高铝煤矸石复合活化及其火山灰效应分析

Composite Activation of High Alumina Coal Gangue and Analysis on Its Pozzolanic Effect

采用胶砂强度法研究了机械粉磨、煅烧、增钙煅烧及与化学活化剂复合对内蒙古某地高铝煤矸石活性的激发效果,并采用SEM,XRD,FTIR分析了不同粉磨时间、不同煅烧温度对高铝煤矸石内部结构变化及其活化效果的影响;以强度活性指数、火山灰效应贡献率为考察指标,分析了不同方式活化的高铝煤矸石的火山灰效应.结果表明:单纯机械粉磨对高铝煤矸石的活性有一定的激发作用,但活化效果有限;煅烧对高铝煤矸石活性有明显的激发作用,其最佳煅烧温度为800℃,此时高铝煤矸石水泥胶砂强度活性指数达126.5%,火山灰效应贡献率达44.7%;增钙煅烧可使其强度活性指数进一步提高到142.6%,火山灰效应贡献率提高到50.9%;在增钙煅烧基础上掺入0.6%(质量分数)的硫酸钠可使其28d抗压强度达到78.9MPa,强度活性指数达到157.0%,火山灰效应贡献率达到55.5%.

In order to develop new activity admixture for cement based material and broaden the comprehensive utilization way for high alumina coal gangue（HACG） from Inner Mongolia, the effect of mechanical, thermal and chemical composite activation on HACG was studied by testing the compressive strength of cement mor- tars with activated HACG. The micro-structure and activation effect of activated HACG under different grind- ing times and calcining temperatures were studied using SEM, XRD and FTIR. Taking the strength activity index（SAD and contribution rate of pozzolanic effect（CRPE） as the inspected objects, the pozzolanic effect of HACG activated by different methods was analyzed. The results show that the HACG can be activated to some extent by mechanical grinding, but the effect is limited. The HACG can be effectively activated by calci- ning, and the optimal calcining temperature is 800 ℃, at this temperature the kaolinite in HACG can be de- composed into high activating SiO2 and Al2 O3, the SAI and CRPE of cement mortars with HACG can reach to 126.5% and 44.7%, respectively. The SAI and CRPE are further increased to 142.6% and 50.9% respectively while being calcinated with Ca（OH）2. After being calcinated with Ca（OH）2 and 0.6 % Na2 SO4 the 28 d compressive strength is up to 78.9 MPa, SAI up to 157% and CRPE up to 55.5%.