Monday, 29 April 2019

Methods of Recycling Non-ferrous Metals

Conscious efforts towards sustainability have led to the recycling of even non-ferrous metals like aluminum, copper, nickel, silver, and tin. These metals retain their original properties even after undergoing recycling repeatedly. As they are found mixed with liquids and solids, extracting and purifying them before recycling can be a complex task. However, recycling is cheaper than mining metals and saves up to 95% of energy costs.

Three methods widely used to recycle non-ferrous metals are:

Electrowinning: Electrowinning, also known as electroextraction, is a relatively simpler procedure of extracting metals, which dissolves them using electricity. If non-ferrous metals are to be extracted for recycling, the procedure involves the metal in any form of waste to be put in a liquid solution, to dissolve it into the liquid a state known as leaching or leachate and then submerging it using cathodes. Hence, non-ferrous metals like copper, nickel, silver, and tin are recycled for further use.

Precipitation: Another widely used method for recycling non-ferrous metals from aqueous solutions is precipitation. It includes two metal removal sub-methods known as co-precipitation and adsorption. The end-result metal is called precipitate and the chemical that causes it to precipitate is called precipitant, which is mostly sodium and calcium hydroxides or oxides used to increase the pH.

Metal Sensors: Metal sensors are widely being used in sorting and extracting non-ferrous metals from scrap found in vehicles or e-waste. The method might falter as non-ferrous metals of similar densities can’t be separated from each other using gravimetric techniques which ultimately require human observation and intervention.

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