This Special Issue of Minerals presents recent, select studies that highlight advances in the fields of hydro- and biohydrometallurgy. It aims to attract the interest of readers and especially of young scientists and students in this fascinating scientific discipline. The topics addressed include the following:• Stirred reactor and heap leaching of laterites (limonitic and saprolitic), as well as iron control during atmospheric acid leaching;• Leaching of a typical porphyry copper sulfide deposit from Antofagasta, Chile, using chloride-ferrous solutions;• Leaching of chalcopyrite ores with various leaching media;• Leaching of white metal from a Teniente converter in NaCl-H2SO4 media; • Study of the galvanic effect of pyrite and arsenopyrite during the leaching of gold ores;• Leaching of marine nodules in the presence of reducing agents to extract Mn;• Bioleaching of gold ores in the presence of iodide-oxidizing bacteria;• A two-step sequential leaching process, involving bioleaching and chemical leaching, to treat apatite ores containing P and U impurities;• Bioreductive dissolution of iron minerals present in monazite in stirred reactors using Acidithiobacillus (A.) species;• Heap leaching of municipal solid waste incineration bottom ash (MSWI BA) for the recovery of Zn and Cu. |