Method and device for removing vanadium from crude titanium tetrachloride

Abstract

The invention discloses a method and a device for removing vanadium from crude titanium tetrachloride, and belongs to the technical field of impurity removal and refining of inorganic matters. The method comprises the following steps: (1) preheating crude titanium tetrachloride liquid, then introducing hydrogen into the crude titanium tetrachloride liquid, and irradiating the crude titanium tetrachloride liquid by adopting ultraviolet light with the wavelength not greater than 274 nm, so that the crude titanium tetrachloride reacts with the hydrogen; and (2) evaporating the reaction product to obtain refined titanium tetrachloride and vanadium-rich slag. According to the method, hydrogen is activated through ultraviolet light to generate H free radical ions, the problem that hydrogen cannot directly react with titanium tetrachloride and vanadium oxytrichloride is successfully solved, the efficient clean reducing agent hydrogen is used for removing vanadium from titanium tetrachloride, the safety and environmental friendliness of the vanadium removal process are effectively improved, the vanadium removal effect is improved, and the method is suitable for industrial production. The titanium tetrachloride with higher purity and the vanadium-rich slag with higher vanadium grade are obtained, an excellent foundation is laid for subsequent use of the titanium tetrachloride and the vanadium-rich slag, and a new thought is provided for vanadium removal of the titanium tetrachloride.

Description

Technical Field

[0001] This invention belongs to the field of inorganic purification technology, and relates to a method and apparatus for removing vanadium from crude titanium tetrachloride. Background Technology

[0002] Titanium tetrachloride (TiCl4) is a raw material for producing sponge titanium via the magnesothermic process. It is usually obtained through a chlorination reaction. However, crude titanium tetrachloride contains a large amount of impurities such as Al, Fe, V, and Mn. Therefore, it is necessary to refine the crude titanium tetrachloride to remove impurities and improve its purity so that it meets the raw material requirements for titanium industry production.

[0003] Vanadium (V) in crude titanium tetrachloride usually exists in the form of vanadium oxychloride (VOCl3), which has a similar boiling point to titanium tetrachloride and cannot be removed along with other impurities during physical distillation. Therefore, chemical methods are typically used to remove V from crude titanium tetrachloride. Commonly used chemical methods include vanadium removal using aluminum powder and vanadium removal using organic materials. While aluminum powder vanadium removal is a mature process, it involves a long operation process and requires subsequent aluminum removal, further increasing the complexity and cost. Moreover, its vanadium removal effect is relatively limited, and the vanadium slag after vanadium removal has a low vanadium grade, making separation and purification difficult and resulting in the ineffective utilization and waste of vanadium resources. The vanadium removal process using organic materials requires the use of organic materials, which can easily create significant environmental pressure. At the same time, the vanadium removal process generates a large amount of complex residue and waste liquid. The residue will adhere to the vessel walls, block the pipes, and affect heat transfer. The waste liquid is difficult to treat and is not conducive to environmental protection. Furthermore, the process introduces additional organic matter that dissolves in titanium tetrachloride, resulting in the introduction of other impurities into the titanium tetrachloride after vanadium removal, which cannot achieve a good impurity removal effect. Using the aforementioned titanium tetrachloride as a raw material will lead to problems such as excessive carbon content in the finished sponge titanium, thereby increasing the defect rate of sponge titanium products.

[0004] Patent application number 201410075517.7 discloses a method for removing vanadium impurities from crude titanium tetrachloride. This method involves adding magnesium hydride powder to reduce vanadium trichloride in crude titanium tetrachloride to vanadium dichloride. Then, utilizing the boiling points of vanadium dichloride and titanium tetrachloride, or the solubility characteristics of vanadium dichloride in titanium tetrachloride, the vanadium dichloride is separated from the titanium tetrachloride, thereby removing vanadium (V) from the titanium tetrachloride. However, magnesium hydride is a toxic and irritating substance that can irritate the eyes, respiratory system, and skin, posing significant safety and environmental risks during its use.

[0005] Therefore, it is necessary to provide a method and apparatus for vanadium removal from crude titanium tetrachloride, which can improve the environmental friendliness and safety of the vanadium removal process, enhance the vanadium removal efficiency, increase the purity of titanium tetrachloride after vanadium removal, and improve the vanadium grade in vanadium-rich slag, thus laying a good foundation for the subsequent use of titanium tetrachloride as a raw material and the separation and purification of vanadium. Summary of the Invention

[0006] To overcome the problems in the prior art, this invention uses ultraviolet light to induce the breakage of hydrogen molecular bonds, generating H· radical ions. The H· radical ions react with TiCl4 to generate TiCl3. TiCl3 further reacts with VOCl3 to generate vanadium oxychloride (VOCl2). At the same time, the H· radical ions also react with VOCl3 to generate VOCl2. Since VOCl2 is insoluble in TiCl4, VOCl2 can be separated from TiCl4 by solid-liquid separation, thus achieving vanadium removal.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution: This invention provides a method for removing vanadium from crude titanium tetrachloride, the method comprising the following steps: (1) Preheat the crude titanium tetrachloride liquid, then introduce hydrogen gas into the crude titanium tetrachloride liquid, and irradiate the crude titanium tetrachloride liquid with ultraviolet light with a wavelength of no more than 274 nm so that the crude titanium tetrachloride reacts with hydrogen gas.

[0008] Hydrogen is a highly efficient and clean reducing agent. Compared to organic matter and magnesium hydride, hydrogen itself is non-toxic and non-irritating, and will not pollute the environment. Therefore, using hydrogen as a reducing agent has high safety and environmental friendliness.

[0009] However, although the Gibbs free energy of titanium tetrachloride and hydrogen is negative at 100℃, the spontaneous reaction between hydrogen and titanium tetrachloride and vanadium oxychloride requires overcoming extremely high potential energy. Therefore, hydrogen cannot directly react with titanium tetrachloride and vanadium oxychloride. Furthermore, because hydrogen molecules are connected by covalent bonds with a bond energy of approximately 436 kJ / mol, according to the second law of photochemistry, irradiation with ultraviolet light with a wavelength not exceeding 274 nm can break the hydrogen molecules, generating H· radical ions. These H· radical ions can directly react with TiCl4 and VOCl3.

[0010] The main chemical reactions involved in the impurity removal process of this invention are as follows: TiCl4 + H· → TiCl3 + HCl TiCl3 + VOCl3 → VOCl2 + TiCl4 VOCl3 + H· → VOCl2 + HCl (2) The product after the reaction is subjected to solid-liquid separation to obtain refined titanium tetrachloride and vanadium-rich slag.

[0011] You can usually determine whether a reaction has been completed by choosing one of the following methods: 1. Observe the color change. Pure titanium tetrachloride is a colorless and transparent liquid, while titanium tetrachloride containing vanadium is a yellow liquid. The higher the vanadium content, the darker the color. 2. The vanadium content in titanium tetrachloride was determined by ICP sampling.

[0012] Preferably, in step (1), the ultraviolet light wavelength is 200~260nm.

[0013] Preferably, in step (1), the preheating temperature is 50~120℃.

[0014] The preheating temperature is further optimized to be 80~110℃.

[0015] Preferably, in step (1), the reaction pressure is 0.1~0.3MPa.

[0016] Preferably, in step (1), the flow rate of hydrogen gas is 0.5~1.0 L / min.

[0017] In another aspect, the present invention provides an apparatus for the above-mentioned vanadium removal method, the vanadium removal apparatus comprising a crude titanium tetrachloride preheating container 1, a reactor 2, and a solid-liquid separator 3, wherein the outlet of the crude titanium tetrachloride preheating container 1 is connected to the inlet of the reactor 2, the outlet of the reactor 2 is connected to the inlet of the solid-liquid separator 3, an ultraviolet light source 4 is installed on the inner wall of the reactor 2, and the reactor 2 is connected to a hydrogen source.

[0018] Due to the chemical properties of titanium tetrachloride, evaporation is usually used in production practice to distill titanium tetrachloride and separate it from vanadium-rich slag. Therefore, the solid-liquid separator 3 is usually an evaporation kettle.

[0019] Reactor 2 can be a conventional photocatalytic reactor.

[0020] Preferably, the ultraviolet light source 4 includes one of a mercury lamp, a xenon lamp, or a UVC-LED.

[0021] Preferably, a hydrogen distributor 5 is installed inside the reactor 2, and the hydrogen distributor 5 is connected to a hydrogen source.

[0022] Preferably, the reactor outlet is provided with an observation window 6.

[0023] The beneficial effects of this invention are: 1. This invention is the first to use hydrogen in the vanadium removal process of titanium tetrachloride, which effectively improves the safety and environmental friendliness of the titanium tetrachloride vanadium removal process.

[0024] 2. This invention uses ultraviolet light to induce hydrogen gas to generate H· free radical ions, thereby successfully using hydrogen as a cleaning reducing agent to remove vanadium from titanium tetrachloride. During the vanadium removal process, ultraviolet light does not introduce any impurities or generate any pollution, which can effectively ensure the safety and environmental friendliness of the vanadium removal process, while ensuring excellent vanadium removal effect.

[0025] 3. The TiCl3 generated in this invention reacts with VOCl3 to produce TiCl4 and VOCl2. Therefore, only HCl gas byproducts are generated during the vanadium removal process. The byproducts are of a single type and are easy to process. Furthermore, HCl gas is almost insoluble in TiCl4 and does not require special separation, which helps to simplify the vanadium removal process of titanium tetrachloride.

[0026] 4. In the vanadium removal process, this invention uses only ultraviolet light and hydrogen gas, without introducing other new impurities. The reaction is more thorough, resulting in high-purity TiCl4 and vanadium-rich slag with a high vanadium grade, which facilitates subsequent separation and purification, and enables efficient recycling of vanadium resources.

[0027] 5. The process of this invention is simple and easy to implement, and the reaction conditions are relatively mild, making it suitable for industrial application. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the vanadium removal method of the present invention; Figure 2 This is a schematic diagram of the overall structure of the vanadium removal device of the present invention; In the figure, 1-Titanium tetrachloride preheating container, 2-Reactor, 3-Solid-liquid separator, 4-Ultraviolet light source, 5-Hydrogen distributor, 6-Observation window. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0030] Example 1 This embodiment uses the following method to remove vanadium from crude titanium tetrachloride: (1) Add the crude titanium tetrachloride (containing 0.1 wt% VOCl3) after distillation to the titanium tetrachloride preheating container 1, preheat the crude titanium tetrachloride to 90°C, and then pump the preheated crude titanium tetrachloride into the reactor 2 (pumping is a conventional technique and is not shown in the figure). Introduce hydrogen into the crude titanium tetrachloride at a flow rate of 0.5 L / min (the hydrogen is introduced into the crude titanium tetrachloride through the hydrogen distributor 5 so that the hydrogen is more evenly distributed in the crude titanium tetrachloride), so that the reaction pressure is 0.1 MPa, and at the same time turn on the ultraviolet light source 4 (in this embodiment, the ultraviolet light source emits ultraviolet light with a wavelength of 230 nm). The reaction system begins to react and VOCl2 precipitate is generated. (2) After the reaction is completed, the product (slurry) is pumped to the solid-liquid separator 3 (pumping is a conventional technology and is not shown in the figure). Solid-liquid separation is carried out by evaporation. The solid after separation is vanadium-rich slag and the liquid is refined titanium tetrachloride.

[0031] During the pumping process, the discharge of the reaction product can be observed through observation window 6.

[0032] The HCl gas produced during the reaction is insoluble in TiCl4 and will escape from TiCl4. The HCl gas can be collected and treated uniformly (the reactor is equipped with an HCl gas exhaust port, which is a conventional technology and is not shown in the figure).

[0033] In the refined titanium tetrachloride obtained in this embodiment, the vanadium content is reduced to below 5 ppm, and the vanadium removal rate exceeds 99%.

[0034] XRD analysis of vanadium-rich slag showed that the main component was VOCl2, and the vanadium content in the vanadium-rich slag exceeded 50%.

[0035] Example 2 This embodiment uses the following method to remove vanadium from crude titanium tetrachloride: (1) Add the crude titanium tetrachloride (containing 0.1 wt% VOCl3) after distillation to the titanium tetrachloride preheating container 1, preheat the crude titanium tetrachloride to 110°C, and then pump the preheated crude titanium tetrachloride to the reactor 2. Introduce hydrogen gas into the crude titanium tetrachloride at a flow rate of 1.0 L / min to make the reaction pressure 0.3 MPa. At the same time, turn on the ultraviolet light source 4 (in this embodiment, the ultraviolet light source emits ultraviolet light with a wavelength of 260 nm). The reaction system begins to react and VOCl2 precipitate is generated. (2) After the reaction is completed, the product (slurry) is pumped to the solid-liquid separator 3 for solid-liquid separation. The solid after separation is vanadium-rich slag and the liquid is refined titanium tetrachloride.

[0036] The HCl gas produced during the reaction is insoluble in TiCl4 and will escape from TiCl4. The HCl gas can be collected and treated uniformly.

[0037] The vanadium removal rate in this embodiment exceeds 99.5%.

[0038] The main component of vanadium-rich slag is VOCl2, and the vanadium content in vanadium-rich slag exceeds 50%.

[0039] Example 3 This embodiment uses the following method to remove vanadium from crude titanium tetrachloride: (1) Add the crude titanium tetrachloride (containing 0.1 wt% VOCl3) after distillation to the titanium tetrachloride preheating container 1, preheat the crude titanium tetrachloride to 80°C, and then pump the preheated crude titanium tetrachloride to the reactor 2. Introduce hydrogen gas into the crude titanium tetrachloride at a flow rate of 0.7 L / min to make the reaction pressure 0.25 MPa. At the same time, turn on the ultraviolet light source 4 (in this embodiment, the ultraviolet light source emits ultraviolet light with a wavelength of 200 nm). The reaction system begins to react and VOCl2 precipitate is generated. (2) After the reaction is completed, the product (slurry) is pumped to the solid-liquid separator 3 for solid-liquid separation. The solid after separation is vanadium-rich slag and the liquid is refined titanium tetrachloride.

[0040] In this embodiment, the vanadium removal effect is similar to that in Example 1, and the vanadium grade in the vanadium-rich slag is similar to that in Example 1.

[0041] Example 4 This embodiment uses the following method to remove vanadium from crude titanium tetrachloride: (1) Add the crude titanium tetrachloride (containing 0.1 wt% VOCl3) after distillation to the titanium tetrachloride preheating container 1, preheat the crude titanium tetrachloride to 50°C, and then pump the preheated crude titanium tetrachloride to the reactor 2. Introduce hydrogen gas into the crude titanium tetrachloride at a flow rate of 0.6 L / min to make the reaction pressure 0.2 MPa. At the same time, turn on the ultraviolet light source 4 (in this embodiment, the ultraviolet light source emits ultraviolet light with a wavelength of 100 nm). The reaction system begins to react and VOCl2 precipitate is generated. (2) After the reaction is completed, the product (slurry) is pumped to the solid-liquid separator 3 for solid-liquid separation. The solid after separation is vanadium-rich slag and the liquid is refined titanium tetrachloride.

[0042] In this embodiment, the vanadium removal effect is similar to that in Example 1, and the vanadium grade in the vanadium-rich slag is similar to that in Example 1.

[0043] Example 5 This embodiment uses the following method to remove vanadium from crude titanium tetrachloride: (1) Add the crude titanium tetrachloride (containing 0.1 wt% VOCl3) after distillation to the titanium tetrachloride preheating container 1, preheat the crude titanium tetrachloride to 120°C, and then pump the preheated crude titanium tetrachloride to the reactor 2. Introduce hydrogen gas into the crude titanium tetrachloride at a flow rate of 0.8 L / min to make the reaction pressure 0.25 MPa. At the same time, turn on the ultraviolet light source 4 (in this embodiment, the ultraviolet light source emits ultraviolet light with a wavelength of 274 nm). The reaction system begins to react and VOCl2 precipitate is generated. (2) After the reaction is completed, the product (slurry) is pumped to the solid-liquid separator 3 for solid-liquid separation. The solid after separation is vanadium-rich slag and the liquid is refined titanium tetrachloride.

[0044] In this embodiment, the vanadium removal effect is similar to that in Example 1, and the vanadium grade in the vanadium-rich slag is similar to that in Example 1.

[0045] In summary, this invention successfully solves the problem that hydrogen cannot directly react with titanium tetrachloride and vanadium oxychloride by activating hydrogen gas with ultraviolet light to generate H· radical ions. It is the first time that hydrogen gas, a highly efficient and clean reducing agent, has been used for vanadium removal from titanium tetrachloride. This effectively improves the safety and environmental friendliness of the vanadium removal process while enhancing the vanadium removal efficiency, resulting in titanium tetrachloride with higher purity and vanadium-rich slag with higher vanadium grade. This lays an excellent foundation for the subsequent use of titanium tetrachloride and vanadium-rich slag, and also provides a new approach to vanadium removal from titanium tetrachloride.

[0046] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A method for removing vanadium from crude titanium tetrachloride, characterized in that: The method includes the following steps: (1) Preheat the crude titanium tetrachloride liquid to the target temperature, then introduce hydrogen into the crude titanium tetrachloride liquid and irradiate the crude titanium tetrachloride liquid with ultraviolet light with a wavelength of no more than 274 nm so that the crude titanium tetrachloride reacts with hydrogen. (2) The product after the reaction is subjected to solid-liquid separation to obtain refined titanium tetrachloride and vanadium-rich slag.

2. The vanadium removal method according to claim 1, characterized in that: In step (1), the ultraviolet light wavelength is 200~260nm.

3. The vanadium removal method according to claim 1, characterized in that: In step (1), the preheating temperature is 50~120℃.

4. The vanadium removal method according to claim 1, characterized in that: In step (1), the reaction pressure is 0.1~0.3MPa.

5. The vanadium removal method according to claim 1, characterized in that: In step (1), the flow rate of hydrogen gas is 0.5~1.0 L / min.

6. A device for removing vanadium from crude titanium tetrachloride, characterized in that, The vanadium removal device is used in the vanadium removal method according to any one of claims 1-5. The vanadium removal device includes a crude titanium tetrachloride preheating container (1), a reactor (2), and a solid-liquid separator (3). The outlet of the crude titanium tetrachloride preheating container (1) is connected to the inlet of the reactor (2). The outlet of the reactor (2) is connected to the inlet of the solid-liquid separator (3). An ultraviolet light source (4) is installed on the inner wall of the reactor (2). The reactor (2) is connected to a hydrogen source.

7. The vanadium removal device according to claim 6, characterized in that: The ultraviolet light source (4) includes one of mercury lamp, xenon lamp, and UVC-LED.

8. The vanadium removal device according to claim 6, characterized in that: A hydrogen distributor (5) is installed inside the reactor (2), and the hydrogen distributor (5) is connected to a hydrogen source.

9. The vanadium removal device according to claim 6, characterized in that: An observation window (6) is provided on the pipe connecting the outlet of the reactor (2) and the inlet of the solid-liquid separator (3).

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