ACARP ACARP ACARP ACARP
Coal Preparation

Large Diameter DM Cyclone Operating Data

Coal Preparation » Gravity Separation

Published: June 02Project Number: C10048

Get ReportAuthor: Warren Weale | QCC Resources

The use of large diameter (greater than 1 m) dense medium cyclones has become widespread in the Australian coal industry, and in the future is likely to be the dominant processing unit. There is little readily available data on the efficiency of these units, particularly with respect to the impact of medium to coal ratio and their effectiveness in treating -4 mm coal. Access to such information will allow the optimisation of the design and operation of plants that include these units.

This project was essentially a scoping study to identify key operating traits of large diameter dense medium cyclones, and to recommend project areas that would yield benefits to the industry if further R&D were carried out.

Project information was gathered from published data, a survey of unpublished plant audit data, and detailed sampling of two operations. Project outcomes were based on the collation, correlation and evaluation of these data..

Readily available information from the literature has been collated to provide a firm basis for the consideration of the observed operational results. Key points to come from this review were:

  • for a given cyclone diameter, there is a particle size, termed the 'breakaway size', below which Ep deteriorates rapidly. As cyclone diameter increases, the breakaway size becomes larger - around 5 mm for 1000 mm cyclones, compared with just over 2 mm for 610 mm cyclones
  • below the breakaway size, Ep increases hyperbolically as particle size decreases
  • also, below the breakaway size, RD50 increases as particle size decreases, by around 0.05 as particle size falls from 4 mm to 1 mm - termed 'density shift'
  • density shift will further contribute to a poorer overall Ep
  • medium:coal ratio (M:C) can have a substantial impact on DMC operation, and will have a disproportionately large impact on the finer particles
  • if M:C is greater than 3:1 in the DMC overflow, then there is little impact on cyclone operation with low Eps and predictable offset between medium density and cut-point
  • if overflow M:C falls below 2:1, then there is substantial loss of low gravity material to the underflow, much poorer Eps and reduced RD50, even below the medium density.

For some time now, there has been a feeling that Ep (75-25) alone does not completely describe the efficiency of cyclone operation, and there have been suggestions of using Ep (90-10) or even Ep (95-5). Error Area was found to be a reliable method of assessing unit efficiency and, together with modern curve fitting techniques, gives a broader and more applicable method of performance assessment, particularly in relation to the fine coal (-4 mm) in the process feed.

Although there are some variations in the data obtained from operations and the plant sampling carried out, the following trends were observed:

  • Generally cyclones gave acceptable results for the processing of +4 mm material, despite some very high levels of near gravity material, with Ep around 0.02 and Aer 10-20.
  • As particle size decreased, there was an increase in D50 and deterioration in efficiency (Ep and cut-point 'drift').
  • Efficiencies were poorer at higher D50s
  • The tendency was for efficiencies on finer particles to deteriorate as cyclone diameter increases.

From the data obtained it was difficult to discern any significant findings with respect to medium to coal ratio.

On the basis of Ep only, the 1000 mm diameter DMC is considered to be in the same order of efficiency as the 710 mm diameter cyclone examined in the detailed JK Handbook work carried out by Wood.

The data examined in this preliminary review showed good correspondence to the trends expected from the JK Model. This encourages further collection and collation of data to develop working models for the industry to use in applying large dense medium cyclone technology in optimising coal preparation.

There were insufficient data supplied in relation to the larger cyclones, up to 1300 mm diameter, to provide the detailed trends and data as were generated on the 1000 mm cyclone. The single set of 1300 mm diameter DMC data indicated that the larger cyclone was less efficient than the 1000 mm cyclone. However, significantly more data is needed before any further comments are made. This is an important area for further studies.

Underground

Health and safety, productivity and environment initiatives.

Underground

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

NERDDC

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

NERDDC