The Slag Furnace Off-Gas Scrubbing Plant for Anglo Platinum in Rustenburg was designed to quench and clean furnace off gas before being vented to atmosphere. The Plant comprised a 3-stage quench and scrub circuit.
The first stage comprised a gas quench which quenches the gas and also removes a portion of entrained dust particles. The liquor drains into a clarifier below the quench column with the slurry generated being periodically removed.
The second stage is a high pressure variable throat wet venturi type gas scrubber. The scrubber removes micron range dust particles as well as an amount of the SO2/SO3 within the gas stream. The scrub liquor drains to a clarifier from where the slurry is pumped to a waste handling facility.
The final treatment is through a packed bed alkali gas scrubber column which removes the majority of the SO2/SO3 using alkali scrub liquor. The gas flow is controlled by VSD managed induced draught fans, with the gases vented to atmosphere via a stack.
The scrub liquor make-up and alkali dosing rates are automatically controlled via online instrumentation and all other plant operating conditions are monitored by instrumentation feeding back to the central PLC and SCADA.