Tag: refining of metals

Separation of impurities from the extracted metals is known as refining of metals.

In the electrolytic refining the process the impure sample is used as anode and pure metal is obtained at cathode. Impurities present at anode are deposited at the bottom and called as anode mud.

Refining of aluminium is done by electrolytic method. The aluminium obtained is 99.99% pure.

Roasting is the method of converting the ore to its oxide form . It is not a method of refining.

When stones are separated from rice, we throw away the solid component. Stones are non useful whereas rice are useful. So we through away non useful solid and then we can have rice for cooking.

Electrolysis is the dissolving of metal from one electrode of an electrolytic cell to another electrode in pure form. It gives the highest purity metal product. The impure silver is cast into a slab which is the anode, while pure silver sheet metal is the cathode.

Sodium is obtained by the electrolysis of fused mixture of $NaCl$ and $CaCl _2$ (Down's process). Reaction can be written as:

After extraction and separation, refining is the last process of Metallurgy. It involves the refining of pure metal finally. 

Copper and Silver are often refined using electrolytic refining, where an impure metal anode is dissolved and pure metal is deposited at the cathode. Silicon and Germanium are typically refined using zone refining.

In electrorefining step, impurities like Fe, Ni, Zn get dissolved in the solution while Au, Ag and Pt are deposited as anode mud below the anode and pure copper deposited at cathode.