RHI AG (German: Radex-Heraklith Industriebeteiligungs AG) is a Vienna-based Austrian company specialising in producing heat-resistant refractory products for the steel, cement, glass, lime and non-ferrous metals industries. The company has an annual producing capacity of 2 million tonnes of refractory products, making it the largest company in the world in this field of activity. The company employs around 7,700 people in 32 locations in 14 countries, with an annual turnover of approximately EUR 1.6 billion.