The Recovery of Pb and Zn in Antimony Smelting Slag
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Fig. 1 Schematic diagram of fuming furnace reactions
PbO(1) + CO(g) = Pb(g) + CO 2 (g)
Sb 2 O 3 (1) + 3CO(g) = 2Sb(1) + 3CO 2 (g)
The molten bath in fuming furnace is agitated by process air, which makes metal
zinc, metal lead, and metal antimony volatilize from molten bath and go to offgas.
The metals lead, zinc, and antimony in the offgas will have reaction with unreacted
O 2 and tertiary air blown from tertiary air tuyere to produce ZnO, PbO, and Sb 2 O 3 .
To ensure reduction reaction in the molten bath, there will be excess CO in the offgas,
which will be combusted in the freeboard. The major reaction in the freeboard is as
follows:
2CO(g) + O 2 (g) = 2CO 2 (g)
2Zn(1) + O 2 (g) = 2ZnO(s)
2Pb(g) + O 2 (g) = 2PbO(g)
4Sb(1) + 3O 2 (g) = 2Sb 2 O 3 (1)