Bionomic Industries Inc., a supplier of air pollution abatement, product, and heat recovery technologies, has installed an air-pollution control system delivered to Southern Peru Copper Corp.’s Ilo, Peru, copper smelting and refining facility.
Secured in conjunction with Hatch Engineering, the project includes Bionomic’s proprietary scrubber/wet electrostatic precipitator system to improve capture efficiency of particulate emissions from the Ilo plant’s small, gas-fired rotary “cupola” furnace, which generates exhaust gas volume of 19,200 Nm3h; gases from this furnace have been partially cleaned in two packed tower/quenchers and then exhausted to atmosphere. The cupola furnace operates in batch mode, consisting of three processing steps: 1) Charging/Melting: calcinated lime, sodium carbonate, borate, anthracite, and crushed shells are slowly fed into the furnace and melted; 2) Cupolation: air and oxygen lancing are used to reduce iron and cadmium; and 3) Nitrogen/Casting: sodium carbonate and nitrate are added to further oxidize the doré and remove selenium and copper.
After nitration, doré is cast into molds and process gas from the cupola furnace is mixed with secondary emission exhaust, then saturated with recirculating water sprays in the quench tower. Scrubber water is bled to the saturation tower sump, which continually bleeds to a sludge collection sump.
While the system is partially effective, the cupola gas is still highly corrosive due to the presence of selenium and weak sulfuric acid. In order to achieve a higher percentage removal of these pollutants along with lead and arsenic, Southern Peru Copper elected to further improve capture efficiency through use of a Bionomic Series 7000 venturi/cyclonic separator followed by Bionomic’s HEI wet electrostatic precipitator. Bionomic reported that this system economically achieves removal of up to 99% of the target pollutants to further reduce stack emissions.