Lead and copper recycling in the Boliden Kaldo

Summary

In 1976 the Lead Kaldo Plant was started up at the Rönnskär Smelter of Boliden. The Lead Kaldo was developed to treat complex dusts from the copper smelter. Over the years the process was modified and production increased.

In the early 1980s the stocks of dusts were consumed, and other materials tested. This included leach residues, lead batteries and concentrates. Copper scrap with high organic content was also successfully smelted.

In 1978 a Copper Kaldo Plant was built for smelting of copper concentrates. It was found that large amounts of scrap could be included in the charge, due to good heat efficiency and mixing in the Kaldo

In 1989 the Copper Kaldo was closed down because of Iack of concentrates and refinery capacity and the Lead Kaldo was modified for smelting of lead concentrates.

Significant for the Boliden Kaldo Processes are high productivity, low energy consumption, low emissions to environment and superior in-plant hygiene.