The influence of activity coefficient and equilibrium constant models on the speciation of aqueous solutions of H<sub>2</sub>SO<sub>4</sub>–MgSO<sub>4</sub>–Al<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub> at 235 and 250°C

Supersaturation occurs in many industrial applications promoting reactive crystallisation between the reactants to form solutes. These solutes accumulate during precipitation, leading formation of scales on inner walls reactor and particularly around stirrer, causing modifications hydrodynamics. This encrustation is responsible for process shutdowns continuous processes. control essential processes aimed at controlling or inhibiting these solids. Knowledge mineral solubility chemical speciation required account composition complexes system their various solid aqueous forms. obtained by considering thermodynamic equilibrium constants dissociation/complexation reactions involved system, pressure, activity coefficients species molecular electrolyte form. From quantities state we can predict direction reaction. study highlights risk lack experimental information high temperatures moderate pressures. Our goal evaluate accuracy existing models classically used constant such very hard conditions encountered hydrometallurgical Furthermore, demonstrate influences estimation coefficient H<sub>2</sub>SO<sub>4</sub>–Al<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub>–MgSO<sub>4</sub> systems, forming hydronium alunite kieserite laterite liquor