Organosolv lignin hydrophobic nanoparticles as low-carbon-footprint biodegradable flotation collectors

Important results from the project

The aim of the project was to improve selectivity of copper extraction from sulphide ores, based on total or partial replacement of fossil-based xanthate collectors by a newly developed lignin-based reagent (OLP). By valorisation of forest residual biomass, the OLP concept tested and assessed at TRL7 has the potential to significantly improve the environmental and economic impact of the mining industry and at the same time offer a synergy with the forest industry.

Expected long term effects

The results indicated that OLP does not perform as a sole collector. However, in a mixture with low concentrations of xanthate it improved the flotation process significantly. While the copper grades were similar, the recovery and selectivity were significantly improved using OLP as a flotation reagent. In addition, lime, used as a pH adjuster and pyrite depressant, could be completely removed from the flotation process, hence showing both an environmental and economic impact of the OLP use.

Approach and implementation

Lignoflot was led by Ulrika Rova, Luleå University of Technology, and conducted in close collaboration with Boliden Mineral and Nouryon. LTU produced the OLP flotation reagents and performed lab-scale and pilot-scale flotations using ores provided by Boliden. Boliden participated in the scale-up trials and contributed to the assessment of the novel concept. Nouryon assisted LTU with characterization of OLP and assisted in the technical, environmental, and economic assessment of the concept.