Which of the following should not be used in the steel melting process?

Coke is primarily used as a fuel and a reducing agent in the steel melting process, particularly in a blast furnace. It contributes to the generation of high temperatures needed to melt iron ore and aids in the reduction of iron oxides to metallic iron. The carbon content in coke also has an enriching effect on the molten iron, adding to its properties.

On the other hand, silicon is often included in small amounts in the steelmaking process to improve various mechanical properties of the final product. Aluminum is sometimes used as a deoxidizer to remove oxygen from molten steel, thereby enhancing the quality of the alloy. Conversely, zinc is typically not used in the steel melting process. Zinc can have detrimental effects on the final properties of steel, including brittleness, and can create environmental issues due to the evolution of toxic gases when heated. Therefore, zinc is avoided in steel production processes, making it the choice that should not be used during melting.