1. Vlad Papangelakis Dept. of Chemical Engineering & Applied Chemistry University of Toronto CNC-IAPWS May 23, 2003 High temperature solution chemistry in Hydrometallurgy Reagents Discharge Vent Feed

2. 1 University of Toronto  High temperature (Pressure) Hydrometallurgy  Solution Chemistry challenges  Research needs Outline

3. 2 University of Toronto Simulation of Laterite Acid Pressure Leaching

4. 3 University of Toronto High Temperature Hydrometallurgy l Processes between 150 - 270°C l Mineral-water systems l Mineral dissolution + salt precipitation l Heterogeneous + multicomponent systems l Saturated + supersaturated solutions l High ionic strength (I = 2 - 3 M) l Acid/base and redox reactions

5. 4 University of Toronto Solution Chemistry Challenges l Insufficient speciation information l Very corrosive environments (pH<1) l Chemical modelling n Highly non ideal behaviour n Multicomponent systems (SO4 and Cl mainly) n Lack of physical data (densities, viscosities) n Lack of thermodynamic data l Heterogeneous + multicomponent systems

6. 5 University of Toronto Research needs – opportunities? l Species ID in very concentrated solutions l Instrumentation for very corrosive environments (pH<1) l Chemical modelling n New thermodynamic data n New speciation information - characterization n Better solution models n Better sampling techniques for saturated systems l Sensor development for acid and redox