阅读说明：本技术 一种熔盐电解二氧化钛制备钛锌合金的方法 (Method for preparing titanium-zinc alloy by electrolyzing titanium dioxide through molten salt ) 是由 秦博 戴玮 马文会 颜恒维 李绍元 雷云 伍继君 陈正杰 于洁 刘战伟 谢克强 于 2019-10-15 设计创作，主要内容包括：本发明公开一种熔盐电解二氧化钛制备钛锌合金的方法,将锌粒置于小坩埚底部,二氧化钛粉末平铺于锌粒上面,钼棒插入小坩埚底部组装成复合阴极；将小坩埚置于大坩埚内,无水氯化钙覆盖小坩埚及大坩埚内部,进行预融,预融完成后将石墨棒和碳棒或钼棒插入到大坩埚内的无水氯化钙中,在惰性气体保护下,石墨棒为阳极,碳棒或钼棒为阴极进行预电解以去除熔盐中残余的水分和少量金属杂质；以复合电极为阴极,石墨棒为阳极,进行电解,结束后缓慢冷却至室温,阴极产物经去离子水冲洗得到块状钛锌合金；本发明能够在较低的温度下、短时间内通过电化学还原制备钛锌合金,整体流程对环境友好,操作简单,适合推广到规模化工业生产中。(The invention discloses a method for preparing titanium-zinc alloy by electrolyzing titanium dioxide through molten salt, which comprises the steps of placing zinc particles at the bottom of a small crucible, paving titanium dioxide powder on the zinc particles, and inserting a molybdenum rod into the bottom of the small crucible to assemble a composite cathode; placing the small crucible in a large crucible, covering the small crucible and the large crucible with anhydrous calcium chloride, pre-melting, inserting a graphite rod and a carbon rod or a molybdenum rod into the anhydrous calcium chloride in the large crucible after the pre-melting is finished, and pre-electrolyzing by taking the graphite rod as an anode and the carbon rod or the molybdenum rod as a cathode under the protection of inert gas to remove residual moisture and a small amount of metal impurities in the molten salt; taking the composite electrode as a cathode and the graphite rod as an anode, carrying out electrolysis, slowly cooling to room temperature after the electrolysis is finished, and washing a cathode product by deionized water to obtain a blocky titanium-zinc alloy; the method can prepare the titanium-zinc alloy by electrochemical reduction at a lower temperature in a short time, has environment-friendly overall process and simple operation, and is suitable for being popularized to large-scale industrial production.)

1. A method for preparing a titanium-zinc alloy by electrolyzing titanium dioxide through molten salt is characterized by comprising the following specific steps:

(1) zinc particles are placed at the bottom of a small crucible, titanium dioxide powder is flatly paved on the zinc particles, and a molybdenum rod is inserted into the bottom of the small crucible to assemble a composite cathode;

(2) placing the small crucible in the step (1) in a large crucible, covering the small crucible and the large crucible with anhydrous calcium chloride, pre-melting under vacuum or inert gas protection, inserting a graphite rod and a carbon rod or a molybdenum rod into the anhydrous calcium chloride in the large crucible after the pre-melting is finished, pre-electrolyzing by taking the graphite rod as an anode and the carbon rod or the molybdenum rod as a cathode under the inert gas protection until the current value is reduced to be less than 100mA, and finishing the pre-electrolysis;

(3) and (3) after the pre-electrolysis in the step (2) is finished, under the protection of inert gas, carrying out electrolysis by taking the composite electrode as a cathode and the graphite rod as an anode, wherein the electrolysis temperature is 850 ~ 900 ℃, the electrolysis voltage is 1.3 ~ 3.0.0V, and the electrolysis time is 1 ~ 3h, cooling to room temperature after the electrolysis is finished, and washing a cathode product by deionized water to obtain the blocky titanium-zinc alloy.

2. The method for preparing the titanium-zinc alloy by electrolyzing the titanium dioxide with the molten salt according to claim 1, wherein the mass ratio of the titanium dioxide powder to the zinc particles in the step (1) is 5 ~ 15: 100.

3. The method for preparing Ti-Zn alloy by electrolyzing titanium dioxide with molten salt according to claim 1, wherein the purity of the titanium dioxide powder in step (1) is not less than 99%, the particle size of the titanium dioxide powder is 0.2 ~ 5 μm, and the purity of zinc particles is not less than 99%.

4. The method of preparing titanium-zinc alloy by electrolyzing titanium dioxide in molten salt according to claim 1, characterized in that: the small crucible in the step (1) and the large crucible in the step (2) are corundum crucibles.

5. The method for preparing the titanium-zinc alloy by electrolyzing the titanium dioxide with the molten salt according to the claim 1, wherein the pre-melting in the step (2) is that the temperature is raised to 200 ~ 300 ℃ and the temperature is kept for 3 ~ 12h at the temperature raising rate of 5 ~ 10 ℃/min, and then the temperature is raised to 800 ~ 900 ℃ and the temperature is kept for 1 ~ 6h at the same temperature raising rate.

6. The method for preparing the titanium-zinc alloy by electrolyzing the titanium dioxide through the molten salt according to claim 1, wherein the voltage of the pre-electrolysis in the step (2) is 1.6 ~ 2.8.8V.

7. The method of preparing titanium-zinc alloy by electrolyzing titanium dioxide in molten salt according to claim 1, characterized in that: and (3) the inert gas in the step (2) and the step (3) is argon with the purity of more than 99.9 percent.

Technical Field

The invention relates to a method for preparing a titanium-zinc alloy by electrolyzing titanium dioxide through molten salt, belonging to the technical field of nonferrous metallurgy.

Background

The titanium-zinc alloy is a building material, mainly used for making titanium-zinc plate, the titanium-zinc plate in the prior art is smelted by high-purity metal zinc (99.995%) meeting European quality standard EN1179 and a small amount of titanium and copper, the content of titanium is 0.06% -0.20%, the creep resistance of the alloy can be improved, and the content of copper is 0.08% -1.00% for increasing the hardness of the alloy.

In 2000, Chen et al expressed as TiO₂Pressing the powder into a solid cathode, CaCl₂The method is called FFC Cambridge method, and the method is characterized in that a graphite rod is used as an anode, electrolysis is carried out under the protection of argon at the temperature of 1000 ℃ plus 800 ℃ and under the external voltage of 2.8-3.2V (higher than the decomposition voltage of titanium dioxide and lower than the decomposition voltage of molten salt), and metal titanium is obtained. The method can directly reduce metal from the solid metal oxide, and compared with the traditional molten salt electrolysis, the method does not need the metal oxide to have certain solubility in molten salt and the electrolysis temperature can be lower than the melting point of the metal, and the method brings the development of the molten salt electrolysis into a new era and is expected to replace the Kroll method to realize the green, continuous and low-energy-consumption industrial production of the titanium sponge.

The Cambridge method mainly comprises three steps of tabletting, sintering and electrolyzing. Firstly, mixing metal oxide powder and a binder (part of which is added with a pore-forming agent) according to a certain proportion, and pressing and molding in a static pressure die pressing sheet machine by selecting proper pressure; under a certain atmosphere, carrying out heat preservation and heating in a muffle furnace for a period of time to remove the binder, and obtaining a cathode sheet body with enough strength and a certain porosity; and finally, winding the cathode sheet body on a current collector molybdenum rod by using a molybdenum wire or a nickel-chromium wire, carrying out electrolysis under the protection of inert gas, and collecting a cathode product after the electrolysis is finished to obtain the pure metal or the alloy. Through the development of many years, the cambridge method still has the problems of more processes before electrolysis, long electrolysis time, low current efficiency and the like in the preparation process of metals and alloys thereof.

Disclosure of Invention

The invention provides a method for preparing titanium-zinc alloy by electrolyzing titanium dioxide through molten salt, aiming at the problems in the prior art, the titanium-zinc alloy can be prepared through molten salt electrolysis reduction in a short time under the condition of lower temperature, the whole process is environment-friendly, the flow is simple, and the method is suitable for being popularized to large-scale industrial production.

A method for preparing titanium-zinc alloy by electrolyzing titanium dioxide with molten salt comprises the following specific steps:

(1) zinc particles are placed at the bottom of a small crucible, titanium dioxide powder is flatly paved on the zinc particles, and a current collector molybdenum rod is inserted into the bottom of the small crucible to assemble a composite cathode;

(2) placing the small crucible in the step (1) in a large crucible, completely covering the small crucible and the large crucible with anhydrous calcium chloride, placing the large crucible in a sealed vacuum drying furnace, pre-melting under the protection of vacuum or inert gas, after the pre-melting is finished, inserting a graphite rod and a carbon rod or a molybdenum rod into the anhydrous calcium chloride in the large crucible, pre-electrolyzing under the protection of inert gas by taking the graphite rod as an anode and the carbon rod or the molybdenum rod as a cathode until the current value is reduced to be less than 100mA, and finishing the pre-electrolysis;

(3) and (3) after the pre-electrolysis in the step (2) is finished, under the protection of inert gas, carrying out electrolysis by taking the composite electrode as a cathode and the graphite rod as an anode, wherein the electrolysis temperature is 850 ~ 900 ℃, the electrolysis voltage is 1.3 ~ 3.0.0V, and the electrolysis time is 1 ~ 3h, after the electrolysis is finished, slowly cooling to the room temperature, and washing a cathode product by deionized water to obtain the blocky titanium-zinc alloy.

The mass ratio of the titanium dioxide powder to the zinc particles in the step (1) is 5 ~ 15: 100.

The purity of the titanium dioxide powder in the step (1) is not less than 99 percent, the particle size of the titanium dioxide powder is 0.2 ~ 5 mu m, and the purity of zinc particles is not less than 99 percent.

The small crucible in the step (1) and the large crucible in the step (2) are corundum crucibles.

The pre-melting in the step (2) is carried out by heating to 200 ~ 300 ℃ at the heating rate of 5 ~ 10 ℃/min and keeping the temperature for 3 ~ 12h, and then heating to 800 ~ 900 ℃ at the same heating rate and keeping the temperature for 1 ~ 6 h.

The voltage of the pre-electrolysis in the step (2) is 1.6 ~ 2.8.8V.

And (3) the inert gas in the step (2) and the step (3) is argon with the purity of more than 99.9 percent.

The invention has the beneficial effects that:

(1) by controlling the particle size of the titanium dioxide powder and the mass ratio of the titanium dioxide powder to the metal zinc particles, the steps of sintering, tabletting and the like of the traditional Cambridge method are omitted, and a molybdenum wire or a nickel-chromium wire is not needed to wind the cathode to form a current collector, so that the material consumption is reduced, and the process is simplified.

(2) Due to the addition of the metal zinc, the depolarization effect of the metal zinc enables the solid oxide of the titanium to be directly electrochemically deoxidized under a lower electrode potential (lower than the theoretical decomposition voltage of titanium dioxide at the temperature), so that the pure metal and the liquid zinc form a titanium-zinc alloy, the energy consumption is reduced, and the current efficiency is improved.

(3) At the electrolysis temperature, because of the density difference, titanium dioxide exists between molten calcium chloride and liquid zinc to form a stable three-phase interface (an electrolysis reaction generation area); compared with the traditional sword bridge method, the three-phase interface area is larger, so that the electrolytic reaction is more violent, the electrolysis can be completed in a short time, and the deoxidation is more thorough.

Drawings

FIG. 1 is a schematic diagram of electrolysis of example 1; (a) a composite electrode (b), a molybdenum rod (c) and a graphite rod;

FIG. 2 is an electron microscope and mapping image of the cathode products of example 3 and comparative example 1; (a) example 3 (b) comparative example 1;

FIG. 3 is a plot of the energy spectrum point analysis for example 3 and comparative example 1;

FIG. 4 is an XPS titanium valence analysis of the cathode product of example 3;

FIG. 5 is an XPS zinc valence analysis of the cathode product of example 3;

FIG. 6 is an XRD analysis of the cathode product of example 3; (a) micro-domain diffraction (b) ordinary diffraction.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments, but the scope of the present invention is not limited to the description.