CN101949038A - Method for preparing TiCxOy composite anode with electrolysis method - Google Patents

Abstract

The invention provides a method for preparing carbon-oxygen-titanium composite anode by electrolysis. The method includes the following steps: using titanium-containing material and carbonaceous reducing agent as raw materials, uniformly mixing according to the chemical reaction ratio, and preparing the composite anode by pressure molding The primary product: the composite anode primary product is used as the cathode, the graphite electrode is the anode, and the alkali metal chloride molten salt is used as the electrolyte to form an electrolytic cell to perform electrolysis; a part of the oxygen in the composite anode primary product is precipitated in the form of ions and migrates to the anode. O ₂ and CO or/and CO ₂ are generated at the anode; another part of the oxygen reacts with the carbon in the raw material to generate CO, and finally a finished composite anode of titanium carbide (TiC _x O _y ) is obtained at the cathode. The method can realize the continuous production of the carbon-oxygen-titanium composite anode, and greatly reduce the production cost of the carbon-oxygen-titanium composite anode.

Description

A kind of method for electrolytic method to prepare carbon-oxygen-titanium composite anode

technical field

The invention relates to a method for preparing a carbon-oxygen-titanium composite anode by electrolysis. The final product of the invention is a carbon-oxygen-titanium composite anode. The carbon-oxygen-titanium composite anode can be directly used as a raw material for the production of metal titanium powder by electrolysis, and belongs to rare metal refining. technology field.

Background technique

As a new metal, titanium metal has a series of excellent properties such as low density, good corrosion resistance, plasticity, and high specific strength. Titanium and its alloys are widely used in aerospace, artificial satellite, military industry, chemical industry, petroleum, metallurgy, light industry, electric power, seawater desalination, naval vessel, textile and medical treatment and other fields.

At present, the industrial production method of sponge titanium is still the Mg thermal reduction method of TiCl ₄ . In this process, titanium minerals are enriched, chlorinated, and refined to produce TiCl ₄ , and then reduced with magnesium in an inert atmosphere such as argon or helium. TiCl ₄ is sponge titanium, and then vacuum distillation is carried out to separate and remove magnesium and MgCl ₂ , and finally after product treatment, the finished sponge titanium is obtained. This method has a large production capacity and is easy to realize commercialization, so so far there is no other process to replace it. However, a series of shortcomings such as long process flow, long cycle, low reduction rate, high price of reducing agent, and difficulty in continuous process have caused the cost of titanium sponge to be too high. And the process has not been greatly improved since it was invented in the 1940s.

With the development of the titanium industry, the smelting of metal titanium has produced the FFC _Cambridge process (WO09964638) based on molten salt electrolysis _. ) as the electrolyte, when the applied voltage is lower than the decomposition voltage of the molten salt, the oxygen on the cathode enters the electrolyte in the form of ions, and _O2 and _CO2 gases are released at the anode, leaving pure metal titanium on the cathode. The estimated cost of this method is lower than that of the Kroll method, and it is considered to be non-toxic, environmentally friendly, simple in process and short in production cycle. Through continuous research, the following problems still exist in the FFC process: the TiO ₂ electrode resistivity is extremely high, it is difficult to achieve stable electrolysis, and the current efficiency is low; the cathode, that is, the impurities in TiO ₂ will all remain in titanium, which requires the raw material of the process to be High-purity TiO ₂ , and the production cost of high-purity TiO ₂ is relatively high, which leads to a reduction in the economy of the overall process route. In addition, the FFC process does not take into account that the reduction of titanium suboxides requires less electrochemical energy than the reduction of titanium dioxide to obtain metal titanium. Therefore, it is more economically feasible to use titanium suboxides as the cathode to reduce metal titanium.

Soluble anodic electrolysis of TiO·mTiC solid solution is also a research hotspot in the preparation of titanium metal by electrolytic method. The research on this aspect was first proposed by researchers in the former Soviet Union in the 1970s, and it was believed that only the potential of titanium oxycarbide with a ratio of carbon and oxygen approximately 1 is very stable. The TiO·mTiC solid solution electrolysis method is to mix TiO ₂ and C and reduce it at high temperature to obtain a TiO·mTiC solid solution, and then electrolytically refine the solid solution anode in an alkali metal molten salt system to obtain pure metal titanium. This process does not produce anode slime during the electrolysis process, and the electrolytic refining and purification effect is good. However, the production of soluble composite anodes in this process is a multi-step, cumbersome process, and the energy consumption of thermal reduction is high. Focusing on low-cost and large-scale production of titanium metal, the preparation process of composite anode still needs to be optimized and improved.

The MER process (WO2005/019501) mentions that TiO ₂ and C are mixed evenly according to the stoichiometric ratio, and then thermally reduced at 1100°C to 1300°C to obtain a mixture of titanium suboxides and carbon, which is then used as a composite anode in alkali metal Electrolyzed in the molten salt system, metal titanium is obtained at the cathode. The method requires high temperature for preparing the anode, which will affect the economical efficiency of the process. The process is a combination of thermal and electrochemical methods, and it is difficult to achieve process continuity.

Contents of the invention

In view of the above-mentioned deficiencies, the object of the present invention is to overcome the defects and deficiencies of the prior art, to provide a kind of use of titanium-containing materials and carbonaceous reducing agents as raw materials, to prepare titanium oxycarbide (TiC _x O _y , wherein 0<x ≤1, 1≤y<2) A composite anode method. Using the composite anode as a soluble anode for electrolysis, finally obtain metal titanium with a purity greater than 99.0wt% at the cathode.

To achieve the above object, the present invention adopts the following technical solutions:

a) using titanium-containing material and carbonaceous reducing agent as raw materials, uniformly mixing according to chemical reaction ratio, and preparing composite anode primary product by pressure molding;

b) Using the composite anode primary product as the cathode, the graphite electrode as the anode, and the alkaline earth metal chloride molten salt as the electrolyte, an electrolytic cell is formed to perform electrolysis;

c) Part of the oxygen in the titanium dioxide in the composite anode is precipitated in the form of ions; a part migrates to the anode, where _O2 and CO or/and _CO2 are generated at the anode, and the other part reacts with the carbon in the raw material to generate CO;

d) Finally, the finished TiC _x O _y composite anode is obtained at the cathode.

According to the method for preparing a carbon-oxygen-titanium composite anode by electrolysis in an exemplary embodiment, the titanium-containing material may include metatitanic acid and titanium dioxide.

According to the method for preparing a carbon-oxygen-titanium composite anode by electrolysis in an exemplary embodiment, the carbonaceous reducing agent may include carbonaceous reducing agents such as graphite powder, petroleum coke, charcoal, and the like.

According to the method for preparing carbon-oxygen-titanium composite anode by electrolysis in an exemplary embodiment, the stoichiometric ratio of titanium-containing material and carbonaceous reducing agent can be set as 100:4 to 100:22.5 in terms of mass ratio of TiO ₂ and C .

According to the method for preparing a titanium-carbon-oxygen composite anode by electrolysis in an exemplary embodiment, the set pressure value of the pressure forming may be 500kg/cm ² -1000kg/cm ² .

According to the method for preparing a titanium-carbon-oxygen composite anode by electrolysis in an exemplary embodiment, the set pressure value of the pressure forming may be 500kg/cm ² -800kg/cm ² .

According to the method for preparing a carbon-oxygen-titanium composite anode by electrolysis in an exemplary embodiment, the alkaline earth metal chloride molten salt may be CaCl ₂ .

According to the method for preparing a titanium oxycarbon composite anode by electrolysis in an exemplary embodiment, the cathode current density during the electrolysis process can be set to 0.01A/cm ² -2A/cm ² .

According to the method for preparing a titanium-carbon-oxygen composite anode by electrolysis in an exemplary embodiment, the cathode current density during electrolysis may be set at 0.1A/cm ² -1.0A/cm ² .

According to the method for preparing a titanium oxycarbon composite anode by electrolysis in an exemplary embodiment, the electrolysis temperature may be set at 800° C. to 850° C. during the electrolysis process.

Detailed ways

The specific implementation manners of the present invention will be further described below in conjunction with exemplary embodiments, and the present invention is not limited to the scope of the described exemplary embodiments. The carbonaceous reducing agent in the present invention refers to a reducing agent mainly composed of carbon, such as graphite powder, petroleum coke, charcoal and the like.

The method for preparing a carbon-oxygen-titanium composite anode according to an exemplary embodiment includes the following steps: using a titanium-containing material and a carbonaceous reducing agent as raw materials, uniformly mixing them according to stoichiometric proportions, and preparing a composite anode primary product by pressure molding; The composite anode primary product is used as the cathode, the graphite electrode is the anode, and the alkaline earth metal chloride molten salt is used as the electrolyte to form an electrolytic cell for electrolysis; the oxygen in the titanium dioxide in the composite anode primary product is partially precipitated in the form of ions; The anode generates O ₂ and CO or/and CO ₂ , and the other part reacts with the carbon in the raw material to generate CO; finally, the finished product TiC _x O _y is obtained at the cathode, where 0<x≤1, 1≤y< 2.

In the method for preparing carbon-oxygen-titanium composite anode according to an exemplary embodiment, the titanium-containing material may include metatitanic acid and titanium dioxide, and the carbonaceous reducing agent may include graphite powder, petroleum coke, charcoal, etc.; the titanium-containing material and The stoichiometric ratio of the carbonaceous reducing agent can be set to 100:4-100:22.5 based on the mass ratio of TiO ₂ and ^{C ;} , if the pressure value is lower than 500kg/cm ^{2 and} the strength of the raw material block is too low, it is easy to cause physical collapse in the molten salt. If the pressure value is higher than 1000kg/cm ² , the strength is too high and too dense, which is not conducive to deoxidation The optimal range is 500kg/cm ² ～800kg/cm ² ; CaCl ₂ can be used as the alkaline earth metal chloride molten salt as the electrolyte; the cathode current density during electrolysis can be set at 0.01A/cm ² ～2A/cm ² , if If the cathode current density is higher than 2A/cm ² , the pressure of the electrolytic cell will be higher than the decomposition voltage of calcium chloride, so that calcium chloride will be electrolyzed. If the current density is too low, it is not conducive to the deoxidation of the cathode, and it is extremely difficult to control if the current density is lower than 0.01. Preferably, the cathode current density can be set at 0.1A/cm ² to 1.0A/cm ² ; the electrolysis temperature can be set at 800°C to 850°C during the electrolysis process, and the setting of the electrolysis temperature is mainly based on the calcium chloride within this range Molten salt has the best fluidity, but the temperature is too high and the equipment cannot bear it and the economy is not good.

Hereinafter, specific examples of preparing titanium-carbon-oxygen composite anodes by electrolytic method will be given, but the examples are only exemplary, and the present invention is not limited thereto.

Embodiment one

Weigh 102g of titanium dioxide ( _TiO2 98wt%) and 4.1g of graphite powder (C content 99wt%), mix them uniformly in a planetary ball mill, and press them with a pressure of 1000kg/ ^cm2 as the cathode, and the graphite rod as the anode. Using calcium chloride molten salt as the electrolyte, the electrolytic cell is protected by argon, and electrolyzed at 800°C. The cathode current density is 0.01A/cm ² , and the electrolysis time is 2 hours. After the electrolysis is completed, take out the cathode and wash away the residual electrolyte with 0.5% dilute hydrochloric acid, then wash the chloride ions with deionized water, and dry it. The main phase is Ti ₄ O ₇ and a small amount of C through XRD phase analysis, and the chemical composition is TiC _0.18 O _1.75 .

Embodiment two

Weigh 102g of titanium dioxide ( _TiO2 98wt%) and 7.8g of petroleum coke (C content 90wt%), mix them uniformly in a planetary ball mill, and press them with a pressure of 500kg/ ^cm2 as the cathode, and the graphite rod as the anode. Using calcium chloride molten salt as the electrolyte, the electrolytic cell is protected by argon, and electrolyzed at 820°C. The cathode current density is 0.1A/cm ² , and the electrolysis time is 5 hours. After the electrolysis is completed, take out the cathode and wash away the residual electrolyte with 0.5% dilute hydrochloric acid, then wash the chlorine ions with deionized water, dry it, and analyze the main phases of Ti ₃ O ₅ , Ti ₂ O ₃ and C through XRD phase analysis. , the chemical composition is TiC _0.35 O _1.63 .

Embodiment Three

Weigh 102g of titanium dioxide ( _TiO2 98wt%) and 16.2g of charcoal (C content 74wt%), mix them uniformly in a planetary ball mill, and press them with a pressure of 800kg/ ^cm2 as the cathode, and the graphite rod as the anode. Using calcium chloride molten salt as the electrolyte, the electrolytic cell is protected by argon, and electrolyzed at 840°C. The cathode current density is 0.4A/cm ² , and the electrolysis time is 10 hours. After the electrolysis is completed, take out the cathode and wash away the residual electrolyte with 0.5% dilute hydrochloric acid, then wash the chloride ions with deionized water, dry them, and analyze the main phases by XRD phases are Ti ₂ O ₃ and C, and a small amount of Ti ₃ O ₅ , the chemical composition is TiC _0.71 O _1.54 .

Embodiment Four

Weigh 102g of titanium dioxide ( _TiO2 98wt%) and 22.7g of graphite powder (C content 99wt%), mix them uniformly in a planetary ball mill, and press them with a pressure of 800kg/ ^cm2 as the cathode, and the graphite rod as the anode. Using calcium chloride molten salt as the electrolyte, the electrolytic cell is protected by argon, and electrolyzed at 840°C. The cathode current density is 1.0A/cm ² , and the electrolysis time is 24 hours. After the electrolysis was completed, the cathode was taken out and washed with 0.5% dilute hydrochloric acid to remove the residual electrolyte, and then the chloride ions were washed with deionized water, and then dried. According to the XRD phase analysis, the main phases were TiO and C, and the chemical composition was TiC _0.99 O.

Embodiment five

Take metatitanic acid (TiO(OH) 98wt%) _125g , graphite powder (C content 99wt%) 22.7 grams, mix uniformly in the planetary ball mill, press molding with 800kg/cm ² as the negative electrode, the graphite rod is anode. Using calcium chloride molten salt as the electrolyte, the electrolytic cell is protected by argon, and electrolyzed at 850°C. The cathode current density is 2.0A/cm ² , and the electrolysis time is 24 hours. After the electrolysis is completed, take out the cathode and wash away the residual electrolyte with 0.5% dilute hydrochloric acid, then wash the chloride ions with deionized water, and dry it. According to XRD phase analysis, the main phases are TiO and C, and the chemical composition is TiCO.

Embodiment six

The carbon-oxygen-titanium composite anode obtained in Example 1, Example 2, Example 3, Example 4 or Example 5 is directly used as the anode, carbon steel is used as the cathode, and NaCl-CaCl ₂ -KCl eutectic mixture is used as the electrolyte to perform electrolysis , adding 3% TiCl _x (2≤x<3) in the electrolyte, wherein the initial current density of the anode is 0.12A/cm ² , and the initial current density of the cathode is 0.80A/cm ² . The electrolysis time was 4 hours, the electrolysis temperature was 720°C, the cathode product was taken out at room temperature, the residual electrolyte was washed with 0.5% hydrochloric acid, the chlorine ions were washed with deionized water, and dried. Chemical analysis showed that the product was titanium metal powder with a purity greater than 99.0wt%.

The invention provides a method for preparing a carbon-oxygen-titanium composite anode (TiC _x O _y , wherein 0<x≤1, 1≤y<2) by using titanium-containing materials and carbonaceous reducing agents as raw materials. Using the composite anode as a soluble anode for electrolysis, the metal titanium with a purity greater than 99.0wt% can be finally obtained at the cathode. The method can realize the continuous production of the carbon-oxygen-titanium composite anode, and greatly reduce the production cost of the carbon-oxygen-titanium composite anode.

Claims (10)

1. A method for electrolytic preparation of carbon-oxygen-titanium composite anode is characterized in that comprising the following steps: Titanium-containing materials and carbonaceous reducing agents are used as raw materials, uniformly mixed according to the chemical reaction ratio, and the composite anode primary product is prepared by pressure molding; the composite anode primary product is used as the cathode, the graphite electrode is used as the anode, and the alkaline earth metal chloride molten salt is Electrolyte, compose electrolytic cell to carry out electrolysis, obtain carbon-oxygen-titanium composite anode at the cathode. 2. The method according to claim 1, characterized in that the titanium-containing material comprises metatitanic acid and titanium dioxide. 3. The method according to claim 1, characterized in that the carbonaceous reducing agent comprises graphite powder, petroleum coke, charcoal. 4. The method according to claim 1, characterized in that the stoichiometric ratio of the titanium-containing material and the carbonaceous reducing agent is set at 100:4 to 100:22.5 by mass ratio of TiO ₂ and C. 5. The method according to claim 1, characterized in that the set pressure value of the pressure forming is 500kg/cm ² -1000kg/cm ² . 6. The method according to claim 1, characterized in that the set pressure of the pressure forming is 500kg/cm ² -800kg/cm ² . 7. The method according to claim 1, characterized in that CaCl ₂ is used as the alkaline earth metal chloride molten salt. 8. The method according to claim 1, characterized in that the cathode current density is set at 0.01A/cm ² -2A/cm ² in the electrolysis process. 9. The method according to claim 1, characterized in that the cathode current density is set at 0.1A/cm ² -1.0A/cm ² during the electrolysis process. 10. The method according to claim 1, characterized in that the electrolysis temperature is set at 800°C to 850°C during the electrolysis process.