Zinc boils before it can be smelted normally — and medieval India solved this with industrial 'downward distillation.'
At Zawar (Rajasthan), archaeological evidence shows large-scale zinc production by distillation from at least the 12th century CE.
— Zawar, Rajasthan (industrial zinc from c. 12th century CE)
Industrial chemistry — distillation to isolate a volatile metal.
A genuine, defensible parallel.
Zinc is tricky: it vaporises (~907°C) below the temperature needed to reduce its ore, so it escapes as smoke in an open furnace. The metalworkers of Zawar engineered a clever solution — rows of sealed retorts with a downward condensation tube, so zinc vapour was captured and collected as liquid metal below. This is genuine industrial-scale chemical engineering, with thousands of tonnes of retorts found at the site.
This is straightforward, well-documented archaeology — among the earliest known true zinc smelting anywhere, and a real ancestor of distillation-based metallurgy. No hedging needed beyond noting it's medieval, not Vedic.