Vlad Papangelakis

Dept. of Chemical Engineering & Applied ChemistryUniversity of Toronto

CNC-IAPWS

May 23, 2003

High temperature solution chemistry in Hydrometallurgy

Reagents

Discharge

VentFeed

2University of Toronto

High temperature (Pressure) Hydrometallurgy

Solution Chemistry challenges

Research needs

Outline

3University of Toronto

Simulation of Laterite Acid Pressure Leaching

AUTOCLAVE

CaCO3

H2S

Feed

PRESSURE LEACHING

NEUTRALIZATION

COUNTER CURRENT DECANTATION

Wash Water

Waste

NiS PRECIPITATION

NiS

T = 260oC

T = 90oC

H2SO4 Steam

4University of Toronto

High Temperature Hydrometallurgy

Processes between 150 - 270°C Mineral-water systems Mineral dissolution + salt precipitation Heterogeneous + multicomponent

systems Saturated + supersaturated solutions High ionic strength (I = 2 - 3 M) Acid/base and redox reactions

5University of Toronto

Solution Chemistry Challenges

Insufficient speciation information Very corrosive environments (pH<1) Chemical modelling

Highly non ideal behaviour Multicomponent systems (SO4 and Cl mainly) Lack of physical data (densities, viscosities) Lack of thermodynamic data

Heterogeneous + multicomponent systems

6University of Toronto

Research needs – opportunities?

Species ID in very concentrated solutions Instrumentation for very corrosive

environments (pH<1) Chemical modelling

New thermodynamic data New speciation information - characterization Better solution models Better sampling techniques for saturated systems

Sensor development for acid and redox