Abstract: A re-processing method for isolating a marketable free iron product and a non-metallic co-product from small-particulate metal production by-product is provided. The re-processing method may be adapted so that the resulting free iron product is marketable granules of various sizes and properties. The method may include refining the metal production by-product into a suitably sized and spaced feedstock. The feedstock may be fed into the system and, through exposure to a first magnetic field, isolated into a first free iron product and a first co-product. The first free iron product may continued through the system so as to further isolate into a second free iron product and a second co-product through exposure to a second magnetic field. The second free iron product may be the marketable granules of free iron product, while the first co-product and the second co-product may be combined and further isolated in the marketable non-metallic co-product.