US Patent 10584393 Smelting process and apparatus

A smelting apparatus that includes (a) a smelting vessel (4) that is adapted to contain a bath of molten metal and slag and (b) a smelt cyclone (2) for pre-treating a metalliferous feed material positioned above and communicating directly with the smelting vessel The apparatus also includes an oft-gas duct (9) extending from the smelt, cyclone for discharging an off-gas from the smelt cyclone. The off-gas duct has an inlet section (18) that extends upwardly from the smelt cyclone and is formed to cause off-gas to undergo a substantial change of direction as it flows through the inlet section of the off-gas duct.