脱硫石膏粉煤灰地聚合物抗压强度和反应机理

经钠水玻璃激发固体废弃物脱硫石膏和粉煤灰,成功研制了脱硫石膏-粉煤灰地聚合物,研究了该地聚合物的抗压强度,并采用X射线衍射分析(XRD)和扫描电镜(SEM)等测试方法研究了其反应机理.研究表明:经800℃焙烧1h后的脱硫石膏结构松弛、缺陷多、活性大,以10%掺量取代粉煤灰,经钠水玻璃激发形成的地聚合物,在75℃养护8h或在23℃养护至28d,抗压强度均可达37.0 MPa.此反应体系中,碱激发与硫酸盐激发作用共存,地聚合反应与水化反应同时进行,生成了地聚合物凝胶、类沸石以及钙矾石等反应产物.脱硫石膏-粉煤灰地聚合物的成功研制,为实现多种工业废弃物的共处置利用,尤其是含硅铝相的工业废弃物和含硫酸钙的工业废弃物的共处置打下了理论基础.

Compressive Strength and Mechanism of Geopolymers from Flue Gas Desulferization Gypsum and Fly Ash

The sodium water glass activated geopolymers were prepared from solid wastes of fly ash and flue gas desulfurization gypsum (FGDG). Compressive strength and mechanism of these geopolymers were also studied using X ray diffraction (XRD) and scanning electron microscopy (SEM). When the FGDG baked at 800 oC for 1 h the FGDG has a more flabby structure and disfigurement, and became more active. The blend of 90% of fly ash and 10% of FGDG baked at 800 oC for 1 h was activated by sodium water glass, and the geopolymer was formed and the specimens were demoulded. The compressive strength of these geopolyme specimens cured at 23 oC for 28 days or at 75 oC for 8 h reached 37.0 MPa. Activated by alkali activator and sulfate activator, geopolymerization products and hydration products of geopolymeric gel, zeolite, and ettringite etc. were formed. Preparation of geopolymes from fly ash and FGDG is beneficial for utilizing of multi industrial wastes, especial the wastes containing silicate, aluminum, and sulfate.