Blast furnaces reduce iron ore through a process combining coke and limestone and a hot blast process whereby hot preheated gases from the blast furnace stoves are injected into the bottom area of the furnace in a series of tuyeres connected to a bustle pipe. The combination of temperature and carbon monoxide generated from the combustion of the coke react with the iron ore reducing iron oxide into liquid iron.
The iron settles to the bottom of the blast furnace and is removed from the furnace via a taphole. The limestone provides the basis for slag that is formed to trap the impurities generated in this process and this material is removed from a taphole as well located above the iron taphole. Due to the extremely reducing nature of this process refractory products must be very stable in all-respects chemically and structurally. Resco's line of blast furnace refractory products have the chemical purity and mineralogy and are fired to a temperature to insure to achieve the needed properties. Typical brands are Krial 50-A, Krial 60, Krial 60-A+, and Krial 65-A for their alkali, creep, and thermal shock resistances.