greillade

— The ore on one side of the furnace being in lumps, the hot carbonic oxide generated by the action of the blast on the charcoal is able to pass freely through its mass, reducing it, after the water has been driven off by heat, to metallic iron. At the same time the ore becomes impregnated with carbon, derived from the decomposition of the gases with which it is charged. The greillade on the other side is much richer in silica than the larger pieces, and from this it results that the quantity of slag will vary with the greillade added.