Research in the Field of Preparing Molded and Unmolded Refractories Based on High-Alumina HCBS. Part 3. Effect of Firing Temperature on Sintering and Mullitization of Materials Prepared on the Basis of Composite Composition HCBS1

Resumo

The effect of firing temperature on sintering and mullitization of six batches of specimens prepared from HCBS based on high-alumina bauxite and very fine quartz glass (VFQG) is studied. In the range 900 – 1200°C (soaking 1 h) normal sintering is noted accompanied by insignificant (0.4 – 0.5%) shrinkage and a sharp increase in ultimate strength in bending (110 – 130 MPa). In the range 1200 – 1400 of 1500°C (depending on composition) specimen growth by 1.0 – 2.5% is noted, due to mullitization. Depending on composition and solid phase fineness the start of sintering for mullitized specimens is noted at temperatures exceeding 1400 – 1500°C. Specimen material modeling a matrix system of high-alumina refractories has high strength and volume constancy after prolonged thermal ageing.