explain the electrolytic refining of copper with diagram
Answers
Unlike aluminum, copper metal is fairly easy to obtain chemically from its ores. By electrolysis, it can be refined and made very pure – up to 99.999%. Pure copper is useful in making electrical wire because copper’s electrical conductivity is reduced by impurities. These impurities include valuable metals like silver, gold and platinum; when they are removed by electrolysis and recovered, they go a long way toward paying electricity bill.
In electrolytic refining of copper, impure copper is made from anode in an electrolyte bath of copper sulphate, , and sulphuric acid, . Cathode is a sheet of very pure copper. As current is passed through solution, positive copper ions, in the solution are attracted to negative cathode, where they take on electrons and deposit themselves as neutral copper atoms, thereby building up more copper on cathode. Meanwhile, copper atoms in positive anode give up electrons and dissolve into electrolyte solution as copper ions. But, impurities in the anode do not go into solution as silver, gold and platinum atoms are not as easily oxidized (converted into positive ions) as copper is. So, silver, gold and platinum fall from anode to bottom of tank, where they can be scrapped up.