Silica-Based 2-Aminomethylpyridine Functionalized Adsorbent for Hydrometallurgical Extraction of Low-Grade Copper Ore

A silica based 2-aminomethylpyridine functionalized adsorbent was synthesized to extract copper. Characterization of the adsorbent was carried out to determine the surface morphology, specific surface area, pore size, and grafting ratio of 2-aminomethylpyridine groups. The adsorption selectivity of the adsorbent for Cu(II) ions was 1353 times higher than that for Fe(III) ions. The adsorption capacity for Cu(II) ions maintained a stable value of 0.53 mmol/g with and without perturbation of Fe(III) ions. Density functional theory (DFT) calculations revealed a mechanism of selective adsorption of copper, through the formation of 2-aminomethylpyridine-Cu(II) complexes. Semi industrial scale experiments revealed that Cu(II) ions in the acidic leachate of low-grade copper ore could be efficiently extracted by the adsorbent even in perturbation of substantial amounts of Fe(III) and other metal ions. Based on the adsorbent, a new process for copper hydrometallurgical extraction was developed, in which the adverse environmental impacts in traditional solvent extraction processes could be avoided.