MetallurgyHard
Question
Which of the following statement(s) is (are) incorrect ?
Options
A.In Serpeck′s process silica is removed by heating the bauxite to 1800oC with coke in a current of N2
B.In extraction of lead from galena roasting and self reduction takes place in the same furnace but under different conditions of temperature and supply of air
C.The tin is obtained by the carbon reduction of black tin.
D.None
Solution
(A) White bauxite contains the impurity of silica which is removed by heating with coke in a stream of N2
SiO2 + 2C
Si↑ + 2CO ; Al2O3 + 3C + N2 
2AlN + 3CO
(B) 2PbS + 3O2
2PbO + SO2 ; 2PbO + PbS 
3Pb + SO2
(C) SnO2 (black tin contains 60 - 70% SnO2) + 2C
Sn + 2CO.
SiO2 + 2C
Si↑ + 2CO ; Al2O3 + 3C + N2 2AlN + 3CO(B) 2PbS + 3O2
2PbO + SO2 ; 2PbO + PbS 3Pb + SO2(C) SnO2 (black tin contains 60 - 70% SnO2) + 2C
Sn + 2CO.Create a free account to view solution
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