P24 - Hydrodynamics of Flow Regime Transition in a Reflux Flotation Cell

Closing Date: 31 December 2022Apply Now

PhD Scholarship

Supervisor: Dr Subhasish Mitra and Professor Geoffrey Evans - The ARC Centre of Excellence for Enabling Eco-Efficient Beneficiation of Minerals is seeking creative and innovative PhD applicants to join our national collaborative Centre, to develop transformational technologies to reduce energy and water consumption and increase metals recovery. This Project aims to examine the flow regime transition in the downcomer region of the reflux flotation cell at a fixed gas flux when the gas bubbles are released as froth from the overflow at different liquid underflow fluxes.

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The Centre’s inclusive and equitable culture is supported by specific equity and diversity initiatives, which will support all members to achieve their career goals.

A significant amount of fine valuable minerals is lost to tailings dams during the processing which can be economically recovered in the novel reflux flotation cell which is a combination of a vertical bubble column section at the top and an array of narrow width inclined channels at the bottom. This device has the potential of overcoming hydrodynamic limitations in the conventional flotation cells and achieving suitable separation at greater throughput near the flooding condition by utilising higher co-flowing gas and liquid fluxes.

The focus of this project is to develop a combined theoretical and experimental approach to quantify multiphase flow regimes in this system under different operating conditions and their effect on the product recovery.

The effect of key hydrodynamic variables, such as gas flux, liquid flux, bubble size and solid concentration on the bubble volume fraction will be investigated. Flow regime transition will be examined using both direct visualization, optical and differential pressure measurement technique. Along with these measurements, minerals recovery will also be quantified for each operating condition.

A theoretical modelling framework will be developed based on the drift-flux theory to identify regime transition by comparing model prediction with measured gas volume fraction. A comprehensive CFD (computational fluid dynamics) model of this three phase system will also be developed treating solid phase as continuum based on the kinetic theory of granular flow. Bubble-particle phase interaction sub-models will be separately incorporated in this modelling framework. The CFD model will be validated by comparing predicted gas volume fraction and minerals recovery with the experiments.

The project outcomes will enhance fundamental understanding of the physical separation mechanisms in a potential mineral separation device like reflux classifier to prevent unwanted flow behaviour resulting in compromised recovery. Establishing the theoretical framework with appropriate experimental validation to predict the likelihood of flow regime transition will provide the necessary design limits so that the system geometry and throughputs can be suitably tailored for optimum product recovery.

For more information on our Centre please visit www.coeminerals.org.au

PhD Scholarship details

Funding: $33,092 per annum (2020 rate) indexed annually. For a PhD candidate, the living allowance scholarship is for 3.5 years and the tuition fee scholarship is for four years. Scholarships also include up to $1,500 relocation allowance and Overseas Student Health Cover at a single rate, for an international candidate.

Supervisor: Dr Subhasish Mitra and Professor Geoffrey Evans

Available to: Domestic and International students


Eligibility Criteria

The applicant will need to meet the minimum eligibility criteria for admission.

Application Procedure

Interested applicants should send an email expressing their interest along with scanned copies of their academic transcripts, CV, a brief statement of their research interests and a proposal that specifically links them to the research project.

Please send the email expressing interest to Subhasish.Mitra@newcastle.edu.au by 5pm on 31 December 2022.

Applications Close 31 December 2022 Apply Now

Contact Dr Subhasish Mitra
Phone +61 2 4033 9208
Email Subhasish.Mitra@newcastle.edu.au

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