“…Water leaching has been suggested by many authors to be an efficient, fast and low cost way to significantly reduce the inorganic constituents' content of the biomass [1,3,7]. It cannot only remove the water-soluble inorganic elements, such as K, Na, Ca, Cl, S, and Mg, but also, in the process of thermal conversion of biomass, improve the quality of the remaining ash [1,3,5,25].…”