Coal Preparation

Investigation of Moisture Reduction Methods for Horizontal Belt Filters with the Single Leaf Filter Test

Coal Preparation » Dewatering

Published: April 99Project Number: C6049

Get ReportAuthor: Florent Bourgeois, Tofazzel Hague, Chris Clarkson | University of Queensland, C Clarkson & Associates

This project builds on earlier work, that concluded that controlling cake microstructure was a potential means of reducing equilibrium cake moisture. This result led to the hypothesis that by modifying cake microstructure during the drying phase of the filtration cycle, cake moisture could possibly be lowered. Secondly, the project established the potential of the Single Leaf Filter Test (SLFT) apparatus as a possible tool for sizing horizontal vacuum belt filters.

The objectives of this project were:

  • to trial microstructure alteration methods for reducing cake moisture on horizontal vacuum belt filters, and
  • to derive and test a scale-up procedure for sizing full-scale horizontal belt filters based on data obtained with the Single Leaf Filter Test (SLFT) apparatus.

Moisture reduction by mechanical cake mixing

Initial attempts to alter cake microstructure using vibration and compaction, conducted on pilot-scale and full-scale horizontal belt filters, concluded that neither altered cake microstructure sufficiently to reduce cake moisture.

Continuous cake mixing trials were conducted under controlled laboratory conditions, using a double-helix ribbon blade mixer to agitate filter cakes formed in top-fed laboratory leaf filtration tests during the drying phase. Such mixing reduced cake moisture by up to 4%. Faster dewatering kinetics were also observed. It is estimated that belt length could be reduced by 20% to 30% while maintaining cake moistures.

Several factors were identified as having an impact on moisture reduction by cake mixing:

  • Moisture reduction was found to be very sensitive to the time at which mixing is initiated during the drying phase.
  • Moderate air purging was found to marginally improve moisture reduction.
  • Mechanical mixing was most effective with finer size fractions.
  • The mixing technique was very effective in coping with the extremely cohesive nature of moist fine coal particles

Projected values for discharge moisture and belt size were obtained from a comprehensive series of laboratory mixing tests with a fine coal flotation concentrate from Central Queensland. The values are summarised in the table below.

With Mechanical mixing time at which mixing starts (s) *Predicted belt area (m2) Cake discharge moisture (%)
No - 100 25.8
Yes 30 67 25.8
Yes 40 80 23.2
* Fixed belt width assumed

Vacuum belt filter sizing using the Single Leaf Filter Test apparatus

The project confirmed the possibility of using the SLFT apparatus to size horizontal vacuum belt filters. Firstly, site tests confirmed the agreement between SLFT and belt filter performance under the same operating conditions. A method for scaling up SLFT test results was derived. It permits calculation of the minimum effective belt filter area required to meet a number of user specified constraints, including feed rate and cake discharge moisture. The technique was compared to actual plant performance data and good agreement resulted. It also proved useful as a means of deriving information about the behaviour of operating belt filters.

In spite of adverse experimental conditions that prevented conclusive comparison of HBF and SLFT form times, excellent agreement was obtained between their respective dewatering kinetics, confirming the potential of the SLFT as an HBF sizing tool.

A sizing scheme was developed from which belt length, width, linear speed, operating cake height and minimum vacuum pump capacity, necessary to treat a specified tonnage and yield a set product moisture, can be determined from SLFT measurements alone. The results were found to compare well with the average HBF performance at BHP Coal Riverside mine.


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