A method for removing vanadium impurity from crude titanium tetrachloride

Abstract

The present invention discloses a method for removing vanadium impurities from crude titanium tetrachloride, belonging to the technical field of refined titanium tetrachloride. The present invention uses an electrochemical method to produce nano-scale TiH2. Specifically, the method comprises: using an active metal hydride as an anode electrode, graphite as a cathode electrode, and placing an anion exchange membrane between the cathode and anode. An anhydrous organic solvent and an active metal chloride are added to the anode electrode; H2 is introduced into the cathode electrode, and TiCl4 and a surfactant are added. Finally, nano-scale TiH2 is produced on the cathode electrode. The nano-scale TiH2 produced by the present invention has strong reducing ability and can therefore be used to remove vanadium impurities from crude titanium tetrachloride. The present invention provides a new method for producing nano-scale TiH2 and removing vanadium impurities from crude titanium tetrachloride.

Description

Technical Field

[0001] The invention relates to a method for removing vanadium as an impurity in crude titanium tetrachloride, belonging to the technical field of refined titanium tetrachloride. Background Art

[0002] Refining titanium tetrachloride mainly removes VOCl3 impurities in crude titanium tetrachloride, which have a boiling point close to that of TiCl4. Currently, a variety of chemical methods are used to remove vanadium impurities in crude titanium tetrachloride to reduce the problems of whiteness of titanium dioxide and hardness of sponge titanium caused by residual vanadium impurities in subsequent production.

[0003] Quan Hui et al., published in CN111087017A, invented a method for removing vanadium from crude titanium tetrachloride. The invention mainly involves mixing catalytically cracked diesel with hydrogen, conducting a hydrogenation reaction in the presence of a hydrogenation catalyst, and separating the reaction effluent to obtain a liquid material. The crude titanium tetrachloride and the liquid material are then brought into countercurrent contact in an evaporation tower to fully remove the vanadium.

[0004] Zhou Li et al., in publication number CN106241860A, disclosed a method for removing vanadium from crude titanium tetrachloride. The method involves first contacting crude titanium tetrachloride with mineral oil and then adding aluminum powder to the liquid phase after solid-liquid separation to remove vanadium.

[0005] E Tao et al., with publication number CN109956498B, disclosed a composite organic material for vanadium removal, including organic base oil, aromatic oil (dimethylaniline), silicone oil (dimethyl silicone oil), graphene (copper-loaded graphene oxide) and metal chloride (zinc chloride).

[0006] Gao Zai et al., with publication number CN114702064A, disclosed a crude titanium tetrachloride vanadium removal reagent, which mainly includes palmitic acid, oleic acid and linoleic acid components, and removes vanadium through a reasonable ratio of the vanadium removal reagent.

[0007] Although these methods are effective, they usually use the principle of removing vanadium with organic matter, which will inevitably leave residual carbon in the refined titanium tetrachloride, which will eventually be enriched in the titanium sponge and affect the product quality of the titanium sponge. Summary of the Invention

[0008] In order to solve the shortcomings of the existing method for removing vanadium from crude titanium tetrachloride, the purpose of the present invention is to provide a method for removing vanadium impurities in crude titanium tetrachloride. The method specifically comprises: placing nano-scale TiH2 in crude titanium tetrachloride, stirring at a constant temperature, reacting at the same constant temperature after the stirring is completed, and performing distillation after the reaction is completed to obtain refined titanium tetrachloride and a residue.

[0009] Preferably, the amount of nano-sized TiH2 added to the crude titanium tetrachloride is 1 g / L to 4 g / L.

[0010] Preferably, the constant temperature is 90-130°C.

[0011] Preferably, the reaction time is 1 to 4 hours.

[0012] Preferably, the distillation temperature is 145-160°C.

[0013] Preferably, the preparation method of the nano-scale TiH2 is as follows: an active metal hydride is used as the anode electrode, graphite is used as the cathode electrode, the anode electrode and the cathode electrode are separated by an anion exchange membrane, the electrolyte on the anode electrode side is composed of an anhydrous organic solvent and an active metal chloride, and is heated during electrolysis; the electrolyte on the cathode electrode side is composed of TiCl4 and a surfactant, and H2 is introduced into the cathode electrode at the same time, and power is applied to finally obtain nano-scale TiH2 on the cathode electrode.

[0014] Preferably, the amount of active metal chloride added to the anhydrous organic solvent is 0.02-0.05 g / mL.

[0015] Preferably, the anhydrous organic solvent is one of tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), dimethylformamide (DMF), acetonitrile (CH3CN), glycerol (C3H8O3) or acetone (CH3COCH3).

[0016] Preferably, the active metal is one of Li, Na, Fe or Al.

[0017] Preferably, the heating temperature is 50-100°C.

[0018] Preferably, the volume ratio of TiCl4 to surfactant is (50-200):(2-5).

[0019] Preferably, the surfactant is one of cetyltrimethylammonium bromide (CTAB), polyethylene glycol (PEG), formamide, rhamnolipid (Rha) or lignin sulfonate dispersant.

[0020] Beneficial effects of the present invention

[0021] (1) The nano-sized TiH2 prepared by the method of the present invention has a small particle size and can fully react with crude titanium tetrachloride. In addition, the hydrogen in TiH2 has a strong reducing ability and can effectively reduce VOCl3, thereby removing vanadium impurities without introducing an additional carbon source. This directly avoids the problem of carbon residue in refined titanium tetrachloride from the source, improves the purity of titanium tetrachloride, and is a more ideal vanadium removal method.

[0022] (2) Compared with the organic matter vanadium removal method, the vanadium removal method using TiH2 does not produce difficult-to-treat organic residues and is more environmentally friendly and efficient.

[0023] (3) In the vanadium removal process, the Ti element in TiH2 can be reasonably utilized to achieve the recovery of titanium tetrachloride, which not only improves the utilization rate of raw materials but also reduces production costs.

[0024] (4) Compared with the four commonly used chemical methods for vanadium removal (aluminum powder removal, hydrogen sulfide removal, copper wire removal, and organic matter removal), the nano-scale TiH2 used in the present invention has the advantages of being non-flammable, non-corrosive to equipment, and easy to recycle titanium tetrachloride. Both the Ti and H elements in TiH2 can be utilized, making it suitable for purifying crude titanium tetrachloride containing high vanadium content. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a process diagram for the electrochemical preparation of nano-scale TiH2 in the present invention.

[0026] Figure 2 The figure is a simplified flow chart of the method for removing vanadium from crude titanium tetrachloride using nano-sized TiH2 of the present invention. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific embodiments. However, the following embodiments are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0028] The chemical reactions involved in the examples are as follows:

[0029] Chemical reactions involved in the electrochemical preparation of nano-sized TiH2:

[0030] The overall reaction is 4MeH+TiCl4=4MeCl+TiH2+H2↑ or 2MeH2+TiCl4=2MeCl+TiH2+H2↑ (Me refers to the active metal)

[0031] Anode reaction formula: 4MeH+4Cl - -4e - =4MeCl+2H2↑; 2MeH2+4Cl - -4e - =2MeCl2+2H2↑, etc.

[0032] Cathode reaction formula: TiCl4+H2+4e - =TiH2+4Cl - ;

[0033] The chemical reactions involved in the vanadium removal process using nano-scale TiH2 are as follows:

[0034] The main reaction is as follows:

[0035] VOCl3+TiH2+3TiCl4→VCl3↓+4TiCl3↓+H2O

[0036] VOCl3+TiH2+2TiCl4→VOCl2↓+3TiCl3↓+H2↑

[0037] 3VOCl3+TiH2→3VOCl2↓+TiCl3↓+H2↑

[0038] Side effects are as follows:

[0039] VOCl3+TiCl3→VOCl2↓+TiCl4

[0040] 2VOCl3+H2(g)→2VOCl2↓+2HCl↑

[0041] VOCl3+H2(g)→VCl3↓+H2O↑

[0042] TiCl4+2H2O→TiO2↓+4HCl

[0043] Example 1

[0044] A method for removing vanadium impurities in crude titanium tetrachloride, the specific steps are as follows:

[0045] (1) Nano-sized TiH2 was prepared by electrochemical method: the anode electrode was an active metal hydride NaH with a mass of 45 g. 50 mL of dimethyl sulfoxide (DMSO) organic solvent and 2 g of NaCl were added to the anode electrode and heated to 100 °C during electrolysis. The cathode electrode was a graphite electrode. H2 was introduced into the electrode and 50 mL of TiCl4 and 2 mL of surfactant hexadecyltrimethylammonium bromide (CTAB) were added. An anion exchange membrane was placed in the middle. Finally, nano-sized TiH2 was obtained on the cathode electrode.

[0046] (2) Weigh 0.1 g of nano-sized TiH2 and place it in 100 mL of crude titanium tetrachloride. The composition of the crude titanium tetrachloride is shown in Table 1.

[0047] (3) Heat the device containing TiH2 and crude titanium tetrachloride to 110°C, stir evenly and allow to react for 2 hours.

[0048] (4) After the reaction is completed, the temperature is raised to 150° C. for distillation to separate and obtain refined titanium tetrachloride and residue.

[0049] The particle size distribution of TiH2 prepared in this example is 60-130 nm. The refined titanium tetrachloride obtained in this example was subjected to ICP detection of the V element content. The test results are shown in Table 1. It can be seen from Table 1 that the V element is 1.0065 ppm and the purity of the refined titanium tetrachloride is 99.91%.

[0050] Example 2

[0051] A method for removing vanadium impurities in crude titanium tetrachloride, the specific steps are as follows:

[0052] (1) Nano-sized TiH2 was prepared by electrochemical method: the anode electrode was an active metal hydride MgH2 with a mass of 70 g. 150 mL of acetonitrile (CH3CN) organic solvent and 5 g of FeCl3 were added to the anode electrode and heated to 80 °C during electrolysis. The cathode electrode was a graphite electrode. H2 was introduced into the electrode and 150 mL of TiCl4 and 3 mL of surfactant polyethylene glycol (PEG) were added. An anion exchange membrane was placed in the middle. Finally, nano-sized TiH2 was obtained on the cathode electrode.

[0053] (2) Weigh 0.2 g of nano-sized TiH2 and place it in 100 mL of crude titanium tetrachloride. The composition of the crude titanium tetrachloride is shown in Table 1.

[0054] (3) Heat the device containing TiH2 and crude titanium tetrachloride to 90°C, stir evenly and allow to react for 4 hours.

[0055] (4) After the reaction is completed, the temperature is raised to 145°C for distillation to separate the refined titanium tetrachloride and the residue.

[0056] The particle size distribution of TiH2 prepared in this example is 76-150 nm. The refined titanium tetrachloride obtained in this example was subjected to ICP detection of the V element content. The test results are shown in Table 1. It can be seen from Table 1 that the V element is 1.4896 ppm and the refined titanium tetrachloride is 99.94%.

[0057] Example 3

[0058] A method for removing vanadium as an impurity in crude titanium tetrachloride, comprising the steps of:

[0059] (1) Nano-sized TiH2 was prepared by electrochemical method: the anode electrode was an active metal hydride LiH, with a mass of 60 g. 200 mL of anhydrous tetrahydrofuran (THF) organic solvent and 10 g of LiCl were added to the anode electrode and heated to 50 °C during electrolysis. The cathode electrode was a graphite electrode. H2 was introduced into the electrode and 200 mL of TiCl4 and 2 mL of surfactant hexadecyltrimethylammonium bromide (CTAB) were added. An anion exchange membrane was placed in the middle. Finally, nano-sized TiH2 was obtained on the cathode electrode.

[0060] (2) Weigh 0.4 g of nano-sized TiH2 and place it in 100 mL of crude titanium tetrachloride. The composition of the crude titanium tetrachloride is shown in Table 1.

[0061] (3) Heat the device containing TiH2 and crude titanium tetrachloride to 130°C, stir evenly and allow to react for 1 hour.

[0062] (4) After the reaction is completed, the temperature is raised to 160°C for distillation to separate the refined titanium tetrachloride and the residue.

[0063] The particle size distribution of TiH2 prepared in this example is 70-155 nm. The refined titanium tetrachloride obtained in this example was subjected to ICP detection of the V element content. The test results are shown in Table 1. It can be seen from Table 1 that the V element is 0.9382 ppm and the refined titanium tetrachloride is 99.95%.

[0064] Table 1 Evaluation of the reaction effect of crude titanium tetrachloride and TiH2

[0065]

[0066] In the present invention, the crude titanium tetrachloride comprises the following components: TiCl4 99.4-99.68wt%, AlCl3 0.08-0.12wt%, FeCl3 0.1-0.15wt%, and VOCl3 0.14-0.33wt%, which can be determined according to different crude titanium tetrachloride components. It should be understood that crude titanium tetrachloride is crude titanium tetrachloride obtained by reacting rutile or high-titanium slag with chlorine and then settling to remove solid matter. It not only includes VOCl3, TiCl4, FeCl3, and AlCl3, but also includes impurity compounds that may be present in the crude titanium tetrachloride, such as SiCl4, which are insoluble in TiCl4.

[0067] The above examples demonstrate that the use of the nano-sized TiH2 vanadium removal agent of the present invention not only enables a cyclic devanadium reaction in titanium tetrachloride but also reduces the carbon source from the source of the vanadium removal agent. Furthermore, compared with aluminum powder, hydrogen sulfide, copper wire, or organic vanadium removal, the nano-sized TiH2 employed in the present invention offers advantages such as being non-flammable, non-corrosive to equipment, easy recovery of titanium tetrachloride, and low residue production. Both the Ti and H elements in the TiH2 can be utilized, making it suitable for purifying crude titanium tetrachloride containing high vanadium content. The present invention discloses a highly efficient method for removing vanadium from crude titanium tetrachloride using nano-sized TiH2, providing a more ideal and efficient method for removing vanadium.

[0068] Thus far, the present invention has described the technical solutions of the present invention in detail through embodiments. However, it will be apparent to those skilled in the art that the scope of protection of the present invention is not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent adjustments or substitutions to the technical features of the present invention, and all such adjustments or substitutions will be considered to fall within the scope of protection of the present invention.

Claims

1. A method for removing vanadium impurities in crude titanium tetrachloride, characterized in that: Nano-sized TiH2 is placed in crude titanium tetrachloride and stirred at a constant temperature. After the stirring is completed, the mixture is reacted at the same constant temperature, which is 90-130°C. After the reaction is completed, the mixture is distilled to obtain refined titanium tetrachloride and a residue. The preparation method of the nano-scale TiH2 is as follows: an active metal hydride is used as the anode electrode, the active metal is one of Li, Na, Fe or Al, and graphite is used as the cathode electrode. The anode electrode and the cathode electrode are separated by an anion exchange membrane. The electrolyte on the anode electrode side consists of an anhydrous organic solvent and a chloride of the active metal, and is heated during electrolysis; the electrolyte on the cathode electrode side consists of TiCl4 and a surfactant. At the same time, H2 is introduced into the cathode electrode, and power is applied to finally obtain nano-scale TiH2 on the cathode electrode.

2. The method for removing vanadium impurities from crude titanium tetrachloride according to claim 1, wherein: The amount of nano-TiH2 added to the crude titanium tetrachloride is 1g / L~4g / L.

3. The method for removing vanadium impurities from crude titanium tetrachloride according to claim 1, wherein: The reaction time is 1~4h.

4. The method for removing vanadium impurities from crude titanium tetrachloride according to claim 1, wherein: The distillation temperature is 145~160℃.

5. The method for removing vanadium impurities from crude titanium tetrachloride according to claim 1, characterized in that: The amount of active metal chloride added to the anhydrous organic solvent is 0.02~0.05g / mL.

6. The method for removing vanadium impurities from crude titanium tetrachloride according to claim 1, characterized in that: The heating temperature is 50~100℃.

7. The method for removing vanadium impurities from crude titanium tetrachloride according to claim 1, characterized in that: The volume ratio of TiCl4 and surfactant is (50~200):(2~5).

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