Patent ID: 7591874

Claim:
A method of reducing a solid metal-oxygen compound wherein solid carbon acts as a reducing agent, comprising: in a first reaction stage, passing CO gas into a reaction chamber containing said metal-oxygen compound, under conditions such that CO is converted to solid carbon and carbon dioxide thereby introducing the solid carbon so formed to said solid metal-oxygen compound, wherein said first reaction stage is performed at a temperature of at most 650° C., and discharging the solid carbon and solid metal oxygen compound from the first stage, and in a second reaction stage, causing said carbon, which is introduced to the metal-oxygen compound in said first reaction stage, to reduce said metal-oxygen compound, wherein said second reaction stage is performed at a temperature of at most 900° C., and discharging solid reduced metal-oxygen compound, wherein the method is performed continuously, said first and second reaction stages being performed simultaneously and said metal-oxygen compound being moved from a first reaction region where said first reaction stage takes place to a second reaction region where said second reaction stage takes place, wherein said second reaction stage is performed at a higher temperature than said first reaction stage, wherein there is present, at least in said second reaction stage, a first promoter material effective to promote the reduction of said metal-oxygen compound, the first promoter material comprising a first promoter metal and/or a compound of a first promoter metal.