Recovery of nickel from strongly acidic bio-ore leachate using a bispicolylamine-based chelating resin

Given the increasing demand for nickel (Ni) in the Li-ion battery industry, the agromining chain of processes, based on phytomining of Ni combined with hydrometallurgy, has the potential to form an important source of Ni. Currently, plants grown on Ni-rich soils (in this case Odontarrhena chalcidica), having hyperaccumulated Ni, are ashed, and the Ni is transferred from ash to solution by sulfuric acid leaching. This work focuses on the recovery of Ni-sulfate from this strongly acidic leachate that contains many cations. For this purpose, a bispicolylamine-based chelating resin (Dowex M4195) was tested to better understand the functioning of this resin under these conditions. Column experiments were performed with model synthetic solutions containing Ni and Na-sulfate at pH 2. A set of reactions has been formulated to describe the interactions involved and used in a model combining transport in porous media and chemical reactions at equilibrium. Excellent agreement between the experimental and the calculated breakthrough curves were obtained by adjusting only two parameters. The set of reactions and parameters allowed to fit with sufficient accuracy the breakthrough curves obtained from an ash leachate of the hyperaccumulator plant O. chalcidica. A better understanding of the use of the Dowex M4195 resin for the extraction of Ni from a strong acid multicomponent solution has been achieved, and this separation has been shown to be promising for the recovery of Ni extracted from hyperaccumulator plant bio-ores as part of the agromining process.