铝电解TiB2/C复合阴极用煤沥青的无机改性

采用无机粒子改性法在200℃下对煤沥青进行改性,分析无机粒子(Al2O3粒子或TiB2粒子)对改性煤沥青结构与性能以及改性沥青基TiB2/C复合阴极性能的影响。研究结果表明:改性煤沥青的结焦值和软化点比未改性煤沥青均有较大提高。无机粒子的添加进一步提高改性煤沥青的结焦能力,但降低改性煤沥青的软化点,与对比改性煤沥青相比,Al2O3粒子和TiB2粒子改性煤沥青的软化点分别降低4.5℃和2.0℃,结焦值分别提高4.85%和5.35%。经过1 000℃炭化,其残炭率相对于对比试样分别增加3.01%和5.87%。与对比复合阴极相比,Al2O3粒子和TiB2粒子改性煤沥青基复合阴极的密度分别增大0.45%和1.79%,开孔率分别降低5.08%和5.78%,电阻率从52.93μΩ·m分别降低到48.86μΩ·m和49.95μΩ·m,抗压强度从24.21 MPa分别增加到28.78 MPa和28.06 MPa,电解膨胀率分别降低0.10%和0.16%。无机改性粒子均匀地分布于粘结剂煤沥青炭中。

Effect of inorganic particles on properties of modified pitches and pitch based TiB2/C composite cathodes for aluminium electrolysis

The effects of inorganic particles on microstructure and properties of modified pitches and properties of pitch based TiB2/C composite cathodes were investigated.Pitches were modified by adding 10% Al2O3 particles or 10% TiB2 particles at 200 ℃,respectively.The results show that both coking value and softening point of modified pitches increase compared to those of the untreated pitch.However,the addition of inorganic particles leads to a higher coking value but a lower softening points of modified pitches.Compared to the direct treated pitch,softening points of Al2O3 particles and TiB2 particles based modified pitch decrease by 4.5 ℃ and 2.0 ℃ while the coking values increase by 4.85% and 5.35%,respectively.Moreover,after carbonized at 1 000 ℃,the carbon yields increase by 3.01 % and 5.87 %,respectively.Besides,properties of inorganic particle modified pitch based cathodes are more greatly improved than that of direct treated pitch based cathode.The bulk density increases by 0.45% and 1.79% and open porosity decreases by 5.08% and 5.78%.Electrical resistivity of their cathodes reduces from 52.93 μΩ·m to 48.86 μΩ·m and 49.95 μΩ·m and the compressive strength increases from 24.21 MPa to 28.78 MPa and 28.06 MPa while modified by Al2O3 particles and TiB2 particles,respectively.What is more,the electrolysis expansion is reduced by 0.10 % and 0.16 %,respectively.Inorganic particles distribute evenly in the binder carbon.