Question

Name the common elements present in the anode mud in electrolytic refining of Copper. Why are they present?

Answer 1

Hint: The impurities that are present in the copper we take for refining may get deposited in the form of anodic mud. Only the ions that are less basic than copper and are present in the solution can be found in the anodic mud.

Complete answer:
The commonly present elements in the anodic mud in electrolytic refining of copper are Gold, Silver, Platinum, Antimony, Selenium, Tellurium, etc...
Now, we generally refine blister copper by electrolytic method to gain pure copper. Blister copper has usually around 98.5% of purity but in other parts, impurities may be present. These impurities include Selenium, Tellurium, Gold, Silver, Platinum, Antimony and Selenium. Now, they all are less basic than copper means they have less reducing potential than copper. So, copper only will be reduced to its metallic form and the metals will remain in the solution and get collected at the bottom of the reaction chamber in the form of anodic mud.

Additional Information In electrolytic refining of the metal, impure impure metal rod is used as anode and pure method gets collected at cathode. The solution we use is an acidified solution of the metal we are refining. So, we use an acidified solution of copper salt. Now in terms of impurity of metal ions, more basic ions than copper are found in the solution because of the acidic nature of the solution and the less basic cations get deposited in the form of anodic mud. Reactions occurring at anode and cathode are as shown below.

\[{\text{Anode: Cu}} \to {\text{C}}{{\text{u}}^{2 + }} + 2{e^ - }\]

\[{\text{Cathode: C}}{{\text{u}}^{2 + }} + 2{e^ - } \to {\text{Cu}}\]

Note: Do not get confused between which elements get deposited at anode and cathode. Remember that only impurities will be present in the anodic mud in the refining process of copper by electrolysis. So, do not include copper there.