Kernite Sodium Borate Concentrate from Mexico
Kernite is a natural sodium borate (Na2B4O7·4H2O) concentrate from evaporated lake beds, used in welding fluxes and herbicides. HTS 2528.00.0050 covers this non-brine natural borate with H3BO3 content below 85% dry weight. Typically exported as crushed or powdered ore.
Duty Rate — Mexico → United States
10%
Rate breakdown
9903.05.5510%Except for products described in headings 9903.05.85–9903.05.92 and 9903.05.94, articles the product of Mexico, as provided for in U.S. note 52 to this subchapter
Import Tips
• Submit mining provenance docs proving non-brine extraction; test for hydration levels affecting weight basis
• Beware of rehydration during ocean transit impacting declared purity