Preparation And Properties Study Of Inert Wettable TiB₂/C Cathode Composite For Aluminum Electrolysis

Based on extensive literature review and previous work of the group that the author affiliated with, a new TiB2/C composite for aluminum electrolysis was developed and its properties and optimization were studies. Main work and achievements are as follows:(1) The better raw material TiB2 powder produced by B4C was chosen through propriety tests; a mixed resin was determined as gluing system; cold compacting sintering process was selected for preparing the TiB2/C cathode composite; methods for the testing of material properties was systemically studied, especially the apparatus for testing Na expansion being improved.(2) The resistibility of the TiB2/C cathode composite to the sodium penetration was studied through testing its expansion rate during electrolysis; the effect and the mechanism of TiB2 content on the resistibility of the composite to sodium penetration was studied and analyzed with SEM and other methods. The experiment results showed that the resistibility to sodium penetration, the wettability to aluminum and the conductivity were improved with the increase of TiB2 content. But considering the two aspects of property and cost, the TiB2 content should be kept in 50%~70%. The good resistibility of the composite to sodium penetration was due to its good wettability to aluminum and the good resistibility to sodium penetration of TiB2.(3) The effects of sintering temperature, carbon materials and carbon fiber on the resistibility of the TiB2/C composite to sodium penetration were studied and the optimization of the composite was carried out. The optimized result was as follows: TiB2 powder 50%, carbon powder 45% (including 35% anthracite and 10% graphite), strengthening additive 0.5%, binder 4.5%, sintering temperature 1200. The tests on the optimized composite proved that its proprieties could reach or exceed the standards of cathode for aluminum electrolysis, being hopeful to be used as inert wettable cathode on new-type aluminum reduction cells.(4) A novel concept of adding sodium-containing material in the raw material for the manufacture of the TiB2/C cathode composite to increaseresistibility of the composite to sodium penetration was first put forward in this paper. The study of using waste cathode liner material as Na additive to prepare the TiB2/C cathode composites was carried, and the results showed that the method could not only decrease the rate of Na penetration but also give an active way for the reuse of waste cathode liner, which could benefit for environment protection.