When you purchase calcined bauxite, the product's "Bulk Density" (BD) value is a critical factor to consider. However, upon examining the specific figures, you might be surprised—as a specification stating "BD: ≥3.20 g/cm³" is indeed unusual.

In the Chinese calcined bauxite industry, the term "BD" does not equate to "loose bulk density" in the conventional sense, even though English export documentation labels it as "Bulk Density".

People generally understand "loose bulk density" as follows: You pour granular material into a known container without vibration or compaction and measure its weight directly; this measurement includes the voids between the particles. Consequently, the loose bulk density of refractory-grade calcined bauxite typically hovers around 2.0 g/cm³—significantly lower than the "BD: ≥3.20 g/cm³" figure that suppliers often cite.

In the context of refractory materials, the term "BD" likely corresponds to the measurement of "granular material density" or "grain density" as standards define. Therefore, when you compile specifications from suppliers, the following translation is consistent with industry conventions:

体积密度 ≥3.2 g/cm³ → Bulk Density (BD) ≥3.2 g/cm³

Why Bulk Density Matters

Calcined Bauxite Product Grades

Grades such as 85, 88 and 90 are conventional refractory-industry designations, not ISO or national standard codes. Compare both chemical composition and physical properties when selecting a grade.

The Importance of Bulk Density

Understanding the relationship between these grades and alumina content explains why bulk density is critical—it is a fundamental physical parameter of the aggregate. For example, if calcination is insufficient, chemical analysis may still measure Al₂O₃ content at 88%, but the bulk density will be low. The material may be riddled with microscopic voids, resulting in high internal porosity and a loose structure. When you use such material to manufacture refractory bricks or castables and place it in a high-temperature kiln, the low aggregate density and high water absorption can compromise the stability of the castable formulation. It can even lead to secondary sintering, causing the refractory lining to crack, spall, or collapse.

Key Basis for Procurement: Batch Quality Inspection Documents

Procurement decisions should not focus solely on Al₂O₃ content. Chemical composition naturally varies between different seams within the same mine; furthermore, slight fluctuations in kiln calcination temperatures mean that material produced at different times cannot be 100% identical in performance. This explains why bauxite of the same grade—but with differing impurity levels or mineral densities—can yield different refractory service lives.

Therefore, suppliers should provide a Certificate of Analysis (COA) detailing the physicochemical properties for every batch of calcined bauxite; this serves as the primary basis for goods acceptance.

The industry commonly uses XRF (X-ray fluorescence spectrometry) for the rapid, routine analysis of the main chemical components of calcined bauxite. For arbitration purposes or when wet chemical analysis is required, you may consult relevant standards such as GB/T 21114 and GB/T 6900. In addition to chemical composition, a comprehensive test report includes physical parameters such as bulk density, water absorption, and particle size distribution.

You can find product information at https://www.seppe.cn/refractory-grade-calcined-bauxite.html.

Product Supply Specifications & Delivery Conditions

Particle Size Options

SEPPE offers refractory-grade calcined bauxite in various specifications, including granules (0–1mm, 1–3mm, 3–5mm, 5–8mm) and fine powders. Customers can purchase specific single-size fractions based on formulation requirements or request customized multi-size blends.

Packaging and Supply

SEPPE supplies calcined bauxite in 50kg small bags, as well as 1.00-tonne, 1.25-tonne, and 1.35-tonne bulk bags.

Please confirm the packaging type, shipment weight, and destination port details when placing an order.