碱激发冶炼铅渣-偏高岭土复合胶凝材料的制备及水化机理

为探究水玻璃碱激发条件下冶炼铅渣和偏高岭土基复合胶凝材料的力学性能,采用单因素试验与正交试验,研究冶炼铅渣球磨时间、碱当量、碱激发剂模数和偏高岭土与冶炼铅渣的质量比对复合胶凝材料力学性能的影响。利用XRD、SEM和FTIR对复合胶凝材料的水化机理进行综合分析。结果表明:以上因素对复合胶凝材料28 d抗压强度的影响顺序依次为碱激发剂模数、冶炼铅渣球磨时间、碱当量、偏高岭土与冶炼铅渣的质量比;当冶炼铅渣球磨时间为4 h,碱当量为6%(质量分数),碱激发剂模数为1.4,偏高岭土与冶炼铅渣的质量比为3∶7时,复合胶凝材料28 d抗压强度达56.18 MPa;偏高岭土能够促进冶炼铅渣水化,产生更多凝胶和网状结构的硅铝酸盐类晶体填充基体孔隙,对胶凝体系后期强度发展起到促进作用。

Preparation and Hydration Mechanism of Alkali-Activated Lead Smelting Slag-Metakaolin Composite Cementitious Materials

In order to explore the mechanical properties of lead smelting slag and metakaolin based composite cementitious materials under sodium silicate alkali excitation, the effects of ball milling time of lead smelting slag, alkali equivalent, alkali activator modulus and the mass ratio of metakaolin to lead smelting slag on the mechanical properties of composite cementitious materials were studied by single factor test and orthogonal test. The hydration mechanism of composite cementitious materials was comprehensively analyzed by XRD, SEM and FTIR. The results show that the order of influence on the 28 d compressive strength of composite cementitious materials is as follows: alkali activator modulus, ball milling time of lead smelting slag, alkali equivalent, mass ratio of metakaolin to lead smelting slag. When the ball milling time of lead smelting slag is 4 h, alkali equivalent is 6% (mass fraction), alkali activator modulus is 1.4, and the mass ratio of metakaolin to lead smelting slag is 3∶7, the 28 d compressive strength of composite cementitious materials reaches 56.18 MPa. Metakaolin promotes the hydration of lead smelting slag and generates more gel and silicaluminate crystals with reticular structure to fill matrix pores, which promotes the late strength development of cementitious system.