Question
Thu November 24, 2011 By:

why sulphides are roasted and other compounds are calcinated?

Expert Reply
Thu November 24, 2011
Extraction of metals from ore is  different, depending  by metal chemical combination. When ore is composed of carbon, it is subjected to an ignition in advance, for removing carbon dioxide. This process is calcination. 
 
Sulfide ores generally are subjected to a prior roasting, to remove sulfur (as sulfur dioxide) and processing sulphide to oxide. As sulphide contain no carbon, they cant undergo calcination.
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