Liquid-Solid Equilibrium LSE

The major application of vapor-liquid equilibrium (VLE) is distillation. The uses of liquid-liquid equilibrium (LLE), liquid-solid equilibrium (LSE), and gas-solid equilibrium (GSE) are much more diverse. They include extraction (both solid and liquid), decantation as a phase separation, vapor-phase deposition (the heart of the semiconductor business), and a host of environmental applications. In all of these applications the equilibrium state and the rate of approaching it are both important. This book discusses only the equiUb-rium state, normally asking what are the compositions of the equilibrium phases when the system has minimized its Gibbs energy, subject to the external constraints and the starting conditions. As with VLE, the working criterion for LLE, LSE, and GSE is that the fugacity of any individual species must be the same in aU the phases at equilibrium (Eq. 7.4). 

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