Zinc smelting

Claim 1

THE METHOD OF SMELTING AN OXIDIC ZINCIFEROUS MATERIAL WITH SOLID CARBONACEOUS REDUCING MATERIAL IN AN ELECTRIC ARC FURNACE WITH THE RESULTING PRODUCTION OF A MOLTEN SLAG AND METALLIC ZINC VAPOR SUBSTANTIALLY FREE FROM DUST-FORMING IMPURITIES WHICH COMPRISES CHARGING TO THE FURNACE THE ZINCIFEROUS MATERIAL AND AN AMOUNT OF THE CARBONACEOUS REDUCING MATERIAL EXCEEDING BUT NOT MORE THAN ABOUT 125% OF THE AMOUNT OF SAID REDUCTION MATERIAL STOICHIOMETRICALLY REQUIRED FOR REDUCTION OF THE ZINC AND OTHER OXIDES IN THE CHARGE READILY REDUCED BY CARBONACEOUS MATERIAL AND THEREBY PRECLUDING THE PRESENCE IN THE MOLTEN SLAG OF MORE THAN 6% BY WEIGHT OF IRON OXIDE (CALCULATED AS FE), FURTHER INCORPORATING IN THE CHARGE AN AMOUNT OF AN EXTRANEOUS FLUXING MATERIAL SELECTED FROM THE CLASS CONSISTING OF LIME AND SILICA SUCH THAT UPON SMELTING OF THE ZINCIFEROUS MATERIAL THE RESULTING MOLTEN SLAG DERIVED FROM CALCAREOUS AND SILICEOUS COMPONENTS OF THE ZINCIFEROUS MATERIAL AND FROM SAID EXTRANEOUS FLUXING MATERIAL WILL CONTAIN NOT MORE THAN 85% BY WIEGHT OF LIME (CAO) AND SILICA (SIO2) IN A RATIO BETWEEN 0.9:1 AND 1.2:1 AND NOT EXCEEDING, WITH RESPECT TO THE TOTAL AMOUNT OF THE OTHER CONSTITUENTS OF THE SLAG THE RATIO REPRESENTED BY THE LINE AB IN FIG. 1 OF THE DRAWING, WHEREBY THE FLUIDITY OF THE SLAG WITHIN THE TEMPERATURE RANGE OF 1250* TO 1450* C. IS SUFFICIENT TO PERMIT HEATING OF THE SLAG BY AN ELECTRIC ARC WITHOUT LOCAL OVERHEATING OF THE CHARGE IN CONTACT THEREWITH TO A TEMPERATURE IN EXCESS OF 1450* C., HEATING SAID BODY OF SLAG BY ELECTRIC ARC HEATING TO A TEMPERATURE WITHIN THE RANGE OF 1250* TO 1450* C., AND DELIVERING THE CHARGE TO THE FURNACE IN SUCH MANNER AS TO PROVIDE A MASS OF THE CHARGE FLOATING ON THE SLAG, SMELTING OF THE CHARGE THUS TAKING PLACE PRIMARILY AT THE INTERFACE BETWEEN THE FLUID SLAG AND THE FLOATING CHARGE BY THE HEAT IMPARTED TO THE CHARGE BY THE SLAG

Claim 2

THE METHOD OF SMELTING AN OXIDIC ZINCIFEROUS MATERIAL WITH SOLID CARBONACEOUS REDUCING MATERIAL IN AN ELECTRIC ARC FURNACE WITH THE RESULTING PRODUCTION OF A MOLTEN SLAG AND METALLIC ZINC VAPOR SUBSTANTIALLY FREE FROM DUST-FORMING IMPURITIES WHICH COMPRISES CHARGING TO THE FURNACE THE ZINCIFEROUS MATERIAL AND AN AMOUNT OF THE CARBONACEOUS REDUCING MATERIAL EXCEEDING BUT NOT MORE THAN ABOUT 125% OF THE AMOUNT OF SAID REDUCTION MATERIAL STOICHIOMETRICALLY REQUIRED FOR REDUCTION OF THE ZINC AND OTHER OXIDES IN THE CHARGE READILY REDUCED BY CARBONACEOUS MATERIAL AND THEREBY PRECLUDING THE PRESENCE IN THE MOLTEN SLAG OF MORE THAN 6% BY WEIGHT OF IRON OXIDE (CALCULATED AS FE), FURTHER INCORPORATING IN THE CHARGE AN AMOUNT OF AN EXTRANEOUS FLUXING MATERIAL SELECTED FROM THE CLASS CONSISTING OF LIME AND SILICA SUCH THAT UPON SMELTING OF THE ZINCIFEROUS MATERIAL THE RESULTING MOLTEN SLAG DERIVED FROM CALCAREOUS AND SILICEOUS COMPONENTS OF THE ZINCIFEROUS MATERIAL AND FROM SAID EXTRANEOUS FLUXING MATERIAL WILL CONTAIN NOT MORE THAN 85% BY WIEGHT OF LIME (CAO) AND SILICA (SIO2) IN A RATIO BETWEEN 0.9:1 AND 1.2:1 AND NOT EXCEEDING, WITH RESPECT TO THE TOTAL AMOUNT OF THE OTHER CONSTITUENTS OF THE SLAG THE RATIO REPRESENTED BY THE LINE AB IN FIG. 1 OF THE DRAWING, WHEREBY THE FLUIDITY OF THE SLAG WITHIN THE TEMPERATURE RANGE OF 1250* TO 1450* C. IS SUFFICIENT TO PERMIT HEATING OF THE SLAG BY AN ELECTRIC ARC WITHOUT LOCAL OVERHEATING OF THE CHARGE IN CONTACT THEREWITH TO A TEMPERATURE IN EXCESS OF 1450* C., HEATING SAID BODY OF SLAG BY ELECTRIC ARC HEATING TO A TEMPERATURE WITHIN THE RANGE OF 1250* TO 1450* C., AND DELIVERING THE CHARGE TO THE FURNACE IN SUCH MANNER AS TO PROVIDE A MASS OF THE CHARGE FLOATING ON THE SLAG, SMELTING OF THE CHARGE THUS TAKING PLACE PRIMARILY AT THE INTERFACE BETWEEN THE FLUID SLAG AND THE FLOATING CHARGE BY THE HEAT IMPARTED TO THE CHARGE BY THE SLAG