Question

Roasting of copper pyrite ores is for which of the following purpose?

• A. To burn off sulphur, arsenic, antimony etc. as oxides and convert all the iron and copper to their oxides.
• B. To burn off arsenic, antimony etc. as oxides and burn off sulphur so that enough of it remains to combine with all the copper.
• C. To burn off sulphur partially, in order to leave enough of sulphur to combine with arsenic, antimony etc. and the to convert all the iron and copper to oxides.
• D. To melt arsenic and antimony sulphides etc. and remove them by liquation and to burn off sulphur partially to leave enough to combine with copper and iron.

Answer 1

The correct option is C To burn off sulphur partially, in order to leave enough of sulphur to combine with arsenic, antimony etc. and the to convert all the iron and copper to oxides.

The ore is partially roasted because, the Sulphur takes the impurities as gases and to react with remaining ore to get Copper metal undergoing auto-reduction.