This course is a methodological teaching which provides students with reasoning and tools allowing to model a complex reactional medium, meaning which implements several equilibria.
This modeling allows to quantify the weight of each physico-chemical parameters and variables (such as pH, concentration of components, equilibrium constants,…).
That way allows to choose the best conditions in order to reach a specific objective, such as to enhance the selectivity of the system, calculate operational values (such as the solubility or the fraction extracted) and to predict its evolution.
This « controlled » chemistry, whose contribution is located before Chemical Engineering, deals, in particular, with the development of the hydrometalurgical processes. Some examples, all concerning nuclear issues, will be developed as practical exercises
1- Chemical reactions in monophasic media
- Complexation as a function of pH and in presence of competitive reagents.
- Selective solubilisation and precipitation using complexation, acid-base and redox phenomena.
- Stabilisation of redox species using selective complexation effect, acidity and selective precipitation.
2- Chemical reactions in biphasic media (liquid – liquid extraction)
- Extractant reagents liquid-liquid classification systems.
- Distribution ratio, extraction isotherm, fraction extracted.
- Chemical conditions influence on the distribution ratio: mass effect, masking effect salting-out effect, competitive reactions in organic phase (synergism).
- Operating conditions influence on the fraction extracted: phase ratio, countercurrent extraction.
Equilibrium constants, mass action law, acid-base and redox reactions, hydrolysis and other complexation reactions, pH, solubility, extractant reagent, phase ratio, fraction extracted