Vanadium-titanium magnetite and stone coal vanadium ore one furnace three sections synergic vanadium extraction process

Abstract

This invention discloses a three-stage synergistic vanadium extraction process for vanadium-titanium magnetite and vanadium shale coal. The process employs a side-blown furnace, which includes a feed inlet, flue, molten iron outlet, slag outlet, and multiple nozzles aligned on both sides. The process comprises the following steps: S1, uniformly mixing vanadium-titanium magnetite and vanadium shale coal in a specific ratio; S2, adding the mixed ore material through the feed inlet of the side-blown furnace, and injecting pulverized coal, natural gas, and oxygen-enriched air into the furnace via nozzles for high-temperature smelting; S3, after the smelting reaction is complete, stopping the feeding and injecting natural gas... Natural gas and oxygen-enriched air are used to raise the temperature, and then the nozzles are closed for static clarification. S4. After a certain period of clarification, the titanium slag is discharged from the slag discharge port. S5. After the titanium slag is separated, the nozzles are reopened to blow oxygen-enriched air into the side-blown furnace for oxygen-enriched vanadium extraction. The feeding process is resumed. This application realizes the reduction smelting, molten iron clarification and oxygen-enriched vanadium blowing of mixed vanadium-titanium magnetite and vanadium shale coal ore through a single side-blown furnace. This changes the traditional multi-process steps, greatly simplifies the blast furnace and non-blast furnace smelting process, and reduces equipment investment costs and environmental impact.

Description

Technical Field

[0001] This application relates to the field of vanadium extraction technology from ore, and in particular to a three-stage synergistic vanadium extraction process for vanadium-titanium magnetite and vanadium-shale coal. Background Technology

[0002] Vanadium-titanium magnetite and vanadium shale are two major minerals that contain vanadium, and vanadium extraction from these two minerals is an important source of vanadium in my country. Vanadium extraction from vanadium-titanium magnetite generally employs pyrometallurgical processes, with some utilizing a combined pyrometallurgical and hydrometallurgical process. Early pyrometallurgical processes for vanadium-titanium magnetite mainly revolved around "blast furnace ironmaking - converter vanadium extraction," resulting in an overall vanadium recovery rate of less than 50% and significant vanadium loss. Simultaneously, blast furnace smelting is energy-intensive, produces large amounts of pollutants, and causes severe environmental pollution. Furthermore, titanium in the mineral readily forms high-melting-point compounds such as CaTiO3 and CaTiSiO5 with elements like calcium and silicon, leading to viscous slag and significant titanium resource loss. To address the difficulties of blast furnace smelting, countries like South Africa and New Zealand have developed non-blast furnace smelting process systems centered on direct reduction and deep molten reduction, which improve vanadium recovery rates while also enhancing titanium slag separation efficiency. For example, rotary kiln direct reduction - electric furnace melting - converter vanadium extraction is a typical non-blast furnace smelting process. However, this non-blast furnace smelting process still faces problems such as long procedures and high energy consumption. Besides pure pyrometallurgical processes like blast furnaces and non-blast furnaces, vanadium-titanium magnetite can also be processed using sodium / calcification roasting to convert vanadium in the ore into soluble vanadates, which are then selectively separated by water / acid leaching. The remaining vanadium-extracting material is then sent to a rotary kiln for reduction and an electric furnace for smelting to obtain molten iron and titanium slag. Although this method is mature and requires relatively low investment, some processes generate harmful flue gas and high-salt wastewater, leading to significant environmental problems.

[0003] Furthermore, my country is rich in vanadium resources found in coal-bearing shale. Vanadium in these shale minerals exists primarily in isomorphous forms within the crystal lattices of mica-like minerals, exhibiting complex occurrence states. Currently, vanadium extraction from coal-bearing shale mainly employs processes such as sodium roasting-water leaching and calcification roasting-acid leaching. Among these, the sodium roasting-water leaching process has a relatively low vanadium extraction rate and generates large amounts of chlorine- or sulfur-containing waste gas, causing environmental pollution. While the calcification roasting-acid leaching process reduces waste gas generation, it involves higher roasting temperatures, higher energy consumption, and greater acid consumption during leaching, leading to severe equipment corrosion. Summary of the Invention

[0004] To reduce costs, decrease energy consumption, and improve efficiency, this application provides a three-stage synergistic vanadium extraction process for vanadium-titanium magnetite and vanadium-shale coal.

[0005] This application provides a three-stage synergistic vanadium extraction process for vanadium-titanium magnetite and vanadium-bearing shale coal, employing the following technical solution:

[0006] A three-stage synergistic vanadium extraction process for vanadium-titanium magnetite and vanadium shale coal ore, comprising a side-blown furnace, wherein the furnace has a feed inlet at the top of the first end and a flue at the top of the last end; the last end has an iron outlet and a slag outlet; multiple nozzles are provided on both side walls, and the nozzles on both sides are aligned; the process includes the following steps:

[0007] S1. Mix vanadium-titanium magnetite and vanadium shale ore evenly in a certain proportion;

[0008] S2. Add the mixed mineral materials from the feed port of the side-blown furnace, and inject pulverized coal, natural gas and oxygen-enriched air into the side-blown furnace through the nozzle for high-temperature smelting, so that the metal oxides such as iron and vanadium in the raw materials undergo a reduction reaction and form a melt, namely vanadium-containing molten iron and titanium slag.

[0009] S3. After the smelting reaction is complete, stop feeding, inject natural gas and oxygen-enriched air, raise the temperature, and then close the nozzle to allow it to stand and clarify.

[0010] S4. After a certain period of clarification, discharge the titanium slag from the slag outlet;

[0011] S5. After the titanium slag is separated, the nozzle is reopened to blow oxygen-enriched air into the side-blown furnace for oxygen-enriched vanadium extraction. After the vanadium extraction is completed, the vanadium slag and molten iron are discharged to the ladle for separation and recovery. The molten iron after vanadium extraction is sent to the steelmaking system. One furnace and three sections complete one cycle, and the feeding is resumed.

[0012] Optionally, in step S1, vanadium-titanium magnetite and vanadium shale ore are uniformly mixed at a mass ratio of 100:(40-45), and the particle size of the mineral material is 200-300 mesh.

[0013] Optionally, in step S2, the smelting temperature is 1450-1550°C, the pulverized coal dosage is 100-150 kg / ton of ore, the oxygen enrichment concentration is 70-80 vol%, and the bed capacity of the side-blown furnace is 40-50 t / m³. 2 •d, the smelting reaction time is 2-3 hours, and the flue gas generated during the process is sent to the waste heat recovery system and purification device through the flue.

[0014] Optionally, all nozzles are perpendicular to the side of the side-blown furnace, and 3 / 4 of the total number of straight nozzles are used to simultaneously spray pulverized coal and oxygen-enriched air, while 1 / 4 of the total number of straight nozzles spray natural gas; the two types of straight nozzles are arranged alternately on the side of the side-blown furnace, driving the material to stir and tumble while injecting fuel and oxygen-enriched air.

[0015] Optionally, in step S3, the temperature of the side-blown furnace needs to be increased to 1500-1600°C.

[0016] Optionally, in step S4, when the temperature of the side-blown furnace drops to 1450-1550°C and the clarification time reaches 30-40 minutes, the titanium slag is discharged from the slag discharge port.

[0017] Optionally, in step S5, the blowing temperature is controlled at 1300-1350°C and the blowing time is 4-7 minutes.

[0018] In summary, this application includes the following beneficial technical effects:

[0019] (1) The reduction smelting, molten iron clarification and oxygen-enriched vanadium blowing of mixed vanadium-titanium magnetite and vanadium shale coal were realized by a single side blowing furnace, which changed the traditional multi-process processing steps, greatly simplified the blast furnace and non-blast furnace smelting process, and reduced equipment investment costs and environmental impact.

[0020] (2) The side-blown furnace effectively improves the gas-solid-liquid three-phase mixing system in the furnace by using multiple nozzles to blow gas, which enhances the mass and heat transfer of reduction smelting and oxygen-enriched vanadium blowing reaction and improves the vanadium extraction efficiency.

[0021] (3) The mixed batching of vanadium-titanium magnetite and vanadium shale coal fully utilizes the dual characteristics of vanadium shale coal as both fuel and reducing medium, providing the heat required for smelting while reducing iron and vanadium oxides. Combined with the three-stage vanadium extraction process in a side-blown furnace, a complex multi-vanadium resource synergistic processing system was constructed, realizing the comprehensive recovery and utilization of vanadium resources. Attached Figure Description

[0022] Figure 1 This is a front view of the overall structure of the apparatus used in the process of this application.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1. Side-blown furnace; 2. Feed inlet; 3. Flue; 4. Nozzle; 5. Slag discharge port; 6. Molten iron discharge port. Detailed Implementation

[0025] The following is in conjunction with the appendix Figure 1 This application will be described in further detail.

[0026] This application discloses a three-stage synergistic vanadium extraction process for vanadium-titanium magnetite and vanadium-bearing shale coal.

[0027] The process employs a side-blown furnace, with a feed inlet at the top of the first end and a flue at the top of the last end; the last end has an iron discharge port and a slag discharge port; multiple nozzles are installed on both side walls, with the nozzles aligned on both sides; all nozzles are perpendicular to the side of the side-blown furnace, and 3 / 4 of the total number of nozzles are used to simultaneously spray pulverized coal and oxygen-enriched air, while the nozzles that spray natural gas account for 1 / 4 of the total number; the two types of nozzles are arranged alternately on the side of the side-blown furnace, driving the material to stir and tumble while injecting fuel and oxygen-enriched air.

[0028] The process includes the following steps:

[0029] S1. Mix vanadium-titanium magnetite and vanadium shale ore evenly at a mass ratio of 100:(40-45), with the particle size of the mineral material being 200-300 mesh;

[0030] S2. The mixed mineral materials are added through the feed inlet of the side-blown furnace. Fuel (pulverized coal and natural gas) and oxygen-enriched air are then injected into the nozzles of the furnace for high-temperature smelting. This causes a reduction reaction of high-valence oxides such as iron and vanadium in the mineral materials, forming a melt containing vanadium iron and titanium slag. The smelting temperature is 1450-1550°C, the pulverized coal dosage is 100-150 kg / ton of ore, the oxygen concentration is 70-80 vol%, and the bed capacity of the side-blown furnace is 40-50 t / m³. 2 •d, the smelting reaction time is 2-3 hours, and the flue gas generated during the process is sent to the waste heat recovery system and purification device.

[0031] S3. After the smelting reaction is complete, stop feeding, inject natural gas and oxygen-enriched air, and raise the temperature of the side-blown furnace to 1500-1600°C. Then close the side-blown furnace nozzles and allow it to stand and clarify.

[0032] S4. When the temperature of the side-blown furnace drops to 1450-1550°C and the clarification time reaches 30-40 minutes, the titanium slag is discharged from the slag discharge port.

[0033] S5. After the titanium slag is separated, the nozzles are reopened to blow oxygen-enriched air into the side-blown furnace for vanadium extraction. The blowing temperature is controlled at 1300-1350°C, and the blowing time is 4-7 minutes. After the blowing is completed, the vanadium slag and molten iron are discharged to the ladle for separation and recovery. The vanadium-extracted molten iron is sent to the steelmaking system. One furnace with three sections completes one cycle, and the feeding is resumed.

[0034] The implementation principle of this process is as follows:

[0035] The process mainly involves the reduction smelting, clarification, and oxygen-enriched vanadium blowing of a mixed mineral feedstock of vanadium-titanium magnetite and vanadium shale coal in a single side-blown furnace. The principle of reduction smelting is that iron oxides (such as Fe3O4) in the mixed mineral feedstock of vanadium-titanium magnetite and vanadium shale coal are reduced to molten iron at high temperatures using C and CO, while high-valence vanadium is reduced to V2O3, which enters the molten iron to form vanadium-containing molten iron. During this high-temperature process, TiO2 is easily reduced to Ti in the strong reducing atmosphere of carbonaceous reducing agents, and then reacts with surrounding carbon and nitrogen to generate byproducts such as TiC and TiN, leading to increased slag viscosity and incomplete metal reduction reaction. To reduce the generation of byproducts such as TiC and ensure sufficient reduction smelting of iron and vanadium metals, while titanium remains stably in the smelting slag, this invention utilizes natural gas to partially replace pulverized coal, providing H2 through CH4 decomposition and reducing CO partial pressure, thereby achieving one-step reduction smelting of vanadium-titanium magnetite and vanadium shale coal in a side-blown furnace to form vanadium-containing molten iron and titanium slag. The principle of oxygen-enriched vanadium blowing is that V2O3 in vanadium-containing molten iron is oxidized to V2O5 by the O2 blown in at high temperature, thus precipitating out of the molten iron to form vanadium slag for vanadium recovery.

[0036] In the following embodiments, the hearth area of ​​the side-blown furnace is 12m². 2 Vanadium-titanium magnetite contains 56.0% Fe, 0.7% V2O5, and 8.0% TiO2; vanadium shale contains 0.58% V2O5, 51% carbon, and 5% volatile matter.

[0037] Example 1

[0038] 17.3 t / h of vanadium-titanium magnetite and 7.7 t / h of coal shale were added to a side-blown furnace. Then, 2.5 t / h of pulverized coal, natural gas, and 80% oxygen-enriched air were injected through nozzles for smelting, controlling the smelting temperature at 1450°C for 2 hours. After smelting, the side-blown furnace temperature was raised to 1500°C, the nozzles were then closed, and the furnace was allowed to settle for 30 minutes to separate the titanium slag from the molten iron, discharging the titanium slag into a slag ladle. Vanadium extraction was then performed by blowing 80% oxygen-enriched air through nozzles into the side-blown furnace at 1300°C for 4 minutes. The vanadium-extracted molten iron was discharged from the side-blown furnace into a ladle, and the vanadium slag was removed. The vanadium content of the vanadium-extracted molten iron was 0.08%, achieving a vanadium extraction rate of 80%.

[0039] Example 2

[0040] 15.5 t / h of vanadium-titanium magnetite and 6.5 t / h of coal shale were added to a side-blown furnace. Then, 3 t / h of pulverized coal, natural gas, and 75% oxygen-enriched air were injected through nozzles for smelting, controlling the smelting temperature at 1480°C for 2.5 hours. After smelting, the side-blown furnace temperature was raised to 1530°C, the nozzles were then closed, and the furnace was allowed to settle for 35 minutes to separate the titanium slag from the molten iron, discharging the titanium slag into a slag ladle. Vanadium extraction was then performed by blowing 75% oxygen-enriched air through nozzles into the side-blown furnace at 1320°C for 6 minutes. The vanadium-extracted molten iron was discharged from the electric furnace into a ladle, and the vanadium slag was removed. The vanadium content of the vanadium-extracted molten iron was 0.07%, and the vanadium extraction rate reached 83%.

[0041] Example 3

[0042] 14.2 t / h of vanadium-titanium magnetite and 5.8 t / h of coal shale were added to a side-blown furnace. Then, 3 t / h of pulverized coal, natural gas, and 70% oxygen-enriched air were injected through nozzles for smelting, controlling the smelting temperature at 1500°C for 3 hours. After smelting, the side-blown furnace temperature was raised to 1550°C, the nozzles were then closed, and the furnace was allowed to settle for 40 minutes to separate the titanium slag from the molten iron, discharging the titanium slag into a slag ladle. Vanadium extraction was then performed by blowing 70% oxygen-enriched air through nozzles into the side-blown furnace at 1350°C for 7 minutes. The vanadium-extracted molten iron was discharged from the electric furnace into a ladle, and the vanadium slag was removed. The vanadium content of the vanadium-extracted molten iron was 0.06%, and the vanadium extraction rate reached 85%.

[0043] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A three-stage synergistic vanadium extraction process for vanadium-titanium magnetite and vanadium-bearing shale coal, characterized in that: This process employs a side-blown furnace. The furnace has a feed inlet at the top of its first end and a flue at the top of its last end. The last end has a molten iron outlet and a slag outlet. Multiple nozzles are installed on both side walls, aligned symmetrically. The process includes the following steps: S1. Mix vanadium-titanium magnetite and vanadium shale ore evenly in a certain proportion; S2. Add the mixed mineral materials from the feed port of the side-blown furnace, and inject pulverized coal, natural gas and oxygen-enriched air into the side-blown furnace through the nozzle for high-temperature smelting, so that the iron and vanadium metal oxides in the raw materials undergo a reduction reaction and form a melt, namely vanadium-containing molten iron and titanium slag. S3. After the smelting reaction is complete, stop feeding, inject natural gas and oxygen-enriched air, raise the temperature, and then close the nozzle to allow it to stand and clarify. S4. After a certain period of clarification, discharge the titanium slag from the slag outlet; S5. After the titanium slag is separated, the nozzle is reopened to blow oxygen-enriched air into the side-blown furnace for oxygen-enriched blowing to extract vanadium. After the blowing is completed, the vanadium slag and molten iron are discharged to the molten iron ladle for separation and recovery. The molten iron after vanadium extraction is sent to the steelmaking system. One furnace and three sections complete one cycle, and the feeding is resumed.

2. The vanadium-titanium magnetite and vanadium-shale coal ore one-furnace three-stage synergistic vanadium extraction process according to claim 1, characterized in that: In step S1, vanadium-titanium magnetite and vanadium shale ore are uniformly mixed at a mass ratio of 100:(40-45), and the particle size of the mineral material is 200-300 mesh.

3. The vanadium-titanium magnetite and vanadium-shale coal ore one-furnace three-stage synergistic vanadium extraction process according to claim 2, characterized in that: In step S2, the smelting temperature is 1450-1550°C, the pulverized coal consumption is 100-150 kg / ton of ore, the oxygen enrichment concentration is 70-80 vol%, and the bed capacity of the side-blown furnace is 40-50 t / m³. 2 •d, the smelting reaction time is 2-3 hours, and the flue gas generated during the process is sent to the waste heat recovery system and purification device through the flue.

4. The vanadium-titanium magnetite and vanadium-shale coal ore one-furnace three-stage synergistic vanadium extraction process according to claim 3, characterized in that: All nozzles are perpendicular to the side of the side-blown furnace, and 3 / 4 of the total number of nozzles are used to simultaneously spray pulverized coal and oxygen-enriched air, while 1 / 4 of the nozzles spray natural gas. The two types of nozzles are arranged alternately on the side of the side-blown furnace, driving the material to stir and tumble while injecting fuel and oxygen-enriched air.

5. The vanadium-titanium magnetite and vanadium-shale coal ore one-furnace three-stage synergistic vanadium extraction process according to claim 4, characterized in that: In step S3, the temperature of the side-blown furnace needs to be increased to 1500-1600°C.

6. The vanadium-titanium magnetite and vanadium-shale coal ore one-furnace three-stage synergistic vanadium extraction process according to claim 5, characterized in that: In step S4, when the temperature of the side-blown furnace drops to 1450-1550°C and the clarification time reaches 30-40 minutes, the titanium slag is discharged from the slag discharge port.

7. The vanadium-titanium magnetite and vanadium-shale coal ore one-furnace three-stage synergistic vanadium extraction process according to claim 1, characterized in that: In step S5, the blowing temperature is controlled at 1300-1350°C and the blowing time is 4-7 minutes.

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