Effect of Ionic Structure on Dissolution Behavior of Nickel in Aluminosilicate Slags

The effects of basicity and anionic species on the solubility of Ni in CaO-MgO-Al2O3-SiO2 slags were investigated based on the thermodynamic evaluation and structural analysis of the coordination number of Al ions via 27Al 500-MHz solid-state nuclear magnetic resonance spectroscopy. Depending on slag basicity, Ni dissolution followed two mechanisms, involving Ni2+ and NiO22− as ionic species. The solubility–basicity plot was found to be a concave upward curve with a minimum value. Structural investigation indicated that Ni solubility decreased with increasing Al2O3 content owing to the concomitant increase in the repulsion between AlO45− and NiO22− ions. The effects of Al2O3- and SiO2-derived anionic species on Ni solubility were also discussed based on the results of the structural analysis of slag and thermodynamic evaluation.