Experimental Research On Wetting And Adhereing Particulate Matter Of Calcium-based Materials Associated With The Desulfurization

In recent years, fog haze weather appears frequently across our country, particlesgenerated by coal combustion have become primary pollutants to Chinese urbanatmospheric environment. The concentration of fine particles is still high after efficientfilters, but can be low by agglomerating fine particles to larger size. The chemicalagglomerate has more advantages than others, but cheap agglomerate agent is animportant problem of the application. Meanwhile, calcium base materials associatedwith the desulfurization can humidify the fine particles by chemical agglomerating,therefore the in-depth research into the mechanism of calcium base materialsagglomerate fine particles has a significance, reducing the dependence on agglomerateagent while guarantee the desulfurization efficiency. Wettability and adhesion are twomain steps of agglomerating fine particles, the stand of wettability generally measuredby contact angle, adhesiveness can be compared with adhesion power and the contactangle and adhesion power are closely related to the adhesion forces.First to study the wetting progress of the four calcium base materials saturatedsolution (CaCO3, CaSO3, CaSO4, Ca(OH)2) on particulate matter. Measuring the surfacetension of four calcium base materials saturated solution, the contact angle of fourcalcium base materials saturated solution and slurry with fly ash (size45-58μm)，analysis the effect of slurry concentration, surfactant type and particle size onwettability. The results indicate that calcium base slurry contact angle will increase withthe increase of slurry concentration、the decrease of the particle size. Adding surfactantcan reduce the contact angle of particles, but the influence of various surfactants isrelated to the types and properties of calcium base. The critical surface tension of theparticulate matter (size45-58μm) is38.8mN/m，belongs to low energy solid surface.Second to study the adhesion process of calcium base material to particulate matter,the adhesion work of calcium base saturated solution and the influence of calcium baseslurry viscosity was studied, comparing the result of the contact angle, receive theconditions that can increase the slurry viscosity and improve the wettability at the sametime. By Young-Dupre equation, the adhesion power of the four calcium base saturatedsolution to particulate matter (size45-58μm) is a convex parabola function of surface tension of these solutions, under the same experimental conditions, when the surfacetension of calcium base saturated solution is43.9mN/m, the adhesion power achievesthe maximum of78.7mJ/m2, adhesion to achieve the best state. It is generallycontradictory that with high viscosity and low contact angle of calcium base materialslurry, and adding some surfactants can enhance wetting while maintaining highviscosity. By Young-Dupre equation, the adhesion power of the four calcium basesaturated solution to particulate matter (size45-58μm) is a convex parabola function ofsurface tension of these solutions, under the same experimental conditions, when thesurface tension of calcium base saturated solution is43.9mN/m, the adhesion powerachieves the maximum of78.7mJ/m2, adhesion to achieve the best state. It is generallycontradictory that with high viscosity and low contact angle of calcium base materialslurry, and adding some surfactants can enhance wetting while maintaining highviscosity.Adhesion force between particles is the basic factor affecting wettability andadhesion process, so in this paper, Design two experiment systems to measure the sizeof adhesion force between particles based on the above research, provides the basis ofestablishment of the test bench in the future.