Chamotte or dinas earths
Other clays (not including expanded clays of heading 68.06), andalusite, kyanite and sillimanite, whether or not calcined; mullite; chamotte or dinas earths. > Chamotte or dinas earths > Chamotte or dinas earths
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Subheadings
Products classified under Tariff item 2508.70
Calcined Chamotte Refractory Clay
Calcined chamotte is a high-alumina fired clay aggregate produced by calcining fireclay at high temperatures. It is used primarily as a raw material in refractory brick manufacturing for furnace linings, and remains in a crude or processed state consistent with Chapter 25 note 1.
2508.70.00Dinas Earth Refractory Grogs
Dinas earth refractory grogs are siliceous chamotte materials derived from quartzite clays and calcined for use as grog in high-silica refractories for steelmaking ladles. They are crude or processed mineral products within the scope of Chapter 25, specifically classified as dinas earths.
2508.70.00Fireclay Chamotte Aggregates 70% Al2O3
Fireclay-based chamotte aggregates with 70% alumina content are calcined clays used as coarse fractions in refractory concrete for kilns and incinerators. These aggregates are chamotte earths in crude or processed form, not exceeding the processing allowed by Chapter 25 note 1.
2508.70.00High-Alumina Chamotte Powder
High-alumina chamotte powder, typically 50-70% Al2O3, is produced by calcining fireclay and grinding it to a powder for addition to monolithic refractories and castables. It is classified as chamotte earth in powdered form, a product of Chapter 25 that has undergone only mechanical processing.
2508.70.00Mullite-Forming Chamotte Grogs
Chamotte grogs engineered to form mullite crystals upon firing are calcined clays used in advanced refractories for petrochemical heaters. These grogs are chamotte earths in an unfinished raw state, within the scope of Chapter 25 as they have not been processed beyond crushing, grinding, or calcination.
2508.70.00Refractory Chamotte for Cement Kilns
Medium-duty chamotte refractory clay optimized for rotary cement kilns is a calcined clay aggregate offering abrasion resistance and thermal shock tolerance. It is classified as chamotte earth in bulk aggregate form, consistent with Chapter 25 note 1 as it has not been processed beyond calcination and mechanical treatment.
2508.70.00Siliceous 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 its low thermal expansion. It is classified as dinas earths under tariff item 2508.70.00, as it is a crude mineral product that has not been processed beyond calcination and mechanical treatment.