1. Properties of iodine

Industrial production of iodine began at the end of the 19th century. Annual consumption rose by an average of 2-2.5% between 1880 and 1960, and by 4-5% between 1960 and 2000. To meet demand, three main producers emerged: Chile, Japan and the United States.

Chile mines iodine as a co-product of sodium nitrates from the northern desert. The first plant started up in 1931 at the Pedro de Valdivia plant, based on open-pit mining.

Japan has been extracting iodine from brine gas deposits since 1934. Industrial production developed between 1934 and 1944, and expanded considerably after 1966 with new processes.

The United States extracted iodine from algal ash in California between 1917 and 1921, then from oil brines in Louisiana between 1928 and 1932. Between 1928 and 1966, California...