Sustainable production of electrolytic manganese dioxide (EMD): A conceptual flowsheet

Abstract

The demand for manganese dioxide is growing fast. A low-cost, green hydrometallurgical process is needed to make it from high- and low-grade manganese ores and secondary manganese resources. The use of high-grade manganese ores (<40%) for conventional pyrometallurgical processes or pyro-pretreatment (roasting) is becoming increasingly unsustainable because of the high carbon footprint and operational costs. Various hydrometallurgical processes have been studied and developed in recent years to recover manganese from other manganese sources (Zhang and Cheng, 2007). This paper proposes a new, energy-efficient method to produce electrolytic manganese dioxide. It eliminates the calcination step and dramatically cuts the use of scrap iron for purification. The proposed process leverages an innovative electrolytic cell design that regenerates iron (II) ions instead of generating hydrogen on the cathodes, enabling their reuse in the leaching stage. Hence, reducing the operating voltage for the electrolysis reduces power consumption. The process allows for the reduction of capital and operating costs, the optimization of resource use, and the reduction of environmental impact.