| Based on extensive literature review and previous work in the author's group, further and deeper investigation was performed for cathode materials and technology with TiB2 composite coating. The developed coating materials and technology would overcome the problem of prebake cells with quite short cell life in China, and could also be found application in innovative aluminum reduction cell as wettable inert cathodic materials.(1) The properties of both TiB2 powder raw materials and TiB2 cathodic coating (TCC) were investigated. A good TiB2 powder was selected from a few kinds of raw materials. The heating up procedure for solidification and carbonization of TCC was determined. The relationship between resistivity of TCC and temperature was measured. It was found that the existence of TCC reduced the resistivity of carbon base materials to an extent. The effect of TiB2 content on resistivity, sodium penetration, and wettability of liquid aluminum was also measured.A simple method was put forward for characterizing sodium-penetration resistance of TCC in aluminum electrolysis. That is, the mathematic model for sodium penetration was determined asamong which a and Q(=a/b) could be used as the factors characterizing the sodium penetration of cathodic materials. The effectiveness of the method has been proved with experimental data from different sources.(2) The mechanism for strengthening TCC was explored. It was explored that the effect of carbon fiber content, surface oxidation treatment of carbon fiber, amount of oxygen radical on carbon fiber surface, and viscosity molecular weight on Tensile Strength and bond strength. TheIVcomposition of TCC was further optimized. And the technique for surface oxidation treatment of carbon fiber was determined.(3) The properties of optimized TCC were as good as or better than semi-graphitic cathodic carbon block, required by the standard GB8744-88 for aluminum electrolysis. The coke bake and electrolysis was simulated in the labscale, which showed there were no cracks and separate layers on the coating after coke bake. The TCC was still good and in integrity after 12h of electrolysis.The TCC technology was successfully applied to two of 160kA prebake cells in Pingguo Aluminum Company. It was shown that no tear-off of TCC was indicated after starting up of the cells. The operation of coating cells was improved to keep good shape of cell chamber, reduce the formation of sludge on the cell bottom, and gain more uniform current distribution. As compared with reference cells, sodium penetration was reduced in TCC cells. The ohmic drop of TCC cell bottom was lessened by 39mV. The current efficiency was increased by about 0.41% in average. It was estimated that the TCC life could be 38 months.(4) The concept of ambient temperature solidification (ATS) of TCC was put forward to simplify the TCC exerting technique, save heating apparatus with high temperature solidification (HTS) of TCC, shorten the time for exerting TCC on industrial cells. It would help spread the TCC technology in aluminum electrolysis industry.The TiB2 cathodic composite coating materials were explored with ambient temperature solidification technique. The TCC with the technique was successfully applied to 160kA and 75kA of prebake cells.The properties of TCC with ATS were as good as the TCC with HTS, better that the requirement of standard GB8744-88 for semi-graphitic carbon block.AbstractAs good as TCC with HTS in industrial cells, the TCC with ATS also reduces the sodium penetration to cathodic lining, no tear-off of the coating was found after starting up of the cells.As compared with reference cells, the operation of coating cells with ATS was also improved to keep good shape of cell chamber, reduce the formation of sludge on the cell bottom, and gain more uniform current distribution. The ohmic drop of TCC cell bottom was lessened by ll.SmV. The current efficiency was increased by about 1 .48% in average. It was estimated that the TCC life could be 44 months.Obvi...
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