**1. Introduction and Scope**

A Special Issue of *Metals* was commissioned that was devoted to aspects of Mineral Processing and Hydrometallurgy. The editors were Prof. Dr. Corby Anderson and Dr. Hao Cui. This issue was designed to include submissions for characterization, along with recycling and waste minimization, mineralogy, geometallurgy, thermodynamics, kinetics, comminution, classification, physical separations, liquid solid separations, leaching, solvent extraction, ion exchange, activated carbon, precipitation, reduction, process economics, and process control. Suggested application areas were gold, silver, PGMs, aluminum, copper, zinc, lead, nickel, and titanium. Critical metal articles on topics such as lithium, antimony, tellurium, gallium, germanium, cobalt, graphite, indium, and the rare earth metals were welcome. Thirty-one high-quality peer-reviewed articles from around the globe were selected and accepted for inclusion.
