La Oroya (Electrolytic) zinc smelter
The La Oroya smelter in Peru uses roast, leach, electrowin technology to produce slab zinc. After floatation to produce a zinc-silver concentrate, around 40% of the leach residues are treated in a Waelz kiln to enhance zinc recovery and to provide a fume feed to the indium plant, the remainder being dumped. The current capacity of the smelter is 43kt/a of slab zinc. The long term future of the smelter is currently in doubt due to a huge debt burden and ongoing environmental issues.