改性剂对含矿物固废添加剂制备的硫氧镁水泥性能的影响

Effects of modifiers on properties of magnesium oxysulfide cement prepared with additives of mineral and solid waste

硫氧镁(MOS)水泥是一种由MgO-MgSO_(4)-H_(2)O三元体系组成的气硬性胶凝材料,在防火门芯板和外墙保温板等领域应用。但传统MOS水泥由于未经改性处理,限制了其更广泛的应用。本文以MgO粉体、硫酸镁为主体原料、矿物偏高岭土和固废粉煤灰为活性掺合料制备MOS水泥,研究柠檬酸、丙二酸、磷酸三钠等改性剂对MOS水泥的物相组成、力学性能及显微结构的影响。结果表明,当使用0.5%的柠檬酸和0.2%的丙二酸时,所制备MOS水泥的5Mg(OH)_(2)·MgSO_(4)·7H_(2)O(5·1·7相)凝结相特征变得显著,试样结构紧实,28d力学性能表现最佳,耐压强度和抗折强度分别达到100.14MPa和28.61MPa。

Magnesium oxysulfide(MOS)cement is a gas-hardening cementitious material composed of MgO-MgSO_(4)-H_(2)O ternary system,which is used in the fields of fireproof door core panels and exterior wall insulation panels.However,traditional MOS cement is limited in wider application due to the lack of modification treatment.In this paper,MgO powder and magnesium sulfate are used as the main raw materials to prepare MOS cement with mineral kaolin and solid waste fly ash as active admixtures.The effects of modifiers,such as citric acid,malonic acid and trisodium phosphate,on the phase compositions,mechanical properties,and microstructures of MOS cement are investigated.The results show that when using 0.5%citric acid and 0.2%malonic acid,the 5Mg(OH)_(2)·MgSO_(4)·7H_(2)O phase characteristics of MOS cement become significant.The sample structure is compact,and its 28-day mechanical properties have the best performance,with compressive strength and flexural strength reaching 100.14MPa and 28.61MPa respectively.