Pressure slip casting of coarse‐grained alumina‐carbon materials

• Published in: International journal of applied ceramic technology 2019-01, Vol.16 (1), p.14-22
• Main Authors: Moritz, Kirsten, Gerlach, Nora, Hubálková, Jana, Aneziris, Christos G.
• Format: Article
• Language: English
• Subjects: Additives; alumina; Aluminous refractories; Aluminum oxide; Carbon; Carbon black; Carbon refractories; Casting; Casting machines; Coal tar; Computed tomography; Graphite; Porosity; Pressure casting; Pressure filtration; processing; Pyrolysis; refractories; Rheological properties; Shock resistance; Slip casting; Slurries; Thermal resistance; Thermal shock
• ISSN: 1546-542X; 1744-7402
• DOI: 10.1111/ijac.13059

This study presents investigations on the application of pressure slip casting to produce shaped coarse‐grained alumina‐carbon refractories. Slurries containing alumina particle size fractions ≤3 mm, a modified coal‐tar pitch, graphite, and carbon black were prepared and examined by rheological measurements and pressure filtration tests on a laboratory scale. A suitable combination of organic additives was chosen. The graphite content was found to have a significant effect on the flow behavior and the apparent porosity of the samples produced from the slurries. Scale‐up experiments were performed in a modified commercial pressure casting machine. It was possible to cast dimensionally stable samples with a size of approximately 220 mm × 220 mm × 40 mm. As shown by means of computed tomography, a homogeneous distribution of the coarse grains over the whole sample was achieved. Quenching tests demonstrated the thermal shock resistance of the carbon‐bonded alumina material obtained after the pyrolysis of the modified coal‐tar pitch.