The GT series bauxite trommel washing screen is a heavy-duty rotary scrubbing and classification unit purpose-built for the demanding conditions of tropical bauxite mining operations. Engineered specifically for the high-clay, high-moisture lateritic bauxite deposits of Brazil’s Pará state and similar tropical mining environments, this trommel screen combines aggressive mechanical scrubbing with multi-aperture classification in a single rotating drum, eliminating the need for separate scrubber and screening units. With processing capacities of 50-200 TPH, the GT series efficiently removes clay and silica fines from ROM bauxite while classifying the washed product into export-grade size fractions ready for drying and shipment.

The GT trommel screen operates on the principle of combined tumbling attrition and size classification. Run-of-mine bauxite ore is fed into the rotating cylindrical drum where internal lifters repeatedly raise and cascade the material, generating inter-particle abrasion that liberates adhering clay and surface coatings from the bauxite nodules. High-pressure water spray bars positioned along the scrubbing section intensify clay dispersion and wash liberated fines through the screen apertures. As the material progresses along the inclined drum toward the discharge end, progressively larger screen apertures allow sized product fractions to exit while oversize material continues through attrition. The scrubbed and classified bauxite product exits from the drum discharge end with clay content typically reduced from 15-30% (ROM) to below 5%, meeting alumina refinery feed specifications. The washed fines (-2mm) containing dispersed clay and silica report to a tailings thickener or settling pond for water recovery.

• Integrated Scrubbing and Classification: The GT series combines aggressive mechanical scrubbing with multi-section size classification within a single drum, eliminating the capital cost and footprint of separate scrubber and screen installations. The scrubbing section occupies 30-40% of the drum length and features heavy-duty lifters that generate high-energy particle-to-particle attrition for effective clay liberation.
• High Clay Handling Capacity: Designed for tropical lateritic ores with ROM clay content up to 30%, the GT trommel screen incorporates a high-volume wash water system (80-300 m³/h) with multiple spray bars delivering water at 2-4 bar pressure. The combination of mechanical attrition and high-pressure water washing effectively disperses and removes even tenacious clay coatings from bauxite nodule surfaces.
• Abrasion-Resistant Wear Protection: All internal surfaces subject to high wear are protected with replaceable liner systems. The scrubbing section employs cast manganese steel lifters (12-14% Mn) with work-hardening properties, while the screening sections use bolt-in polyurethane or rubber screen panels with service lives of 2,000-4,000 operating hours depending on ore abrasivity.
• Tropical Climate Durability: The drum shell is fabricated from weather-resistant structural steel with a three-layer marine-grade epoxy coating system. The trunnion bearing housings are sealed with labyrinth and lip seal combinations to exclude water and abrasive fines, and all exposed fasteners are 316 stainless steel for corrosion resistance in the high-humidity, 28-35°C ambient conditions of Pará state tropical mining regions.
• VFD Speed and Inclination Control: Drum rotation speed is adjustable from 15 to 30 r/min via VFD, enabling optimization of scrubbing intensity and residence time for varying ore characteristics. The drum inclination angle is field-adjustable (3-8°) through the trunnion support jacking system, providing additional control over material residence time and throughput.
• Low Maintenance Trunnion Drive: The drum is supported on four heavy-duty trunnion rollers with spherical roller bearings rated for L10 service life exceeding 50,000 hours. The trunnion drive arrangement eliminates the complexity and maintenance requirements of ring gear and pinion drives commonly used on smaller trommels, while providing smooth torque transmission and low noise operation.

The GT series trommel washing screen is purpose-designed for high-clay tropical ore processing applications. Primary applications include bauxite washing and classification in Pará state (Brazil) where ROM bauxite containing 15-30% kaolinite and gibbsitic clay requires intensive scrubbing to produce export-grade washed bauxite with <5% reactive silica. The trommel simultaneously achieves clay removal and size classification, producing sized bauxite fractions suitable for direct shipment or calcination. Secondary applications include lateritic nickel ore washing and classification ahead of RKEF (rotary kiln electric furnace) or HPAL (high-pressure acid leach) processing, alluvial gold and diamond deposit washing and screening, iron ore scrubbing to remove clay coatings from hematite and itabirite ores, and heavy mineral sand (ilmenite, rutile, zircon) desliming. The GT series is also deployed in aggregate washing applications where clay-bound alluvial gravels require scrubbing to meet concrete aggregate cleanliness specifications. The replaceable screen panel and liner systems enable rapid reconfiguration of aperture sizes and wear protection materials for different ore types and feed conditions.

Each GT trommel screen is factory assembled and test-run for a minimum of 2 hours at full operating speed with vibration monitoring at all bearing locations. The drum assembly is dynamically balanced to G6.3 grade (ISO 1940) to ensure smooth, low-vibration operation. Welds on the drum shell and lifter attachments receive 100% ultrasonic or magnetic particle inspection. For shipment, the drum assembly is transported on a purpose-built steel shipping cradle with bearing journals protected by temporary corrosion-inhibiting coating and padded guards. The drive motor, gearbox, and trunnion roller assemblies are individually crated, and screen panels and wear liners are palletized with complete bolt sets for each panel. Documentation includes complete assembly and installation drawings, operating and maintenance manual in English and Portuguese, and detailed wear parts identification and ordering guide. Our field service engineers provide on-site supervision of mechanical assembly, commissioning, and operator training. A 12-month warranty from commissioning covers all mechanical and structural components.