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-Al 2 O 3 -SiO 2 slags were investigated based on the thermodynamic evaluation and structural analysis of the coordination number of Al ions via 27 Al 500-MHz solid-state nuclear magnetic resonance spectroscopy. Depending on slag basicity, Ni dissolution followed two mechanisms, involving Ni 2+ and NiO 2 2− 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 Al 2 O 3 content owing to the concomitant increase in the repulsion between AlO 4 5− and NiO 2 2− ions. The effects of Al 2 O 3 - and SiO 2 -derived anionic species on Ni solubility were also discussed based on the results of the structural analysis of slag and thermodynamic evaluation.