CN105220180B - The preparation method of composite anode during electroextraction Titanium - Google Patents

Abstract

The invention relates to a method for producing metal by molten salt electrolytic metallurgy, in particular to a method for extracting metal titanium by molten salt electrolysis, and in particular to a method for preparing a composite anode when electrolytically extracting metal titanium. The method of the present invention comprises the following steps: a, raw material preparation: measuring the titanium content M in the titanium liquid obtained in the process of producing titanium white by the sulfuric acid method; b, mixing composite anode materials: adding a reducing agent and viscose to the titanium liquid obtained in step a binder, rinsing to obtain a uniformly mixed mixed material; c, composite anode preparation: press the mixed material under a pressure of 0.5 to 1.5 MPa, dry, and calcinate to obtain a titanium-containing composite anode; d, preparation of titanium metal: The titanium-containing composite anode is used as the battery anode, carbon steel is used as the cathode, and metal titanium is obtained on the battery cathode according to the molten salt electrolysis method. The method for preparing the anode material is simple, the energy consumption is low, and the reaction rate of the anode material is fast.

Description

Preparation method of composite anode for electrolytic extraction of titanium metal

technical field

The invention relates to a method for producing metal by molten salt electrolytic metallurgy, in particular to a method for extracting metal titanium by molten salt electrolysis, and in particular to a method for preparing a composite anode when electrolytically extracting metal titanium.

Background technique

Titanium and its alloys are widely used in modern aviation, rocket and missile industry, aerospace technology, guns and ships, biomedical materials and chemical equipment due to their high melting point, light specific gravity, high strength and strong corrosion resistance.

At present, the only titanium production method used in industrial production in the world is the Kroll method, that is, the magnesium reduction method. The sponge titanium produced can be purified by vacuum consumable electrode remelting or electron beam melting. The whole production process of the Kroll method includes four main parts: electrolysis of magnesium chloride, chlorination of titanium-containing raw materials, magnesium thermal reduction and vacuum distillation to remove magnesium chloride and excess metal magnesium. Due to its long process, many processes, high energy consumption and other factors, the cost of titanium sponge remains high. Its price is much higher than the price of steel, and the price per unit weight is more than three times that of metal aluminum, which limits the application of titanium in various industries.

There are many researches on the preparation of titanium metal, such as the FFC method proposed by the University of Cambridge, the OS method proposed by the Kyoto University in Japan, the PRP process proposed by Okabe in Japan, and the reduction of fluorotitanate. These methods all have technical problems that cannot be overcome at present, so all have not realized industrialization.

The publication number is "CN1712571A", which discloses a titanium production method using titanium dioxide as the main raw material. The method uses carbon or titanium carbide to reduce titanium dioxide to prepare a conductive solid solution TiC TiO, and then uses the solid solution as a soluble anode. Perform molten salt electrolysis, and finally metal titanium can be obtained on the cathode. This method has the advantages of simple process and continuous electrolysis process, but it needs to prepare solid solution TiC·TiO under the condition of high temperature and vacuum, which makes the method consume a lot of energy.

The U.S. patent with the publication number "US 7410562 B2" discloses a method for preparing metal titanium with TiO ₂ -C composite anode. This method is a method of combining thermal and electrochemical processes. The oxide is heat-treated to form a TiCxOy composite anode, and then the TiCxOy composite anode is used as a soluble anode for molten salt electrolysis, and metal titanium is obtained at the cathode. This method has similar advantages and disadvantages to the above-mentioned Chinese invention patents. Similarly, thermal reduction under high temperature and vacuum is required to prepare composite anodes, so the energy consumption of this method is still relatively high.

In the thermal reduction step of the above two patents, C in the titanium-containing material overflows in the form of CO, which leads to a large amount of reducing agent.

Contents of the invention

Aiming at the deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a method for preparing metal titanium by molten salt electrolysis with low energy consumption and high reaction efficiency.

The preparation method of the composite anode during the electrolytic extraction of metal titanium of the present invention comprises the following steps:

a. Raw material preparation: measure the titanium content M in the titanium liquid obtained in the process of producing titanium dioxide by the sulfuric acid method;

b. Mixing of composite anode materials: add 12%M to 20%M reducing agent to the titanium solution obtained in step a, then add 1%M to 5%M binder, and mix evenly to obtain a mixed material; wherein, Reducing agent + binder = 13%M ~ 23%M;

c. Preparation of composite anode: press the mixed material obtained in step b under a pressure of 0.5-1.5MPa, dry at 100-120°C for 3-5 hours, and calcinate at 300-350°C for 2-4 hours to obtain a titanium-containing composite anode;

d. Production of titanium metal: the titanium-containing composite anode obtained in step c is used as the battery anode, and carbon steel is used as the cathode. According to the molten salt electrolysis method, metal titanium is obtained on the battery cathode.

Further, as a more preferred technical solution, the above-mentioned method for preparing a composite anode when electrolytically extracting metal titanium, wherein in step b, preferably 17% M reducing agent is added to the titanium solution, and 3% M viscose is preferably added. Binder.

The method for preparing a composite anode for the electrolytic extraction of titanium metal described above, wherein the reducing agent is carbon powder.

The above-mentioned method for preparing composite anode for electrolytically extracting metal titanium, wherein the binder is pitch.

Further, as a more preferred technical solution, the above-mentioned method for preparing a composite anode for the electrolytic extraction of titanium metal, wherein in step c, the mixed material is pressed under a pressure of 1MPa, dried at 100°C for 4 hours, and then dried at 300°C Calcined for 4 hours to obtain a titanium-containing composite anode.

In the preparation method of the composite anode for the electrolytic extraction of metal titanium in the present invention, no visible reduction reaction occurs during the preparation process of the composite anode, but during molten salt electrolysis, the amount of _CO produced is 1/3 to 1/3 of that of CO 2. In this way, the consumption of reducing agent can be reduced, and the production cost can be reduced. XRD detection of the prepared anode material shows that there are still only two phases of TiO ₂ and C, but the reaction efficiency in electrolysis is better than that of the prior art Therefore, it can be concluded that in the calcination process, the mixture of the present invention undergoes a slight reaction, and its effect has a catalytic effect, so that the anode reaction is accelerated during electrolysis.

detailed description

The preparation method of the composite anode during the electrolytic extraction of metal titanium of the present invention comprises the following steps:

a. Raw material preparation: measure the titanium content M in the titanium liquid obtained in the process of producing titanium dioxide by the sulfuric acid method;

b. Mixing of composite anode materials: add 12%M to 20%M reducing agent to the titanium solution obtained in step a, then add 1%M to 5%M binder, and mix evenly to obtain a mixed material; wherein, Reducing agent + binder = 13%M ~ 23%M;

c. Preparation of composite anode: Press the mixed material obtained in step b under a pressure of 0.5-1.5MPa, dry at 100-120°C for 3-5 hours, and calcinate at 300-350°C for 2 ～4h, is that the crystal water is removed from the material at high temperature to obtain a titanium-containing composite anode;

d. Production of titanium metal: the titanium-containing composite anode obtained in step c is used as the battery anode, and carbon steel is used as the cathode. According to the molten salt electrolysis method, metal titanium is obtained on the battery cathode.

Drying and calcining are carried out after the mixed material of this method is pressed and formed, and wherein drying is to release free water (or adsorbed water), and is generally carried out at low temperature, and the material block of the present invention can also be released from free water (or adsorbed water) as long as it takes a long time in an air atmosphere at room temperature. Water, increasing the temperature can shorten the drying time; but at the beginning, it cannot be directly dried at high temperature, otherwise the block will crack and fall off; calcining is to remove crystal water, so a certain temperature is required. The present invention has no upper limit on the calcining temperature in theory. However, in order to reduce energy consumption, the present invention determines the calcination temperature to be 300-350°C.

Further, as a more preferred technical solution, the above-mentioned method for preparing a composite anode when electrolytically extracting metal titanium, wherein in step b, preferably 17% M reducing agent is added to the titanium solution, and 3% M viscose is preferably added. Binder.

The method for preparing a composite anode for the electrolytic extraction of titanium metal described above, wherein the reducing agent is carbon powder.

The above-mentioned method for preparing composite anode for electrolytically extracting metal titanium, wherein the binder is pitch.

Further, as a more preferred technical solution, the above-mentioned method for preparing a composite anode for the electrolytic extraction of titanium metal, wherein in step c, the mixed material is pressed under a pressure of 1MPa, dried at 100°C for 4 hours, and then dried at 300°C Calcined for 4 hours to obtain a titanium-containing composite anode.

In the step of producing metatitanic acid by hydrolysis of titanium solution by sulfuric acid method, the amount of metatitanic acid is obtained according to the hydrolysis rate of titanium solution, and a calculated amount of carbonaceous reducing agent is added, and asphalt is added as a binder, and mixed together Rinsing (the production process of sulfuric acid titanium dioxide has a rinsing process), so that after several times of beating and rinsing, the titanium-containing raw material (metitatanic acid) can be completely mixed with the carbonaceous reducing agent and binder, which is beneficial to the anode during electrolysis. The reaction went completely. Asphalt belongs to hydrophobic material, it is impermeable and almost insoluble in water. The present invention utilizes the insoluble property of asphalt so that it can exert its bonding performance during the calcining process.

Simultaneously, the adding of carbonaceous reductant has improved the filtration performance of metatitanic acid, and this mixed material shortens greatly than the solid-liquid separation time of simple metatitanic acid; This has also eliminated the mixing step of prior art, and according to the present invention Operation, the mixing of the two materials is more uniform, which is conducive to the reduction reaction.

After rinsing, the filter block is formed, dried, and calcined (the original process of sulfuric acid titanium dioxide), and a composite anode that meets the requirements of electrolysis is obtained.

The test found that the strength of the block without adding pitch was poor after calcination and could not be used as a composite anode during electrolysis; however, when a certain amount of pitch was added as a binder, the strength of the block after calcination fully met the requirements of electrolysis.

The thermal reduction step in the prior art generates a solid solution of TiO/TiC, thereby making the resistance of the anode material low during molten salt electrolysis, good anode reaction, and high efficiency; but the anode material prepared by the present invention is detected by XRD, showing that there is still only Two phases of TiO ₂ and C exist, but the reaction efficiency during electrolysis is higher than that of the prior art. This shows that during the calcination process, the mixture has a slight reaction, and its effect has a catalytic effect, which accelerates the anode reaction during electrolysis and improves the production efficiency.

The present invention utilizes the hydrolysis of titanium liquid to produce metatitanic acid (hydrated titanium dioxide), decomposes fresh _TiO2 molecules during calcination, and reacts with the added reducing agent C to produce a small amount of new ecological substances, and then takes away the _TiO2 during electrolysis. The O plays a catalytic role. But note that once TiO ₂ is stored (it is placed for a long time after it is generated), it needs a very high temperature to react with C.

The specific implementation of the present invention will be further described below in conjunction with the examples, and the present invention is not limited to the scope of the examples.

Example 1

Step 1, anode preparation

Raw materials: titanium liquid, carbon powder, asphalt;

According to a certain volume of titanium liquid, according to the determined hydrolysis rate, calculate the Ti content after hydrolysis, add 17% carbon powder and 3% pitch according to the mass ratio, and mix evenly. Rinse according to the existing steps of sulfuric acid titanium dioxide to obtain a titanium-containing mixture. Forming according to the pressure of 10kg/ ^cm2 , and then drying at 100-120°C for 3-5 hours, after the free water is released from the formed block, it is calcined at 300-350°C for 2-4 hours, so that the material can remove crystal water at high temperature, A composite anode containing titanium material was obtained, and the obtained sample block fell freely at a height of 1 meter, and the sample block remained intact, which could meet the requirements of the next step of electrolysis. Analysis of this material by means of X-ray diffraction showed that it was still a mixture of C and _TiO2 .

Step 2, molten salt electrolysis

The block raw material obtained in step 1 is used as the anode, and the carbon steel is used as the cathode, and the composite anode is electrolyzed according to the conventional molten salt electrolysis method. During the electrolysis process, the gas analyzer is used to detect the gas composition, and the protective gas used is argon;

At the same time, the anode block in the patent with the publication number "CN1712571A" is used as the anode, and the carbon steel is used as the cathode. The electrolysis is carried out under the same electrolysis system and the same electrolysis parameters. The results obtained are shown in Table 1 below:

Table 1 Comparison of anodic reaction rates before and after electrolysis

By comparing the data in Table 1, it is found that the amount of gas produced by the patent "CN1712571A" before electrolysis is the same as that of the anode material of the present invention. After 20 minutes of electrolysis, under the same circumstances, the amount of CO and _CO produced by the present invention is higher than that in the patent "CN1712571A". More gas is produced, which shows that: under the same conditions, the reaction efficiency of the present invention is higher than that of the patent "CN1712571A"; in addition, during molten salt electrolysis, the amount of _CO produced is 1/3 to 1 of CO /2, so that the consumption of reducing agent can be reduced and the production cost can be reduced.

Comparative example 1

Step 1, anode preparation

Raw materials: titanium liquid;

According to a certain volume of titanium liquid, according to the determined hydrolysis rate, calculate the Ti content after hydrolysis, add 20% carbon powder according to the mass ratio, and mix evenly. Rinse according to the existing steps of sulfuric acid titanium dioxide to obtain a titanium-containing mixture. Forming according to the pressure of 10kg/ ^cm2 , and then drying at 300°C under normal pressure for 4 hours to obtain a composite anode containing titanium materials. The obtained sample block fell freely at a height of 1 meter, and the sample block was completely crushed, which could not meet the requirements of the next step of electrolysis. .

Claims (5)

1. the preparation method of composite anode when electrowinning titanium metal, it is characterized in that: comprise the following steps: a. Raw material preparation: measure the titanium content M in the titanium liquid obtained in the process of producing titanium dioxide by the sulfuric acid method; b. Mixing of composite anode materials: add 12%M to 20%M reducing agent to the titanium solution obtained in step a, then add 1%M to 5%M binder, and mix evenly to obtain a mixed material; wherein, Reducing agent + binder = 13%M ~ 23%M; c. Preparation of composite anode: press the mixed material obtained in step b under a pressure of 0.5-1.5MPa, dry at 100-120°C for 3-5 hours, and calcinate at 300-350°C for 2-4 hours to obtain a titanium-containing composite anode; d. Production of titanium metal: the titanium-containing composite anode obtained in step c is used as the battery anode, and carbon steel is used as the cathode. According to the molten salt electrolysis method, metal titanium is obtained on the battery cathode. 2. The preparation method of composite anode during electrolytic extraction of titanium metal according to claim 1, characterized in that: in the b step, 17% M reducing agent is added to the titanium solution, and then 3% M binding agent is added. 3. The method for preparing a composite anode during the electrolytic extraction of titanium according to claim 1 or 2, wherein the reducing agent is carbon powder. 4. The method for preparing a composite anode during electrolytic extraction of titanium according to claim 1 or 2, characterized in that: the binder is pitch. 5. The preparation method of the composite anode during the electrolytic extraction of titanium metal according to claim 1, characterized in that: in step c, the mixed material is pressed and molded under a pressure of 1MPa, dried at 100°C for 4h, then calcined at 300°C for 4h, A composite anode containing titanium is obtained.