Abstract The influence of the pH value and of an anionic polyelectrolyte on the zeta potential of different raw materials that are used for producing carbon-bonded alumina refractories was studied by measurements of the electrokinetic sonic amplitude (ESA). The following raw materials were investigated: alumina CT 3000 SG, tabular alumina T60/T64, modified coal tar pitch Carbores® P, graphite AF 96/97, carbon black LUVOMAXX® MT N-991 and RW micro-silica. The isoelectric points of these materials were identified, except for the graphite and the micro-silica, which exhibited a negative surface potential over the entire pH range investigated (pH 3–11). An anionic polyelectrolyte (Dolapix CA) was found to increase not only the value of the zeta potential of the oxides at the inherent suspension pH but also that of the graphite and the carbon black. Its addition to concentrated slurries containing a mixture of the investigated raw materials reduced the viscosity and resulted in a decrease in the apparent porosity of carbon-bonded alumina samples produced by pressure filtration. The suitability of the suspension composition for shaping large-sized samples by pressure slip casting and the high thermal shock resistance of the fabricated alumina-carbon refractory have been demonstrated.

中文翻译：

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Al 2 O 3 -C 耐火材料原料水悬浮液的电声研究

摘要 通过电动声波振幅 (ESA) 的测量，研究了 pH 值和阴离子聚电解质对用于生产碳键氧化铝耐火材料的不同原材料的 zeta 电位的影响。研究了以下原材料：氧化铝 CT 3000 SG、板状氧化铝 T60/T64、改性煤焦油沥青 Carbores® P、石墨 AF 96/97、炭黑 LUVOMAXX® MT N-991 和 RW 微硅粉。确定了这些材料的等电点，除了石墨和微硅粉，它们在所研究的整个 pH 范围内（pH 3-11）表现出负表面电位。发现阴离子聚电解质 (Dolapix CA) 不仅会增加氧化物在固有悬浮液 pH 值下的 zeta 电位值，还会增加石墨和炭黑的 zeta 电位值。将其添加到含有所研究原料混合物的浓缩浆液中，降低了粘度，并导致通过压力过滤生产的碳键合氧化铝样品的表观孔隙率降低。已经证明悬浮液组合物适用于通过压力泥浆浇铸成型大尺寸样品以及制备的铝碳耐火材料的高抗热震性。