Study on Particles Wetted by the Calcium-Based Slurries and the Slurries Viscosity with the Wetting Agents

Chemical agglomeration can reduce the particulates (including PM2.5) concentration emitted from fly ash particulates and the wet flue gas desulfurization (WFGD) system. However, the calcium-based slurries affect the regulation of agglomeration compared to water, in particular, the wettability of the particulates and the viscosity of the calciumbased slurry. The wettability and the viscosity are the important factors affecting agglomeration, conversely. This manuscript studied the two factors affecting the calcium-based slurries. The sessile drop method was used to measure the contact angle. Four kinds of calcium-based slurries (CaCO3, CaSO3, CaSO4, Ca(OH)2) respectively were mixed with five kinds of wetting agents’ wet particles, and the wetting regulation was studied. The viscometer was used to measure the viscosity of the calcium-based slurry with the wetting agents, and the variation of the viscosity was analyzed as well. The results showed that the smaller the particle size was, the more it is difficult to be wet, and the wetting agents could enhance the wettability greatly, but the effect was related to the properties of the calcium-based material and the wetting agents. There were variable viscosities of different calcium-based slurries after adding the wetting agents. Overall, the Compound No. 3 had the optimal qualities in improving particle wettability and maintaining the calcium-based slurry with a high viscosity. Therefore, the Compound No. 3 is considered the optimal in facilitating chemical agglomeration.