Method for preparing titanium metal by molten salt electrolysis

Abstract

A method for preparing titanium metal by molten salt electrolysis is provided. The method includes constructing an electrochemical system, where an anode chamber is filled with an anode molten salt electrolyte that contains a titanium-containing raw material and inserted with an anode, a cathode chamber is filled with a cathode molten salt electrolyte and inserted with a cathode, and the anode molten salt electrolyte and the cathode molten salt electrolyte are not in contact with each other, but are connected by a liquid alloy at the bottom of the electrolytic cell; the system for electrolysis is powered on to obtain the titanium metal product at the cathode. The method of the present disclosure can treat low-quality titanium-containing materials, can be operated continuously, and can obtain relatively high-quality titanium.

1 . A method for preparing a titanium metal by a molten salt electrolysis, wherein:
 the method is implemented using an electrolytic cell, the electrolytic cell comprises an anode chamber and a cathode chamber, the anode chamber is filled with an anode molten salt electrolyte and inserted with an anode, wherein the anode molten salt electrolyte comprises a titanium-containing raw material, the cathode chamber is filled with a cathode molten salt electrolyte and inserted with a cathode, a bottom of the electrolytic cell is further filled with a liquid alloy, and the anode molten salt electrolyte and the cathode molten salt electrolyte are connected by the liquid alloy and not in contact with each other;   the method comprises powering on and running the electrolytic cell, reducing the titanium-containing raw material in the anode chamber to titanium atoms at an interface between the anode molten salt electrolyte and the liquid alloy, and simultaneously dissolving the titanium atoms into the liquid alloy; at the same time, oxidizing the titanium atoms in the liquid alloy are oxidized to titanium ions at an interface between the liquid alloy and the cathode molten salt electrolyte, and simultaneously allowing the titanium ions to enter the cathode molten salt electrolyte and subsequently reducing the titanium ions entered to titanium atoms on a surface of the cathode se as-to form the titanium metal.   
     
     
         2 . The method for preparing the titanium metal by the molten salt electrolysis according to  claim 1 , wherein the titanium-containing raw material is a titanium-containing slag or a titanium-rich slag. 
     
     
         3 . The method for preparing the titanium metal by the molten salt electrolysis according to  claim 2 , wherein the anode molten salt electrolyte further comprises one or more of Al 2 O 3 , CaO, Na 2 O, CaF 2 , SiO 2 , FeO, and MgO. 
     
     
         4 . The method for preparing the titanium metal by the molten salt electrolysis according to  claim 3 , wherein the anode molten salt electrolyte further comprises TiO 2 . 
     
     
         5 . The method for preparing the titanium metal by the molten salt electrolysis according to  claim 1 , wherein the anode is made of a carbon material or is an inert anode; and the cathode is made of one of a stainless steel material, a tungsten material, and a molybdenum material. 
     
     
         6 . The method for preparing the titanium metal by the molten salt electrolysis according to  claim 1 , wherein the cathode molten salt electrolyte is a halide molten salt, wherein the halide molten salt comprises one or more of NaCl, KCl, CaCl 2 ), MgCl 2 , NaF, KF, CaF 2 , and MgCl 2 , with TiCl 2  and TiCl 3  in different proportions. 
     
     
         7 . The method for preparing the titanium metal by the molten salt electrolysis according to  claim 1 , wherein the liquid alloy is an alloy formed by a solute metal Ti and a solvent metal, a metal activity of the solvent metal is lower than a metal activity of the solute metal Ti, the solvent metal and the solute metal Ti form a low-melting-point alloy with a melting point below 1000° C. 
     
     
         8 . The method for preparing the titanium metal by the molten salt electrolysis according to  claim 1 , wherein when the electrolytic cell works normally, a temperature of the anode molten salt electrolyte is controlled to range from 700° ° C. to 1,400° C., a temperature of the cathode molten salt electrolyte is controlled to range from 400° ° C. to 1,100° C., and an anode current density ranges from 0.01 A/cm 2  to 2 A/cm 2 . 
     
     
         9 . The method for preparing the titanium metal by the molten salt electrolysis according to  claim 7 , wherein the liquid alloy is formed by Ti and one or more of Cu, Sn, Sb, Zn, Pb, Bi, Ni, and Co.