Bubble-particle systems are encountered in a wide range of industrial and
environmental applications (flotation, bioreactors, slurry bubble columns) but
the complex dynamics and interactions make the design and operation of such
systems particularly challenging. This collaborative project between the
University of Birmingham and McGill University (Montreal, Canada) aims at better
understanding bubble-particle dynamics for novel applications in recycling.
This project is in collaboration with Professor Kristian Waters at McGill
University, with the possibility of a research placement in his laboratories
during the PhD. The student will also benefit from association with the EPSRC
PREMIERE Programme Grant (https://premiere.ai) and be part of the PREMIERE
research team including researchers from Birmingham, UCL and Imperial College.
Froth flotation is an established method of separating minerals in a slurry
based upon the relative hydrophobicity of the particles and while it has been
used for decades in the minerals industry to recover high value materials, less
attention has been paid to ridding water of low value ones (e.g. plastics).
Surface active agents known as collectors are used to enhance the particle
separation with the polar part of the molecule becoming attached to surface of
the target particles, with the hydrophobic part forming a surface which is
attracted to bubbles in the liquid. The target particles rise with the bubbles
to form a froth, which overflows the cell to be recovered. To maintain stable,
small bubbles, frothing agents known as frothers are added. The froth flotation
principle has the potential to be used in a variety of novel applications
outside its original use in the minerals industry, for example in the recycling
of plastics or battery materials. However, there are many aspects of its
operation which are still poorly understood which affect the overall efficiency
of the process.
This project will aim at investigating:
- the dynamics of the frothing agent with the forming bubble interfaces: how
the surface-active molecules alter the local interfacial tension and how
Marangoni stresses may impact the performance of the froth and the attachment of
the particles;
- the interaction of the particles in the wake of the bubbles, where recent
research has shown that this may be an important feature affecting the process
selectivity, therefore efficiency. Both are critical to understanding the
overall potential and efficiency of separation in novel applications.
The research will involve a series of experimental work involving visualisation
of particle and bubble dynamics in small-scale test cells and measurements of
interfacial properties including dynamic interfacial tension. These will feed
into a finite volume numerical model based on open-source libraries (OpenFOAM or
Basilisk). The interfacial properties measured in the lab will be implemented
and 3D numerical simulations of bubbly flows will be performed. The dynamics of
the solid particles will also be coupled to the bubble dynamics and will be
compared to the experiments in terms of flow structure, entrainment in the wake
and adhesion to the interface. The understanding of these phenomena at reduced
scale will help in developing empirical or data-driven models for improving
larger scale models and the design of flotation columns.
Funding: EPSRC DTP/College studentship in support of EPSRC PREMIERE Programme
Grant (EP/T000414/1).
Applicant: Applicants must be eligible for home fee status and should have a
first-class degree or good 2:1 (or equivalent) in Chemical Engineering,
Mechanical Engineering, Computing, Mathematics, or related areas. We are looking
for an enthusiastic and self-motivated person with a keen interest in conducting
numerical simulations, as well as experimental work in the lab.
Deadline: The position will be filled as soon as a suitable person has been
found; hence you are encouraged to apply as soon as possible (by email to
t.abadie@bham.ac.uk or online https://www.birmingham.ac.uk/schools/chemical-
engineering/postgraduate/phd-research.aspx). PhD Starting October 2024 or soon
after.
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