Physics of novel system hydrodynamics
About Program 1
We will apply our advances in‘fast, efficient beneficiation’ of fine particles to solid-liquid separation in order to increase product recovery and to recover waste solids, reducing water wastage and increasing water productivity. We will then recover targeted solids and exploit hydrophobic interactions to enhance de-watering.
Maximising the robustness, efficiency, and speed of separation are the critical elements of any transformational mineral beneficiation technology. This will be achieved by building knowledge and understanding of a broad range of novel hydrodynamic systems to determine the potential to approach the theoretical limits of separation, traversing the particle size range of interest.
In minerals processing, physical and physico-chemical properties, amongst others, are routinely exploited to achieve separations. The target minerals, which are embedded within a quartz or granite host rock or medium, must be released through breakage and ultimately grinding. This preparation produces a low portion of high value particles consisting of the target mineral, composite particles consisting of the mineral and unwanted host rock known as gangue, and a high proportion of unwanted gangue particles. The liberated minerals often exhibit a higher density and hence weight force at a given particle size, a basic property exploited in gravity separation. The liberated minerals of interest also associate with specific collectors, chemicals that yield strong hydrophobicity, in contrast to the unwanted gangue material that usually remains hydrophilic. Hydrophobic surfaces have an affinity for media other than water, such as air bubbles in froth flotation, and oils in agglomeration.
Program 1 consists of four sub-programs
The first is concerned with establishing advanced forms of characterisation of mineral particles, and mineral surfaces, how to quantify the extent of mineral liberation, and the theoretical limits linking the maximum possible metal grade (wt%) to a given metal recovery (%).
The second is concerned with addressing the objective of achieving early-gangue rejection, through the establishment of relatively coarse particle separations to remove the unwanted gangue at a coarser grind size. Approaches using both froth flotation and dry separations will be investigated.
The third is focused on the separations required when the particles have been ground to a particle size sufficient for full liberation. There is substantial scope to fully exploit the potential of the hydrophobic effect to achieve a substantial increase in the speed of fine particle processing, by a factor of 10 – 100, including higher product grade, and recovery.
The fourth is concerned with the recovery of the process water, the goal being to reduce the ultrafine solids sent to the tailings stream and deliver the tailings at a concentration sufficient for stackable storage of the solids.