The physicochemical and surface properties of steelmaking flue dust have been investigated by scanning electron (SEM) and X-ray diffraction (XRD) measurements, chemical analysis, FT-IR studies, zeta potential measurement, Brunauer-Emmett-Teller (BET) surface area determination, and potentiometric titration techniques. The results show that the dust consists of very fine spherical particles, which contain mainly iron oxide, iron ferrite, calcium (magnesium) oxide, calcium (magnesium) carbonate, and other metal oxides. The dust possesses a high BET surface area (14·65 m2 g-1 ) and a reversible surface charge. The point of zero charge pHpzc of the surface is around pH 6. Solubility tests show that the dust releases very little heavy metals in solution in the pH range 4·5-11·8 and has a high capacity to neutralise strong acid in solution