A review of steel pickling and acid regeneration an environmental contribution

A review on most important pickling technologies of steel, mild steel as well as alloyed steel types, will be detailed and the technology of the recycling of pickling acids described. The paper shows the pickling technology using acids such as sulphuric acid and hydrochloric acid, as well as mixed acids for high alloyed steels. The technology of spray roasting of hydrochloric acid is detailed. A new technological approach to regaining spent mixed acid, i.e. a nitric and hydrofluoric mixture, is explained and presented here. The environmental contribution of the acid recycling technology used in the steel industry will be discussed, in view of the example of statistical data of global hydrochloric acid emissions.