煅烧温度及冷却条件对造纸污泥灰火山灰活性的影响

Effects of calcination temperature and cooling conditions on pozzolanic activity of papermaking sludge ash

通过结合水率和水泥胶砂强度实验,研究了煅烧温度、冷却方式对造纸污泥灰火山灰活性的影响,并结合X射线衍射、红外光谱、扫描电镜对污泥灰矿物组成、化学结构及微观形貌进行了研究。结果表明:高温煅烧和水淬处理均可有效提高造纸污泥的火山灰活性,最合理的煅烧温度为950℃左右;当煅烧温度从450℃提高至850℃,污泥灰主要矿物为方解石、石英、利蛇纹石、刚玉和硅灰石,温度升高至950℃、1 050℃,方解石衍射峰消失,弥散峰增强,污泥灰微观结构变得疏松,大部分晶体转变为玻璃体;相比空气冷却,水淬急冷处理的污泥灰含有更多玻璃体及微观孔隙,火山灰活性更高。

This research investigated the effects of calcining temperature and type of cooling on the pozzolanic activity of papermaking sludge ash by testing bound water rate and cement mortar strength. In addition, the mineral composition, chemical structure and microscopic morphology of sludge ash were researched using X ray diffractometer, infra-red spectroscopy and scanning electron microscope. The results indicated that both high temperature calcination and water quenching treatment could effectively improve the pozzolanic activity of papermaking sludge ash with the best calcination temperature of 950 ℃. When the calcination temperature increased from 450 to 850 ℃, the primary minerals of sludge ash were calcite, quartz, lizardite, corundum and wollastonite.When the temperature increased from 950 to 1 050 ℃, the dispersion peak of calcite increased while its diffraction peak disappeared, the microstructure of sludge ash became loose, meanwhile most of the crystals changed into vitreum. Compared with that processed by air cooling, the sludge ash after water quenching treatment contained more vitreum and micro pores, with higher pozzolanic activity.