A process for making steel from pig iron. A vertical cylindrical steel vessel (converter) is used, lined with a refractory material. Air is blown through the molten iron and carbon is oxidized and thus removed from the iron. Other impurities – silicon, sulfur, and phosphorus – are also oxidized. Irons containing large amounts of phosphorus are treated in a converter lined with a basic material, so that a phosphate slag is formed. The required amount of carbon is then added to the iron to produce the desired type of steel. The process is named for the British inventor and engineer Sir Henry Bessemer (1813–98).