Abstract
This study focused on identifying the Cl-bearing phases in fly-ash after the washing treatment. The influence of carbonation was also considered, which was hypothesized to decompose the insoluble chlorine in the ash products. Four samples (A-o,A-w,B-o,B-w) were investigated before and after washing (O:original, W:washed). XRD and SEM-EDX were used to determine the mineralogical content and elemental composition in the samples. XRF was also employed to determine the bulk chemistry of the ash products. The results verified that soluble chlorine decreased after the washing process while the insoluble chlorine could not be removed. Therefore it might have been fixed in some stable phases such as Friedel’s salt. Carbonation experiment was conducted in all the samples to evaluate any possible changes in the insoluble chlorine. Upon carbonation, the insoluble chlorine ratio considerably decreased that indicates the influence of carbonation process on the decomposition of Cl-bearing stable phases. However the insoluble chlorine could not be completely converted into soluble state after carbonation which is indicative of the existence of other stable Cl-bearing phases in the wood fly-ash. This needs to be investigated with further details.
