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

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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.