Chemistry - Metallurgy Question with Solution | TestHub

In the blast furnace, CO acts as the major reducing agent in the upper zone, and at higher temperatures CO is continuously regenerated by: $\mathrm{C}+{\mathrm{CO}}_2\to 2\mathrm{CO}$.

Limestone acts as flux because it decomposes to CaO which removes silicate impurities as molten slag that separates from molten iron.

The reaction

FeO(s) +C(s) → Fe(s/ℓ) + CO(g)

becomes feasible above ~1073 K because beyond this temperature the (C, CO) line lies below the (Fe, FeO) line in the Δ_r , G⁰ vs T plot

Since CO is a gaseous reducing agent, the reaction

FeO(s) + CO(g) → Fe(s) + CO₂ (g)

becomes more feasible at higher temperature due to increasing entropy; hence CO reduces FeO most effectively in the hottest zone of the furnace.