What roles do coke and fluxes play when chromite ore is smelted?

In the smelting of chromite ore, coke and fluxes serve distinct but essential functions to facilitate the production of ferrochromium:

• Coke: This material serves as the primary source of carbon. In an electric furnace, it acts as a reducing agent, reacting with the ore to extract the metal. Because the process typically occurs in the presence of carbon, the resulting metal is often carbon-saturated.12
• Fluxes: These substances are added to the melt to manage the physical and chemical properties of the slag. By adjusting the composition of the slag—for example, by adding lime—metallurgists can decrease its viscosity, which influences the reaction rate and the final carbon content of the alloy. Generally, fluxes are used to promote fluidity and assist in the removal of impurities by forming slag, which floats on the molten metal to protect it from oxidation.234

When processing fine ores, both coke and fluxes are often blended with the ore and preheated or prereduced before being charged into the furnace to ensure efficient smelting.1