Small-area XPS and XAES study of early iron metallurgy slags

A group of slags dating back to Iron Age II (Aramean Period, 800-720 BC), which appeared to be iron-smelting by-products, has been found at Tell Afis (Northwestern Syria). The chemistry of these materials has been studied by means of small-area x-ray photoelectron spectroscopy and x-ray-induced Auger electron spectroscopy. The results indicate that the slags can be associated with an iron smelting process and show the presence of large amounts of FeO1-x, Fe3O4 and FeOOH mixed with different aluminum and silicon compounds. As evidenced by the Wagner two-dimensional chemical-state plots of silicon and aluminum, these latter consist essentially of quartz and various silicates, such as wollastonite, Mg[SiO4] or Mg[SiO6] compounds, melilite and other complex aluminosilicates. Chemical information agrees with the predictions of the model of early iron-making furnaces and is used to elucidate some aspects of the early iron-making process.