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Dense medium separation (DMS), also called heavy media separation, is a gravity-based pre-concentration method. Crushed and screened ore is mixed with a controlled suspension of water and finely ground magnetite or ferrosilicon.
Particles with a density higher than the selected medium density report to the dense fraction, while lighter particles report to the light fraction. This allows suitable ore to be upgraded or waste gangue to be rejected before fine grinding.
DMS is commonly used where the target minerals and gangue have sufficient density contrast and the feed has been prepared within an appropriate size range.
DMS may be considered when:
Typical applications may include:
DMS is not normally selected for very fine feeds, heavily weathered slimes, or ore with insufficient density contrast unless testwork supports the route.
Crushing & Screening → Feed Preparation → Dense Medium Mixing → DMS Cyclone Separation → Drain & Rinse → Medium Recovery → Concentrate and Reject Handling
The final flowsheet is determined by testwork, material characteristics, and the required downstream recovery route.
Run-of-mine ore is crushed and screened to produce a stable feed for DMS separation. Oversize material may return for further crushing, while undersize fines and slimes may be removed or treated separately.
Feed preparation is important because excessive fines can increase medium consumption, reduce separation efficiency, and make density control more difficult.
A practical DMS plant therefore considers:
Prepared feed is mixed with the dense medium and pumped to a dense medium cyclone.
Inside the cyclone, separation occurs under centrifugal force:
Depending on the project objective, the dense fraction may become a pre-concentrate for further treatment, while the light fraction may be discarded, stockpiled, or processed separately.
The selected cut density is not fixed. It is determined through testwork and adjusted through medium-density control.
The dense medium is recovered after separation through drain-and-rinse screening. Medium adhering to the products is washed back into the medium circuit.
A typical medium recovery system may include:
Magnetite or ferrosilicon recovery helps control operating cost and supports stable separation performance. Density, viscosity, particle-size distribution, and contamination of the circulating medium should be monitored during operation.
DMS concentrate can be directed to the next recovery stage according to the ore and project objective. Possible downstream routes include:
DMS rejects may be discarded, stockpiled, used as construction material where suitable, or evaluated for secondary recovery. The final decision depends on mineralogy, economics, and environmental requirements.
| Process stage | Typical equipment |
|---|---|
| Crushing and screening | Feed hopper, vibrating feeder, jaw crusher, cone crusher, vibrating screen |
| Feed preparation | Storage bin, transfer conveyor, desliming or washing equipment where required |
| Medium preparation | Magnetite or ferrosilicon storage, mixing tank, density-control system |
| DMS separation | Dense medium cyclone, feed sump, slurry pump, distribution box |
| Drain and rinse | Drain-and-rinse screen, spray water system, product conveyors |
| Medium recovery | Dilute-medium tank, magnetic separator, medium circulation pumps |
| Product and reject handling | Dewatering screen, stockpile conveyor, bins, transport system |
A DMS plant should be configured from representative ore data and separation testwork. LIPU can help match the circuit and equipment around:
LIPU provides equipment matching and plant configuration for crushing, screening, dense medium separation, medium recovery, dewatering, and downstream mineral-processing stages.
The objective is to determine whether DMS can provide practical pre-concentration for the specific ore—not to apply a standard heavy-media circuit to every project.
Send your ore information, target capacity, feed-size range, mineral analysis, density data, testwork results, and downstream recovery requirements. Our team can help develop an appropriate DMS flowsheet and equipment configuration.
What is the difference between DMS and flotation?
DMS separates particles primarily by density in a controlled medium. Flotation separates minerals according to surface properties using reagents and air bubbles. DMS is often used for pre-concentration before downstream flotation or grinding when the ore is suitable.
Can DMS process fine particles?
DMS generally performs best with a prepared size fraction. Excessive fines and slimes can reduce separation efficiency and increase medium losses. Fine material may require desliming or a separate recovery route.
Which medium is used in DMS plants?
Magnetite and ferrosilicon are common dense media. The selected medium depends on required density, feed characteristics, operating conditions, and recovery-circuit design.
What is a DMS cut density?
Cut density is the effective separation density at which particles are more likely to report to either the dense or light product. It is selected through testwork and controlled through the medium circuit.
Can DMS be used before gold or base-metal recovery?
Yes. Where testwork supports pre-concentration, DMS can reject low-density gangue before downstream grinding, gravity recovery, flotation, or leaching.
Does every ore need a DMS circuit?
No. DMS should be selected only when the ore has suitable density contrast, feed characteristics, and testwork results. It is not a universal replacement for grinding, flotation, or other recovery methods.
We provide a variety of mining and processing equipment, including feeders, rock crushers, grinders, classifying and screening machines, washing machines, gravity separators, flotation machines, magnetic separators, electric separators, dewatering equipment and laboratory mineral processing equipment.
