Grant: Research Tools and Instruments - Category 1 (<$150,000)

The mining and mineral processing industry creates wealth for Canada, accounting for up to 4% of GDP. However, the fine grinding required to liberate the valuable minerals from gangue consumes almost 70% of the total energy in mineral processing plant, which poses tough challenges in the operating cost and environment management such as CO2 emissions of greenhouse gases. Technically, as particles become smaller during the grinding, the slurry viscosity and yield stress increase due to the high specific surface area created and the complex intermolecular and surface forces induced by the chemistry of various processing water. The throughput of the grinding mills is limited due to the high slurry viscosity and yield stress, leading to high consumption in grinding energy and high operating cost. To improve the grinding efficiency, it is desirable to have the mineral slurry with a high solid loading and a low yield stress and viscosity. The fundamental understanding of the effects of particle size and the intermolecular and surface forces between the particles on slurry rheology is an essential step in reducing the grinding energy. The role of particle size distribution and particle-particle interaction in controlling slurry rheology will be studied using Rheometer ARES-G2 at various solid contents and water chemistry. The particle size distribution will be measured using a set of sieves or Malvern particle size analyzer, while the particle-particle interaction will be determined by atomic force microscopy (AFM) and zeta-potential measurements. The particular system of interest is the rheology of ultramafic Ni-bearing sulfide slurry since the significant reduction in grinding energy of ultramafic Ni-bearing sulfide ores was observed after microwave treatment in our recent studies.