Waste heat and energy recovery system from smelter offgas for a platinum processing plant

Most mineral processing companies are energy intensive especially if smelting is used in extraction. After processing, the energy is correspondingly dissipated as heat and toxic gases, requiring stringent controls for sustainability and safety. In recent years, Southern Africa has grappled with power shortages resulting in the scaling down of company operations. Increases in manufacturing activities demand for more energy but this has evidently outstripped supply due to the depletion of natural resources. Mineral processing industries are probably the worst affected due to fluctuations in world metal prices. These challenges require sustainable production strategies to remain in business. This research was carried out at a platinum processing company in Zimbabwe which uses smelting in extractive metallurgy, consuming millions of dollars in energy but also dissipating this as heat and furnace exhaust gases. The focus of the research was on finding ways to turn these challenges into opportunities by recovering the heat and using it for other purposes. A waste heat and energy recovery system was designed to work in conjunction with the smelters and electrostatic precipitator. The proposed system is expected to increase furnace efficiency by 8.5% with an anticipated output of 1.033 MW and an overall plant efficiency of 22.7%.