复合改性高模数水玻璃试验及其表征研究

Experiment and Characterization of Composite Modified High Modulus Sodium Silicate

用聚丙烯酰胺、四硼酸钾和四硼酸锂对高模数水玻璃进行复合改性,测定改性后水玻璃砂试样的1 h抗拉强度、24 h抗拉强度和950℃残留强度。通过XRD、SEM、EDS和DSC分析改性剂对水玻璃砂性能、砂粒间粘结状况和粘结桥形貌的影响机理。结果表明,改性剂成分优化添加量为:四硼酸钾2.5%、四硼酸锂0.15%、聚丙烯酰胺0.1%。优化的水玻璃砂试样1 h强度为0.261 MPa,24 h强度为0.72 MPa,残留强度为7.2 MPa。改性剂的加入在一定程度上提高了水玻璃砂的常温强度并改善了其溃散性。

High modulus sodium silicate was modified by polyacrylamide, potassium tetraborate and lithium tetraborate, and its tensile strength of 1 h, 24 h and residual strength at 950 ℃ were measured. The influence mechanism of the modifier on the properties of sodium silicate sand, the bonding state between sand particles and the morphology of the bond bridge were analyzed by XRD, SEM, EDS and DSC. The results show that the optimum dosage of modifier composition was potassium tetraborate 2.5%, lithium tetraborate 0.15%, polyacrylamide 0.1%. The 1 h tensile strength, the 24 h tensile strength, and the residual strength of the modified sand samples were 0.261 MPa, 0.72 MPa and 7.2 MPa, respectively. The addition of modifier increases the normal temperature strength of sodium silicate sand to some extent and improves its collapsibility.