DEVICE AND METHOD FOR PREPARING PURE TITANIUM BY ELECTROLYSIS-CHLORINATION-ELECTROLYSIS

Abstract

A device and a method for preparing pure titanium by electrolysis-chlorination-electrolysis, wherein the device includes a first electrolytic cell, a second electrolytic cell, a chlorination reactor and guide tubes. The Cl.sub.2 generated at the anode of the first electrolytic cell is introduced into a chlorination reactor containing the TiC.sub.xO.sub.y or TiC.sub.xO.sub.yN.sub.z raw materials via a guide tube, and a chlorination is carried out to generate TiCl.sub.4 gas at a temperature of 200 C.-600 C. The TiCl.sub.4 gas passes through a guide tube into a cathode of the second electrolytic cell, and then an electrolysis is performed to obtain the high-purity titanium in the second electrolytic cell. At the same time, the Cl.sub.2 generated at the anode of the second electrolytic cell is recycled into the chlorination reactor in the first electrolytic cell to continue to participate in the chlorination of TiC.sub.xO.sub.y or TiC.sub.xO.sub.yN.sub.z.

Claims

1. A device for preparing pure titanium by electrolysis-chlorination-electrolysis, comprising a first electrolytic cell, a second electrolytic cell, a chlorination reactor and a plurality of guide tubes; wherein, the first electrolytic cell and the second electrolytic cell are horizontally disposed; a first heating and temperature controlling system is provided at a bottom and a periphery of the first electrolytic cell and a bottom and a periphery of the second electrolytic cell to control a temperature of a electrolyte in the first electrolytic cell and the second electrolytic cell; the chlorination reactor is located at an upper position of an anode of the first electrolytic cell, and a porous ceramic partition plate is disposed at a bottom of the chlorination reactor; a shell of the chlorination reactor is made of steel, and the chlorination reactor is lined with a ceramic material; a second heating and temperature controlling system is arranged outside the chlorination reactor to control a temperature of materials inside the chlorination reactor; a first guide tube of the plurality of guide tubes is located at a position of the anode in the first electrolytic cell and is connected to the bottom of the chlorination reactor; a first end of a second guide tube of the plurality of guide tubes is connected to a top of the chlorination reactor, and a second end of the second guide tube is located at a position of a cathode in the second electrolytic cell; a first end of a third guide tube of the plurality of guide tubes is located at a position of an anode in the second electrolytic cell, and a second end of the third guide tube is connected to the first guide tube in the first electrolytic cell; the plurality of guide tubes are made of steel and are lined with ceramic or polytetrafluoroethylene.

2. A method for preparing pure titanium by means of the device of claim 1, comprising: 1) uniformly mixing titanium dioxide and carbonaceous material powder according to a stoichiometric ratio to obtain a mixture and performing a press molding on the mixture, in a temperature range of 900 C. to 1600 C., preparing TiC.sub.xO.sub.y in vacuum or TiC.sub.xO.sub.yN.sub.z in a nitrogen atmosphere to introduce into the chlorination reactor; 2) in the first electrolytic cell, using a molten alkali metal chloride, a molten alkaline earth metal chloride, molten aluminum chloride or a mixture of the molten alkali metal chloride, the molten alkaline earth metal chloride and the molten aluminum chloride as a supporting electrolyte, using a carbon material as an anode and a metal material as a cathode, controlling a temperature of the first electrolytic cell at 150 C. to 1000 C., and controlling a temperature of the chlorination reactor at 200 C. to 600 C.; wherein after an electrolysis starts, Cl.sup. migrates to the anode and reacts to produce Cl.sub.2; the Cl.sub.2 at the anode passes through a porous partition plate and enters the chlorination reactor via the first guide tube and reacts with TiC.sub.xO.sub.y or TiC.sub.xO.sub.yN.sub.z in the chlorination reactor to produce TiCl.sub.4 gas; the TiCl.sub.4 gas enters the cathode of the second electrolytic cell via the second guide tube; 3) in the second electrolytic cell, using a molten alkali metal chloride, a molten alkaline earth metal chloride or a mixture of the molten alkali metal chloride and the molten alkaline earth metal chloride as a supporting electrolyte, using a carbon material as an anode and a metal material as a cathode, and controlling a temperature of the second electrolytic cell at 500 C. to 1000 C.; wherein after an electrolysis starts, the TiCl.sub.4 gas transported by the second guide tube enters the the supporting electrolyte at a position of the cathode of the second electrolytic cell, Ti.sup.4+ reacts at the cathode to generate low-valent titanium ions, and the low-valent titanium ions continue to react for deposition to obtain pure titanium at the cathode, and the reaction is as follows:
Ti.sup.4++e=Ti.sup.3+
Ti.sup.3++e=Ti.sup.2+
Ti.sup.2++2e=Ti Cl.sup. migrates to an anode of the second electrolytic cell and generates Cl.sub.2 at the anode of the second electrolytic cell; then, the Cl.sub.2 is transported into the first guide tube via the third guide tube, and is mixed with the Cl.sub.2 generated at the anode of the first electrolytic cell to enter the chlorination reactor to participate in a chlorination of TiC.sub.xO.sub.y or TiC.sub.xO.sub.yN.sub.z; 4) after an end of one electrolysis cycle, taking a first product at the cathode of the first electrolytic cell and a second product at the cathode of the second electrolytic cell, and performing pickling, washing, and drying on the first product and the second product; wherein the second product is high-purity titanium, and the first product is byproducts including alkali metal, alkaline earth metal, aluminum or alloy; 5) after completing the step 4), mounting the cathode of the first electrolytic cell into the first electrolytic cell and mounting the cathode of the second electrolytic cell into the second electrolytic cell, and putting new TiC.sub.xO.sub.y or TiC.sub.xO.sub.yN.sub.z raw material into the chlorination reactor for a new round of operation to produce the high-purity titanium by electrolysis.

3. The method for preparing the pure titanium according to claim 2, wherein, the carbonaceous material powder is one or a combination of graphite, petroleum coke, carbon black, coal, and charcoal.

4. The method for preparing the pure titanium according to claim 2, wherein, a ratio of a number of oxygen atoms in the titanium dioxide to a number of carbon atoms in the carbon material powder is 1.2:1-0.5:1.

5. The method for preparing the pure titanium according to claim 2, wherein, a ratio of a number of oxygen atoms in the titanium dioxide to a number of carbon atoms in the carbon material powder is 1:1-0.667:1.

6. The method for preparing the pure titanium according to claim 2, wherein, the metal material for the cathode in the first electrolytic cell and the metal material for the cathode in the second electrolytic cell are titanium, carbon steel or nickel.

7. The method for preparing the pure titanium according to claim 2, wherein, during the electrolysis in the first electrolytic cell, current densities are 0.01 A/cm.sup.2 to 2.00 A/cm.sup.2 at the anode and 0.01 A/cm.sup.2 to 2.00 A/cm.sup.2 at the cathode; and during the electrolysis in the second electrolytic cell, current densities are 0.01 A/cm.sup.2 to 2.00 A/cm.sup.2 at the anode and 0.01 A/cm.sup.2 to 2.00 A/cm.sup.2 at the cathode.

8. The method for preparing the pure titanium according to claim 4, wherein, the ratio is 1:1-0.667:1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIGURE is a schematic diagram of a device for preparing pure titanium by electrolysis-chlorination-electrolysis according to the present disclosure.

[0028] In the FIGURE: 1. first electrolytic cell, 2. second electrolytic cell, 3. chlorination reactor, 4. porous ceramic partition plate, 5. first guide tube, 6. second guide tube, 7. third guide tube.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiment 1

[0029] Titanium dioxide and graphite powder are uniformly mixed at a mass ratio of 40:12, and then press-molded and sintered for 3 hours at 1400 C. in vacuum to obtain TiC.sub.0.5O.sub.0.5. The TiC.sub.0.5O.sub.0.5 is put into a chlorination reactor. The first electrolytic cell uses a NaClAlCl.sub.3 eutectic salt as an electrolyte, and the second electrolytic cell uses a NaClKCl eutectic salt as an electrolyte. The two electrolytic cells are protected by inert gas. During the electrolysis, in the first electrolytic cell, the temperature is controlled at 150 C., and both the cathode and the anode are made of graphite, the current density at the cathode is 0.5 A/cm.sup.2 and the current density at the anode is 1 A/cm.sup.2; in the second electrolytic cell, the temperature is controlled at 750 C., the anode is made of graphite, the cathode is made of a nickel plate, the current density at the cathode is 1 A/cm.sup.2 and the current density at the anode is 2 A/cm.sup.2. After the end of one electrolysis cycle, high-purity titanium is collected from the cathode, made of the nickel plate, of the second electrolytic cell, and the high-purity titanium is processed by pickling, washing, drying, and encapsulation to obtain the powder or crystal of the high-purity titanium. The aluminum is collected from the cathode of the first electrolytic cell.

Embodiment 2

[0030] Titanium dioxide and graphite powder are uniformly mixed at a mass ratio of 40:15, and then press-molded and sintered for 2 hours at 1600 C. in vacuum to obtain TiC.sub.0.25O.sub.0.75. The TiC.sub.0.25O.sub.0.75 is put into a chlorination reactor. The first electrolytic cell uses a NaClMgCl.sub.2AlCl.sub.3 eutectic salt as an electrolyte, and the second electrolytic cell uses a NaClLiClKCl eutectic salt as an electrolyte. The two electrolytic cells are protected by inert gas. During the electrolysis, in the first electrolytic cell, the temperature is controlled at 550 C., and both the cathode and the anode are made of graphite, the current density at the cathode is 0.5 A/cm.sup.2 and the current density at the anode is 1.5 A/cm.sup.2; in the second electrolytic cell, the temperature is controlled at 600 C., the anode is made of graphite, the cathode is made of a titanium plate, the current density at the cathode is 0.5 A/cm.sup.2 and the current density at the anode is 1 A/cm.sup.2. After the end of one electrolysis cycle, high-purity titanium is collected from the cathode, made of the titanium plate, of the second electrolytic cell, and the high-purity titanium is processed by pickling, washing, drying, and encapsulation to obtain the powder or crystal of the high-purity titanium. The magnesium-aluminum alloy is collected from the cathode of the first electrolytic cell.

Embodiment 3

[0031] Titanium dioxide and graphite powder are uniformly mixed at a mass ratio of 40:12, and then press-molded and sintered for 3 hours at 1300 C. in a nitrogen atmosphere to obtain TiC.sub.0.2O.sub.0.2N.sub.0.6. The TiC.sub.0.2O.sub.0.2N.sub.0.6 is put into a chlorination reactor. The first electrolytic cell uses a LiClKCl eutectic salt as an electrolyte, and the second electrolytic cell uses a NaClCaCl eutectic salt as an electrolyte. The two electrolytic cells are protected by inert gas. During the electrolysis, in the first electrolytic cell, the temperature is controlled at 750 C., and both the cathode and the anode are made of graphite, the current density at the cathode is 0.2 A/cm.sup.2 and the current density at the anode is 1.5 A/cm.sup.2; in the second electrolytic cell, the temperature is controlled at 800 C., the anode is made of graphite, the cathode is made of a nickel plate, the current density at the cathode is 0.5 A/cm.sup.2 and the current density at the anode is 1.5 A/cm.sup.2. After the end of one electrolysis cycle, high-purity titanium is collected from the cathode, made of the nickel plate, of the second electrolytic cell, and the high-purity titanium is processed by pickling, washing, drying, and encapsulation to obtain the powder or crystal of the high-purity titanium. The potassium is collected from the cathode of the first electrolytic cell.

[0032] Of course, the present invention may have many different embodiments, and various changes and modifications can be made to the present disclosure by those skilled in the art without deviating from the technical essence of the present disclosure. Such corresponding changes and modifications shall fall within the protection scope of the claims of the present invention.