Natural borates and concentrates thereof (whether or not calcined), but not including borates separated from natural brine; natural boric acid containing not more than 85 percent of H3BO3 calculated on the dry weight
Natural borates and concentrates thereof (whether or not calcined), but not including borates separated from natural brine; natural boric acid containing not more than 85 percent of H3BO3 calculated on the dry weight
Duty Rate (from China)
Except for products described in headings 9903.03.02–9903.03.11, articles the product of any country, as provided for in subdivision (aa) of U.S. note 2 to this subchapter
Except as provided in headings 9903.88.13, 9903.88.18, 9903.88.33, 9903.88.34, 9903.88.35, 9903.88.36, 9903.88.37, 9903.88.38, 9903.88.40, 9903.88.41, 9903.88.43, 9903.88.45, 9903.88.46, 9903.88.48, 9903.88.56, 9903.88.64, 9903.88.66, 9903.88.67, 9903.88.68, or 9903.88.69, articles the product of China, as provided for in U.S. note 20(e) to this subchapter and as provided for in the subheadings enumerated in U.S. note 20(f)
Subheadings
Products classified under HTS 2528.00.00
Calcined Colemanite Borate Ore
Colemanite is a naturally occurring calcium borate mineral mined primarily in Turkey, calcined to remove moisture while preserving its borate content. It falls under HTS 2528.00.00 as a natural borate concentrate, not separated from brine, used mainly in glass and ceramic production. The calcination process is explicitly allowed without changing its classification.
Ulexite Sodium Calcium Borate Mineral
Ulexite, known as TV rock, is a naturally hydrated sodium calcium borate ore concentrated from deposits in California and Chile. Classified under HTS 2528.00.00 as a natural borate not from brine, it's supplied in powdered or granular form for industrial flux applications. Its fibrous crystal structure is a hallmark of unaltered natural borates.
Natural Boric Acid Powder from Rasorite
Rasorite (refined kernite) yields natural boric acid through concentration and limited processing, containing ≤85% H3BO3 on dry weight basis. This product qualifies for HTS 2528.00.00 as it derives from solid mineral deposits, not brine, and serves agriculture and glass industries. It's distinguished from synthetic boric acid by its natural impurity profile.
Anhydrous Borax Concentrate
Anhydrous borax concentrate is produced by calcining natural tincal or kernite ores, resulting in dehydrated sodium borate suitable for welding fluxes. HTS 2528.00.00 covers this as calcined natural borates from solid sources, excluding brine-derived products. It's valued for high boron content in metallurgical applications.
Priceite Calcium Borate Ore
Priceite is a rare natural calcium borate mineral from boron-rich deposits, supplied as crushed ore or powder for specialty ceramics. It meets HTS 2528.00.00 criteria as an unrefined natural borate concentrate without brine origin. Low-volume imports highlight its niche use in high-temperature glazes.
Kernite Borate Concentrate
Kernite, a sodium borate mineral from California's Searles region, is concentrated into powder for export, often partially calcined. HTS 2528.00.00 applies as it's a natural borate from solid deposits, not brine, powering boron supply chains. Essential for herbicides and enamels.
Tincal Crude Borax Ore
Tincal is crude native borax found in Tibetan salt lakes (solid form), concentrated without brine separation for glassmaking. Classified in HTS 2528.00.00 as natural sodium borate, it's the historical source of refined borax. Supplied in lumps or ground form.