Rotary Scrubber: Breaking Up Clay-Bound Gold Ore

A rotary scrubber is a rotating drum, fitted with internal lifter bars, that tumbles ore with water long enough to break sticky clay off gravel and release the gold trapped inside it. Where a trommel screens and lightly scrubs in one pass, a dedicated scrubber gives ore far more residence time in the drum, which is what breaks down heavy clay that a trommel alone will not. It is the equipment that decides whether a rainy-season wash plant actually works or chokes on its own ore.

Gold Processing & Recovery·9 min read·Updated 2026-09-14
Rotary scrubber drum washing clay-bound alluvial ore

Rotary Scrubber Specifications

The figures below describe typical industry specifications for this class of equipment rather than a single fixed model. Use them to scope a requirement, then confirm exact figures against the supplied unit before purchase.

Typical specification range for the Rotary Scrubber
SpecificationTypical value
Drum diameter1.2–3.0 m
Drum length4–12 m
Retention time3–8 minutes, longer for heavier clay
Drive11–75 kW depending on size
Speed30–45% of critical, typically 8–14 rpm
Water2–5 m³ per m³ of feed in fat clay; less in light clay
Internal fittingsLifter bars and, in heavy-duty units, internal spray manifolds
Discharge screenTrommel-style discharge screen, or feeds a separate trommel
Capacity10–120 t/h depending on drum size and clay content
MountingSkid, trailer or static frame

Rotary Scrubber: Uses and Applications

  • Sticky, clay-bound alluvial and eluvial gold ore
  • Ahead of a trommel, where the trommel alone cannot break the clay
  • Reprocessing old amalgamation tailings bound in clay
  • Any wet-season ore that forms balls rather than breaking apart in water

Maintenance Schedule

Most premature failures in this equipment class trace back to a missed routine check rather than a design fault. The intervals below are a practical starting schedule; adjust them to your duty cycle and the manufacturer manual.

Recommended maintenance intervals
IntervalTask
Every shiftConfirm spray water is reaching the full drum length; listen for abnormal drum or trunnion noise; check discharge for unbroken clay balls.
WeeklyInspect lifter bars and liner plates for wear; check trunnion rollers or tyres.
MonthlyGrease trunnions and drive components; inspect seals for water ingress; check drive-chain or gear tension.
AnnuallyReplace worn lifter bars and liner sections as a planned set; overhaul the drive.

Frequently Asked Questions

Do I need a scrubber if I already have a trommel?

Depends on the clay. A trommel gives ore a short pass with light scrubbing, which is enough for gravel with little or no clay. Sticky ore that forms balls in water needs the much longer retention time a dedicated scrubber gives it. If clay balls are coming off your trommel unbroken, or gold is being lost inside them, add a scrubber ahead of it.

How much does a scrubber slow the plant down?

Throughput usually drops compared with a dry-feed rate, because retention time is what does the work. Sizing the scrubber for your actual tonnage, not squeezing it in as an afterthought, is what keeps overall plant throughput on target.

Can the scrubber discharge go straight to a centrifugal concentrator?

No. Scrubber and trommel discharge still contains coarse material. Screen to below 2 mm before it reaches a centrifugal concentrator; larger material blocks the bowl and lowers recovery. Route the 2 mm and above fraction to a sluice or jig instead. See the alluvial gold wash plant page for how the sizes are split.

How much water does a scrubber use?

More than a trommel alone: 2–5 cubic metres per cubic metre of feed in heavy clay. Water recycling through a settling pond is standard, not optional, especially where water is limited in the dry season and the plant still has to handle wet-season stockpile.

Supply and Delivery Across Tanzania

Bart Mining supplies rotary scrubber and related equipment to mining operations throughout Tanzania, with primary coverage of the Lake Victoria Goldfields (Mwanza, Kahama, Geita, Shinyanga and Bukombe), alongside the Lupa Goldfields around Chunya and Mbeya, and delivery nationwide from Dar es Salaam.

MwanzaKahamaGeitaShinyangaBukombeNyangʼhwaleTaboraDodomaArushaMbeyaChunyaSongweDar es SalaamMorogoroMtwaraKigoma
Specification note. The values on this page are industry-standard ranges for the equipment category, published so buyers can scope requirements before enquiring. They are not a quotation and do not describe a specific stocked model. Contact us with your duty, site conditions and power supply for a specification and quotation against your actual requirement.

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