MetallurgyHard
Question
Select the correct statement(s) with respect to the differences between roasting and calcination.
Options
A.In roasting at higher temperature sulphide ores of the some metal like Cu, Pb, Hg etc. are reduced directly to metal but not in calcination.
B.Partial fusion occurs in calcination but not in roasting.
C.Calcination is done in limited supply of air or absence of air but in roasting supply of excess air is required.
D.Combustion reaction occurs in roasting but not in calcination.
Solution
(A) Roasting. It is a process of heating the concentrated ore (generally sulphide ore) strongly in the excess of air or O2 below its melting point. Roasting at high temperature. The sulphide ores of some of the metals like Cu, Pb, Hg, Sb etc., when heated strongly in the free supply of air or O2 are reduced directly to the metal rather than to the metallic oxides.
(C) Calcination. It is a process of heating the concentrated ore strongly in a limited supply of air or in the absence of air.
(C) Calcination. It is a process of heating the concentrated ore strongly in a limited supply of air or in the absence of air.
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