Calcined Bentonite Clay
Bentonite subjected to controlled calcining to enhance adsorption properties for foundry sand bonding, still classifiable as clay under the heading allowing calcined forms. Excluded items like dolomite mixes (3816) do not apply to this pure mineral product.
Import Duty Rates by Country of Origin
Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If dolomite ramming mix
Chapter note (e) specifically excludes dolomite ramming mixes from clays to heading 3816.
If mixed with other earth colors
Blends of calcined earth colors fall under 2530 per chapter note.
If refractory bricks from chamotte
Worked refractory products from clays move to Chapter 69.
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Import Tips & Compliance
• Provide thermal processing certificates showing calcination temperature below fusion to confirm clay status
• Separate from additives; mixtures with resins could classify as Chapter 38 preparations
• Test for phase changes via XRD to rule out conversion to mullite (also in 2508 but different stats)
Related Products under HTS 2508.10.00.00
Natural Sodium Bentonite Clay
A naturally occurring sodium-based bentonite clay mined from volcanic ash deposits, used primarily as a drilling mud additive in oil and gas exploration. It falls under HTS 2508.10.00.00 as unprocessed bentonite clay, distinct from expanded clays or other minerals excluded by chapter notes.
Calcium Bentonite Powder
Fine-ground calcium bentonite clay suitable for animal feed binders and soil amendments, retaining its natural colloidal properties. Classified under HTS 2508.10.00.00 as bentonite, whether or not calcined but excluding medicaments or processed forms noted in exclusions.
High-Swelling Bentonite for Drilling
Premium Wyoming sodium bentonite with high swelling capacity, supplied in bulk for preparing water-based drilling fluids in oilfield operations. HTS 2508.10.00.00 covers this unexpanded, raw bentonite clay explicitly in the clays subheading.
Bentonite for Cat Litter Base
Granular sodium bentonite clay serving as the absorbent core material for clumping cat litters, imported in bulk for further processing. HTS 2508.10.00.00 applies to this unprepared clay, not final consumer preparations excluded to other chapters.
Foundry Grade Bentonite
Selected bentonite with optimal montmorillonite content for green sand molding in metal casting foundries. As a raw, unexpanded clay, it precisely matches HTS 2508.10.00.00 specifications in the clays hierarchy.
Agricultural Bentonite Sealant
Coarse sodium bentonite pellets for pond liners and irrigation canal sealing in farming applications. Remains under HTS 2508.10.00.00 as unprocessed bentonite clay, not fabricated into setts or excluded products.