[0018] Preferably, in step (2), the drying temperature of the green balls is 150-400°C, and the drying time is 3-10 min; the preheating temperature is 800-1100°C, and the preheating time is 5-30 min; the oxidation roasting temperature is 1150-1300°C, and the roasting time is 5-30 min; and the compressive strength of the pre-oxidized balls is greater than 500N / piece.

[0019] Preferably, in step (3), the reduction temperature is 800-1300° C., and the reduction treatment adopts gas-based reduction or coal-based reduction equipment selected from any one of a shaft furnace, a rotary kiln, a rotary hearth furnace, and a tunnel kiln.

[0020] More preferably, the reducing gas used in the vertical furnace includes one or more of natural gas, hydrogen, and coke oven gas, and the reducing agent used in the rotary kiln or rotary hearth furnace includes one or more of coke powder, anthracite, bituminous coal, biochar, and lignite.

[0021] Preferably, in step (3), the average compressive strength of the pre-reduced pellets is ≥2000N / piece, and the average metallization rate is greater than 60%.

[0022] Preferably, in step (4), the electric furnace smelting temperature is 1550-1650° C., and the smelting time is 20-120 min; the reducing agent is one or more of coke powder, coal powder, biochar and semi-coke.

[0023] Preferably, in step (4), the obtained vanadium-containing molten iron is used for vanadium extraction in a converter or is blown in a converter to separate semi-steel and vanadium slag;

[0024] The obtained titanium-containing slag is used to recover titanium resources by sulfuric acid method.

[0025] The advantages of the present invention are that by co-processing a variety of vanadium-containing raw materials, the vanadium resources therein can be more fully extracted and utilized, thereby improving the recovery rate of vanadium. Adding some vanadium-containing steel slag during the pelletizing process can strengthen the consolidation of the pellets and obtain qualified pellets at a lower preheating roasting temperature; adding vanadium-containing shale can strengthen the reduction of the pellets, and the coupling effect of the internal carbon source of the pellets and the external reducing agent can be used to improve the reduction effect of the pellets. The pelletizing and reduction processes can reduce energy consumption in the smelting process and reduce production costs. In addition, by utilizing the complementarity between different raw materials, dependence on a single raw material can be reduced, and raw material costs can be reduced. The reuse of vanadium-containing steel slag can reduce the emission of solid waste. Compared with traditional blast furnace smelting, electric furnace smelting can better control the emission of pollutants and reduce the impact on the environment.

[0026] The present invention adopts a pre-oxidation-pre-reduction-reduction process to effectively treat vanadium-containing shale and vanadium-titanium magnetite concentrate, has a simple process flow, is easy to operate, and reduces production costs.

[0027] The present invention effectively extracts vanadium, iron and titanium elements, reduces environmental pollution and meets the requirements of sustainable development. DETAILED DESCRIPTION

[0028] The specific embodiments of the present invention are further described below by way of examples, but the specific embodiments of the present invention are not limited to the following examples.

[0029] In the embodiment of the present invention, the effective components of the vanadium-containing shale ore are: C=15.12%, SiO2=58.96%, and V2O5=1.15%.

[0030] The main components of vanadium-containing steel slag are: TFe = 21.14%, CaO = 42.96%, SiO2 = 10.34%, V2O5 = 2.56%, TiO2 = 7.95%, and MgO = 8.66%.

[0031] The effective components of the vanadium-titanium magnetite concentrate are: TFe = 58.69%, TiO2 = 15.36%, V2O5 = 0.68%.

[0032] The present invention is described in detail below with reference to specific embodiments.

[0033] Example 1

[0034] A method for comprehensive utilization of vanadium-containing shale, vanadium-containing steel slag and vanadium-titanium magnetite concentrate comprises the following steps:

[0035] (1) crushing and finely grinding vanadium-containing shale ore, vanadium-containing steel slag, and vanadium-titanium magnetite concentrate to a particle size of less than -200 mesh (≥80%), mixing the finely ground vanadium-containing shale, vanadium-containing steel slag, vanadium-titanium magnetite concentrate, and calcium flux and magnesium flux according to a set ratio, and pelletizing the resulting mixture to obtain green balls; the mass ratio of vanadium-containing shale ore, vanadium-containing steel slag, and vanadium-titanium magnetite concentrate is 20:10:70;

[0036] Calcium flux includes limestone, and its addition amount is adjusted according to the CaO / SiO2 mass ratio of 0.5 in the mixture;

[0037] The magnesia flux includes magnesite, and its addition amount is adjusted to 3% by mass fraction of MgO in the mixture;

[0038] The particle size of the obtained green balls is 8mm to 20mm, the drop strength of the green balls is greater than 3.0 times / (0.5m·ball), and the compressive strength is greater than 10N / ball;

[0039] (2) drying, preheating, and oxidative roasting the obtained green pellets in sequence to obtain pre-oxidized pellets;

[0040] The drying temperature of the green pellets is 300°C, and the drying time is 8 minutes; the preheating temperature is 900°C, and the preheating time is 10 minutes; the oxidation roasting temperature is 1200°C, and the roasting time is 10 minutes; the compressive strength of the obtained pre-oxidized pellets is 2600N / piece;

[0041] (3) reducing the obtained pre-oxidized pellets using a vertical furnace process, using natural gas as the reducing gas, a reduction temperature of 900° C., and a reduction time of 1 hour to obtain pre-reduced pellets;

[0042] The average metallization rate of the obtained pre-reduced pellets is 75%;

[0043] (4) The obtained pre-reduced pellets and coke powder are added to an electric furnace for reduction smelting at a temperature of 1600° C. for 60 min; vanadium-containing molten iron and titanium-containing slag are separated.

[0044] In Example 1, based on the calculation of the vanadium-containing molten iron entering, the recovery rate of vanadium is 95.12%, the recovery rate of iron is 99.25%; the TiO2 content in the titanium-containing slag is 47.56%.

[0045] Example 2

[0046] A method for comprehensive utilization of vanadium-containing shale, vanadium-containing steel slag and vanadium-titanium magnetite concentrate comprises the following steps:

[0047] (1) crushing and finely grinding vanadium-containing shale ore, vanadium-containing steel slag, and vanadium-titanium magnetite concentrate to a particle size of less than -200 mesh (≥80%), mixing the finely ground vanadium-containing shale, vanadium-titanium magnetite concentrate, and calcium flux and magnesium flux according to a set ratio, and pelletizing the resulting mixture to obtain green balls; the mass ratio of vanadium-containing shale ore, vanadium-containing steel slag, and vanadium-titanium magnetite concentrate is 30:5:65;

[0048] Calcium flux includes limestone and dolomite, and its addition amount is adjusted according to the CaO / SiO2 mass ratio of 0.2 in the mixture;

[0049] Magnesia flux includes dolomite and magnesite, and its addition amount is adjusted according to the mass fraction of MgO in the mixture being 4%;

[0050] The particle size of the obtained green balls is 8mm to 20mm, the drop strength of the green balls is greater than 3.0 times / (0.5m·ball), and the compressive strength is greater than 10N / ball;

[0051] (2) drying, preheating, and oxidative roasting the obtained green pellets in sequence to obtain pre-oxidized pellets;

[0052] The drying temperature of the green pellets is 400°C and the drying time is 3 minutes; the preheating temperature is 900°C and the preheating time is 30 minutes; the compressive strength of the obtained pre-oxidized pellets is 530N / piece;

[0053] (3) reducing the obtained pre-oxidized pellets using a rotary kiln process, using bituminous coal as a reducing agent, at a reduction temperature of 1200° C. for 1 hour to obtain pre-reduced pellets;

[0054] The average metallization rate of the obtained pre-reduced pellets is 62%;

[0055] (4) The obtained pre-reduced pellets and coke powder are added to an electric furnace for reduction smelting at a temperature of 1550° C. for 120 min; vanadium-containing molten iron and titanium-containing slag are separated.

[0056] In Example 2, based on the calculation of the vanadium-containing molten iron entering, the recovery rate of vanadium is 94.68%, the recovery rate of iron is 99.12%; the TiO2 content in the titanium-containing slag is 46.59%.

[0057] Example 3

[0058] A method for comprehensive utilization of vanadium-containing shale, vanadium-containing steel slag and vanadium-titanium magnetite concentrate comprises the following steps:

[0059] (1) crushing and finely grinding vanadium-containing shale ore, vanadium-containing steel slag, and vanadium-titanium magnetite concentrate to a particle size of less than -200 mesh (≥80%), mixing the finely ground vanadium-containing shale, vanadium-containing steel slag, vanadium-titanium magnetite concentrate, and calcium flux and magnesium flux according to a set ratio, and pelletizing the resulting mixture to obtain green balls; the mass ratio of vanadium-containing shale ore, vanadium-containing steel slag, and vanadium-titanium magnetite concentrate is 20:5:75;

[0060] Calcium flux includes limestone and dolomite, and its addition amount is based on the CaO / SiO2 mass ratio of 1.5 in the mixture;

[0061] Magnesia flux includes dolomite and magnesite, and its addition amount is adjusted according to the mass fraction of MgO in the mixture to be 3%;

[0062] The particle size of the obtained green balls is 8mm to 20mm, the drop strength of the green balls is greater than 3.0 times / (0.5m·ball), and the compressive strength is greater than 10N / ball;

[0063] (2) drying, preheating, and oxidative roasting the obtained green pellets in sequence to obtain pre-oxidized pellets;

[0064] The drying temperature of the green pellets is 150°C and the drying time is 10 minutes; the preheating temperature is 1100°C and the preheating time is 5 minutes; the oxidation roasting temperature is 1300°C and the roasting time is 5 minutes; the compressive strength of the obtained pre-oxidized pellets is 2130N / piece;

[0065] (3) reducing the obtained pre-oxidized pellets using a shaft furnace process, using a reducing gas of 50% hydrogen and 50% coke oven gas, a reduction temperature of 950° C., and a reduction time of 2 hours to obtain pre-reduced pellets;

[0066] The average metallization rate of the obtained pre-reduced pellets is greater than 60%;

[0067] (4) adding the obtained pre-reduced pellets and coke powder into an electric furnace for reduction smelting at a temperature of 1650° C. for 20 min; and separating to obtain vanadium-containing molten iron and titanium-containing slag.

[0068] In Example 3, based on the calculation of the vanadium-containing molten iron entering, the recovery rate of vanadium is 96.35%, the recovery rate of iron is 99.36%; the TiO2 content in the titanium-containing slag is 45.62%.

[0069] Comparative Example 1

[0070] Other conditions are the same as those in Example 1, except that no vanadium-containing shale and vanadium-containing steel slag are added in step 1;

[0071] The drying, preheating and roasting conditions in step 2 were the same, and pre-oxidized pellets with a strength of 1356N / P were obtained;

[0072] The reduction conditions in step 3 were the same, and pre-reduced pellets with a metallization rate of 45% were obtained;

[0073] The smelting conditions in step 4 were the same, and the vanadium recovery rate was 76.12% and the iron recovery rate was 97.56%.

[0074] The above is only a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiment. For those skilled in the art, improvements and modifications obtained without departing from the technical concept of the present invention should also be considered as the scope of protection of the present invention.

Claims

1. A method for comprehensive utilization of vanadium-containing shale, vanadium-containing steel slag and vanadium-titanium magnetite concentrate, characterized in that: The following steps are involved: (1) grinding vanadium-containing shale ore, vanadium-containing steel slag, and vanadium-titanium magnetite concentrate to a predetermined fineness, mixing the finely ground vanadium-containing shale, vanadium-containing steel slag, vanadium-titanium magnetite concentrate, and additives in a set proportion, and pelletizing the resulting mixture to obtain green balls; (2) drying, preheating, and oxidatively roasting the green pellets obtained in step (1) to obtain pre-oxidized pellets; (3) subjecting the pre-oxidized pellets obtained in step (2) to a reduction treatment to obtain pre-reduced pellets; (4) adding the pre-reduced pellets and the reducing agent obtained in step (3) into an electric furnace for reduction smelting, and separating to obtain vanadium-containing molten iron and titanium-containing slag.

2. The method for comprehensive utilization of vanadium-containing shale, vanadium-containing steel slag and vanadium-titanium magnetite concentrate according to claim 1, characterized in that: In step (1), the vanadium-containing shale ore, vanadium-containing steel slag, and vanadium-titanium magnetite concentrate are crushed and finely ground to a particle size of less than -200 meshes (≥80%).

3. The method for comprehensive utilization of vanadium-containing shale, vanadium-containing steel slag and vanadium-titanium magnetite concentrate according to claim 2, characterized in that: The fine grinding treatment method includes one or more combinations of damp grinding, high-pressure roller grinding, and vertical grinding. The mass ratio of the vanadium-containing shale, vanadium-containing steel slag and vanadium-titanium magnetite concentrate is (5-30): (5-10): (60-90).

4. The method for comprehensive utilization of vanadium-containing shale, vanadium-containing steel slag and vanadium-titanium magnetite concentrate according to claim 1, characterized in that: In step (1), the additives are calcium flux and magnesium flux, and the particle size of the additives is -200 mesh ≥ 80%; The calcium flux includes one or more of limestone, dolomite, slaked lime, quicklime and high calcium slag, and the amount thereof added is adjusted according to the CaO / SiO2 mass ratio in the mixture of 0.2 to 1.5; The magnesia flux comprises one or more of dolomite, magnesite, magnesium silicate, serpentine and magnesia slag, and the added amount thereof is adjusted to a mass fraction of MgO in the mixture of 1 to 5%.

5. The method for comprehensive utilization of vanadium-containing shale, vanadium-containing steel slag and vanadium-titanium magnetite concentrate according to claim 1, characterized in that: In step (1), the particle size of the green balls is 8 mm to 20 mm, the drop strength of the green balls is greater than 3.0 times / (0.5 m·ball), and the compressive strength is greater than 10 N / ball.

6. The method for comprehensive utilization of vanadium-containing shale, vanadium-containing steel slag and vanadium-titanium magnetite concentrate according to claim 1, characterized in that: In step (2), the drying temperature of the green balls is 150-400°C, and the drying time is 3-10 minutes; the preheating temperature is 800-1100°C, and the preheating time is 5-30 minutes; the oxidation roasting temperature is 1150-1300°C, and the roasting time is 5-30 minutes; the compressive strength of the pre-oxidized balls is greater than 500N / piece.

7. The method for comprehensive utilization of vanadium-containing shale, vanadium-containing steel slag and vanadium-titanium magnetite concentrate according to claim 1, characterized in that: In step (3), the reduction temperature is 800-1300° C., and the reduction treatment adopts gas-based reduction or coal-based reduction equipment, selected from any one of a vertical furnace, a rotary kiln, a rotary hearth furnace, and a tunnel kiln.

8. The method for comprehensive utilization of vanadium-containing shale, vanadium-containing steel slag and vanadium-titanium magnetite concentrate according to claim 7, characterized in that: The reducing gas used in the vertical furnace includes one or more of natural gas, hydrogen, and coke oven gas, and the reducing agent used in the rotary kiln or rotary hearth furnace includes one or more of coke powder, anthracite, bituminous coal, biochar, and lignite.

9. The method for comprehensive utilization of vanadium-containing shale, vanadium-containing steel slag and vanadium-titanium magnetite concentrate according to claim 1, characterized in that: In step (3), the average metallization rate of the pre-reduced pellets is greater than 60%.

10. The method for comprehensive utilization of vanadium-containing shale, vanadium-containing steel slag and vanadium-titanium magnetite concentrate according to claim 1, characterized in that: In step (4), the electric furnace smelting temperature is 1550-1650° C., and the smelting time is 20-120 min; the reducing agent is one or more of coke powder, coal powder, biochar and semi-coke.