Effect of carbon on the solubility of nitrogen in slag

Abstract

Abstract The effect of carbon on nitrogen solubility in slag was investigated for the ternary CaO–MgO–SiO2 and the quaternary Al2O3–CaO–MgO–SiO2 slag systems at 1873 K under controlled oxygen and nitrogen potentials. Gas–slag equilibration experiments were conducted using molybdenum and graphite crucibles. In the absence of carbon, the nitrogen solubility was very low. The presence of carbon greatly increased the nitrogen solubility in slag. The total nitrogen content was found to increase with SiO2 and MgO concentration for the carbon saturated slags. Low levels of cyanide were found by wet chemistry with considerable uncertainty. The results analyzed by different methods ruled out cyanide formation being the main reason for the large increase in nitrogen solubility in the presence of pure carbon.