Magnesium is one of the most abundant minerals in seawater. Extracting magnesium from seawater could reduce cost of this mineral, resulting in positive implications for industries that use it. This book addresses mineral process engineering with emphasis on magnesium and provides practicing engineers and students with comprehensive knowledge on magnesium and how it is extracted from seawater and magnesium ores. It takes a chemical engineering approach as separation of magnesium from seawater involves the application of the powerful science of chemistry and transport phenomena principles. This monograph discusses magnesium resources and occurrence, includes an exploration study on deriving magnesium and mineral salts from seawater, and features coverage of magnesium chloride. It also covers commercial methods for magnesium production as an end product, current and prospective applications in the energy domain, and offers an account of the use of magnesium to store hydrogen in the form of magnesium hydride.