CN111187916A

CN111187916A - Method for preparing high-purity titanium by using industrial titanium slag

Info

Publication number: CN111187916A
Application number: CN202010092231.5A
Authority: CN
Inventors: 卢惠民; 高志江
Original assignee: Beijing Oufei Jintai Technology Co ltd
Current assignee: Beijing Oufei Jintai Technology Co ltd
Priority date: 2020-02-14
Filing date: 2020-02-14
Publication date: 2020-05-22
Anticipated expiration: 2040-02-14
Also published as: CN111187916B

Abstract

The invention provides a method for preparing high-purity titanium by using industrial titanium slag, belonging to the field of resource recycling. The invention has the following advantages: 1) the industrial titanium slag is used as a raw material, and the problems of titanium resource waste and serious environmental pollution caused by unavailable utilization of the industrial titanium slag at present are solved. 2) And molten salt electrolysis refining to obtain refined titanium, wherein elements such as silicon, iron, manganese and the like are mainly removed. 3) And (4) further removing impurities by electron beam melting to obtain high-purity titanium with the purity of 99.99-99.999%. 4) The preparation process is short and the cost is low.

Description

Method for preparing high-purity titanium by using industrial titanium slag

Technical Field

The invention relates to the technical field of resource recycling, in particular to a method for preparing high-purity titanium by using industrial titanium slag.

Background

The compact metal titanium is silvery white and looks like stainless steel; the titanium powder is dark gray, has high melting point, small density (only 57 percent of steel), high strength (equal to steel), easy processing and forming, and excellent corrosion resistance, is a metal with high application value, and is widely applied to various fields of agricultural production, national defense and scientific technology.

At the present stage, the metallurgical methods for titanium, which have been industrially produced, are the Kroll method and Hunter method. The method is widely applied to industrial production at presentOnly Kroll process. It is generally accepted that the most potential method for application, other than the Kroll and Hunter processes, is to use TiCl₄The metallic titanium is prepared by a molten salt electrolysis method. The Kroll method has long technological process, each operation process is difficult to realize continuous operation, the energy consumption is too high, and TiO in the raw materials must be treated in the production process₂Conversion to TiCl₄Among them, Cl is involved₂And various chloride derivatives, e.g. HCl, COCl₂、CCl₄、AlCl₃And the like, which are toxic and harmful substances, cause more or less pollution to the environment, and the treatment cost of three wastes is high, so the production cost of the metal titanium prepared by adopting the process route is too high. The hunter process generally considers that the continuous production is easy to realize because the melting point of magnesium is high in the Kroll process, the melting point of sodium is low, the molten sodium is easy to preserve heat, and is easy to be conveyed by an inert gas pressure pump or an electromagnetic pump, when a reduction product is taken out, the sponge titanium of the magnesium process is tightly adhered to the wall of the device, and the taking out is difficult; the sodium-method titanium sponge is separated from the wall of the vessel by a salt layer, so that the titanium sponge is easy to take out. The treatment of the magnesium reduction product and the multi-purpose vacuum distillation method have the disadvantages of complex identification system and high energy consumption; the sodium method reduction product is subjected to hydrometallurgy leaching, so that the equipment is simpler, the energy consumption is less, and the continuity is easier. However, the existing method for preparing titanium has the problems of long process, need of chloridizing roasting and further environmental pollution.

Disclosure of Invention

In view of the above, the present invention aims to provide a method for preparing high purity titanium by using industrial titanium slag. The method takes the industrial titanium slag as a raw material, has short flow, does not need chloridizing roasting, and can obtain high-purity titanium.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a method for preparing high-purity titanium by using industrial titanium slag, which comprises the following steps:

mixing industrial titanium slag, aluminum powder, calcium oxide, calcium fluoride and an explosive to obtain a reactant, wherein the explosive comprises potassium chlorate and/or sodium chlorate;

placing an ignition layer on the surface of the reactant and then igniting to obtain an aluminum-containing coarse titanium alloy;

carrying out molten salt electrolytic refining on the aluminum-containing crude titanium alloy to obtain refined titanium;

and carrying out electron beam melting on the refined titanium to obtain high-purity titanium, wherein the mass content of titanium in the high-purity titanium is not less than 99.99%.

Preferably, the mass ratio of the industrial titanium slag to the aluminum powder to the calcium oxide to the calcium fluoride to the detonation agent is 500-600: 260-280 parts of: 80.28-90.28: 30.08-32.05: 150 to 160.

Preferably, the reactant further comprises magnesium oxide.

Preferably, the ignition layer comprises aluminum powder and an ignition agent, the ignition agent comprises potassium chlorate and/or sodium chlorate, and the mass ratio of the aluminum powder to the ignition agent is 1: 2.

Preferably, the temperature of molten salt electrolytic refining is 800-900 ℃, the polar distance is 8-15 cm, the cell voltage of an electrolytic cell is 0.6-1.8V, and the cathode current density of high-purity titanium is 0.8-1.0A/cm²The current density of the aluminum-containing coarse titanium alloy anode is 0.8-1.0A/cm²The electrolysis time is 20-30 h, the electrolysis atmosphere is vacuum or argon, and the electrolyte is NaCl-KCl-NaF-TiCl_xFused salt, x is 2 or 3.

Preferably, the electrolyte is prepared by a method comprising the following steps:

mixing NaCl, KCl and NaF, and drying to obtain a mixture;

mixing TiCl₄Adding into an electrolytic bath to react with a high-purity titanium cathode to obtain TiCl₃And TiCl₂Dissolving into the mixture to obtain the electrolyte.

Preferably, the mass ratio of the NaCl to the KCl to the NaF is 1-2: 1-0.5.

Preferably, after the molten salt electrolytic refining, the obtained cathode plate sediment is sequentially crushed, hydrolyzed, subjected to first acid leaching and subjected to second acid leaching, wherein the first acid leaching is performed for 30-40 minutes under a ventilation condition by using 1-2 wt% of hydrochloric acid, the solid-to-liquid ratio is 1-2: 5-10, and the second acid leaching is performed for 30-40 minutes under a ventilation condition by using 0.5-1 wt% of hydrochloric acid, the solid-to-liquid ratio is 1-2: 5-8.

Preferably, after the second acid leaching, the second acid leaching solution is washed to be neutral and then dried in vacuum to obtain the refined titanium.

Preferably, the vacuum degree of the electron beam melting is 2.6 multiplied by 10^-3Pa, the temperature is 3000-4000 ℃, and the time is 4-5 hours.

The invention provides a method for preparing high-purity titanium by using industrial titanium slag, which comprises the following steps: mixing industrial titanium slag, aluminum powder, calcium oxide, calcium fluoride and an explosive to obtain a reactant, wherein the explosive comprises potassium chlorate and/or sodium chlorate; placing an ignition layer on the surface of the reactant and then igniting to obtain an aluminum-containing coarse titanium alloy; carrying out molten salt electrolytic refining on the aluminum-containing crude titanium alloy to obtain refined titanium; and carrying out electron beam melting on the refined titanium to obtain high-purity titanium, wherein the mass content of titanium in the high-purity titanium is not less than 99.99%.

The invention has the following advantages:

1) the industrial titanium slag is used as a raw material, and the problems of titanium resource waste and serious environmental pollution caused by unavailable utilization of the industrial titanium slag at present are solved.

2) And molten salt electrolysis refining to obtain refined titanium, wherein elements such as silicon, iron, manganese and the like are mainly removed.

3) And (4) further removing impurities by electron beam melting to obtain high-purity titanium with the purity of 99.99-99.999%.

4) The preparation process is short and the cost is low.

Drawings

FIG. 1 is a schematic representation of an aluminum-containing crude titanium alloy obtained in example 1;

FIG. 2 is an SEM photograph of the aluminum-containing crude titanium alloy obtained in example 1;

FIG. 3 is an SEM and EDS spectra of a second phase of the aluminum-containing crude titanium alloy obtained in example 1, wherein (a) and (b) are SEM images of the second phase of the aluminum-containing crude titanium alloy at different magnifications, (c) is an EDS spectrum of the second phase of the aluminum-containing crude titanium alloy at the point indicated in (a), and (d) is an EDS spectrum of the second phase of the aluminum-containing crude titanium alloy at the point indicated in (b);

fig. 4 is SEM and EDS spectra of the aluminum-containing raw titanium alloy matrix phase obtained in example 1, wherein (a) and (b) are SEM images of the aluminum-containing raw titanium alloy matrix phase at different magnifications, (c) is an EDS spectrum of the aluminum-containing raw titanium alloy matrix phase at the 3-point spectrum indicated in (a), and (d) is an EDS spectrum of the aluminum-containing raw titanium alloy matrix phase at the 6-point spectrum indicated in (b).

Detailed Description

The method comprises the step of mixing industrial titanium slag, aluminum powder, calcium oxide, calcium fluoride and an explosive to obtain a reactant, wherein the explosive comprises potassium chlorate and/or sodium chlorate. In the invention, the industrial titanium slag is preferably titanium slag produced by a blast furnace and a submerged arc furnace, and in a specific embodiment of the invention, the industrial titanium slag is more preferably Panzhihua blast furnace titanium slag, and the content of titanium dioxide in the Panzhihua blast furnace titanium slag is preferably 40-80 wt%.

In the invention, the mass ratio of the industrial titanium slag, the aluminum powder, the calcium oxide, the calcium fluoride and the detonating agent is preferably 500-600: 260-280 parts of: 80.28-90.28: 30.08-32.05: 150 to 160. In the invention, the calcium fluoride mainly plays a role of agglomerating to generate alloy, and the calcium oxide mainly plays a role of absorbing heat so as to prevent the reaction from being too violent. In the present invention, the particle size of the powdery aluminum is preferably 0.125 to 0.42 mm.

In the invention, the reactant preferably further comprises magnesium oxide, and the weight percentage of the magnesium oxide in the reactant is preferably 5-8%.

The invention is ignited after an ignition layer is arranged on the surface of the reactant, and the aluminum-containing coarse titanium alloy is obtained.

In the invention, the ignition layer preferably comprises aluminum powder and an ignition agent, the ignition agent comprises potassium chlorate and/or sodium chlorate, and the mass ratio of the aluminum powder to the ignition agent is 1: 2. In the invention, the mass ratio of the industrial titanium slag to the aluminum powder in the ignition layer is preferably 100-120: 3 to 4.

In the present invention, said ignition is preferably carried out in the apparatus disclosed in CN 201920613590.3. In a specific embodiment of the invention, industrial titanium slag, aluminum powder, calcium oxide, calcium fluoride and an explosive are mixed to obtain a reactant, wherein the explosive comprises potassium chlorate and/or sodium chlorate; the specific process for obtaining the aluminum-containing crude titanium alloy is preferably as follows: weighing industrial titanium slag, aluminum powder, calcium oxide, calcium fluoride and an explosion initiating agent, uniformly mixing, putting into a graphite crucible, putting an ignition layer on the mixture again, putting a molybdenum wire on the ignition layer, switching on an igniter, and allowing the reaction to rapidly occur, wherein an aluminum-containing coarse titanium alloy is settled at the bottom of the crucible after the reaction is finished.

After the aluminum-containing crude titanium alloy is obtained, molten salt electrolytic refining is carried out on the aluminum-containing crude titanium alloy to obtain refined titanium.

In the invention, the temperature of the molten salt electrolytic refining is preferably 800-900 ℃, the polar distance is preferably 8-15 cm, the cell voltage of an electrolytic cell is preferably 0.6-1.8V, and the cathode current density of high-purity titanium is preferably 0.8-1.0A/cm²The current density of the aluminum-containing coarse titanium alloy anode is preferably 0.8-1.0A/cm²The electrolysis time is preferably 20-30 h, the electrolysis atmosphere is preferably vacuum or argon, and the electrolyte is preferably NaCl-KCl-NaF-TiCl_xFused salt, x is 2 or 3. In the invention, aluminum-containing crude titanium alloy is used as a soluble anode, high-purity titanium is used as a cathode, and NaCl-KCl-NaF-TiCl_xFor molten salt electrolytes, by electrolysis, titanium and other metals having a more negative reduction potential will preferentially dissolve into the electrolyte in ionic form, and impurity elements having a more positive reduction potential than titanium will remain in the anode slime, so that only titanium and elements having a more negative reduction potential than it will be in the electrolyte, while at the cathode titanium will preferentially precipitate, so that at the cathodeRefined titanium can be obtained. In the aluminum-containing coarse titanium alloy, impurity elements such as Si, Ba, Na, K, Mg, Cu, Ni, Ag, Mo or Fe which have larger difference with the reduction potential of titanium ions are easier to remove by electrolysis, while elements such as Mn, Al, Zr, Zn, Cr or V which have electrode potential close to the reduction potential of titanium ions are harder to remove.

In the present invention, the electrolyte is preferably prepared by a method comprising the steps of:

mixing NaCl, KCl and NaF, and drying to obtain a mixture;

In the invention, the mass ratio of NaCl to KCl to NaF is preferably 1-2: 1-0.5.

In the invention, the electrolytic cell is preferably subjected to pretreatment, and the pretreatment is preferably that all parts in the electrolytic cell, particularly an inner crucible, a cathode and anode rod, an anode basket and the like are polished by sand paper to remove surface oxides, then the parts are washed twice by hydrochloric acid and three times by deionized water in sequence, and the parts are installed after drying.

In the present invention, it is preferable that NaCl, KCl and NaF are mixed and then added to the inner crucible, and then vacuum-evacuated and dried at elevated temperature to obtain a mixture. In the present invention, moisture seriously degrades the quality of the electrolytic product, raising O, H content; the drying process of the molten salt is therefore very critical.

After the mixture is obtained, TiCl is reacted in the invention₄Adding into an electrolytic bath to react with a high-purity titanium cathode to obtain TiCl₃And TiCl₂Dissolving into the mixture to obtain the electrolyte.

In the present invention, the TiCl₄The amount of (b) is preferably 10 to 15% of the mass of the mixture.

In the invention, after the electrolyte is preferably obtained, hydrogen is filled to positive pressure, the temperature is raised to the electrolysis temperature, the cathode and the anode are lowered, the direct-current power supply is switched on, the electrolysis is carried out according to the preset electrolysis parameters, after the electrolysis is carried out for a certain time, the cathode and the anode are lifted, and the electrolysis is finished when the power is cut off.

In the invention, the method preferably further comprises the steps of sequentially crushing, hydrolyzing, carrying out first acid leaching and carrying out second acid leaching on the obtained cathode plate sediment, wherein 1-2 wt% of hydrochloric acid is used for the first acid leaching, the solid-to-liquid ratio is 1-2: 5-10, the first acid leaching is carried out for 30-40 minutes under a ventilation condition, 0.5-1 wt% of hydrochloric acid is used for the second acid leaching, the solid-to-liquid ratio is 1-2: 5-8, and the second acid leaching is carried out for 30-40 minutes under a ventilation condition.

In the present invention, it is preferable that the second acid leaching further comprises washing the second acid leaching extract with water to neutrality, and then vacuum-drying the second acid leaching extract to obtain the refined titanium.

After the refined titanium is obtained, the invention carries out electron beam melting on the refined titanium to obtain the high-purity titanium, wherein the mass content of titanium in the high-purity titanium is not less than 99.99%.

In the present invention, the degree of vacuum of the electron beam melting is preferably 2.6 × 10^-3～2.6×10^-2Pa, the temperature is preferably 3000-4000 ℃, the specific electric energy is preferably 2-3 kWh/kgTi, the melting power is preferably 120-125 kW, the melting rate is preferably 50-60 kg/h, and the time is preferably 4-5 hours.

In order to further illustrate the present invention, the method for preparing high purity titanium using industrial titanium slag according to the present invention will be described in detail with reference to examples, but they should not be construed as limiting the scope of the present invention.

Example 1

Taking Panzhihua blast furnace titanium slag as an example, the Panzhihua blast furnace titanium slag contains 22-26 wt% of titanium dioxide and also contains silicon dioxide, and the silicon dioxide is found through thermodynamic analysis to be capable of carrying out reduction reaction with aluminum under the condition of sufficient heat and entering aluminum-silicon alloy.

Weighing 500g of titanium slag, 260g of aluminum powder, 80.28g of calcium oxide, 30.08g of calcium fluoride and 150g of potassium chlorate, uniformly mixing, putting into a graphite crucible of a device disclosed in patent CN201920613590.3, putting 30g of potassium chlorate and 15g of aluminum powder on reactants again to play a role of an ignition agent, putting a molybdenum wire on the ignition agent, switching on an igniter, enabling the reaction to rapidly occur, and settling metal at the bottom of the crucible after the reaction is finished to obtain the aluminum-containing crude titanium alloy. And taking out the obtained metal to prepare a metallographic sample, and then carrying out SEM and EDS component analysis on the metallographic sample. The physical diagram of the obtained aluminum-containing crude titanium alloy is shown in fig. 1, and fig. 2 is an SEM diagram of the aluminum-containing crude titanium alloy, and it can be seen from the diagram that the obtained aluminum-containing crude titanium alloy is relatively dense, and the phase composition is two phases, i.e., a light gray region (matrix phase) and a white region (second phase), but the distribution of the second phase is relatively insignificant. FIG. 3 is an SEM and EDS spectra of a second phase of the aluminum-containing crude titanium alloy obtained in example 1, wherein (a) and (b) are SEM images of the second phase of the aluminum-containing crude titanium alloy at different magnifications, (c) is an EDS spectrum of the second phase of the aluminum-containing crude titanium alloy at the point indicated by 1 in (a), (d) is an EDS spectrum of the second phase of the aluminum-containing crude titanium alloy at the point indicated by 4 in (b), and the mass percentages of Al, Si, Ti, V and Mo in (c) are respectively 0.46%, 38.32%, 47.76%, 4.72% and 8.74%; (d) wherein the mass percentages of Al, Si, Ti, V and Mo are respectively 12.0%, 33.97%, 41.75%, 3.03% and 9.26%. The main components of the second phase are metallic titanium and silicon, Mo is introduced into the alloy because the molybdenum wire for initiating the reaction is melted in the reaction process;

FIG. 4 is SEM and EDS spectra of the aluminum-containing crude titanium alloy matrix phase obtained in example 1, wherein (a) and (b) are SEM images of the aluminum-containing crude titanium alloy matrix phase at different magnifications, (c) is an EDS spectrum of the aluminum-containing crude titanium alloy matrix phase at the point 3 of the spectrum indicated in (a), (d) is an EDS spectrum of the aluminum-containing crude titanium alloy matrix phase at the point 6 of the spectrum indicated in (b), and the mass percentages of Al, Si, Ti, V and Mo in (c) are 58.56%, 8.96%, 24.34%, 4.25% and 3.90%, respectively; (d) wherein the mass percentages of Al, Si, Ti, V and Mo are 58.98%, 7.89%, 25.05%, 4.51% and 3.57%, respectively. It is stated that the main components of the matrix phase are metallic aluminum and titanium, and since it is necessary to ensure sufficient heat during the reaction, the amount of aluminum added is excessive, which results in a high aluminum content in the alloy to be finally obtained. The presence of silicon, in turn, demonstrates that the aluminum also reacts with the silica, and that Mo is introduced into the alloy as a result of the molybdenum wire used to initiate the reaction melting during the reaction. The presence of the second phase indicates that segregation occurs to some extent during cooling and solidification of the metal at the end of the reaction, and silicon is mainly present in these phases.

Molten salt electrolysis refining of aluminum-containing crude titanium alloy

1, equipment and molten salt pretreatment: all the parts inside the cell, in particular the inner crucible, the cathode and anode rods, the anode basket, etc., have the possibility of introducing impurities into the electrolysis product, thus requiring a pre-treatment of all the parts. All the parts are polished by sand paper to remove oxides on the surfaces, then acid-washed hydrochloric acid is used twice, deionized water is used for washing three times, and all the parts are installed after drying. Then a certain amount of NaCl-KCl-NaF mixture (the mass ratio is 1:1:1) is added into the inner crucible, the inner crucible is vacuumized and heated to be dried, the quality of an electrolysis product is seriously reduced by moisture in the molten salt, the O, H content is increased, and therefore the drying process of the molten salt is very critical.

2, preparing low-valence titanium molten salt: after the molten salt is dried, the furnace temperature is continuously raised, and a certain amount of TiCl is added into the electrolytic cell₄(in an amount of 10 wt% of the NaCl-KCl-NaF mixture), TiCl₄Will react with the titanium sponge in the anode basket to generate TiCl₃And TiCl₂，TiCl₃And TiCl₂Has higher solubility in the molten salt, can be quickly dissolved in the molten salt to form NaCl-KCl-NaF-TiCl_xAnd (3) melting salt. This process lasts for about 3 hours, depending on the desired concentration of titanium suboxide.

3 electrolyzing to obtain NaCl-KCl-NaF-TiCl_xAnd after the molten salt is prepared, filling hydrogen to positive pressure, heating to the electrolysis temperature, lowering the cathode and the anode, switching on a direct current power supply, and electrolyzing according to preset electrolysis parameters. After the electrolysis is carried out for a certain time, the cathode and the anode are lifted, and the electrolysis is finished after power failure.

Table 1 shows the parameters of the molten salt electrorefining process

The optimal process conditions are that the electrolysis temperature is 850 ℃, and the anode current density is less than 0.9A/cm²Cathode current density of 0.9A/cm²And the electrolysis time is 25 h. The chemical composition of the electrolytic titanium obtained by electrolysis is tested by an ICP-AES method, wherein the contents of Ni, Si, Al, Fe and Mn are all less than 10 ppm.

The molten salt electrolytic refining process conditions are as follows: anode current density 0.8A/cm at 800 deg.C²Cathode current density of 0.8A/cm²Electrolyzing for 20 hours, wherein the contents of Ni, Si, Al, Fe and Mn are all more than 10 ppm; 900 ℃ and anode current density of 1A/cm²Cathode current density 1A/cm²And when the electrolysis is carried out for 30 hours, the contents of Al, Fe and Mn are all more than 10 ppm.

4, cathode product treatment: taking and crushing the sediment of the cathode plate, and removing the salt in an acid leaching way to prevent a large amount of low-valent titanium compounds from being hydrolyzed. The leaching process is divided into two stages, 1% hydrochloric acid is used in the first stage of removal, the solid-to-liquid ratio is 1:5, and the leaching time is 30 minutes under the ventilation condition; in the second stage, 0.5% hydrochloric acid is used, the solid-liquid ratio is 1:5, and the leaching time is 30 minutes under the ventilation condition. After leaching, washing the obtained metal particles with deionized water until the metal particles are neutral, wherein the solid-liquid ratio is 1:5, 10 minutes each time, and after washing, carrying out suction filtration and vacuum drying for 24 hours.

Charging the electrorefining titanium into an electron beam melting furnace with the vacuum degree of 2.6 multiplied by 10^-3Pa, the temperature is 3000 ℃, the specific electric energy is 3kWh/kgTi, the melting power is 125kW, the melting rate is 60kg/h, the smelting is carried out for 5 hours, and finally, the high-purity titanium ingot is prepared. GDMS analysis shows that the impurities in the high-purity titanium are less than 1ppm, the aluminum is 1ppm, and the purity of the titanium is 99.999 percent, so that the impurity content reaches or exceeds the 4N5 standard, and the result shows that the impurity Al content can be further reduced in the electron beam melting process.

Example 2

Taking titanium slag of a certain submerged arc furnace as an example, the titanium slag contains 40-45 wt% of titanium dioxide.

Weighing 600g of titanium slag, 280g of aluminum powder, 90.28g of calcium oxide, 32.05g of calcium fluoride and 160g of potassium chlorate, uniformly mixing, putting into a graphite crucible of a device disclosed in patent CN201920613590.3, putting 30g of potassium chlorate and 15g of aluminum powder on reactants again to play a role of an ignition agent, putting a molybdenum wire on the ignition agent, switching on an igniter to enable the reaction to occur rapidly, and settling metal at the bottom of the crucible after the reaction is finished to obtain the aluminum-containing crude titanium alloy.

Molten salt electrolysis refining of aluminum-containing crude titanium alloy

The electrolysis temperature is 800 ℃, and the anode current density is 0.85A/cm²Cathode current density 1.0A/cm²And the electrolysis time is 24 h. The chemical composition of the electrolytic titanium obtained by electrolysis is tested by an ICP-AES method, wherein the contents of Ni, Si, Al, Fe and Mn are all less than 10 ppm.

Charging the electrorefining titanium into an electron beam melting furnace with the vacuum degree of 2.6 multiplied by 10^-2Pa, the temperature is 2500 ℃, the specific electric energy is 2kWh/kgTi, the melting power is 120kW, the melting rate is 50kg/h, the smelting is carried out for 4 hours, and finally, the high-purity titanium ingot is prepared. GDMS analysis shows that the impurities in the high-purity titanium are less than 1ppm, the aluminum is 1ppm, and the purity of the titanium is 99.999 percent, so that the impurity content reaches or exceeds the 4N5 standard, and the result shows that the impurity Al content can be further reduced in the electron beam melting process.

The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be construed as the protection scope of the present invention.

Claims

1. A method for preparing high-purity titanium by using industrial titanium slag is characterized by comprising the following steps:

2. The preparation method according to claim 1, wherein the mass ratio of the industrial titanium slag to the aluminum powder to the calcium oxide to the calcium fluoride to the detonation agent is 500-600: 260-280 parts of: 80.28-90.28: 30.08-32.05: 150 to 160.

3. The method according to claim 1 or 2, wherein the reactant further comprises magnesium oxide.

4. The preparation method according to claim 1, wherein the ignition layer comprises aluminum powder and an ignition agent, the ignition agent comprises potassium chlorate and/or sodium chlorate, and the mass ratio of the aluminum powder to the ignition agent is 1: 2.

5. The preparation method according to claim 1, wherein the temperature of the molten salt electrorefining is 800-900 ℃, the polar distance is 8-15 cm, the cell voltage of the electrolytic cell is 0.6-1.8V, and the cathode current density of the high-purity titanium is 0.8-1.0A/cm²The current density of the aluminum-containing coarse titanium alloy anode is 0.8-1.0A/cm²The electrolysis time is 20-30 h, the electrolysis atmosphere is vacuum or argon, and the electrolyte is NaCl-KCl-NaF-TiCl_xFused salt, x is 2 or 3.

6. The production method according to claim 5, wherein the electrolyte is produced by a method comprising the steps of:

mixing NaCl, KCl and NaF, and drying to obtain a mixture;

7. The preparation method according to claim 6, wherein the mass ratio of NaCl, KCl and NaF is 1-2: 1-0.5.

8. The preparation method of claim 1, wherein the molten salt electrolytic refining further comprises the steps of crushing, hydrolyzing, primary acid leaching and secondary acid leaching the obtained cathode plate sediment in sequence, wherein the primary acid leaching is performed for 30-40 minutes under ventilation conditions by using 1-2 wt% of hydrochloric acid, the solid-to-liquid ratio is 1-2: 5-10, and the secondary acid leaching is performed for 30-40 minutes under ventilation conditions by using 0.5-1 wt% of hydrochloric acid, the solid-to-liquid ratio is 1-2: 5-8.

9. The method according to claim 8, wherein the second acid leaching further comprises washing the second acid leaching extract with water to neutrality, and vacuum-drying the second acid leaching extract to obtain the refined titanium.

10. The production method according to claim 1, wherein the degree of vacuum of the electron beam melting is 2.6 x 10^-3Pa, the temperature is 3000-4000 ℃, and the time is 4-5 hours.