| Popis: |
Due to excellent properties as a construction material slag is rising in popularity as a resource. However, some properties prevent usage, one of those is leaching of chromium. The leaching of slag is governed by the solubility of theminerals. By eliminating soluble minerals that contain chromium the chromiumleaching should decrease. In some low alloy EAF slag, brownmillerite, has beensuspected to leach chromium. By increasing the basicity of slag the formation of brownmillerite should be avoided. Low alloy EAF slag with basicity of 2.7 was altered by remelting the slag with SiO2 additions. The mineralogical composition was identified using SEM EDS and XRD. Slag samples were treated inan autoclave to simulate ageing. The autoclave treatment was successful as theremelted slag without modification leached with the same magnitude as the naturallyaged reference sample. At basicity 2.7, the investigated slag had the highest leaching of chromium, at average 2 mg/kg. The chromium leaching decreased to 0.2 mg/kg at basicity 2.4. The decrease of chromium leaching was connected to the decrease of brownmillerite. Lower basicity did not eliminate leaching ofchromium as merwinite, another mineral able to contain chromium, was formed instead of brownmillerite. |
