Mullite Chamotte Grogs
Mullite chamotte grogs are fired, crushed mullite particles used as aggregate in refractory brick formulations. Classified under HTS 2508.60.00.00 alongside chamotte or dinas earths as processed refractory materials.
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Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If fused magnesia or dead-burned materials
Chapter note prioritizes 2517 for certain calcined refractory materials over 2508.
If for industrial furnace construction sets
Mullite grogs in assembled refractory sets classify as complete ceramic structures.
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Import Tips & Compliance
• Provide firing temperature records (typically >1400°C) confirming chamotte processing
• Document grog sizing (0-5mm typical) and avoid any assembly into shapes
• Watch for reclassification if moisture content suggests hydraulic binders (heading 3816)
Related Products under HTS 2508.60.00.00
Calcined Mullite Aggregate
Calcined mullite aggregate consists of crushed and heat-treated mullite grains used as a raw material in high-temperature refractories and castables. Classified under HTS 2508.60.00.00 as calcined mullite among other refractory earths.
Bauxite-Derived Calcined Mullite
Bauxite-derived calcined mullite is produced by calcining bauxite to form the mullite phase, used in abrasive refractories. HTS 2508.60.00.00 covers this as calcined mullite distinct from raw bauxite ores.
Micronized Mullite Flour
Micronized mullite flour (D50 <5μm) serves as a fine filler in technical ceramics and casting slips. Remains under HTS 2508.60.00.00 as processed mullite powder, not chemical preparations.
Synthetic Mullite Powder
Synthetic mullite powder is a high-alumina ceramic material produced by sintering or fusing alumina and silica, used primarily in refractory applications. It falls under HTS 2508.60.00.00 as mullite, a specific aluminosilicate mineral classified among other clays and earths, whether or not calcined.
Fused Mullite Grain 200 Mesh
Fused mullite grain in 200 mesh size is electrically fused mullite for precision casting molds and advanced ceramics. It qualifies under HTS 2508.60.00.00 as processed mullite, not excluding fusion per chapter provisions.
High Purity Mullite for Investment Casting
High purity mullite specifically graded for investment casting shells provides thermal stability and low thermal expansion. Falls under HTS 2508.60.00.00 as specialized mullite earth for industrial refractory use.