... sewage treatment, the dehydration of the sludge, the etching for the printed circuit board. Ferric Chloride [FeCl3] •Package ... by woven bag or paper box.•Usage:Mainly used for the sewage treatment, the dehydration of the sludge, ... the etching for the printed circuit board,the erosion of the stainless ... /l≤5mg/l 40% liquid ferric chloride for Industrial Wastewater Treatment