Andalusite, kyanite and sillimanite
Other clays (not including expanded clays of heading 68.06), andalusite, kyanite and sillimanite, whether or not calcined; mullite; chamotte or dinas earths. > Andalusite, kyanite and sillimanite > Andalusite, kyanite and sillimanite
Duty Rate (from China)
Products classified under Tariff item 2508.50.00
Calcined Andalusite 55% Al2O3
Calcined andalusite with 55% alumina content, heat-treated to partially convert to mullite for improved thermal shock resistance. This product falls under tariff item 2508.50.00 as calcined andalusite, which is explicitly covered by the heading regardless of calcination.
Calcined Kyanite Powder
Calcined kyanite powder, heat-stabilized to prevent volume expansion during ceramic firing. As a calcined form of kyanite, it is explicitly included in tariff item 2508.50.00, which covers andalusite, kyanite and sillimanite whether or not calcined.
Indian Sillimanite Sand
Indian sillimanite sand, washed and dried to -100+200 mesh, sourced from beach sand deposits. This naturally concentrated sillimanite is covered by tariff item 2508.50.00, which includes sillimanite in its crude or processed state as long as processing is limited to washing, drying, or mechanical sizing.
Kyanite Flour -325 Mesh
Kyanite flour ground to -325 mesh (<44 microns), used as a filler in porcelain insulators and spark plugs. This ground kyanite is classified under tariff item 2508.50.00 as it has only been mechanically ground, which is permitted processing under Chapter 25 notes.
Mullite-Forming Kyanite Concentrate
Beneficiated kyanite concentrate with 99%+ purity, selected for optimal mullite formation during firing. This uncalcined kyanite has been processed by mechanical or physical methods only, placing it under tariff item 2508.50.00 per Chapter 25 definitions.
Raw Andalusite Ore
Raw andalusite ore consisting of natural crystals extracted from deposits, containing 55-60% alumina. This uncalcined andalusite is directly covered by tariff item 2508.50.00, which includes andalusite in its crude state without further processing.
Sillimanite Grain for Refractories
Sillimanite grains, crushed and sized for use in refractory castables and ramming mixes. This unprocessed sillimanite, valued for high alumina content, falls under tariff item 2508.50.00 as sillimanite in a crushed or ground state, which is permitted under Chapter 25.
South African Andalusite Lumps
South African andalusite lumps, sized 10-100mm, containing 58% Al2O3, from Namaqualand deposits. This natural uncalcined mineral is covered by tariff item 2508.50.00 as andalusite in its crude state, used in steel ladle refractories.