Gold Centrifugal Concentrator | Knelson Type Gravity Separator for Free Native Gold Recovery

1. Product Overview

The Gold Centrifugal Concentrator (Knelson type) is a high-efficiency gravity separation machine designed to recover free native gold from ore slurry. Installed in the grinding circuit (typically at the ball mill discharge or hydrocyclone underflow), it uses high centrifugal force — up to 60 times gravity — to separate dense gold particles from lighter gangue minerals. The machine continuously accepts slurry feed and periodically discharges a high-grade gold concentrate.

Because native gold is far denser (19.3 g/cm³) than quartz and other gangue (2.6 – 2.8 g/cm³), centrifugal concentration captures coarse and medium free gold particles far more effectively than sluice boxes or shaking tables. Our centrifugal concentrators are widely used in hard rock gold CIL plants, placer gold wash plants and small-to-medium mining operations across Africa, Latin America, Central Asia and Southeast Asia.

2. Working Principle

Slurry from the grinding circuit enters the rotating conical separation bowl. The high-speed rotation generates strong centrifugal force, pushing dense gold particles into the interlocking rifling grooves on the inner wall of the bowl. Lighter gangue minerals are carried upward and out through the tailings discharge. After a preset accumulation time, the feed stops and high-pressure water jets fluidize the bed, flushing the concentrated gold-rich material out as a high-grade concentrate for further cleaning (shaking table, panning or smelting).

3. Key Advantages

• High Gold Recovery for Free Gold — Up to 95% recovery for liberated coarse and medium free gold, far exceeding sluice boxes and shaking tables.
• High Concentrate Grade — Produces a very high-grade gold concentrate ready for direct smelting or panning.
• Compact Footprint — Small floor area compared to shaking tables; suitable for retrofitting into existing grinding circuits.
• Automatic Operation — PLC-controlled feed, rinse and discharge cycle; minimal operator intervention.
• Water-Efficient — Only small jetting water required for concentrate discharge; total water consumption is low.
• Protects Gold from Over-grinding — Captures free gold early in the grinding circuit before it becomes too fine and reports to tailings.
• Versatile Application — Suitable for hard rock gold, placer gold, alluvial gold and tailings reprocessing projects.

4. Technical Parameters

Note: STL series is our Knelson-type centrifugal concentrator. Larger models (STL-180, STL-200) available for high-capacity operations. Actual selection depends on ore throughput and free gold particle size.

5. Applications

• Hard Rock Gold CIL Plant — Installed at ball mill discharge to recover coarse free gold before CIL leaching
• Placer / Alluvial Gold Wash Plant — Final gold recovery step after sluice box, polishing gold concentrate
• Tailings Reprocessing — Recover residual free gold from old tailings dams
• Quartz Vein Gold Mine — Captures coarse gold from crushed and ground ore
• Mixed Gold-Ore Projects — Supplementary gravity recovery before flotation for gold-bearing sulfide ores

6. Consumables & Spare Parts

• Bowl Rifling Liners — Replaceable polyurethane / rubber grooves inside the separation bowl, replaced every 6 – 12 months
• Drive Belts & Bearings — Routine maintenance of the rotating assembly
• Water Jet Nozzles — High-pressure rinse nozzles for concentrate discharge
• Seals & O-rings — For the rotating shaft and water system
• Feed & Discharge Piping — Wear-resistant slurry pipes and valves
• Drive Motor Spares — Motor bearings, belts and electrical components

7. FAQ for Gold Centrifugal Concentrator

Q1: What is a Knelson / centrifugal gold concentrator?

A1: It is a gravity separator that uses high centrifugal force (up to 60 G) to recover free native gold from grinding circuit slurry. Dense gold particles are trapped in the bowl rifling, while lighter gangue is discharged as tailings. Concentrate is flushed out periodically.

Q2: Where should I install the centrifugal concentrator in the plant?

A2: The standard position is at the ball mill discharge or hydrocyclone underflow, inside the grinding closed circuit. This captures free gold as soon as it is liberated, before it can be over-ground and lost to tailings. It can also be placed after a sluice box in placer gold operations for final polishing.

Q3: What size gold particles can it recover?

A3: The centrifugal concentrator is most effective for coarse and medium free gold particles (75 µm to several millimeters). It is less effective for very fine “flour gold” below 40 µm — for fine gold, CIL leaching or flotation is still required.

Q4: What is the difference between centrifugal concentrator and shaking table?

A4: A shaking table uses gravity only (1 G) and has limited capacity per unit floor area. A centrifugal concentrator amplifies gravity to 60 G, achieves higher recovery for free gold, handles much larger throughput per unit, and has a smaller footprint. Shaking tables are still used for final concentrate cleaning, not primary recovery.

Q5: Does it replace CIL or flotation?

A5: No. The centrifugal concentrator only recovers free, liberated gold. Gold locked inside sulfide minerals (such as pyrite or arsenopyrite) cannot be recovered by gravity — those ores still require flotation and / or CIL leaching. The centrifugal unit is a supplementary gravity recovery step, not a replacement for downstream processes.

Q6: What concentrate grade can I expect?

A6: Concentrate grade is extremely high — typically several hundred to several thousand grams of gold per tonne of concentrate, depending on feed grade. It can be directly smelted into doré bar or further cleaned on a shaking table before smelting.

Q7: Do you provide installation and after-sales service?

A7: Yes. We provide factory FAT inspection, containerized delivery, on-site installation guidance, operator training and long-term spare parts supply (bowl liners, belts, nozzles) for gold centrifugal concentrator projects worldwide.