Use of nonionic surfactant to reduce sulfuric acid mist in the copper electrowinning process

Abstract

During the copper electrowinning process, sulfuric acid mist is released into the air above the electrowinning tanks. This mist causes health problems for the operators in the electrowinning plant. Therefore, the Occupational Safety and Health Administration (OSHA) has mandated that electrowinning tanks comply with new stringent regulations. This has sparked an interest by copper mines to develop new techniques to reduce acid mist. Foam blankets have been employed as a possible solution. Through designed experiments, a range of surfactant concentrations and space velocities that reduced the acid mist were identified. In this paper, foam blankets using a BASF Pluronic F67 nonionic surfactant were proven to be a viable technique for acid mist reduction. The foam blankets examined may be effective in facilities that operate at evolved gas space velocities around 2.0 cm/min. This method leads to over a 90% reduction of sulfuric acid mist, thus, providing one option for putting the electrowinning system in compliance with OSHA's regulations.