Abstract: The existential state of chromium has a great influence on stability of chromium in stainless steel slag, and spinel phase is considered to be the optimal stable phase for preventing the chromium from leaching. In order to effectively stabilize chromium element in stainless steel slag and reduce the leaching of chromium to decrease the risk of pollution, in the present work, the effect of slag basicity on the migration behavior and existential state of chromium was investigated in the experiment. The samples were heated for 30 min at 1 600 ℃ for completely melting and soaking for 30 min at 1 600 ℃and 1 300 ℃ before quickly quenched in water. The microstructure and existential state of chromium were determined by scanning electron microscopeenergy dispersive spectroscopy (SEMEDS) and Xray powder diffraction (XRD). The results showed that the basicity significantly influenced the migrant and enrichment behavior of chromium in stainless steel slag. It was beneficial for chromium enriching in spinel phase with w(CaO)/w(SiO₂) ratio of 1.5, especially at 1 300 ℃, the enrichment degree of chromium was nearly up to 100 %. When the basicity was 1.0, the solubility of chromium in the liquid phase was relatively high, and only minor amount of spinel phase could be formed at 1 300 ℃. As the basicity increased to 2.0, the chromiumbearing periclase phase was precipitated.

Key words: stainless steel slag, spinel, enrichment degree, basicity, chromium