水热条件下Mg(OH)_2-石英-水体系反应固化性质研究

Hydrothermal Solidification and Mechanical Properties of Mg( OH)_2-quartz-water System

为揭示镁质硅酸盐胶凝体系的水热反应过程及固化性质,本文以氢氧化镁、磨细石英砂和水为原料,系统考察了水热反应温度、时间以及原料配比等工艺参数对试样力学强度的影响规律,并通过扫描电镜和X射线衍射技术手段对产物结构特征及发展机制进行了细致表征。实验表明,水热反应温度200℃、反应时间6 h、Mg(OH)2掺量40wt%条件下对纤蛇纹石产物的形成最为有利,样品力学强度最高。研究结果可增进对Mg(OH)2-石英-水体系水热反应机制的理解,有助于高性能镁质胶凝材料的研发,还可用于低品位镁矿、硼泥等含镁工业废弃物的综合回收利用等。

In order to reveal the hydrothermal generation and cementitious properties of magnesium silicate hydrate, Mg （OH）2 and finely-ground quartz sand were selected as the raw materials to produce chrysotile-based specimens by a process of hydrothermal solidification, in which the compressive strength was investigated in details to reveal the effects of the reaction factors, including the temperature and time of hydrothermal reaction, mixing ratio of the raw materials and so on, while X-ray diffraction （XRD） and scanning electron microscopy（SEM） were employed to characterize the hydrothermal structural development during the solidification. The optimized conditions for the formation of chrysotile in Mg（OH） ：quartzwater system were suggested to realize a maximum strength by, i.e. the reaction temperature and time was 200 ℃ and 6 h, respectively, while the Mg（OH）2 content was 40wt% in the starting materials. The results must be helpful to understand the hydrothermal reaction in Mg （OH）2-quartz-water system, to produce high-quality magnesium-based cemenfifious materials, and to realize the resourced utilizations of magnesium-containing waste such as low-grade magnesite and boron slurry.