燃煤循环流化床锅炉灰、渣超微粉胶凝特性研究

针对燃煤循环流化床锅炉(CFB)灰渣资源化利用问题,利用超音速蒸汽粉磨机对CFB灰与渣进行超细化处理,对比研究了CFB灰、渣超微粉及其复配料的胶凝特性,包括抗压强度、标准稠度用水量、安定性、凝结时间等。结果表明:在保证满足P·F 42.5强度标准的前提下,CFB灰在水泥中的掺入量可达到40%,CFB灰超微粉为55%,CFB渣超微粉为25%,CFB灰与渣按照2∶1复配,超微粉的掺入量可达到40%;CFB灰渣超微粉的掺入,显著增加了水泥体系标准稠度用水量。且在掺入量高(≥70%)时会导致胶凝体系出现早凝现象,掺入量低(≤55%)时则体现出缓凝的作用。固废超微粉掺入导致水泥体系体积安定性变差,但仍满足GB 175—2020《通用硅酸盐水泥》标准要求(＜5 mm)。

CEMENTITIOUS CHARACTERISTICS OF ULTRAFINE POWDER FOR COAL-FIRED CFB ASH AND CFB SLAG

Aiming at the problem of resource utilization of coal-fired circulating fluidized bed boiler (CFB) ash and slag, the CFB ash and slag were ultra-refined by a supersonic steam mill. The cement-based cementitious properties of CFB ash ultrafine powder and their mixtures were compared and studied, including compressive strength, water requirement of normal consistency, stability and setting time. The results showed that under the premise of meeting the P·F 42.5 strength standard, the incorporation of CFB original ash in cement reached 40%, the CFB ash ultrafine powder was 55%, the CFB slag ultrafine powder was 25%, and the incorporation of CFB ash and slag wltrafine powder reached 40% if the CFB ash and slag were mixed according to 2∶1. The incorporation of CFB slag ultrafine powder significantly increased the water requirement of normal consistency of the cement system. A large dosage (≥70%) would lead to the early setting of the cementitious system, and less dosage (≤55%) would show retarding effect. Although the addition of solid waste superfine powder led to the deterioration of volume stability of the cement system, it still met the requirements of China’s national standard, GB 175—2020 Common Portland Cement (＜5 mm).