Explain the following. Both coke and flux are used in smelting process of metallurgy.

PLACEHOLDER ANSWER - the answer is an explanation. Coke is the fuel and the reducing agent; it burns to supply heat and forms CO, which reduces the oxide ore, for example $$\text{Fe}_2\text{O}_3 + 3\text{CO} \rightarrow 2\text{Fe} + 3\text{CO}_2$$. The flux combines with the earthy impurities (gangue) to form a fusible slag that separates from the molten metal, for example $$\text{CaO} + \text{SiO}_2 \rightarrow \text{CaSiO}_3$$.