Question

Silver is refined by cupellation. Explain.

Answer 1

Cupellation:

• Cupellation is a metallurgical process for refining ores or alloyed metals that uses controlled operations at extremely high temperatures to separate the noble metals—such as gold and silver—from the base metals—such as lead, copper, zinc, arsenic, antimony, or bismuth—that are present in the ore.
• The concept behind cupellation is that noble metals are chemically inert and do not oxidize.
• Noble metals react with other metals, contaminants, and other compounds at high temperatures to produce slag or other compounds.
• Large-scale cupellation seldom yields native silver, and silver is typically associated with lead sulphide or lead carbonate.
• Smelting is used to separate silver from lead. The process of heating ore to produce metal is known as smelting.
• Due to the fact that silver melts at about 950 degrees Celsius and lead melts at around 300 degrees Celsius, alloys must be melted at high temperatures in an oxidizing environment to separate the two metals. Lead oxidation results in lead monoxide, which is expelled.

Silver is refined by the cupellation method.

• Cupellation, separation of gold or silver from impurities by melting the impure metal in a cupel and then directing a blast of hot air on it in a special furnace.
• The impurity present in the silver is lead.