Arsenic
A toxic by-product of copper and gold smelting, used in wood preservatives and in gallium-arsenide chips for phones, satellites and defence.
Tech & minor metals · No. 47
- EU critical 2023
- US critical 2025
- HHI 4,137 · highly concentrated
Arsenic is a smelter's waste problem, yet ultra-pure arsenic is essential to gallium-arsenide chips in satellites and defence.
Chart: Illustration: Arsenic
Where it comes from
Chart: Map of where it comes from
Arsenic occurs in arsenopyrite and in copper minerals such as enargite, often with gold. Roasting or smelting these ores drives it into the flue dust, from which trioxide is refined.
Three things to know
- China bans imports of copper ore with more than 0.5% arsenic, so for copper miners it is mostly a penalty element.
- Purity splits arsenic into two markets: 99% metal and trioxide at about $2-4/kg, and 6N-7N metal for semiconductor wafers.
- The US has made no arsenic trioxide or metal since 1985, and China supplied 95% of its metal imports in 2021-24.
The journey
- 1 OresCopper, gold or cobalt ores with arsenic
- 2 RoastingArsenic leaves in smelter flue dust
- 3 TrioxideRefined to arsenic trioxide
- 4 Acid or metalArsenic acid for preservatives, or metal
- 5 Purification99.9999% metal for GaAs wafers