In the United States, magnesia refractories are used in a multitude of heat processing industries, but the greatest quantity is used by the steel industry. Within this industry, the types and amounts of magnesia refractories have dramatically changed over the years and continue to evolve as the steel-making process technology, which requires magnesia refractories, matures. For example, the major application of magnesia refractories in the 1950s and 1960s was in