Effect of zircon addition on the physical properties and coatability adherence of MgO-2CaO·SiO₂-3CaO·SiO₂ refractory materials

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• 作者：Wei Meng ; Chengliang Ma ; Tiezhu Ge ; Xiangchong Zhong
• 关键词：Zircon ; Calcium silicate ; Refractories ; Physical properties ; Coatability adherence
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：15 May 2016
• 年：2016
• 卷：42
• 期：7
• 页码：9032-9037
• 全文大小：2142 K

文摘

MgO–2CaO·SiO₂–3CaO·SiO₂ refractory compositions incorporated with zircon (ZrO₂·SiO₂) were obtained by solid state sintering at 1550 °C for 3 h. The effect of different ZrO₂ contents (0%, 0.5%, 1.0%, 1.5%, 2.0% and 2.5%) on the physical properties and adherence ability to cement clinker were investigated. Specimens were characterized by bulk density, apparent porosity, cold crushing strength, cold and hot modulus of rupture and coatability adherence with the combination of crystalline phase formation (XRD) and microstructural analysis (SEM). The results showed that CaZrO₃ was generated in the matrix grain boundaries and triple points, forming direct bonding between MgO and calcium silicate. Densification of the composites was promoted, and the apparent porosity decreased to 8.9% when the content of ZrO₂ was 1.5%. The cold crushing strength increased steadily from 65 MPa to 124.2 MPa. The cold modulus of rupture slightly decreased in the ZrO₂ content range of 0.5–1.5% and then reached 43.2 MPa, whereas the hot modulus of rupture reached its highest value of 4.4 MPa with 1.5% ZrO₂ addition. The highest adherence strength (7.1 MPa) was obtained for 0.5% ZrO₂ addition because the dissolution of CaZrO₃ into the cement clinker increased the viscosity of the clinker and the bonding with the specimen. At high ZrO₂ concentrations (1.0–2.5%), penetration of the clinker into the matrix was hindered by CaZrO₃, thus resulting in lower adherence strength.