Same chapter3 marksDifficulty: Medium
Name three methods of refining a crude metal and state where each is used.
General Principles and Processes of Isolation of Elements
3 marksDifficulty: Medium
What is froth flotation, and for which ores is it used?
Original Khojo Papers practice question — not from a past board paper.
Answer
In froth flotation the powdered ore is agitated with water, pine oil and air. The sulphide particles are preferentially wetted by the oil and rise with the froth, while the gangue is wetted by water and sinks. It is used for sulphide ores such as those of zinc, lead and copper.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
Depressants such as sodium cyanide can be used to separate two sulphides from each other.
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