Theoretical concept on slag–oxygen sensors to measure oxide activities related to FeO, SiO 2 , and CaO contents of steelmaking slags

A theoretical concept is presented on the slag–oxygen sensors for in situ measurements of the FeO, SiO2 , and CaO contents of steelmaking slags in the furnace and in the ladle. The purpose of this disclosure is to stimulate R & D interest in academia and technical institutes to further the development of new measuring devices applicable in steelmaking operations. The slag–oxygen sensor conceived* consists of two dissimilar electrodes such that when immersed in molten slag there will be a difference in oxygen potentials at the slag/ electrode interface between the two electrodes, registering an open circuit cell emf. Examples are given of different types of electrodes for different oxides in the slag; also, equations are derived for the theoretical relation between the oxide activity and sensor emf reading.