The aim of the research project presented in this paper is to devise a process to treat waste liquors from the pickling of iron or steel with hydrochloric acid in rolling mills, recovering the high iron content in the form of oxides or oxyhydroxides which can later be used in other industrial processes. In addition to reducing water pollution, such a process attaches a new value to this ferrous waste.Chlorinated liquors are oxyprecipitated, leading to the formation of different combinations of iron oxides and oxyhydroxides, with the total removal of Fe+2 and the production of ammonium chloride solutions easily broken down into hydrochloric acid and ammonia. The precipitates have different industrial outlets, making the oxyprecipitation process an attractive solution for the treatment of waste pickling liquors.