活化方式对CFBC脱硫灰自硬化性能的影响

Influence of Activation Methods on Self-cementitious Properties of CFBC Desulfurized Ash

通过物理粉磨、化学激发和物理-化学联合激发3种方式系统研究了循环流化床锅炉燃烧脱硫灰(CFBC脱硫灰)物理力学性能的变化规律,并采用水化热,FTIR,XRD和SEM测试方法分析了活化方式对CFBC脱硫灰自硬化水化历程及性能的影响机理.结果表明:物理粉磨、化学激发和联合活化均提高了脱硫灰的自硬强度及水化反应程度,且降低了需水量比.与原状CFBC脱硫灰相比,粉磨后试样需水量比降低了13%(质量分数),7,28d抗压强度分别提高了210.0%,25.4%;改性剂A,B加入后混磨试样需水量比降低了19%,7,28d抗压强度各自提高了337.0%,96.5%.在相同的A掺量下,CFBC脱硫灰与A混合后混磨试样的强度效果优于粉磨后A的外加.CFBC脱硫灰的主要水化产物为AFt,Ca(OH)2,CaSO4.2H2O,C-S-H凝胶.

Change of physical and mechanical properties of circulating fluidized bed combustion（CFBC） de- sulphurized ash were systematically investigated by three different ways including physical activation, chemical activation and physically-chemically combined activation. Mechanisms of the self-cementitious properties and hydration process of CFBC desulfurized ash were studied by hydration heat, FTIR, XRD and SEM. The results show that self-cementitious strength and its degree of hydration of CFBC desulphur- ized ash are improved and water requirement ratio is reduced by the physical, chemical activation and com- bined activation. Compared with original CFBC desulfurized ash, the water requirement ratio of grinded sample is reduced by 13% （by mass）, 7 d and 28 d compressive strengths are increased by 210.0% and 25.4% respeetively; the water requirement ratio of grinded sample which is mixed with modifier A and B is reduced by 19%, 7 d and 28 d compressive strengths are increased by 337.0% and 96.5% respectively. If the amount of A added was the same, the compressive strength of the sample which was ground after CF- BC desulfurized ash and A were mixed was better than that of the sample which was ground before A was added. CFBC desulfurized ash hydration products are mainly AFt, Ca（OH）2, CaSO4 · 2H2O, and C-S-H gel.