Smelters apply price penalties for elevated levels of lead, iron, cadmium, arsenic, and other impurities in zinc concentrate, as these complicate processing. However, penalty elements do not affect HTS classification — all zinc ores and concentrates fall under the same subheading regardless of grade or impurity profile.

Once zinc has been smelted and refined to unwrought zinc metal, it is classified under the chapter covering zinc and articles thereof. Intermediate products such as zinc oxide or zinc sulfate fall under the inorganic chemicals chapter. Heading 2608 is limited to ore and beneficiated concentrate prior to smelting.