Coal Preparation

Improvement of Hydrodynamic Behaviours in Large Coal Flotation Cells

Coal Preparation » Fine Coal

Published: June 15Project Number: C23044

Get ReportAuthor: Shenggen Hu and Philip Ofori | CSIRO

The performance of flotation cells can be impaired by the occurrence of unfavourable hydrodynamic behaviours, such as channel flows, pulp circulation flows, dead volumes and excessive shear stress. In ACARP project C21051, hydrodynamic behaviours in both Microcel columns and Jameson cells were studied by using residence time distribution (RTD) tests combined with measurements of gas holdup distribution. Plant-scale investigations indicated that strong downward channel flows occurred along the axial direction in the Microcel columns studied, leading to large stagnant volumes of up to 70% of the total cell volume. In a plant-scale investigation of hydrodynamic behaviours in a large Jameson cell, it was found that the flow pattern was a type of perfect mixing (i.e. fast and intensive mixing) and a significant fraction of multiphase mixture exiting the downcomer could discharge from the tailings exit in a very short period of time. The intensive mixing could generate high shear stress, leading to the detachment of some particles from the particle-bubble aggregates, particularly for coarse and/or less hydrophobic particles.


The project objective was to improve the hydrodynamic behaviours of Microcel columns and Jameson cells, via:

· Designing and constructing simple and cost-effective modifications to reduce undesirable hydrodynamic behaviours in Microcel columns and Jameson cells;

· Carrying out plant-scale experiments to determine the effectiveness of modifications on Microcel columns performance; and

· Evaluating the performance of modification concepts for Jameson cells in pilot-scale tests.


Main Findings and Conclusions

The project has successfully completed the following tasks for improving the hydrodynamic behaviours of Microcel columns and Jameson cells:

· Development of simple and cost-effective modifications of slurry feed inlets and air sparger inlets to reduce undesirable hydrodynamic behaviours in Microcel columns;

· Assessment of the effectiveness of modified slurry feed inlets and two modifications of air sparger inlets in large scale Microcel columns;

· Performance evaluation of modified downcomer and aerosol addition of MIBC-water mixture for Jameson cells in pilot-scale tests.


Industrial Applications

The modification of air sparger inlets with extended length is a low-cost modification as only 6 of 12 original air sparger inlets are involved in the simple extension of length. Therefore, this cost-effective and reliable modification can be used without modifying the original slurry feed inlets to improve the performance of existing Microcel columns with a diameter of 4.8 metres and a height of 16 metres. It could be anticipated that the extended length in the range of 0.7 to 0.8 meters would give a further improvement. The use of air sparger inlets with extended length Microcel columns with a height of 9 meters would require further evaluation tests as the column height also plays an important role in determining the hydrodynamics behaviours of flotation columns.



The outputs from this project led to the following recommendations:

· More studies are required to develop an improved air sparging system which can provide sufficient mixing energy and at same time produce uniform gas holdup distribution in Microcel columns.

· Unbiased slurry feed and diesel collector distributions to parallel Microcel columns should be accomplished before evaluating any modification to improve flotation performance.

· Although tests on a 300mm Jameson cell have shown the potential of the modified downcomer, its performance needs to be thoroughly assessed against the unmodified downcomer on a scale-up cell under practical feed conditions at a mine site. Test data from these assessments is essential for industry to adopt this modification to the downcomer.

· Atomization with MIBC-water mixtures proved to mitigate the fire hazard by dilution and cooling in a pilot scale Jameson cell with a diameter of 300mm. It would be beneficial to examine the implementation methodology and effectiveness of this safe aerosol addition approach on a large scale Jameson cell at a mine site in reducing frother usage while maintaining or improving process performance.


Health and safety, productivity and environment initiatives.


Open Cut

Safety, productivity and the right to operate are priorities for open cut mine research.

Recently Completed Projects

C19024Establishing Ecologically Sustainable Mine Water Release Criteria In Seasonally Flowing Streams

Extreme rainfall conditions in the Fitzroy Catchment over an approxi...

C25030Coal Mine Open Pit Final Void Closure And Relinquishment - Addressing Uncertainty In Coal Mine Environmental Planning

This report addresses uncertainties faced by coal mine operators whe...

C27046Estimation Of True Deformation Vector From Slope Radar Monitoring

Slope deformation radar monitors are now widely used in open cut coa...

Open Cut

Coal Preparation

Maximising throughput and yield while minimising costs and emissions.

Recently Completed Projects

C27004Improving Coal Flotation With Oscillatory Air Supply

This report provides detailed information on coal flotation with os...

C25018Improving Solids Recovery And Moisture Reduction In Ultrafine Coal Dewatering

This report provides detailed information on fine coal dewatering in...

C27028Lab Froth Flotation Testing Guide With Coal Quality

Correct outcomes from laboratory froth flotation testing in coal bor...

Coal Preparation

Technical Market Support

Market acceptance and emphasising the advantages of Australian coals.

Recently Completed Projects

C26039Nanoporosity In Cokes: Their Origin, Control And Influence On CO2 Reactivity

This project using the outcomes of previous project C24060, examine...

C28063A Comprehensive Technical Review Of High-Efficiency Low-Emission (HELE) Pulverised Coal Combustion Technologies For Power Generation

Research and development has been undertaken worldwide to realise co...

C28064Carbon Structure Transformation During Coking Of Australian Coking Coals: Better Understanding The Coke Formation

Carbon structures of coke that are formed during the plastic layer a...

Technical Market Support

Mine Site Greenhouse Gas Mitigation

Mitigating greenhouse gas emissions from the production of coal.

Recently Completed Projects

C28076Selective Absorption Of Methane By Ionic Liquids (SAMIL) - Phase 2 Demonstration In A Packed Bed Reactor

An alternative approach to high temperature oxidation of ventilation...

C26004CFD Modelling Of Reverse Thermal Oxidisers For VAM Abatement - CFD Modelling Of Fixed-Bed RTO Devices

The project is part of a larger multi‐phase program of study a...

C27058Technological Assessment Of A Recycle Reactor For VAM Abatement

Underground coal mining emits high volumes of methane, diluted in ve...

Mine Site Greenhouse Gas Mitigation

Low Emission Coal Use

Step-change technologies aimed at reducing greenhouse gas emissions.

Recently Completed Projects

C17060BGasification Of Australian Coals

Four Australian coals were trialled in the Siemens 5 MWth pilot scale ga...

C17060AOxyfuel Technology For Carbon Capture And Storage Critical Clean Coal Technology - Interim Support

The status of oxy-fuel technology for first-generation plant is indicate...

C18007Review Of Underground Coal Gasification

This report consists of a broad review of underground coal gasification,...

Low Emission Coal Use

Mining And The Community

The relationship between mines and the local community.

Recently Completed Projects

C16027Assessing Housing And Labour Market Impacts Of Mining Developments In Bowen Basin Communities

The focus of this ACARP-funded project has been to identify a number...

C22029Understanding And Managing Cumulative Impacts Of Coal Mining And Other Land Uses In Regions With Diversified Economies

The coal industry operates in the context of competing land-uses that sh...

C23016Approval And Planning Assessment Of Black Coal Mines In NSW And Qld: A Review Of Economic Assessment Techniques

This reports on issues surrounding economic assessment and analysis ...

Mining And The Community


National Energy Research,Development & Demonstration Council (NERDDC) reports - pre 1992.

Recently Completed Projects

1609-C1609Self Heating of Spoil Piles from Open Cut Coal Mines

Self Heating of Spoil Piles from Open Cut Coal Mines

1301-C1301Stress Control Methods for Optimised Development...

Stress Control Methods for Optimised Development and Extraction Operations

0033-C1356Commissioned Report: Australian Thermal Coals...

Commissioned Report: Australian Thermal Coals - An Industry Handbook