A method for removing vanadium from crude titanium tetrachloride using a synergistic catalyst

Abstract

The present invention relates to a method for removing vanadium from crude titanium tetrachloride using a synergistic catalyst, belonging to the technical field of organic matter-based titanium tetrachloride purification. Organic matter and crude titanium tetrachloride are mixed and stirred at room temperature to obtain a mixed liquid; the synergistic catalyst is added to the mixed liquid, the temperature is raised to 100-130°C, and the mixture is stirred for 1-4 hours to fully react; the synergistic catalyst is composed of an oxide support, a metal chloride complexing agent, and an active metal; the temperature is further raised to 140-160°C, and the titanium tetrachloride is distilled to obtain refined titanium tetrachloride and an easily handled residue. By optimizing the selection of organic matter and adding the synergistic catalyst, the present invention can reduce the formation of agglomerated carbon-containing small molecules, lower the carbon content in the titanium sponge, and thus improve the rigidity and production quality of the titanium sponge.

Description

Technical Field

[0001] The invention relates to a method for removing vanadium from crude titanium tetrachloride using a synergistic catalyst, belonging to the technical field of refining titanium tetrachloride from organic matter. Background Art

[0002] Purification of titanium tetrachloride is a critical step in the production of high-quality titanium dioxide and titanium sponge. Organic purification methods are widely used due to their abundant raw materials, low cost, non-toxicity, and ease of operation. However, this method also presents challenges. One major issue is the high carbon content in the resulting titanium sponge, primarily due to the varying structures of the residues produced when different organic compounds react with crude titanium tetrachloride. Common organic compounds, such as fatty acids and vegetable oils, have relatively low cracking temperatures and readily form small carbon molecules. These small molecules, as they evaporate from the refined titanium tetrachloride, are enriched fourfold in the titanium sponge, reducing its rigidity and compromising its production quality. Furthermore, the residues generated by common organic reagents, such as fatty acids and vegetable oils, are difficult to remove, adding complexity to the production process. Selecting organic compounds that are less susceptible to cracking can reduce the formation of small carbon molecules and residues, but this can slow the vanadium removal rate and potentially increase production costs. To address these issues, the development of an efficient synergistic catalytic agent is crucial. Such a synergistic catalytic agent can increase the cracking rate of organic compounds, thereby reducing organic compound usage and modifying the structure of the residue.

[0003] Quan Hui et al., published in CN111087017A, invented a method for removing vanadium from crude titanium tetrachloride. This method involves mixing cracked diesel with hydrogen and then hydrogenating it in the presence of a hydrogenation catalyst. The reaction effluent is separated to produce a liquid phase. The crude titanium tetrachloride and liquid phase streams are then brought into countercurrent contact in an evaporation tower for full vanadium removal. This method utilizes a composition rich in an ideal vanadium removal component to achieve excellent vanadium removal from titanium tetrachloride, addressing the technical issue of using organic matter for vanadium removal in existing processes, which produces a large amount of residue that affects heat transfer. The hydrogenation reaction conditions disclosed in this invention are shown in Table 1.

[0004] Table 1

[0005]

[0006] The invention, with publication number CN111087017A, has a distillation range of 150°C to 370°C for catalytic cracking diesel. The high reaction temperature of the hydrogenation catalyst used for vanadium removal results in high energy consumption and high costs, making it unsuitable for practical production. Furthermore, the addition of hydrogen catalyst to the catalytically cracked diesel increases production costs and slows vanadium removal efficiency. The present invention, through the development and application of a highly efficient synergistic catalytic reagent, can achieve more efficient organic matter cracking in the titanium tetrachloride refining process, reduce residue generation, and lower the carbon content in titanium sponge, thereby improving the rigidity and production quality of titanium sponge. This is of great significance for the production of high-quality titanium dioxide and titanium sponge. Summary of the Invention

[0007] To address the aforementioned problems and shortcomings of the prior art, the present invention provides a method for removing vanadium from crude titanium tetrachloride using a synergistic catalyst. By optimizing the selection of organic matter and adding a synergistic catalyst, the present invention reduces the formation of agglomerated carbon-containing small molecules and lowers the carbon content in titanium sponge, thereby improving the rigidity and production quality of the titanium sponge. This invention is achieved through the following technical solutions.

[0008] A method for removing vanadium from crude titanium tetrachloride using a synergistic catalyst comprises the following steps:

[0009] (1) mixing an organic matter with crude titanium tetrachloride at room temperature and stirring to obtain a mixed solution;

[0010] (2) adding a synergistic catalyst to the mixed solution, heating it to 100-130°C, and stirring it for 1-4 hours to fully react; wherein the synergistic catalyst is composed of an oxide support, a metal chloride complexing agent, and a small amount of active metal;

[0011] (3) Continue to raise the temperature to 140-160°C to distill titanium tetrachloride to obtain refined titanium tetrachloride and an easily handled residue.

[0012] The organic matter in step (1) is one of hydrocarbon polymers, oil organic matter, hydrocarbon chain organic matter, or a mixture of any of the above organic matter and crude titanium tetrachloride, and the mass ratio of the organic matter to the crude titanium tetrachloride is 0.5 to 3:1000.

[0013] The hydrocarbon-containing polymer in step (1) is polyethylene, polypropylene or polyvinyl chloride.

[0014] The oily organic matter in step (1) is mineral oil, animal oil, vegetable oil or oleic acid.

[0015] In the step (2), the oxide carrier in the synergistic catalyst is Al2O3, and the amount of the oxide carrier added is such that the mass ratio of the oxide carrier to the crude titanium tetrachloride is 0.1 to 2.5:1000.

[0016] In the step (2), the metal chloride complexing agent in the synergistic catalyst is a chloride containing a valence state transition, the chloride containing a valence state transition is FeCl2, FeCl3, CuCl or CuCl2, and the amount of the metal chloride complexing agent added is a mass ratio of 0.5 to 3:1000 to the crude titanium tetrachloride.

[0017] In the step (2), the active metal is Fe or Ti, and the mass ratio of the active metal added to the crude titanium tetrachloride is 0.5 to 2:1000.

[0018] The beneficial effects of the present invention are:

[0019] (1) The oxide support used in the synergistic catalyst of the present invention can accelerate the reaction rate and reduce the reaction temperature. In addition, the synergistic catalyst of the present invention can change the product structure, make the residue easier to handle, and be more conducive to the removal of vanadium from organic matter.

[0020] (2) The structure of the residue product of the present invention is changed, and the chain-like, porous residue morphology is generated, that is, the carbon-containing small molecules that are not easy to agglomerate, which will further reduce the carbon content in sponge titanium in the later stage.

[0021] (3) The metal chloride complexing agent used in the synergistic catalyst of the present invention can better catalyze the decomposition of organic carbon and hydrogen atoms in the form of a complex due to the change in valence state, reducing VOCl3 to VOCl2 or VCl3 to remove vanadium.

[0022] (4) A small amount of metal can be used to reduce titanium tetrachloride to low-valent titanium TiCl3 under the other effects of the synergistic catalyst, and low-valent titanium converts VOCl3 into VOCl2, thereby promoting the vanadium removal rate.

[0023] (5) The synergistic catalyst used in the present invention mainly increases the vanadium removal rate and reduces the amount of organic matter by catalyzing the cracking of organic matter. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a SEM morphology characterization image of the residue in Example 1 of the present invention;

[0025] Figure 2 This is a SEM morphology characterization image of the residue in Example 2 of the present invention;

[0026] Figure 3 This is a SEM morphology characterization diagram of the residue in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0028] Example 1

[0029] The method for removing vanadium from crude titanium tetrachloride using a synergistic catalyst comprises the following steps:

[0030] (1) mixing an organic substance (polyethylene organic substance containing hydrocarbon polymer) with 1000 g of crude titanium tetrachloride (wherein the V content is mainly VOCl3, with a volume ratio of 0.002785%) at a mass ratio of 2:1000 at room temperature to obtain a mixed solution;

[0031] (2) adding a synergistic catalyst to the mixed solution, heating it to 115°C, and stirring it for 2 hours to fully react; wherein the synergistic catalyst is a mixture of Al2O3, FeCl3 and a small amount of Fe, and the mass ratio of the oxide carrier to the crude titanium tetrachloride is 0.5:1000; the amount of the metal chloride complexing agent added is 1:1000 to the crude titanium tetrachloride; and the amount of the active metal added is 0.5:1000 to the crude titanium tetrachloride;

[0032] (3) Continue heating to 140°C to distill titanium tetrachloride to obtain refined titanium tetrachloride and an easily handled residue.

[0033] In this example, the refined titanium tetrachloride obtained was subjected to ICP detection for V element content. The detection results are shown in Table 2. From Table 2, it can be seen that the volume ratio of V element is 0.0000013%, and the vanadium removal rate is 99.95%.

[0034] The residue in this embodiment was characterized by SEM morphology, and the SEM morphology is shown in FIG. Figure 1 As shown in the figure, the residue morphology is long-chain fiber.

[0035] Example 2

[0036] The method for removing vanadium from crude titanium tetrachloride using a synergistic catalyst comprises the following steps:

[0037] (1) mixing an organic substance (a polypropylene organic substance containing a hydrocarbon polymer) with 1000 g of crude titanium tetrachloride (wherein the V content is mainly VOCl3, with a volume ratio of 0.002785%) at a mass ratio of 2:1000 at room temperature to obtain a mixed solution;

[0038] (2) adding a synergistic catalyst to the mixed solution, heating it to 120°C, and stirring for 2 hours to fully react; wherein the synergistic catalyst is a mixture of Al2O3, FeCl3 and a small amount of Fe, and the mass ratio of the oxide support to the crude titanium tetrachloride is 1:1000; the mass ratio of the metal chloride complexing agent to the crude titanium tetrachloride is 1.5:1000; the mass ratio of the active metal to the crude titanium tetrachloride is 0.5:1000;

[0039] (3) Continue heating to 140°C to distill titanium tetrachloride to obtain refined titanium tetrachloride and an easily handled residue.

[0040] In this example, the refined titanium tetrachloride obtained was subjected to ICP detection for V element content. The detection results are shown in Table 2. From Table 2, it can be seen that the volume ratio of V element is 0.0000008%, and the vanadium removal rate is 99.97%.

[0041] The residue in this embodiment was characterized by SEM morphology, and the SEM morphology is shown in FIG. Figure 2 As shown, the residue morphology is long chain short chain.

[0042] Example 3

[0043] The method for removing vanadium from crude titanium tetrachloride using a synergistic catalyst comprises the following steps:

[0044] (1) Mixing organic matter (oleic acid organic matter of oil) and 1000 g of crude titanium tetrachloride (V content of which is mainly VOCl3, with a volume ratio of 0.002785%) at a mass ratio of 1.5:1000 at room temperature to obtain a mixed solution;

[0045] (2) adding a synergistic catalyst to the mixed solution, heating it to 100°C, and stirring it for 1 hour to fully react; wherein the synergistic catalyst is a mixture of Al2O3, FeCl3 and a small amount of Fe, and the mass ratio of the oxide support to the crude titanium tetrachloride is 1:1000; the mass ratio of the metal chloride complexing agent to the crude titanium tetrachloride is 2:1000; the mass ratio of the active metal to the crude titanium tetrachloride is 1:1000;

[0046] (3) Continue heating to 140°C to distill titanium tetrachloride to obtain refined titanium tetrachloride and an easily handled residue.

[0047] In this example, the refined titanium tetrachloride obtained was subjected to ICP detection for V element content. The detection results are shown in Table 2. From Table 2, it can be seen that the volume ratio of V element is 0.0000018%, and the vanadium removal rate is 99.94%.

[0048] Comparative Example 1

[0049] The method for removing vanadium from crude titanium tetrachloride using a synergistic catalyst comprises the following steps:

[0050] (1) mixing an organic substance (polyethylene organic substance containing hydrocarbon polymer) with 1000 g of crude titanium tetrachloride (wherein the V content is mainly VOCl3, with a volume ratio of 0.002785%) at a mass ratio of 4:1000 at room temperature to obtain a mixed solution;

[0051] (2) Add Al2O3 to the mixed solution, heat to 115°C, and stir for 2 hours to fully react; wherein the mass ratio of the oxide support to the crude titanium tetrachloride is 2:1000;

[0052] (3) Continue heating to 140°C to distill titanium tetrachloride to obtain refined titanium tetrachloride and an easily handled residue.

[0053] In this comparative example, the refined titanium tetrachloride obtained was subjected to ICP detection for V element content. The detection results are shown in Table 2. From Table 2, it can be seen that the volume ratio of V element is 0.0000432%, and the vanadium removal rate is 98.45%.

[0054] The residue in this embodiment was characterized by SEM morphology, and the SEM morphology is shown in FIG. Figure 3 As shown, the residue morphology is a long chain of spheres.

[0055] Comparative Example 2

[0056] The method for removing vanadium from crude titanium tetrachloride using a synergistic catalyst comprises the following steps:

[0057] (1) mixing an organic substance (a polypropylene organic substance containing a hydrocarbon polymer) with 1000 g of crude titanium tetrachloride (wherein the V content is mainly VOCl3, with a volume ratio of 0.002785%) at a mass ratio of 5:1000 at room temperature to obtain a mixed solution;

[0058] (2) adding FeCl3 to the mixed solution, heating to 120°C, and stirring for 2 hours to fully react; wherein the amount of the metal chloride complexing agent added is a mass ratio of 3:1000 to the crude titanium tetrachloride;

[0059] (3) Continue heating to 140°C to distill titanium tetrachloride to obtain refined titanium tetrachloride and an easily handled residue.

[0060] In this example, the refined titanium tetrachloride obtained was subjected to ICP testing for V content. The test results are shown in Table 2. From Table 2, it can be seen that the volume ratio of V element is 0.0000263%, and the vanadium removal rate is 99.05%.

[0061] Comparative Example 3

[0062] The method for removing vanadium from crude titanium tetrachloride using a synergistic catalyst comprises the following steps:

[0063] (1) Mixing organic matter (oleic acid organic matter of oil) and 1000 g of crude titanium tetrachloride (V content of which is mainly VOCl3, with a volume ratio of 0.002785%) at a mass ratio of 5:1000 at room temperature to obtain a mixed solution;

[0064] (2) Add a small amount of Fe to the mixed solution, heat it to 100°C, and stir for 1 hour to fully react; the mass ratio of the active metal added to the crude titanium tetrachloride is 1:1000;

[0065] (3) Continue heating to 140°C to distill titanium tetrachloride to obtain refined titanium tetrachloride and an easily handled residue.

[0066] In this example, the refined titanium tetrachloride obtained was subjected to ICP testing for V content. The test results are shown in Table 2. From Table 2, it can be seen that the volume ratio of V element is 0.0000289%, and the vanadium removal rate is 98.96%.

[0067]

[0068] According to the results of the embodiments and comparative examples, it can be seen that when any one of the synergistic catalysts is added alone, the required organic content increases, and the resulting residue morphology is aggregated together through spherical connections, which easily produces small molecules of carbon, and is easily enriched in the titanium sponge with the distillation of titanium tetrachloride. The simultaneous addition of three synergistic catalysts in different proportions reduces the amount of organic matter added, and the resulting residue morphology is chain-like with large pores, which is not easy to agglomerate to form small carbon-containing molecules, thereby reducing the carbon content in the titanium sponge. The present invention discloses a method for removing vanadium from crude titanium tetrachloride using a synergistic catalytic agent, which catalyzes the cracking of stable carbon-hydrogen-containing polymeric organic matter, effectively reduces the amount of organic matter added, changes the residue morphology, and reduces the carbon content in the titanium sponge.

[0069] The above describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the scope of the present invention.

Claims

1. A method for removing vanadium from crude titanium tetrachloride using a synergistic catalyst, characterized in that the steps include: (1) Mixing organic matter and crude titanium tetrachloride at room temperature and stirring to obtain a mixed solution; (2) Add a synergistic catalyst to the mixed solution, raise the temperature to 100-130°C, and stir for 1-4 hours to fully react; wherein the synergistic catalyst is composed of an oxide support, a metal chloride complexing agent, and an active metal; (3) Continue to raise the temperature to 140-160°C to distill titanium tetrachloride to obtain refined titanium tetrachloride and an easily handled residue; The organic matter in step (1) is one of hydrocarbon polymers, oil-based organic matter, hydrocarbon chain organic matter, or a mixture of any of the above; In the step (2), the oxide carrier in the synergistic catalyst is Al2O3; In the step (2), the metal chloride complexing agent in the synergistic catalyst is FeCl2, FeCl3, CuCl or CuCl2; The active metal in step (2) is Fe or Ti.

2. The method for removing vanadium from crude titanium tetrachloride using a synergistic catalyst according to claim 1, wherein: In the step (1), the mass ratio of the organic matter to the crude titanium tetrachloride is 0.5-3:1000.

3. The method for removing vanadium from crude titanium tetrachloride using a synergistic catalyst according to claim 2, wherein: The hydrocarbon-containing polymer in step (1) is polyethylene, polypropylene or polyvinyl chloride.

4. The method for removing vanadium from crude titanium tetrachloride using a synergistic catalyst according to claim 2, wherein: The oily organic matter in step (1) is mineral oil, animal oil, vegetable oil or oleic acid.

5. The method for removing vanadium from crude titanium tetrachloride using a synergistic catalyst according to claim 1, wherein: The amount of oxide support added in step (2) is such that the mass ratio of oxide support to crude titanium tetrachloride is 0.1-2.5:1000.

6. The method for removing vanadium from crude titanium tetrachloride using a synergistic catalyst according to claim 1, wherein: In the step (2), the mass ratio of the metal chloride complexing agent added to the crude titanium tetrachloride is 0.5-3:1000.

7. The method for removing vanadium from crude titanium tetrachloride using a synergistic catalyst according to claim 1, wherein: The mass ratio of the active metal added in step (2) to the crude titanium tetrachloride is 0.5-2:1000.

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