METHOD FOR PREPARING METALLIC TITANIUM BY MOLTEN SALT ELECTROLYSIS REDUCTION OF TITANIUM DIOXIDE
20240240344 ยท 2024-07-18
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Abstract
The present application relates to a method for preparing metallic titanium by molten salt electrolysis reduction of titanium dioxide, the method includes: constructing an electrochemical system, including an anode chamber filled with an anodic molten salt electrolyte and inserted with an anode, and a cathode chamber filled with a cathodic molten salt electrolyte and inserted with a cathode, where the anodic molten salt electrolyte and the cathodic molten salt electrolyte are connected through a liquid alloy accommodated at an inner bottom of the electrolytic cell without contacting with each other; and adding titanium dioxide to the anode chamber, and energizing for electrolysis to obtain metallic titanium at the cathode. The method of the present application has advantages such as low requirements for the titanium dioxide raw material, simple process flow, low energy consumption, environmental friendliness, and direct acquisition of high-purity metallic titanium.
Claims
1. A method for preparing metallic titanium by molten salt electrolysis reduction of titanium dioxide, wherein the method is implemented with an electrolytic cell; the electrolytic cell comprises an anode chamber and a cathode chamber, the anode chamber is filled with an anodic molten salt electrolyte and inserted with an anode, the cathode chamber is filled with a cathodic molten salt electrolyte and inserted with a cathode, and a liquid alloy is accommodated at an inner bottom of the electrolytic cell; the anodic molten salt electrolyte and the cathodic molten salt electrolyte are connected through the liquid alloy without contacting with each other; and the method comprises: adding titanium dioxide to the anode chamber and powering on the electrolytic cell, the titanium dioxide in the anode chamber is reduced into titanium atoms at an interface between the anodic molten salt electrolyte and the liquid alloy and dissolved in the liquid alloy, the titanium atoms in the liquid alloy are oxidized into titanium ions at an interface between the liquid alloy and the cathodic molten salt electrolyte and enter the cathodic molten salt electrolyte, and the titanium ions to be reduced into titanium atoms on a surface of the cathode, thereby forming the metallic titanium.
2. The method for preparing metallic titanium through molten salt electrolysis reduction of titanium dioxide according to claim 1, wherein the anodic molten salt electrolyte and the cathodic molten salt electrolyte both are halide molten salts.
3. The method for preparing metallic titanium through molten salt electrolysis reduction of titanium dioxide according to claim 2, wherein the anodic molten salt electrolyte comprises one or more selected from the group consisting of CaCl.sub.2, BaCl.sub.2, LiCl, NaCl, KCl, CsCl, LiF, NaF, and KF.
4. The method for preparing metallic titanium through molten salt electrolysis reduction of titanium dioxide according to claim 2, wherein the cathodic molten salt electrolyte comprises TiCl.sub.2 and/or TiCl.sub.3, and one or more selected from the group consisting of LiCl, NaCl, KCl, CaCl.sub.2, and MgCl.sub.2.
5. The method for preparing metallic titanium through molten salt electrolysis reduction of titanium dioxide according to claim 1, wherein the anode is graphite, and the cathode is a stainless steel, tungsten, or molybdenum cathode.
6. The method for preparing metallic titanium through molten salt electrolysis reduction of titanium dioxide according to claim 1, wherein the liquid alloy is formed from a solute metal Ti and a matrix metal; the matrix metal has a lower metal activity than the titanium, and is mixed with the titanium to produce an alloy with a low melting point of lower than 1,000? C.; and preferably, the matrix metal is one or more selected from the group consisting of Cu, Sn, Sb, Zn, Pb, Bi, and Ni.
7. The method for preparing metallic titanium through molten salt electrolysis reduction of titanium dioxide according to claim 1, wherein an area of the cathode is 1 to 20 times an area of the anode; and when the electrolytic cell operates normally, an anode current density is 0.05 A/cm.sup.2 to 2.0 A/cm.sup.2 and a temperature is 400? C. to 1,000? C.
Description
BRIEF DESCRIPTION OF THE DRAWING
[0024]
[0025] where 1anode; 2anodic molten salt electrolyte; 3liquid alloy; 4titanium dioxide inlet; 5cathode; and 6cathodic molten salt electrolyte.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0026] To make the objectives, technical solutions, and advantages of the present application clearly, the technical solutions of the present application will be described in detail below. Apparently, the described examples are some rather than all of the examples of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the examples of the present application without creative efforts should fall within the protection scope of the present application.
[0027] The method for preparing metallic titanium through molten salt electrolysis reduction of titanium dioxide in the following examples of the present application is implemented with an electrolytic cell shown in
EXAMPLE 1
[0028] Anodic molten salt electrolyte: 200 g of CaCl.sub.2 was weighed. Cathodic molten salt electrolyte: NaCl and KCl were mixed according to a mass ratio of 1:1 to obtain 200 g of a mixture, and then 7.8 wt % low-valent titanium chloride (TiCl.sub.2: TiCl.sub.3: 4:1) was added. 400 g of a metal alloy was prepared from Cu, Sn, and Ti according to a mass ratio of 73:16:11.
[0029] The metal alloy was placed in the electrolytic cell and heated to 950? C. for melting; and the anodic molten salt electrolyte and the cathodic molten salt electrolyte were separately added to a crucible and melted. A graphite electrode was adopted as an anode, and stainless steel was adopted as a cathode. While titanium dioxide was added at a uniform rate to the anode chamber, an anode current density was controlled at 50 mA/cm.sup.2 (an area of the cathode was 1 time an area of the anode), and electrolysis was conducted for 24 h; [0030] 27 g of metallic titanium was replenished to the liquid metal, the original current density was remained, titanium dioxide was added at a uniform rate to the anode chamber, and electrolysis was conducted for 24 h; [0031] 27 g of metallic titanium was further replenished to the liquid metal, a current density of 50 mA/cm.sup.2 was further remained, titanium dioxide was further added at a uniform rate, and electrolysis was conducted for 24 h; and [0032] the cathode was taken out, and a mass of the cathode was measured to obtain 138.3 g of metallic titanium.
EXAMPLE 2
[0033] Anodic molten salt electrolyte: CaCl.sub.2 and NaCl were mixed according to a mass ratio of 54:46 to obtain 2 kg of a mixture. Cathodic molten salt electrolyte: NaCl and KCl were mixed according to a mass ratio of 1:1 to obtain 2 kg of a mixture, and then 8.7 wt % low-valent titanium chloride (TiCl.sub.2: TiCl.sub.3: 5:1) was added. 4 kg of a metal alloy was prepared from Sn and Ti according to a mass ratio of 90:10.
[0034] The metal alloy was placed in the electrolytic cell and heated to 900? C. for melting; and the anodic molten salt electrolyte and the cathodic molten salt electrolyte were separately added to a crucible and melted. A graphite electrode was adopted as an anode, and stainless steel was adopted as a cathode. While industrial titanium dioxide was added at a uniform rate to the anode chamber, an anode current density was controlled at 100 mA/cm.sup.2 (an area of the cathode was 1 time an area of the anode), and electrolysis was conducted for 12 h; [0035] 270 g of metallic titanium was replenished to the liquid metal, the original current density was remained, industrial titanium dioxide was added at a uniform rate to the anode chamber, and electrolysis was conducted for 12 h; [0036] 270 g of metallic titanium was further replenished to the liquid metal, a current density of 100 mA/cm.sup.2 was further remained, industrial titanium dioxide was further added at a uniform rate to the anode chamber, and electrolysis was conducted for 12 h; and [0037] the cathode was taken out, and a mass of the cathode was measured to obtain 1276.5 g of metallic titanium.
EXAMPLE 3
[0038] Anodic molten salt electrolyte: CaCl.sub.2 and KCl were mixed according to a mass ratio of 54:46 to obtain 200 g of a mixture. Cathodic molten salt electrolyte: NaCl and KCl were mixed according to a mass ratio of 1:1 to obtain 200 g of a mixture, and then 11.3 wt % low-valent titanium chloride (TiCl.sub.2) was added. 4,000 g of a metal alloy was prepared from Cu, Sn, and Ti according to a mass ratio of 23:74.5:2.5.
[0039] The metal alloy was placed in the electrolytic cell and heated to 700? C. for melting; and the anodic molten salt electrolyte and the cathodic molten salt electrolyte were separately added to a crucible and melted. A graphite electrode was adopted as an anode, and stainless steel was adopted as a cathode. While industrial titanium dioxide was added at a uniform rate to the anode chamber, an anode current density was controlled at 50 mA/cm.sup.2 (an area of the cathode was 1 time an area of the anode), and electrolysis was conducted for 24 h; [0040] 27 g of metallic titanium was replenished to the liquid metal, the original current density was remained, industrial titanium dioxide was added at a uniform rate to the anode chamber, and electrolysis was conducted for 24 h; [0041] 27 g of metallic titanium was further replenished to the liquid metal, a current density of 50 mA/cm.sup.2 was further remained, industrial titanium dioxide was further added at a uniform rate to the anode chamber, and electrolysis was conducted for 24 h; and [0042] the cathode was taken out, and a mass of the cathode was measured to obtain 145.39 g of metallic titanium.
EXAMPLE 4
[0043] Anodic molten salt electrolyte: 200 g of CaCl.sub.2 was weighed. Cathodic molten salt electrolyte: NaCl and KCl were mixed according to a mass ratio of 1:1 to obtain 200 g of a mixture, and then 10.6 wt % low-valent titanium chloride (TiCl.sub.3) was added. 400 g of a metal alloy was prepared from Cu, Sn, and Ti according to a mass ratio of 73:16:11.
[0044] The metal alloy was placed in the electrolytic cell and heated to 950? C. for melting; and the anodic molten salt electrolyte and the cathodic molten salt electrolyte were separately added to a crucible and melted. A graphite electrode was adopted as an anode, and stainless steel was adopted as a cathode. While titanium dioxide was added at a uniform rate to the anode chamber, an anode current density was controlled at 50 mA/cm.sup.2 (an area of the cathode was 1 time an area of the anode), and electrolysis was conducted for 24 h and then stopped.
[0045] The stainless steel cathode was taken out. A corundum tube wrapped with a metal W rod was connected to the liquid metal; tungsten at a top of the corundum tube was allowed to be in contact with the liquid metal, and tungsten at a bottom of the corundum tube was connected to a power supply; the electrode of the anode chamber was connected to an anode of the power supply, and the W rod was connected to a cathode of the power supply; and a current density was controlled at 50 mA/cm.sup.2, titanium dioxide was added at a uniform rate to the anode chamber, and electrolysis was conducted for 24 h and then stopped.
[0046] With a graphite electrode as an anode and a stainless steel plate as a cathode, while titanium dioxide was added at a uniform rate to the anode chamber, an electric field was applied, a current density was controlled at 50 mA/cm.sup.2, and electrolysis was conducted for 24 h and then stopped.
[0047] The cathode electrode was taken out and weighed to obtain 84.4 g of metallic titanium.
EXAMPLE 5
[0048] Anodic molten salt electrolyte: CaCl.sub.2 and BaCl.sub.2 were mixed according to a mass ratio of 35:65 to obtain 200 g of a mixture. Cathodic molten salt electrolyte: 200 g of NaCl was weighed, and then 9.3 wt % low-valent titanium chloride (TiCl.sub.2: TiCl.sub.3: 1:1) was added. 400 g of a metal alloy was prepared from Cu, Sn, and Ti according to a mass ratio of 73:16:11.
[0049] The metal alloy was placed in the electrolytic cell and heated to 1000? C. for melting; and the anodic molten salt electrolyte and the cathodic molten salt electrolyte were separately added to a crucible and melted. A graphite electrode was adopted as an anode, and stainless steel was adopted as a cathode. While titanium dioxide was added at a uniform rate to the anode chamber, an anode current density was controlled at 2,000 mA/cm.sup.2 (an area of the cathode was 1 time an area of the anode), and electrolysis was conducted for 1 h and then stopped.
[0050] The stainless steel cathode was taken out. A corundum tube wrapped with a metal W rod was connected to the liquid metal; tungsten at a top of the corundum tube was allowed to be in contact with the liquid metal, and tungsten at a bottom of the corundum tube was connected to a power supply; the electrode of the anode chamber was connected to an anode of the power supply, and the W rod was connected to a cathode of the power supply; and a current density was controlled at 2,000 mA/cm.sup.2, titanium dioxide was added at a uniform rate to the anode chamber, and electrolysis was conducted for 1 h and then stopped.
[0051] With a graphite electrode as an anode and a stainless steel plate as a cathode, while titanium dioxide was added slowly to the anode chamber, an electric field was applied, a current density was controlled at 2,000 mA/cm.sup.2, and electrolysis was conducted for 1 h and then stopped.
[0052] The cathode electrode was taken out and weighed to obtain 60.3 g of metallic titanium.
EXAMPLE 6
[0053] Anodic molten salt electrolyte: CaCl.sub.2, LiCl, and NaCl were mixed according to a mass ratio of 8:1:1 to obtain 200 g of a mixture. Cathodic molten salt electrolyte: NaCl and KCl were mixed according to a mass ratio of 1:1 to obtain 200 g of a mixture, and then 8.5 wt % low-valent titanium chloride (TiCl.sub.2: TiCl.sub.3: 3:1) was added. 400 g of a metal alloy was prepared from Cu and Ti according to a mass ratio of 3:1.
[0054] The metal alloy was placed in the electrolytic cell and heated to 950? C. for melting; and the anodic molten salt electrolyte and the cathodic molten salt electrolyte were separately added to a crucible and melted. A graphite electrode was adopted as an anode, and stainless steel was adopted as a cathode. While titanium dioxide was added at a uniform rate to the anode chamber, an anode current density was controlled at 1,000 mA/cm.sup.2 (an area of the cathode was 10 times an area of the anode), and electrolysis was conducted for 2 h; [0055] 22 g of metallic titanium was replenished to the liquid metal, the original current density was remained, titanium dioxide was added at a uniform rate to the anode chamber, and electrolysis was conducted for 2 h; [0056] 22 g of metallic titanium was further replenished to the liquid metal, a current density of 1,000 mA/cm.sup.2 was further remained, titanium dioxide was further added at a uniform rate to the anode chamber, and electrolysis was conducted for 2 h; and [0057] the cathode was taken out, and a mass of the cathode was measured to obtain 133.4 g of metallic titanium.
EXAMPLE 7
[0058] Anodic molten salt electrolyte: CaCl.sub.2, LiCl, and NaCl were mixed according to a mass ratio of 8:1:1 to obtain 200 g of a mixture. Cathodic molten salt electrolyte: NaCl and KCl were mixed according to a mass ratio of 1:1 to obtain 200 g of a mixture, and then 8 wt % low-valent titanium chloride (TiCl.sub.2) was added. 1,000 g of a metal alloy was prepared from Sb and Ti according to a mass ratio of 96:4.
[0059] The metal alloy was placed in the electrolytic cell and heated to 900? C. for melting; and the anodic molten salt electrolyte and the cathodic molten salt electrolyte were separately added to a crucible and melted. A graphite electrode was adopted as an anode, and stainless steel was adopted as a cathode. While a high-titanium slag powder (TiO.sub.2>94%) was added at a uniform rate to the anode chamber, an anode current density was controlled at 50 mA/cm.sup.2 (an area of the cathode was 20 times an area of the anode), and electrolysis was conducted for 24 h, where during the electrolysis, a reverse current of 1 min was increased every 29 min; [0060] 27 g of metallic titanium was replenished to the liquid metal, the original current density was remained, the high-titanium slag powder was added at a uniform rate to the anode chamber, and electrolysis was conducted for 24 h; [0061] 27 g of metallic titanium was further replenished to the liquid metal, a current density of 50 mA/cm.sup.2 was further remained, the high-titanium slag powder was further added at a uniform rate to the anode chamber, and electrolysis was conducted for 24 h; and [0062] the cathode was taken out, and a mass of the cathode was measured to obtain 142.9 g of metallic titanium.
EXAMPLE 8
[0063] Anodic molten salt electrolyte: CaCl.sub.2 and LiCl were mixed according to a mass ratio of 54:46 to obtain 200 g of a mixture. Cathodic molten salt electrolyte: NaCl and KCl were mixed according to a mass ratio of 1:1 to obtain 200 g of a mixture, and then 11.3 wt % low-valent titanium chloride (TiCl.sub.2) was added. 4,000 g of a metal alloy was prepared from Cu, Sn, and Ti according to a mass ratio of 23:74.5:2.5.
[0064] The metal alloy was placed in the electrolytic cell and heated to 700? C. for melting; and the anodic molten salt electrolyte and the cathodic molten salt electrolyte were separately added to a crucible and melted. A graphite electrode was adopted as an anode, and stainless steel was adopted as a cathode. While industrial titanium dioxide was added at a uniform rate to the anode chamber, an anode current density was controlled at 50 mA/cm.sup.2 (an area of the cathode was 1 time an area of the anode), and electrolysis was conducted for 24 h; [0065] a circuit was disconnected; a corundum rod wrapped with a metal wire was inserted into the liquid alloy, with a metal end in contact with the liquid alloy; with the graphite electrode of the anode chamber as an anode and the metal wire connected to the cathode, energization was conducted for 24 h to make a metallic titanium content in the liquid alloy reach an initial content; then the cathode of the corundum rod (internal metal wire) was taken out, and the stainless steel of the cathode chamber was allowed to serve as a cathode; the original current density was remained, industrial titanium dioxide was further added at a uniform rate to the anode chamber, and electrolysis was conducted for 24 h; [0066] 27 g of metallic titanium was further replenished to the liquid metal, a current density of 50 mA/cm.sup.2 was further remained, industrial titanium dioxide was further added at a uniform rate to the anode chamber, and electrolysis was conducted for 24 h; and [0067] the cathode was taken out, and a mass of the cathode was measured to obtain 145.39 g of metallic titanium.
EXAMPLE 9
[0068] Anodic molten salt electrolyte: LiCl and KCl were mixed according to a mass ratio of 45:55 to obtain 200 g of a mixture. Cathodic molten salt electrolyte: LiCl and KCl were mixed according to a mass ratio of 45:55 to obtain 200 g of a mixture, and then 2.3 wt % low-valent titanium chloride (TiCl.sub.2) was added. 4,000 g of a metal alloy was prepared from Sn and Ti according to a mass ratio of 99.7:0.3.
[0069] The metal alloy was placed in the electrolytic cell and heated to 400? C. for melting; and the anodic molten salt electrolyte and the cathodic molten salt electrolyte were separately added to a crucible and melted. A graphite electrode was adopted as an anode, and tungsten was adopted as a cathode. While industrial titanium dioxide was added at a uniform rate to the anode chamber, an anode current density was controlled at 0.05 A/cm.sup.2 (an area of the cathode was 20 times an area of the anode), and electrolysis was conducted for 24 h; [0070] a circuit was disconnected; a corundum rod wrapped with a metal wire was inserted into the liquid alloy, with a metal end in contact with the liquid alloy; with the graphite electrode of the anode chamber as an anode and the metal wire connected to the cathode, energization was conducted for 24 h to make a metallic titanium content in the liquid alloy reach an initial content; then the cathode of the corundum rod (internal metal wire) was taken out, and the stainless steel of the cathode chamber was allowed to serve as a cathode; the original current density was remained, industrial titanium dioxide was further added at a uniform rate to the anode chamber, and electrolysis was conducted for 24 h; [0071] 27 g of metallic titanium was further replenished to the liquid metal, a current density of 50 mA/cm.sup.2 was further remained, industrial titanium dioxide was further added at a uniform rate to the anode chamber, and electrolysis was conducted for 24 h; and [0072] the cathode was taken out, and a mass of the cathode was measured, obtain metallic titanium.
COMPARATIVE EXAMPLE
[0073] Anodic molten salt electrolyte: 200 g of CaCl.sub.2 was weighed. Cathodic molten salt electrolyte: NaCl, KCl, TiCl.sub.2, and TiCl.sub.3 were mixed according to a mass ratio of 1:1 to obtain 200 g of a mixture, and then 7.8 wt % low-valent titanium chloride (TiCl.sub.2: TiCl.sub.3: 4:1) was added. 400 g of a metal alloy was prepared from Cu and Sn according to a mass ratio of 3:1.
[0074] The metal alloy was placed in the electrolytic cell and heated to 950? C. for melting; and the anodic molten salt electrolyte and the cathodic molten salt electrolyte were separately added to a crucible and melted. A graphite electrode was adopted as an anode, and stainless steel was adopted as a cathode. While titanium dioxide was added at a uniform rate to the anode chamber, the same current density as in the examples was controlled (an area of the cathode was 1 time an area of the anode), and electrolysis was conducted for 24 h.
[0075] A metallic titanium with high tin contents was produced at the cathode.
[0076] The above are merely specific implementations of the present application, but are not intended to limit the protection scope of the present application. Any variation or replacement readily conceived by a person skilled in the art within the technical scope disclosed in the present application shall fall within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.