HS Code for Mullite

Mullite is classified under HS code 2508.60. This classification is found in Chapter 25, which covers salt, sulfur, earths and stone, plastering materials, lime, and cement. Heading 2508 is dedicated to various types of clays, whether or not calcined, but excluding expanded clays of heading 6806. Mullite (3Al2O3·2SiO2) is a rare silicate mineral of aluminum and silicon that is highly valued for its refractory properties, meaning it can withstand extremely high temperatures without melting or deforming. While it occurs naturally, it is often produced synthetically by heating aluminosilicates. For customs purposes, both natural and synthetic mullite are generally classified here, provided they have not been further worked into finished articles. The classification is based on the mineralogical identity of the substance as a raw material for the ceramic and refractory industries.

Products Included

• Natural mullite mineral
• Synthetic mullite (sintered or fused)
• Mullite aggregates for refractory use
• Calcined mullite-based clays
• Mullite grains and flours

Common Misclassification

Mullite is often confused with HS code 3816.00, which covers refractory cements, mortars, and concretes. While mullite is a component of these mixtures, 3816.00 is for composite preparations, whereas 2508.60 is for the mineral itself. Another common error is 2508.30 (fire-clay), which is a different type of refractory clay. Additionally, if the mullite has been shaped into bricks or pipes, it must be classified in Chapter 69 (Ceramic products), specifically under headings like 6902 or 6903.

FAQ

What is the HS code for Mullite?

The HS code for mullite in its raw or aggregate form is 2508.60.

Is synthetic mullite classified differently than natural mullite?

Generally, no; both natural and synthetic mullite are classified under 2508.60 as long as they remain in the form of raw materials or aggregates.