Controllable preparation method of titanium-containing ionic liquid based on sponge titanium anode dissolution

Abstract

The invention provides a controllable preparation method of titanium-containing ionic liquid based on sponge titanium anode dissolution, which belongs to the technical field of nonferrous metallurgy, and comprises the following steps: S1, in an inert atmosphere, slowly mixing aluminum trichloride with an organic matter to obtain ionic liquid; s2, by taking sponge titanium as an anode, graphite or metal as a cathode and a platinum wire as a reference electrode, pre-treating and then assembling into an electrolytic cell; s3, ionic liquid is added into the electrolytic bath, and heat preservation is conducted at the temperature of 20-120 DEG C; s4, carrying out constant-current electrolysis on the electrolytic bath; and S5, analyzing the electrolyzed ionic liquid, determining the content of titanium in the ionic liquid, and selecting to add the ionic liquid or continuously electrolyze according to the content of titanium to obtain the electrolyte with the required titanium content. Compared with a method for directly adding high-cost titanium-containing salt or titanium-containing organic matter, the method provided by the invention has the characteristics of low cost and energy consumption and green and environment-friendly process flow.

Description

Technical Field

[0001] The invention relates to the technical field of nonferrous metallurgy, and in particular to a controllable preparation method of titanium-containing ion liquid based on sponge titanium anode dissolution. Background Art

[0002] Titanium-aluminum alloys are corrosion-resistant, high-temperature-resistant, and have high specific strength. They are widely used in aerospace, energy, chemical, and medical fields. At present, titanium-aluminum alloys are usually prepared by melting aluminum and titanium in industrial production. This method requires high temperatures, high energy consumption, low product purity, and easy segregation. In addition, the price of titanium powder, one of the raw materials, is high, which limits the application of titanium-aluminum alloys. Subsequently, new, lower-cost methods have been developed, such as the method reported in the prior art of adding titanium dioxide to the electrolytic system for producing pure aluminum and producing titanium-aluminum alloys by electrolysis. Compared with the melting method, this method reduces energy consumption, but has higher requirements for the reactor and temperature, and the cost is still high.

[0003] In recent years, there have been a series of reports on low-temperature electrodeposition of aluminum alloys using ionic liquids synthesized from aluminum chloride, other metal salts and organic matter. Among them, titanium-aluminum alloys can be prepared by electrodeposition using titanium-containing salts or titanium-containing organic matter as titanium sources in ionic liquids. Since it is not necessary to maintain high temperatures and ionic liquids have a wide electrochemical window and good electrical conductivity, this preparation method can usually obtain better titanium-aluminum alloys at a lower cost. However, the price of titanium sources commonly used in such ionic liquids (such as titanium tetrachloride, titanium tetrabromide, titanium tetrafluoride, tetrabutyl titanate and tetraisopropyl titanate) is relatively high, which limits its application in the preparation of titanium-aluminum alloys.

[0004] Therefore, it is necessary to seek a method for preparing titanium-containing ionic liquid without adding titanium-containing salts or titanium-containing organic matter. Summary of the invention

[0005] In view of the defects in the prior art, the present invention creatively proposes a controllable preparation method of titanium-containing ionic liquid based on sponge titanium anode dissolution. The present invention mixes aluminum chloride and organic matter in an inert atmosphere to obtain an ionic liquid; electrolyzes in an electrolytic cell with sponge titanium as the anode; after a period of electrolysis, a small amount of electrolyte is taken to analyze the titanium content, and ionic liquid is added or the titanium content is continued to be electrolyzed to adjust the titanium content, thereby obtaining an ionic liquid with a determined titanium content. Compared with directly adding titanium-containing salts or titanium-containing organic matter, the present invention has the characteristics of lower cost and energy consumption, and the process flow is green and environmentally friendly. The ionic liquids with different titanium contents finally obtained can be used to prepare titanium-aluminum alloys. Specifically:

[0006] A controllable preparation method of titanium-containing ionic liquid based on titanium sponge anode dissolution, comprising:

[0007] Step S1, in an inert atmosphere, slowly mixing aluminum chloride and an organic matter to obtain an ionic liquid;

[0008] Step S2, using titanium sponge as anode, graphite or metal as cathode, and platinum wire as reference electrode, assembling them into an electrolytic cell after pretreatment, with the distance between cathode and anode being 0.5-10 cm;

[0009] Step S3, adding ionic liquid into the electrolytic cell and keeping the temperature at 20-120°C;

[0010] Step S4: Perform constant current electrolysis on the electrolytic cell, and control the anode current density to 1-20 mA / cm 2 ;

[0011] Step S5, analyzing the electrolyzed ionic liquid to determine the titanium content therein, and adding ionic liquid or continuing electrolysis according to the titanium content to obtain an electrolyte with a desired titanium content.

[0012] The use of the ionic liquid system and titanium used in the present invention can significantly reduce production costs.

[0013] Optionally, in step S1, aluminum chloride is in powder form; the organic matter is selected from one or more of 1-ethyl-3-methylimidazole chloride, 1-propyl-3-methylimidazole chloride, 1-butyl-3-methylimidazole chloride, 1-pentyl-3-methylimidazole chloride, 1-pentyl-3-methylimidazole chloride, 1-ethylpyridine chloride, 1-butylpyridine chloride, trimethylammonium chloride, triethylammonium chloride, benzylethylammonium chloride, dimethylaniline chloride, and dimethyl sulfoxide; and the inert atmosphere is selected from argon or helium.

[0014] Optionally, in step S1, the molar ratio of aluminum chloride to organic matter is 1-2, the temperature is kept below 60°C during the mixing process, and stirring is continued for more than 10 hours to obtain a completely clear ionic liquid.

[0015] Optionally, in step S2, the pre-treatment method for all electrodes is: polishing with 2000 mesh, 4000 mesh, 6000 mesh, 8000 mesh and 10000 mesh sandpaper in sequence, then ultrasonic cleaning with acetone, dilute hydrochloric acid and deionized water in sequence, and finally immersing in dichloromethane for degreasing; wherein the metal is selected from at least one of carbon steel, stainless steel, iron, nickel, molybdenum, titanium, and precious metals. Preferably, when nickel is used as the cathode, titanium-aluminum alloy is not prone to electrodeposition (titanium-aluminum alloy deposition may occur during the electrolysis process), so the cathode material is preferably nickel.

[0016] Optionally, in step S4, the electrolysis process needs to strictly control the cathode potential to be higher than -1.4 V vs. Pt (ie, the potential is more positive than -1.4 V compared to the Pt reference electrode) to reduce or avoid the deposition of titanium aluminum alloy.

[0017] Optionally, in step S4, the electrolyte is continuously stirred during the electrolysis process.

[0018] Optionally, in step S5, the titanium content is tested by the following method: taking a certain volume of electrolyte, using a strong acid or an oxide to digest organic matter, and then using an inductively coupled plasma spectrometer (ICP), titration or spectrophotometry to determine the titanium content therein.

[0019] The beneficial effects brought about by the technical solution provided by the present invention include at least:

[0020] The present invention uses sponge titanium anode electrochemical dissolution instead of titanium-containing salts or titanium-containing organic matter as the titanium source, which is expected to reduce the preparation cost of titanium-containing ionic liquids; the process does not involve highly volatile titanium salts, reduces post-processing steps, and is green and environmentally friendly; compared with other titanium sources, no additional anions are introduced to interfere with subsequent use. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 is the cyclic voltammetry curve of Example 1 of the present invention, wherein Figure 1 (a) before electrolysis, Figure 1 (b) After electrolysis. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is described below.

[0024] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word "example" is intended to present the concept in a specific way. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or it can be either of the two.

[0025] In the embodiments of the present invention, sometimes a subscript such as W1 may be mistakenly written as a non-subscript such as W1. When the difference is not emphasized, the meanings to be expressed are consistent.

[0026] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0027] Example 1

[0028] 26.67 g of aluminum chloride and 17.47 g of 1-butyl-3-methylimidazole chloride were slowly mixed for 10 h in argon protection to prepare an ionic liquid, and placed in an electrolytic cell. The temperature was maintained at 60 °C, 10 g of titanium sponge was pressed as the anode, and low-carbon steel was used as the cathode, with a distance of 2 cm between the two electrodes. Constant current electrolysis was carried out under the condition of stirring the electrolyte at 60 °C, where the anode current density was 5 mA / cm 2 , the cathode potential is higher than -1.3V (vs. Pt). After continuous electrolysis for 3 hours, take 1mL of the supernatant after standing, digest it with nitric acid, and then perform ICP test to determine the titanium content in the ionic liquid. It was found that the titanium content was slightly high, and an appropriate amount of ionic liquid was added and stirred for 1 hour. The ionic liquid in the electrolytic cell was taken out and stored in a suitable container, and finally an ionic liquid with a titanium ion concentration of 0.04 mol / L was obtained. The ionic liquid electrolyte before and after electrolysis was sampled and analyzed, and the results are as follows Figure 1 As shown, Figure 1 (a) is the electrolyte before electrolysis, indicating that there are no Ti ions in it; Figure 1 (b) After a period of electrolysis, it shows that the anode titanium sponge has dissolved into the ionic liquid, that is, there are titanium ions in the ionic liquid.

[0029] Example 2

[0030] 20 g aluminum chloride and 15 g 1-ethyl-3-methylimidazole chloride were slowly mixed in argon protection to form an ionic liquid. After stirring for 15 h, it was refined using aluminum wire. The temperature was kept at 40 °C during the refining process for 12 h. 5 g of titanium sponge was pressed as the anode and nickel sheet as the cathode with an inter-electrode spacing of 1 cm. The anode current density was 10 mA / cm under the condition of stirring the electrolyte at 40 °C. 2 , constant current electrolysis with cathode potential higher than -1.3V (vs. Pt), electrolysis lasts for 10 h. After standing, take 0.5 mL of supernatant, perform ICP test after hydrogen peroxide digestion, determine the titanium content in the ionic liquid, and find that the titanium content is slightly low. Continue electrolysis under the above conditions for 1 h and repeat the above test, add appropriate amount of ionic liquid and stir for 1 h. Store the ionic liquid in the electrolytic cell in a suitable container. Finally, an ionic liquid with a titanium ion concentration of 0.05 mol / L is obtained.

[0031] Example 3

[0032] Aluminum trichloride and 1-butylpyridinium chloride with a molar ratio of 2 were slowly mixed in argon protection to form an ionic liquid. After stirring for 12 hours, aluminum wire was used for refining. The temperature during the refining process was maintained at 50 °C. 12 g of titanium sponge was pressed as the anode and nickel sheet as the cathode with an inter-electrode spacing of 5 cm. The temperature was maintained at 100 °C and constant current electrolysis was performed under stirring of the electrolyte. The anode current density was controlled to be 15 mA / cm 2 , the cathode potential is higher than -1.2V (vs. Pt). The electrolysis time is 12 h. After standing, 1 mL of the supernatant is taken. After nitric acid digestion, the titanium content in the ionic liquid is determined by titration. It is found that the titanium content is slightly high. After adding an appropriate amount of ionic liquid and stirring for 2 h, the ionic liquid in the electrolytic cell is stored in a suitable container. Finally, an ionic liquid with a titanium ion concentration of 0.12 mol / L is obtained.

[0033] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A controllable preparation method of titanium-containing ionic liquid based on titanium sponge anode dissolution, characterized in that: include: Step S1, in an inert atmosphere, slowly mixing aluminum chloride and an organic matter to obtain an ionic liquid; Step S2, using titanium sponge as anode, graphite or metal as cathode, and platinum wire as reference electrode, assembling them into an electrolytic cell after pretreatment, with the distance between cathode and anode being 0.5-10 cm; Step S3, adding ionic liquid into the electrolytic cell and keeping the temperature at 20-120°C; Step S4: Perform constant current electrolysis on the electrolytic cell, and control the anode current density to 1-20 mA / cm 2 ; Step S5, analyzing the electrolyzed ionic liquid to determine the titanium content therein, and adding ionic liquid or continuing electrolysis according to the titanium content to obtain an electrolyte with a desired titanium content.

2. The method according to claim 1, characterized in that In step S1, aluminum chloride is in powder form; the organic matter is selected from one or more of 1-ethyl-3-methylimidazole chloride, 1-propyl-3-methylimidazole chloride, 1-butyl-3-methylimidazole chloride, 1-pentyl-3-methylimidazole chloride, 1-pentyl-3-methylimidazole chloride, 1-ethylpyridine chloride, 1-butylpyridine chloride, trimethylammonium chloride, triethylammonium chloride, benzylethylammonium chloride, dimethylaniline chloride, and dimethyl sulfoxide; and the inert atmosphere is selected from argon or helium.

3. The method according to claim 1, characterized in that In step S1, the molar ratio of aluminum chloride to organic matter is 1-2, the temperature is kept below 60°C during the mixing process, and stirring is continued for more than 10 hours.

4. The method according to claim 1, characterized in that: In step S2, the pretreatment method is: polishing with 2000 mesh, 4000 mesh, 6000 mesh, 8000 mesh and 10000 mesh sandpaper in sequence, then ultrasonic cleaning with acetone, dilute hydrochloric acid and deionized water in sequence, and finally immersing in dichloromethane for degreasing; the metal is selected from at least one of carbon steel, stainless steel, iron, nickel, molybdenum, titanium and precious metals.

5. The method according to claim 1, characterized in that In step S4, the cathode potential during electrolysis is higher than -1.4 V vs. Pt.

6. The method according to claim 1, characterized in that In step S4, the electrolyte is continuously stirred during the electrolysis process.

7. The method according to claim 1, characterized in that In step S5, the titanium content is tested by the following method: a certain volume of electrolyte is taken, organic matter is digested with a strong acid or an oxide, and the titanium content thereof is determined using an inductively coupled plasma spectrometer, titration or spectrophotometry.

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