Abstract: A slag fluidizing and conditioning agent for use in combination with lime and/or limestone as the basic fluxing agent in iron and steel-making processes comprising a particulated mixture composed of controlled proportions of calcium fluoride and a metal aluminum silicate, selected from the group consisting of potassium aluminum silicate, sodium aluminum silicate, calcium aluminum silicate, barium aluminum silicate, as well as mixtures thereof. The slag conditioning agent may further advantageously include a controlled proportion of particulated iron or iron oxide and the mixture preferably is agglomerated in the form of a pellet, briquette or brick employing a fugitive type binder.