Flux : An outside substance added to ore to lower its melting point is known as flux.
`rarr` Flux combines with gangue and forms easily fusible slag.
`"gangue "+"Flux "rarr "slag"`
Eg : `underset("gangue")(FeO)+underset("Flux")(SiO_(2))rarrunderset("slag")(FeSiO_(3))`
