Two-stage conversion of iron oxide into iron

Claim 1

A PROCESS FOR THE PRODUCTION OF IRON FROM OXIDES OF IRON WHICH COMPRISES PASSING COKE OVEN GAS ONCE THROUGH IN CONTACT WITH IRON OXIDE MAINTAINED AT A TEMPERATURE BETWEEN 1200* F. AND 1400* F. FOR A TIME SUFFICIENT TO EFFECT AT LEAST 95% REMOVAL OF OXIDE-OXYGEN FROM THE IRON OXIDE, PASSING HYDROGEN GAS CONTAINING BETWEEN 4 AND 20 GRAINS WATER PER CUBIC FOOT GAS MEASURED AT 60* F. AND 30 INCHES MERCURY IN CONTACT WITH THE INCOMPLETELY REDUCED IRON OXIDE AT A TEMPERATURE BETWEEN 1250* F. AND 1500* F., RECIRCULATING HYDROGEN GAS IN CONTACT WITH THE INCOMPLETELY REDUCED IRON OXIDE AT A TEMPERATURE BETWEEN 1250* F. AND 1500* F. FOR A LENGTH OF TIME SUFFICIENT TO CONVERT MORE THAN 98% OF THE IRON OXIDE TO IRON AND TO REDUCE THE CARBON CONTENT OF THE IRON TO LESS THAN 0.55%, AND REDUCING THE MOISTURE CONTENT IN THE HYDROGEN GAS PRIOR TO EACH PASSAGE IN CONTACT WITH THE INCOMPLETELY REDUCED IRON OXIDE TO BETWEEN 4 AND 20 GRAINS PER CUBIC FOOT GAS MEASURED AT 60* F. AND 30 INCHES MERCURY THEREBY REGULATING THE CARBON IN THE IRON PRODUCT FROM ABOUT 0.55% CARBON WHEN EMPLOYING HYDROGEN CONTAINING 4 GRAINS MOISTURE PER CUBIC FOOT TO ABOUT 0.08% CARBON WHEN EMPLOYING HYDROGEN CONTAINING 20 GRAINS PER CUBIC FOOT.