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   Why is there a need for the re-extraction of rare earth metals from e-waste? The first reason depends on the material type; rare earth metals are embedded in low concentrations in rocks. They are not that rare, but they are called rare earth metals because they are difficult to isolate.    Another reason is that; 20 to 50 million metric tons of e-waste are disposed of worldwide every year. India generates about   2 million tonnes (MT) of e-waste annually. Cell phones and other electronic items contain high amounts of precious metals like gold or silver.   Credits:  https://res-4.cloudinary.com/the-university-of-melbourne/image/upload/s--ChrUAFwF--/c_limit,f_auto,q_75,w_892/v1/pursuit-uploads/832/c0f/1de/832c0f1de3e358be33922a69f1919272d43d93064c5158d6ba5f7e9a6f95.jpg One tonne of mobile phones has as much as 340 grams of gold, 3.5 kilograms of silver, 140 grams of palladium, and 130 kilograms of copper. Americans dump phones containing over $60 million in gold/silver every year. Onl

Introduction : - I n 1994 H.G.T Ellingham proposed the Ellingham diagram to predict the spontaneity of reduction of various metal oxides. The Ellingham diagram is basically a curve which relates the Gibbs energy value with the temperature. Gibbs equation also known as free energy equation helps us to predict the spontaneity of a reaction on the basis of enthalpy and entropy values. It helps us to know the feasibility of a reaction under usual conditions. Gibbs energy is given as: ΔG = ΔH – TΔS Where ΔH is the change in enthalpy and ΔS is the change in entropy. With respect to a reaction, Gibbs energy can be related to the equilibrium constant as: ΔG o = – RTlnK Where K is the equilibrium constant. Gibbs free energy can also be considered as the energy left in the system to do work. If we freeze a reaction then, with the knowledge of gibbs energy we can predict the equilibrium status of the reaction. It also helps us to check whether an equilibrium shift in case of physical changes.  Th