Principle of Vapour Phase Refining of Metals

The refining of metals has relevance and importance in the field of metallurgy. It is believed that any type of metal that is obtained from the ore is considered an impure form of metal. Crude metal is known as an impure form of metal that is flushed out and has the least usage. In the process of refining, all the impurities are removed from the metals to obtain high-quality purity metal.

There are different methods that have been used to remove the impurities of metals depending on the quality of the metal and the impurities. Metals are found in the ore in compound form with several other types of metals by the process of metal extraction. In the process of metal extraction, metals are extracted from its ore or their residues, whereas in the process of refining, metal extraction is from its ore.

Process of Refining Impure Metals

It is very common to have impurities in metals which are produced by different reduction methods. This results in the production of metals which are impure. The process of purifying metals is called Refining Metals. Therefore, metal refining means Metal Purification.

The nature of the metal and of the impurities present in metal decides the process of refining metals. There are different types of processes used for the removal of impurities. Usually, the impurities of metals are removed from crude metals by using various metals depending on the properties of the impurities. There are various methods used in the refining process of crude metals.

Liquation Process

This process is used for metals which have a low melting point, i.e. the melting points are taken into consideration in this process. Impurities have a high melting point compared to metals. To convert them into the liquid condition, the temperature of the heat is higher than the metal’s melting point. After these impurities are left as residue, the pure metal melts and flows down the furnace.

Distillation Process

In this process of distillation, the boiling point is low to purify metals that include mercury and zinc. In this process, metals which are impure are heated at more than their boiling point so that vapours are created. A requirement of this process is that the impurities must be separated from the metals, since the impurities do not evaporate. Pure metal vapours are condensed and the impurities are left behind.

Vapour Phase Refining Process

In this purification process, the metals need to produce a volatile compound in the presence of a reagent that can break down easily to recover the metal. The metal is then converted to a gaseous compound. This chemical is later decomposed to yield pure metals. For instance, nickel is purified by processing through vapour phase refining.

Chromatographic Process

In this process, the mixture of crude is put in a liquid or gaseous medium. To transfer this medium, an absorbent is used. There are different components of this mixture that are absorbed in different levels of the column. After using the appropriate solvents, the mixture components are removed.

Process of Zone Refining

This process is used when removing impurities such as silicon, germanium, gallium, boron and indium. The impure form of metal on one end is connected to the circular mobile heater. As the heater is moved, the pure metal crystallises out, and the impurities transfer to the adjoining part of the metal. The impurities are then accumulated on the other end, which is later cut down to yield the pure metal.

The Principle of Vapour Phase Refining

The principle that governs the principle of vapour phase shifts into volatile compounds. That is, metals that are impure are converted into volatile compounds. This volatile compound is collected from different spaces. The principle on which vapour phase refining is based, is that the metals which are impure are converted as volatile compounds. These compounds can be extracted from any different point. After that, it will go through the process of decomposition and then be used again to produce the pure metal.

Conclusion

It can be concluded that the process of refining metals is very important in metallurgy and that any type of metal that comes from the ore is known as an impure form of metal. Crude metal is known as an impure form of metal.

To obtain high-quality metal, there are several processes of removing impurities of metals, which are used according to the quality of metal and properties of the metal’s impurities. Some of the processes for refining impure metals are the distillation process, liquation process, vapour phase refining process, chromatographic process and zone refining process.