Explanatory notes
… of butadiene, anti‑friction alloys, or titanium or zirconium metallurgy. The heading excludes sodium amalgam ( … argon, the refining of copper or steel, the manufacture of zirconium, calcium hydride (hydrolith), anti‑friction … separated from the other metals contained in the ore (lead, zinc, tin, bismuth) by filtration, distillation in a vacuum, …