ABSTRACT
The smelting methods used for metal magnesium can mainly be categorized into two, electrolysis and thermal reduction. Electrolysis comprises electrolyzing the magnesium chloride included in seawater and extracting the metal magnesium. The magnesium chloride in seawater exists as hydrous magnesium chloride and is not suitable to electrolyze as it is. Anhydrous magnesium chloride is generated when chlorine is added to the separated magnesium oxide. Electrolysis was once the lowest-cost method for magnesium smelting. Until the 21st century the main countries producing magnesium were the United States, Norway, and Russia, and they used electrolysis. Magnesium smelted by the Pidgeon method comes with a higher purity compared with the one smelted by electrolysis. China lowered smelting cost markedly by introducing low-cost coal into the Pidgeon method. As a result, the list of the main countries producing magnesium changed completely. In place of the former main countries, the United States, Norway, and Russia, China is the country with the highest magnesium production.
