The present invention is an apparatus and method for the direct reduction of
iron oxide utilizing a rotary
hearth furnace to form a high purity carbon-containing
iron metal button. The
hearth layer may be a
refractory or a vitreous
hearth layer of
iron oxide, carbon, and silica compounds. Additionally,
coating materials may be introduced onto the
refractory or vitreous hearth layer before
iron oxide ore and carbon materials are added, with the
coating materials preventing
attack of the molten iron on the hearth layer. The
coating materials may include
compounds of carbon, iron
oxide,
silicon oxide,
magnesium oxide, and / or aluminum oxide. The
coating materials may be placed as a
solid or a
slurry on the hearth layer and heated, which provides a protective layer onto which the iron oxide ores and carbon materials are placed. The iron oxide is reduced and forms molten globules of high purity iron and
residual carbon, which remain separate from the hearth layer. An improved apparatus includes a cooling plate that is placed in close proximity with the
refractory or vitreous hearth layer, cooling the molten globules to form
iron metal buttons that are removed from the hearth layer. The improvements due to the present apparatus and method of operation provide high purity iron and carbon
solid buttons, which are separate from
slag particulates, and discharged without significant loss of iron product to the interior surfaces of the furnace.