脱硫石膏-偏高岭土-水泥复合胶凝体系研究

Flue Gas Desulphurization Gypsum-metakaolin-cement Compound Cementitious System

摘要:

对50%脱硫石膏和偏高岭土组成的辅助胶凝材料与50%水泥组成的复合胶凝体系进行了试验研究.结果表明：800 ℃热激活脱硫石膏为无水石膏，透射电子显微镜（TEM）分析表明存在明显空腔结构和晶体缺陷；脱硫石膏经400~800 ℃热激活处理后试样10 min~7 d的溶解速率不同，且经800 ℃热激活处理的脱硫石膏溶解速度最快；标养条件下选用经800 ℃热激活的脱硫石膏作为复合胶凝体系的组分能够获得较高抗压强度，而蒸养条件下可选用未经热激活的脱硫石膏；脱硫石膏与偏高岭土配比按CaSO4和Al2O3摩尔比控制，其比值在0.7~1.1范围内较为适宜，能够达到理想的强度且体积稳定性良好.

关键词:脱硫石膏; 热激活; 脱硫石膏偏高岭土水泥复合; 强度与体积稳定性

Abstract:

A series of researches were made into the mortar specimens which were prepared with 50% of flue gas desulphurization (FGD) gypsum and metakaolin(MK), 50% of cement. The results show that 800℃ activated FGD gypsum is anhydrite with obvious cavity and crystal defect tested by transmission electron microscope(TEM). The dissolution rates of FGD gypsum in water after thermal activating at 400~800 ℃ during 10 min~7 d are different, and the dissolution rate of FGD gypsum activated at 800 ℃ is the fastest. The higher compressive strength is obtained with 800 ℃ activated FGD gypsum in condition of standard curing and the non activated FGD gypsum is preferred for steam curing. The molar ratio of CaSO4 in FGD gypsum and active alumina in MK range from 0.7 to 1.1 is good for compressive strength and volume stability simultaneously.

Key words:flue gas desulphurization gypsum; thermal activated; flue gas desulphurization gypsum metakaolin cement complex; strength volume stability