The physicochemical characteristics of fly ash from coal combustion were analyzed by X-ray fluorescence(XRF)

scanning electron microscopy(SEM) and particle distribution analyzer

etc.The influencing factors of vapor mercury adsorption by the fly ash were conducted by using a bench-scale fixed-bed apparatus.A simulated flue gas was prepared by mixing heated

nitrogen gas streams containing mercury vapors(by an elemental mercury diffusion tube) and basic compositions of flue gas.Experiments indicated that with the inlet mercury concentration continuously increasing

the adsorption efficiency of mercury by fly ash firstly decreased

and to certain extent increased

but it still was lower than that of the lower mercury concentration and it may dropped again with increasing to some extent.With the inlet mercury concentration gradually improving

the relative adsorption capacity of mercury by fly ash was thereupon becoming lager and lager

but the adsorption efficiency of mercury was not always increasing.The mercury adsorption of fly ash was primarily physical adsorption in the range of 40～120 ℃

and the adsorption efficiency of mercury decreased with the temperature increasing.When the particle diameter was between 50 μm and 74μm

the optimum effect of mercury adsorption was possibly realized.