Treatise on Process Metallurgy: Volume 5: Energy, Environment, and Future Aspects of Process Metallurgy, Second Edition is divided into two parts, with the first covering sustainable development as it pertains to process metallurgy, addressing issues arising from sustained economic growth, long-term mineral and metal supply, and energy requirements in metallurgical industries. It also examines energy resources, including fossil and renewable sources, and discusses the resource efficiency of the circular economy through simulation-based analyses. The second part delves into the future of metals production globally, with a focus on raw material and energy availability. It presents current CO2 emissions and future projections, with emphasis on reducing CO2 generation in steelmaking technologies. Additional topics discussed include flash smelting, FINEX process outlook, the rotary hearth furnace, and an extensive coverage of hydrogen steelmaking.