Research

Program 1 - Physics of novel system hydrodynamics

About Program 1

Program 1 comprises 32 projects across four sub-programs, aimed at reducing energy and water consumption, while maximising the recovery of the resource to deliver high-grade product. Additionally, characterisation tools are being developed to investigate mineral properties and separation processes.

–

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.

Professor Bill Skinner has shared some 2022 Program 1 highlights & future priorities

Characterising bulk and surface properties of minerals (Projects 1 – 8)

  • High Resolution X‑ray Microtomography (HRXMT) analysis methodology has succeeded
    in producing partition curves for describing mineral separations, in close agreement with traditional float-and-sink methods but requiring less time.
  • A methodology has been developed to follow the changing pulp/​surface chemistry of mineral particles as a function of size and time during grinding.

Pre-concentration through coarse particle beneficiation to reduce the need for grinding
(Projects 9 – 18)

  • A new algorithm has been developed to allow universal comparison of flotation separation
    efficiency, based on rate constants.
  • A Computational Fluid Dynamics (CFD) model has been developed that can accurately predict
    the turbulence distribution in a large laboratory flotation cell.
  • Novel coarse particle flotation technologies supported by industry partners are progressing
    to pilot scale.

Fine particle separations to achieve faster and more efficient separations (Projects 19 – 27)

  • A multiphase CFD model has been developed to study the bubble plume dispersion behaviour
    in the top fluidised bed section of a REFLUX Flotation Cell (RFC).
  • Theoretical work on permeable interfaces has confirmed and supported the observed high capture rates of hydrophobic, ultrafine mineral particles using the novel emulsion binder
    system.
  • The Concorde CellTM has been installed in Western Australia for full-scale application.
  • Pilot scale trials of the Reflux Classifier to investigate the benefits of the new channel spacing in recovering fine manganese have commenced on Groote Eylandt following industry-supported Centre research.

Solid-liquid separations to eliminate tailings dams (Projects 28 – 32)

  • Successful demonstration of permeable oil film aggregation and densification in a helical uplift pelletiser has been achieved.
  • A series of dewatering reagent molecules have been successfully shown to enhance dewatering of fine mineral tailings slurries under g‑forces such that their subsequent rheological properties may enable effective and safe disposal.

Some research objectives for 2023:

  • The Centre will host an international symposium on flotation science and engineering innovation in July, attracting leading researchers from around the world.
  • Development of a new Graviton technology prototype with FLSmidth for the purpose of large
    scale and efficient desliming at 10 microns applicable to many problems in minerals processing.
    Construction of a continuous flow pelletiser system for aggregation and densification, using permeable oil film emulsions.
  • Demonstration of recovery and mass balance of coarse magnetic-matrix synthetic composite
    particles from HydroFloatTM fluidised-bed flotation.
  • Advancing the recovery and upgrading of Cassiterite (Tin) from NSW tailings dam, and in turn solving a longstanding intractable problem, paving the way to addressing many other similar challenges.


Dig into all the details in our 2022 Annual Report, which can be found here.