Aqueous and Environmental Process Engineering

The mining and metals industry is facing the need to develop novel technology that addresses the requirements for sustainability in the extraction and processing of natural mineral resources. The Aqueous Process Engineering and Chemistry (APEC) group is providing solutions in the processing of complex mineral resources by studying the fundamentals of aqueous process chemistry and engineering to recover and produce metals or metallic products by hydrometallurgical routes. The research focuses on developing novel chemical processing ideas to:

• Treat increasingly complex mineral deposits with low metal content including wastes, for the recovery and separation of base, precious and critical rare earth metals;
• Reduce the environmental impact (on water, land, and air), as well as minimize the use of energy and chemicals including water;

Specific project examples are:

1. Water purification by forward osmosis: Removal of soluble salts by lower energy consuming technologies compared to reverse osmosis and evaporation. Introduces low-cost bleed of salts and process water recycling to minimise fresh water intakes.
2. Bio-hydrometallurgy of sulphidic wastes for base metal recovery, and remediation:Bioleaching of sulphidic wastes to recover pay metals and discharge the acid-mine-drainage toxicity of tailings.
3. Aqueous chemistry and recovery of rare earth elements: Ion exchange leaching of ionic clays and production of a mixed oxide product by novel process configurations.
4. Recovery of metals by molten salt hydrate systems: Development of new chemistry that uses very little water and moderate energy input to extract metals from raw materials.
5. Pressure oxidation of metallurgical wastes (slags) for base metal recovery and remediation: Total remediation and cleanup of waste slags with simultaneous recovery of base metals by POX technology.
6. Development of sensors for acid and redox monitoring in aqueous streams at high temperatures: In situ monitoring by robust sensors in a variety of slurry streams in temperatures ranging from room to those in autoclaves
7. Chemical modeling of complex aqueous electrolyte solutions: Development of dedicated databases for modeling the chemistry (i.e., speciation, solubility, vapor-liquid equilibria) of salts and other compounds in complex multicomponent process solutions within very wide temperature ranges.