Method for reducing metal oxides

Claim 1

A METHOD FOR REDUCING METAL OXIDES WHICH COMPRISES: IN A FIRST REDUCTION TREATMENT, MIXING A STREAM COMPRISING AN OXYGEN-CONTAINING GAS MAINTAINED AT A TEMPERATURE BETWEEN ABOUT 60*F. AND ABOUT 1800*F. TO CAUSE A PORTION OF SAID REDUCING GAS TO BE HEATED TO AN ELEVATED TEMPERATURE; CONTACTING A MASS OF A METAL OXIDE WITH THE RESULTING GASEOUS MIXTURE TO REDUCE A PORTION OF SAID METAL OXIDE; IN A SECOND REDUCTION TREATMENT, MIXING A STREAM COMPRISING AN OXYGEN-CONTAINING GAS MAINTAINED AT A TEMPERATURE BETWEEN ABOUT 60*F. AND ABOUT 1800*F. WITH A STREAM COMPRISING A REDUCING GAS MAINTAINED AT A TEMPERATURE BETWEEN ABOUT 60*F. AND ABOUT 1800*F. IN A MOL RATIO GREATER THAN THAT EMPLOYED IN SAID FIRST REDUCTION TREATMENT TO CAUSE A PORTION OF SAID REDUCING GAS TO BE HEATED TO AN ELEVATED TEMPERATURE; CONTACTING A MASS OF SAID PARTIALLY REDUCED METAL OXIDE FROM SAID FIRST REDUCTION TREATMENT WITH THE RESULTING GASEOUS MIXTURE TO FURTHER REDUCE A PORTION OF SAID METAL OXIDE TO THE METALLIC STATE; IN A THIRD REDUCTION TREATMENT, CONTACTING THE MASS OF SAID PARTIALLY REDUCED METAL OXIDE FROM SAID SECOND REDUCTION TREATMENT WITH A STREAM COMPRISING A REDUCING GAS TO REDUCE A FURTHER PORTION OF SAID PARTIALLY REDUCED METAL OXIDE TO THE METALLIC STATE; EMPLOYING HEAT CONTAINED IN SPENT GAS WITHDRAWN FROM SAID FRIST REDUCTION TREATMENT TO HEAT REDUCING GAS WITHDRAWN FROM SAID THIRD REDUCTION TREATMENT; AND PASSING SAID THUS-HEATED GAS FROM SAID THIRD REDUCTION TREATMENT TO SAID SECOND REDUCTION TREATMENT.

Claim 2

A METHOD FOR REDUCING METAL OXIDES WHICH COMPRISES: IN A FIRST REDUCTION TREATMENT, MIXING A STREAM COMPRISING AN OXYGEN-CONTAINING GAS MAINTAINED AT A TEMPERATURE BETWEEN ABOUT 60*F. AND ABOUT 1800*F. TO CAUSE A PORTION OF SAID REDUCING GAS TO BE HEATED TO AN ELEVATED TEMPERATURE; CONTACTING A MASS OF A METAL OXIDE WITH THE RESULTING GASEOUS MIXTURE TO REDUCE A PORTION OF SAID METAL OXIDE; IN A SECOND REDUCTION TREATMENT, MIXING A STREAM COMPRISING AN OXYGEN-CONTAINING GAS MAINTAINED AT A TEMPERATURE BETWEEN ABOUT 60*F. AND ABOUT 1800*F. WITH A STREAM COMPRISING A REDUCING GAS MAINTAINED AT A TEMPERATURE BETWEEN ABOUT 60*F. AND ABOUT 1800*F. IN A MOL RATIO GREATER THAN THAT EMPLOYED IN SAID FIRST REDUCTION TREATMENT TO CAUSE A PORTION OF SAID REDUCING GAS TO BE HEATED TO AN ELEVATED TEMPERATURE; CONTACTING A MASS OF SAID PARTIALLY REDUCED METAL OXIDE FROM SAID FIRST REDUCTION TREATMENT WITH THE RESULTING GASEOUS MIXTURE TO FURTHER REDUCE A PORTION OF SAID METAL OXIDE TO THE METALLIC STATE; IN A THIRD REDUCTION TREATMENT, CONTACTING THE MASS OF SAID PARTIALLY REDUCED METAL OXIDE FROM SAID SECOND REDUCTION TREATMENT WITH A STREAM COMPRISING A REDUCING GAS TO REDUCE A FURTHER PORTION OF SAID PARTIALLY REDUCED METAL OXIDE TO THE METALLIC STATE; EMPLOYING HEAT CONTAINED IN SPENT GAS WITHDRAWN FROM SAID FRIST REDUCTION TREATMENT TO HEAT REDUCING GAS WITHDRAWN FROM SAID THIRD REDUCTION TREATMENT; AND PASSING SAID THUS-HEATED GAS FROM SAID THIRD REDUCTION TREATMENT TO SAID SECOND REDUCTION TREATMENT.