In the auto-reduction step of Lead extraction, the roasted products react with the unroasted Galena — Metallurgy and Isolation of Elements Chemistry Question

💡 Solution & Explanation

During the partial roasting of Galena ($PbS$), both Lead(II) oxide ($PbO$) and Lead(II) sulphate ($PbSO_4$) are formed. In the subsequent auto-reduction step in the absence of air, both $PbO$ and $PbSO_4$ react with the remaining $PbS$ to produce metallic Lead and $SO_2$ gas.