Question

Metal having low melting point such as tin can be purified by$?$

Answer 1

Metal having a low melting point such as tin can be purified by the liquation process. Liquation, technique for separating constituents of an ore, a metal, or an alloy by partial melting. When the material is heated to a temperature where one of the constituents melts and the other remains solid, the liquid constituent can be drained off.

Complete answer:
The low melting metals can be separated from high melting metals by liquation process.
Liquation is a metallurgical process to purify mineral metals. It is employed to separate valuable metals from ores that are a mixture of two or more valuable metals. The process involves heating the ore until the metal with a lower melting point is separated from the one with higher melting point.
It is used to treat both impure tin and dross from smelting, it removes those impurities that have a higher melting temperature than tin. The materials to be treated are placed on a sloping hearth in a reverberatory furnace and heated to a temperature just above the melting point of tin. The tin melts slowly and runs down the slope, to be collected in a vessel, leaving the unmelted residues on the hearth. These are subsequently removed and treated.

Note:
Remember this process is not $100\%$ efficient. Liquation is used for the refining of metals having low melting point and having impurities of high melting point or vice versa. There must be a difference in the melting point of the constituent.