Battery-grade lithium carbonate falls under subheading 283691. Importers should verify whether specific tariff lines are subject to Section 301 measures, as applicability depends on the country of origin and the precise 10-digit HTS line. Consult a licensed customs broker for current duty treatment.

Soda ash (anhydrous or light/dense sodium carbonate, Na₂CO₃) is classified under 283620, while sodium bicarbonate (NaHCO₃, also called baking soda) falls under 283630. The chemical formula and degree of carbonation are the key distinguishing factors; supporting documentation such as a certificate of analysis should accompany the shipment.