The Kaldo Process Top Blown Rotary Converter - TBRC

THE KALDO PROCESS (TOP BLOWN ROTARY CONVERTER - TBRC) 

This system absorbs SO2 from the variable gas stream into cold water, which is stored and then continuously stripped by heating to 60°C before return to the sea. The system is only practical because of the unlimited supply of cold low-salinity sea water available to the smelter. Alternative processes are available using amine solutions for the absorption of SO2, which can be recovered by steam stripping. However, the inventory cost of the amine reagent can be quite high. In other situations the handling of intermittent gas flow is a major impediment for the Kaldo Process. 

Final slag is below one per cent Pb and contains between seven and 15 per cent Zn and around 22 - 29 per cent Fe, 23 - 25 per cent Si02 and 20 per cent CaO, and is sent to a slag fuming furnace to recover zinc. 

Dusts produced contain of the order of 65 per cent Pb and six to ten per cent Zn, and can contain around 20 per cent of the lead input. 

Capacity of the standard furnace has been given as close to 55 000 t/a of lead bullion from average lead concentrates at 62 per cent Pb, with typical fuel and consumption data as  

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