Chrome Alluvial Ore Beneficiation Solution (Gravity + Magnetic Separation)

Stage 1: Pre-Treatment & Desliming

Raw river or beach sand is fed evenly from a silo into the wash circuit to prepare the ore for gravity sorting.

• Rotary Scrubber: For sticky sand, a scrubber is used for preliminary intensive washing to break apart clay balls.
• Trommel Screen: A heavy-duty trommel performs accurate particle size grading, rejecting oversized waste gravel, roots, and debris.

Stage 2: Gravity Roughing (High-Volume Enrichment)

The graded sand is pumped to gravity separators tailored to the specific particle sizes (0.1mm - 5mm):

• Fine Particles (-0.5mm): Fed to arrays of Spiral Chutes. Spirals act as massive roughers and sweepers, instantly discarding light silica sand and concentrating the heavy black chromite sand.
• Coarse Particles (+0.5mm): (If present) Fed to Mineral Jigs for high-efficiency coarse chromite recovery.

Stage 3: Magnetic Separation (Iron Removal)

Gravity separation recovers the heavy minerals, but it also recovers heavy magnetic iron impurities (like magnetite) which lower the value of the chrome.

• Magnetic Sorting: The gravity concentrate is passed through Permanent Magnet Multi-Cylinder Magnetic Separators.
• Purification: By adjusting the magnetic field strength (1500-7000 Gauss), the separators strip away the iron impurities, deeply purifying the chromite and boosting the critical Chromium-to-Iron (Cr/Fe) ratio.

Optional Extended Process: For highly complex associated ores, Shaking Tables can be added to further mechanically clean the concentrate, or a targeted flotation process can be introduced.

• Plant Processing Capacity: Single line up to 20 - 500 t/h (Daily capacity can be scaled up to 10,000 tons).
• Target Concentrate Grade: Cr₂O₃ ≥ 45% (Commercial Metallurgical Grade).
• Operating Cost Reduction: Physical separation eliminates grinding costs, reducing OPEX by 30-40% compared to hard rock processing.
• Return on Investment (ROI): Due to low CAPEX/OPEX, the payback period is typically 1 to 2 years.

Q1: Why do I need Magnetic Separators for Chrome sand?

A: While gravity separation (Spirals/Jigs) is excellent at discarding light silica sand, it will collect all the heavy black sands together. In alluvial deposits, chromite is almost always mixed with heavy iron minerals like magnetite. Because smelters require a high Chromium-to-Iron (Cr/Fe) ratio, you must pass the heavy sand through a magnetic separator to pull the iron out, leaving the purified chromite behind.

Q2: Are chemical reagents required for this process?

A: No. One of the massive economic advantages of alluvial chrome mining is that it relies on 100% physical beneficiation. The spirals and jigs use only water (recycled up to 90%), and the magnetic separators use permanent magnets. This means zero chemical pollution, simplified environmental permitting, and extremely low operating costs.

Full-Cycle EPC Seaside Placer Engineering Services

GravityMineral provides end-to-end technical support for Alluvial Chrome Sand projects globally. We supply solutions ranging from small mobile beneficiation devices to massive stationary production lines.

• Process Design: Customized flowsheet configurations based on your specific mineral ratios and production scale.
• Manufacturing & Supply: We build and supply the complete suite of heavy-duty wash equipment, spirals, and magnetic separators.
• Installation & Training: Global on-site engineer deployment to guide installation, tune recovery rates, and train your operators.

Maximize the value of your chrome resources. Contact our engineering team today for a customized plant layout and equipment quotation.