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Wondering which gravity separation equipment fits your processing plant? Different types of machines are designed to handle different ore sizes, densities, and daily goals. Now, let’s take a look at the main types and how they work.
Gravity separation equipment separates mineral particles according to differences in specific gravity, supported by particle size, shape, and movement through water, air, or a dense medium. Heavy liberated particles respond differently from lighter gangue under gravity, pulsation, flowing-film action, or centrifugal force.
The process does not replace liberation. If valuable mineral remains locked inside gangue, both phases behave as one composite particle. Screening, desliming, washing, and staged grinding are often needed before separation.
The six machines cover different particle sizes and flowsheet roles. The table gives a practical starting point; the final choice should follow mineralogical analysis and separation tests.
| Equipment type | Typical duty | Main advantage | Critical control |
|---|---|---|---|
| Jig concentrator | Coarse to medium liberated feed | High throughput and simple operation | Pulsation, bed condition, and feed sizing |
| Shaking table | Fine cleaning and concentrate upgrading | Visible product bands and adjustable split | Deck slope, stroke, wash water, and feed rate |
| Spiral concentrator | Roughing and cleaning of classified slurry | No moving separation parts and low power | Feed density, size distribution, and distributor balance |
| Centrifugal concentrator | Fine heavy minerals and grinding-circuit recovery | Enhanced gravity field | Fluidization water, cycle, bowl speed, and feed stability |
| Sluice box | Placer gold roughing and low-cost recovery | Simple, mobile, and easy to inspect | Water velocity, riffles, matting, and feed rate |
| Dense media separator | Coarse preconcentration and waste rejection | Sharp density cut before grinding | Medium density, viscosity, drainage, and recovery |
A jig sends pulsating water through a bed of ore. Each pulse loosens the bed; during settling, denser particles move downward while lighter particles remain higher and leave as tailings. Jigs tolerate wider feed sizes and higher tonnage than most tables, making them useful after crushing, washing, and screening.
Feed should still be sized closely enough to prevent a large coarse light particle from behaving like a smaller heavy particle. The TOMINE coarse diaphragm jigger is intended for coarse mineral separation. Control pulsation frequency and amplitude, ragging, bed depth, and discharge to stabilize the density split.
A shaking table combines an inclined riffled deck, asymmetric reciprocating motion, and cross-flow wash water. Heavy particles move along the riffles toward the concentrate end; lighter particles wash sideways. Operators can see the bands and adjust the concentrate, middlings, and tailings cuts during operation.
Tables provide high upgrade ratios for fine liberated tin, tungsten, gold, and other heavy minerals, but capacity per deck is limited. Stable feed size and density are essential. TOMINE offers high-efficiency shaking tables and multi-deck versions for greater floor-area productivity.
A spiral concentrator receives slurry at the top of a helical trough. As the slurry flows downward, density, particle size, drag, and secondary flow create bands across the trough. Splitters collect heavy concentrate, middlings, and light tailings. The separation section has no moving mechanical parts, so power and routine maintenance are low.
Spirals need consistent classification, feed density, and even distribution. Excess slimes can increase viscosity and blur the separation. Use test work to select the profile, number of starts, rougher-cleaner arrangement, and recycle load. Review TOMINE’s spiral concentrator options for mineral sands, iron ore, chromite, tin, tungsten, and gold circuits.
A centrifugal concentrator rotates a bowl to create an enhanced gravity field. Fine dense particles are retained against the bowl while lower-density material exits. Semi-batch machines periodically rinse concentrate; continuous units discharge concentrate during operation. These units are often installed in grinding circuits or tailings retreatment where liberated heavy minerals would escape conventional gravity equipment.
Recovery depends on bowl speed, feed rate, solids density, particle liberation, cycle time, and fluidization water. The TOMINE TPC800 centrifugal concentrator is a continuous unit for particles up to 2 mm, with published slurry throughput up to 100 m3/h. Confirm the actual duty by test work.
A sluice is an inclined channel fitted with riffles and capture matting. Water carries the feed along the channel while dense particles settle into low-velocity zones. Sluices are inexpensive and portable, so they remain useful for alluvial gold roughing and bulk sampling. Poor water balance, surging feed, excess clay, or overloaded riffles can wash fine gold away.
Use a scrubber or trommel ahead of the sluice when clay must be broken and oversize removed. Do not assume a longer sluice automatically improves recovery; riffle geometry, mat condition, slope, feed rate, and cleanup interval need field testing.
Dense media separation suspends fine ferrosilicon or magnetite in water to create a controlled fluid density. Material denser than the medium sinks, while lighter material floats. Baths suit larger particles; dense medium cyclones handle smaller screened fractions. The method can reject barren rock before milling, reducing downstream grinding and processing load.
The circuit needs close control of medium density and viscosity, effective drain-and-rinse screens, and magnetic recovery of the medium. It is not attractive when density contrast is weak, ore is poorly liberated at a coarse size, or media loss and water balance cannot be controlled.
Measure valuable-mineral density, gangue density, mineral associations, and the size at which particles become liberated. A large density contrast cannot compensate for locked particles. Use staged crushing or grinding only as far as needed, because overgrinding may create slimes that lower the performance of jigs, tables, and spirals.
Use jigs or dense media for coarse preconcentration, spirals for steady classified slurry, tables for lower-capacity cleaning, and centrifugal concentrators when enhanced gravity is justified. Check the full size distribution, not only the top size. Slimes, clay, and fluctuating feed density can change recovery even when throughput stays constant.
Run tests on representative ore and report recovery, concentrate grade, mass pull, water demand, circulating load, and sensitivity to feed variation. The SGS mineral beneficiation overview identifies jigging, shaking tables, and spirals as standard gravity test methods. TOMINE can also perform a beneficiation experiment before equipment sizing.
TOMINE can compare jigs, shaking tables, spirals, and centrifugal concentrators against your ore mineralogy, size distribution, target recovery, and plant capacity. Review our gravity separation equipment range or send a representative sample and duty data for a test-work and equipment proposal.
Gravity separation equipment concentrates minerals by exploiting differences in particle density and movement through water, air, or dense media. Common machines include jigs, shaking tables, spirals, centrifugal concentrators, sluices, and dense media separators.
Jigs and dense media separators usually fit coarse liberated feed. The choice depends on top size, density contrast, required cut accuracy, throughput, water balance, and whether the plant can recover and control dense medium.
Centrifugal concentrators are often used for fine liberated gold, followed by a shaking table for concentrate cleaning. Actual recovery depends on liberation, particle shape, feed consistency, and operating settings, so sample testing is required.
The spiral trough itself has no powered moving parts; gravity moves slurry downward. The plant still needs pumps, distributors, screens, and sometimes wash water, so total circuit energy is not zero.
Only when valuable minerals are sufficiently liberated and have a useful density contrast with gangue. Many plants combine gravity separation with flotation, magnetic separation, or leaching to recover different size and mineral fractions.
