The zone of blast furnace, close to `1273K`, in the metallurgy of iron is called zone of slag information. Here, the flux `CaO` rects with impurity of `SiO_(2)` to produce slag `CaSiO_(3)`.
`underset("Flux")(CaO)+underset("Impuritiy")(SiO_(2))tounderset("Slag")(CaSiO_(3))`