Factor effect of operating conditions on the leaching of fly ashes from a pulp and paper mill.

The non-process-elements (NPE's) in the pulp and paper production, in particular chloride (Cl) and potassium (K), eventually accumulate in a sodium sulfate recovery cycle of a paper plant, especially on boiler fly ashes (flue gas cleaning). This accumulation often leads to fouling and corrosion. Thus, in order to reduce such problems, a leaching unit is typically integrated aiming to remove Cl and K and recover sodium sulfate (NaSO) from boiler fly ashes.