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THE COPPER CLIFF SMELTER AND COPPER REFINERY ARE LOCATED AT SUDBURY, ONTARIO. THE OPERATIONS MAKE UP PART OF A LARGE COPPER/NICKEL MINING AND MILLING OPERATION IN THE SUDBURY AREA, CONSIDERED TO BE THE LARGEST IN THE WORLD. THE OPERATION PRODUCES NICKEL, COPPER, PRECIOUS METALS, COBALT, AND SULFURIC ACID. THE SMELTER OPERATION IS COMPLEX, SINCE MOST COPPER/NICKEL OPERATIONS PRODUCE A COMBINED WHITE METAL WHICH IS SEPARATED AT THE REFINERY; THIS SMELTER PRODUCES BOTH COPPER AND VARIOUS NICKEL PRODUCTS WITH INTERNAL PROCESS CROSS FLOWS, THUS IT IS DIFFICULT TO ESTABLISH A CLEAR CUT BREAK BETWEEN COPPER AND NICKEL IN TERMS OF COST OR ENERGY ANALYSES. THE PLANT WILL BE MODERNIZED OVER THE NEXT FOUR YEARS (AS OF 1990) IN ORDER TO ACHIEVE A 60% REDUCTION IN SULFER DIOXIDE EMISSIONS. OTHER CHANGES IN MILLING TECHNOLOGY AND SMELTER PROCESS FLOWS ARE ALSO PLANNED. THE SMELTER FACILITY PERFORMS SOME, BUT VERY LITTLE CUSTOM OR TOLL SMELTING. THE BASIC COPPER CIRCUIT CONSISTS OF DRYING THE COPPER CONCENTRATES FROM AN INITIAL MOISTURE CONTENT OF 8 TO 10%, TO A FINAL VALUE OF 0.1 TO 0.3% PRIOR TO FLASH SMELTING. THE DRIED CONCENTRATE IS SEPARATED FROM THE DRYER OFFGASES IN A BAGHOUSE WITH AN ESTIMATED EFFICIENCY OF 99.9% OFFGASES AND CONVERTER GASES ARE FURTHER CLEANED IN A HOT ELECTOSTATIC PRECIPITATOR. SILICA FLUX IS ADDED TO THE CONCENTRATES PRIOR TO DRYING TO MAXIMIZE BLENDING. THE DRIED FURNACE FEED IS STORED AT EACH END OF THE FURNACE IN SEPARATE BINS, WHICH IN TURN, FEED TWO CONCENTRATE BURNERS LOCATED AT EACH END OF THE FLASH FURNACE. THE FEED IS CARRIED FROM THE BINS BY SCREW CONVEYOR, AND DROPPED TO THE BURNER THROUGH SANKYO IMPACT MEASURING DEVICES, WHICH INDICATE THE FEED RATE TO THE BURNER. THE FLUXED CONCENTRATE FEED MIXTURE IS COMBUSTED AT EACH END OF THE FURNACE WITH PURE TECHNICAL OXYGEN (96%) WHICH MIXES WITH THE CONCENTRATES IN THE BURNER AND INJECTS T THE MIXTURE INTO THE FURNACE. THE LIMITATION ON THE RATIO OF O2 TO CONCENTRATE (0.22 TO 7.0) IS THE HEAT BALANCE AND AND PROTECTION OF THE FURNACE |
