Chemistry - Metallurgy Question with Solution | TestHub
How many of the given consequences are in general the results of roasting and / or calcination of concen trated ores?
(i) Removal of moistures
(ii) Reduction of metal oxides into metal.
(iii) Removal of volatile impurities as elemental vapour or volatile oxides
(iv) Conversion of concentrated ores into corresponding oxides
(v) Melting of concentrated ores
(vi) Ores become porous
Answer:
Solution:
Roasting and calcination are thermal treatments applied to concentrated ores.
(i) Removal of moisture: Yes, heating removes water.
(ii) Reduction of metal oxides into metal: No, this is typically done in a separate reduction step.
(iii) Removal of volatile impurities: Yes, impurities like S, As, Sb are removed as volatile oxides.
(iv) Conversion of concentrated ores into corresponding oxides: Yes, e.g., carbonates and hydroxides convert to oxides (calcination), sulfides convert to oxides (roasting).
(v) Melting of concentrated ores: No, these processes are usually carried out below the melting point.
(vi) Ores become porous: Yes, due to the removal of volatile components.
Thus, (i), (iii), (iv), and (vi) are correct.
The final answer is .
