Direct gaseous reduction of oxidic metal ores with dual temperature cooling of the reduced product

In a process for the batchwise reduction of metal oxide to sponge metal by contact with a hot reducing gas in a multiple unit reactor system of the type in which separate fixed beds of metal-bearing material are simultaneously treated in a plurality of reactors including at least one cooling reactor and at least one reduction and a cool carbon-containing reducing gas is passed through a cooling reactor of said system, heated to a temperature of 950.degree. to 1100.degree. C. and then passed through a reduction reactor of said system, the method of cooling and carburizing the bed of metal-bearing material in said cooling reactor which comprises pre-heating a stream of said cool reducing gas to a temperature of 250.degree. to 800.degree. C. before it comes in contact with said metal bearing material, passing said preheated stream of reducing gas through the bed of metal-bearing material in said cooling reactor for a first period of time to carburize the metal thereof and reduce metal oxide present therein, then passing a stream of said cool but not pre-heated reducing gas through said bed of metal-bearing material for a second period of time to further cool said material, cooling and recirculating a relatively small proportion of the gas passing through said bed during said second time period, thereafter during a third time period passing a stream of said cooled reducing gas through said bed of metal-bearing material and cooling and recycling a relatively large proportion of the gas passing through said bed during said third period to rapidly complete the cooling of said material.