A New Method of Acid Regeneration in Steel Pickling Plants: The Case Study of Kashan Amirkabir Steel Company

One of the common methods of removing iron oxide from the surface of hot rolled steel sheets is to wash the sheet with acid. The most common acid used in steel industry for this purpose is hydrochloric acid. One of the methods of recycling hydrochloric acid from acid leaching effluent used in steel industry is acid recycling method using fluidized bed reactor. To this end, the effect of this method on the reduction of g environmental challenges, an optimal use of energy, and an increase in efficiency and productivity in steel industry was investigated. In this research, the solvent extraction method as well as evaporation and crystallization method for acid recycling was proposed. The results showed that the solvent extraction method has low efficiency, requires strict system control as well as continuous monitoring; however, the evaporation and crystallization method with the least man power, energy consumption environmental pollution as well as with high efficiency has an acceptable preference. In the evaporation and crystallization method, 17.5% hydrochloric acid solution and iron chloride are recycled; such event has many uses and can be sold. The water from the evaporation and crystallization process can also be used as a product in the factory or used to irrigate the green space in the factory.