Bauxite aggregate

When evaluating Bauxite Aggregate, the Al2O3 (Alumina) content is the most critical factor, typically ranging from 50% to 85% depending on the grade. For refractory applications, you must verify the Fe2O3 (Iron Oxide) levels, which should ideally be below 2.5% to ensure high-temperature stability. Additionally, check the Bulk Density (typically >2.8g/cm³) and Water Absorption rates, as these dictate the material's performance in construction and casting.

The quality is heavily dependent on the kiln type (Rotary Kiln vs. Shaft Kiln). Rotary Kiln Bauxite generally offers better homogeneity and higher density, making it superior for precision refractory products. You should request the Calcination Temperature records; properly calcined bauxite (usually treated at 1450°C - 1600°C) ensures the conversion to Mullite and Corundum phases, which prevents volume expansion or shrinkage during end-use.

Suppliers should provide ISO 9001 certification for quality management. For specific applications like road surfacing (High Friction Surfacing), ensure the aggregate meets the PSV (Polished Stone Value) requirements, typically >70. Always request a recent Third-Party Chemical Analysis Report (SGS or PONY) to confirm that the chemical composition matches the technical data sheet provided by the seller.

Bauxite is usually supplied in specific grain sizes such as 0-1mm, 1-3mm, 3-5mm, or 5-8mm, as well as fine powders (200 mesh, 325 mesh). It is vital to specify the sieve analysis requirements in your contract to avoid excessive 'fines' (dust), which can negatively impact the mixing ratio in refractory or concrete formulations.

The biggest risk is Quality Inconsistency between the sample and the bulk shipment. Because bauxite is a mined product, mineral veins can vary. To mitigate this, use Made-in-China.com's Secured Trading services and mandate a Pre-shipment Inspection (PSI). Another risk is moisture weight fraud; ensure the contract specifies pricing based on Dry Metric Tons (DMT) to avoid paying for water weight accumulated during storage or transport.

For large volumes, negotiate based on tiered pricing—discounts of 5-10% are common for orders exceeding 500 tons. Regarding logistics, FOB (Free On Board) is often preferred for buyers who have established relationships with freight forwarders specializing in bulk commodities. Ensure the supplier uses Jumbo Bags (1-1.5 tons) with UV protection and inner liners to prevent contamination and tearing during sea freight.

Always verify the supplier's Business License and Export Permits specifically for mineral products. Conduct transactions through Audit Reports available on Made-in-China.com to confirm the supplier's production capacity. Never wire full payments upfront to unverified accounts; utilize Letter of Credit (L/C) or Escrow-style payment systems to ensure funds are only released upon presentation of the Bill of Lading (B/L) and quality certificates.