KINETICS AND MECHANISM OF THE OXYPRECIPITATION OF WASTE HYDROCHLORIC PICKLING LIQUORS

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 wit h hydrochloric acid in rolling mills, recovering the high iron content in the form of oxides or oxyhydroxides which can later be used in oth er industrial processes. In addition to reducing water pollution, such a process attaches a new value to this ferrous waste. Chlorinated liq uors are oxyprecipitated, leading to the formation of different combin ations of iron oxides and oxyhydroxides, with the total removal of Fe2 and the production of ammonium chloride solutions easily broken down into hydrochloric acid and ammonia. The precipitates have different i ndustrial outlets, making the oxyprecipitation process an attractive s olution for the treatment of waste pickling liquors.