Mark E. Schlesinger is a graduate of the University of MissouriâRolla and the University of Arizona. He has spent a combined 31 years of teaching at The University of Utah and the Missouri University of Science and Technology. He is an author of: âĸ Mass and Energy Balances in Materials Engineering âĸ Extractive Metallurgy of Copper (4th and 5th Englishâlanguage editions; Chinese edition) âĸ Aluminum Recycling (two English language editions)Professor Schlesinger is a member of the (U.S.) Metals, Minerals, and Materials Society; the American Institute for Steel Technology; and the Society of Mining, Metallurgy and Exploration. He is a former Fulbright Scholar (Royal Institute of Technology (Sweden), 2002), and Leif Eriksson Fellow (Norwegian University of Science and Technology, 2012â13). He was named a Fellow of ASM International (2018).Kathryn C. Sole has 30 years' global experience in the chemistry and process engineering of hydrometallurgical extractive processes, with specialist expertise in solvent extraction, ion exchange, and electrowinning. She is currently an independent consultant, with clients spanning six continents. Kathy has worked with copper production operations in Africa, USA, and South America, including those of Anglo American, Eurasian Resource Group, Glencore, Vedanta, First Quantum, and BHP. Kathy holds an adjunct appointment at the University of Pretoria and regularly presents accredited Continuing Professional Development training courses, many of which focus on hydrometallurgy of copper. She has authored/coauthored over 90 publications, including Extractive Metallurgy of Copper (5th ed.), and is a member of the Editorial Boards of the journals Minerals Processing & Extractive Metallurgy Review and Solvent Extraction & Ion Exchange. She founded and chairs the Copper Cobalt Africa conference series. Kathy obtained her PhD in metallurgical engineering from the University of Arizona, USA, following BSc(Hons) and MSc degrees in chemistry from Rhodes University, South Africa. She has been awarded the Silver Medal of the Southern African Institute of Mining and Metallurgy, the Bronze Medal of the South African Association for the Advancement of Science, and received the Milton E. Wadsworth Award of the Society of Mining, Metallurgy and Exploration in 2019.