Calcined Chamotte Refractory Clay
Calcined chamotte is a high-alumina fired clay aggregate used primarily in refractory brick manufacturing for high-temperature applications like furnace linings. It falls under HTS 2508.70.00.00 as chamotte earth, which is specifically defined as a type of dinas earth processed through calcination to achieve thermal stability. This material is not expanded and remains in granular or powdered form suitable for refractory production.
Import Duty Rates by Country of Origin
Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If not fired or calcined
Unfired kaolin or other clays fall under heading 2507 as raw clays before processing into chamotte.
If expanded into lightweight aggregate
Expanded clays for refractory use are excluded from Chapter 25 and classified under 6806 as manufactured articles.
If shaped into refractory bricks
Once formed into finished refractory products like bricks, classification shifts to Chapter 69 for refractories.
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Import Tips & Compliance
• Verify calcination process documentation to distinguish from raw clays; ensure particle size specs match chamotte standards to avoid reclassification; obtain supplier certificates confirming suitability only for refractory use, not expanded forms
Related Products under HTS 2508.70.00.00
Dinas Earth Refractory Grogs
Dinas earth grogs are siliceous chamotte materials derived from quartzite clays, calcined for use as grog in high-silica refractories for steelmaking ladles. Classified under HTS 2508.70.00.00 due to its definition as dinas earth, a specific refractory clay not further manufactured. It provides skeletal structure in refractory mixes without being expanded or shaped.
High-Alumina Chamotte Powder
High-alumina chamotte powder, typically 50-70% Al2O3, is produced by calcining fireclay for addition to monolithic refractories and castables. It is classified in HTS 2508.70.00.00 as chamotte earth in powdered form, distinct from raw clays or finished articles. This ensures accurate duty application for bulk refractory raw materials.
Fireclay Chamotte Aggregates 70% Al2O3
Fireclay-based chamotte aggregates with 70% alumina content serve as coarse fractions in refractory concrete for kilns and incinerators. Under HTS 2508.70.00.00 as chamotte or dinas earths, these are calcined clays not expanded or otherwise manufactured beyond aggregation. They enhance volume stability in high-heat environments.
Siliceous Dinas Earth for Glass Furnace Refractories
Siliceous dinas earth, calcined from quartz-rich clays, is specialized for crown refractories in glass melting furnaces due to low thermal expansion. HTS 2508.70.00.00 captures it as dinas earths, excluding finished or expanded forms per chapter notes. Bulk granules ensure proper classification as raw refractory material.
Mullite-Forming Chamotte Grogs
Chamotte grogs engineered to form mullite crystals upon firing, used in advanced refractories for petrochemical heaters. Classified under HTS 2508.70.00.00 as chamotte earths, these calcined clays remain unfinished raw materials. Their high purity supports consistent mullite development in end products.
Refractory Chamotte for Cement Kilns
Medium-duty chamotte refractory clay optimized for rotary cement kilns, offering abrasion resistance and thermal shock tolerance. HTS 2508.70.00.00 applies to this dinas earth variant in bulk aggregate form, per chapter exclusions for expanded or shaped goods. Essential for sustainable kiln lining formulations.