Converting

Converting

The liquid or granulated black copper along with other cold charges of copper scraps and alloyed materials is fed into the convertor furnaces (TBRC or Top Blown Rotating Convertors). In this phase material is oxidised by means of natural gas and oxygen and the copper is separated from most other metal components, except for nickel and precious metals. The liquid copper is transferred to the anode furnace before being cast into anode moulds.

The slag generated in the convertors is further processed to recover tin and lead.  In this stage of the process, additional raw materials containing tin and lead can be added. The resulting crude solder alloy is processed in the Pb/Sn refinery.

Once the metal values from the slag are extracted, the iron silicate slag is granulated in a high pressure water jet.

All furnaces are equipped with highly efficient off gas cleaning systems. Depending on the composition, the dust collected is either recycled back into the production process (low zinc content), or sold to zinc producers (high zinc content).