Zinc smelting by downward distillation (Zawar)
Fundición de zinc por destilación descendente (Zawar)
- Date
- c. century IX · confidence medium
- Place
- Zawar, Udaipur, Rajasthan, India
- Credited to
- Metallurgists of Rajasthan
- Field
- Matter & energy
What it is
Clay retorts loaded with ore and charcoal were placed mouth-down over a cold condenser, so that zinc vapour escaped the furnace and condensed as metal before it could reoxidise. It was the first large-scale industrial production of metallic zinc.
The Zawar mines have been worked since the 5th century BCE; the oldest retorts date to the 9th century and mass production to the 12th-14th centuries. William Champion patented a similar process in Bristol in 1738, perhaps inspired by the Indian one.
What it led to
- high-grade brass and bidri ware in India
- zinc exported to Europe and China
- understanding of metal volatility