ABSTRACT
This chapter examines one application of Gibbs energy, namely the theory of the extraction of metals from naturally occurring oxide minerals. As an example of the practical application of thermodynamics to reaction equilibria, it explores its application to the production and refining of metals using high-temperature processing. There are many ways to produce metals through the application of aqueous chemistry, electrochemistry and high-temperature processing. The route selected for a particular metal depends upon, among other factors, the stability and nature of the host mineral, the thermodynamically feasible reactions to produce the metal and the cost of processing. The reduction of an oxide could in principle be achieved either physically or chemically. The pressure of the system could be lowered and/or the temperature raised until the oxygen potential of the oxide exceeds that of the surroundings. The carbothermic reduction of most oxides is endothermic and is more endothermic the more stable the oxide.
