High quality clinker created with Chinese flyash

This article summarizes the use of two fly ashes in the synthesis of Portland/calcium sulfoaluminate (OPC/CSA or A/CSA) clinkers. They are from the Shentou second power plant located in the Shanxi Province and from the Zhungeer power plant located in Inner Mongolia, China. The Zhungeer ash was collected dry, and the Shentou ash is from a pond.

Their chemical compositions differ highly, especially the SiO2 and Al2O3 contents. The high contents of silica and alumina make both ashes candidates as a partial or total substitute for bauxite, an expensive source of alumina, in the production of OPC/CSA clinkers. These particular hybrid clinkers are composed mainly of alite (C3S) and calcium sulfoaluminate (C4A3S), both phases responsible for the high early strength development in OPC and CSA cements, respectively.

The production of high-quality OPC/CSA clinkers was produced with both ashes with the additions of hydrated lime, flue gas desulfurization (FGD) gypsum, fluorite, and bauxite at 1250°C for 60 minutes with final composition ranges of 29–41 wt% C3S, 20–22 wt% C2S, 30–45 wt% C4A3S, ´ and 1–4 wt% C4AF

http://www.coalcgp-journal.org/papers/2019/1946-0198-11-1-59.pdf