Method and apparatus for melting copper

Claim 1

IN A METHOD FOR PRODUCING MOLTEN COPPER HAVING A DESIRED OXYGEN CONTENT IN WHCIH COPPER IS PASSED DOWNWARDLY IN A VERTICAL FURNACE THROUGH A REDUCING ATMOSPHERE MAINTAINED IN THE FURNACE BY PASSING HOT PRODUCTS OF COMBINATION UPWARDLY THROUGH THE FURNACE, THE IMPROVEMENT WHICH COMPRISES PASSING MOLTEN COPPER DOWNWARDLY THROUGH SAID FURNACE WHILE INJECTING INTO THE FURNACE AT LEAST ONE STREAM FOR SUPPLYING HOT PRODUCTS OF COMBUSTION TO THE FURNACE, EACH OF SUCH INJECTED STREAMS CONSISTING ESSENTIALLY OF THE HOT PRODUCTS OF COMBUSTION OBTAINED BY UNITING FUEL WITH AN OXYGEN CONTAINING GAS IN AMOUNTS TO PROVIDE INSUFFICIENT OXYGEN IN THE INJECTED STREAM TO COMPLETELY BURN THE FUEL CONTAINED THEREIN, MAINTAINING IN EACH INJECTED STREAM THE DIFFERENCE BETWEEN THE AVERAGE TOTAL OXYGEN CONTENT INTENDED FOR THE STREAM AND THE HIGHEST TOTAL OXYGEN CONTENT FOUND IN AT LEAST A PREPONDERANT PROPORTION OF THE AREA OF A PLANE PERPENDICULAR TO THE PATH OF THE STREAM AT A VALUE BELOW A SELECTED VALUE PRIOR TO INJECTING THE STREAM IN TO THE FURNACE, SAID SELECTED VALUE BEING LESS THAN 4.21 TOTAL OXYGEN, IGNITING EACH INJECTED STREAM PRIOR TO INJECTING IT INTO THE FURNACE, AND CONTROLLING THE COMBUSTION OF THE OXYGEN IN EACH INJECTED STREAM TO PROVIDE AT LEAST A MINOR DEGREE OF COMBUSTION OF THE OXYGEN IN THE INJECTED STREAM BEFORE THE LATTER HAS TRAVELLED INTO THE FURNACE MORE THAN ABOUT SIX INCHES FROM THE FURNACE WALL.