An apparatus includes at least one container with at least one carbonaceous material inlet, at an upper end of the container, for providing carbonaceous material into an internal chamber of the container; at least one first carbonaceous material outlet, at a lower end of the container, for removing carbonaceous material from the internal chamber; and at least one gas outlet for removing gas from the internal chamber. The internal chamber includes a first carbonaceous material communication pathway between the carbonaceous material inlet and the first carbonaceous material outlet, and carbonaceous material which travels along the first carbonaceous material communication pathway in use at least passes consecutively through a first reduction zone, a first oxidation zone, and a second reduction zone.