Sustainable recovery of phosphorous from mine tailings

Phosphorus (P) is an essential element for the growth of plants. The most common P fertilizers are manufactured from phosphate rock which is not sustainable as the global P resource is finite and also geographically restricted. To meet the growing global demand for food, a secure supply and a sustainable P management is one of the key challenges for the UN´s Sustainable Developments Goals. The most common phosphate mineral is apatite. So far production of apatite concentrate has not been economically viable and hence apatite is part of the mine tailings currently deposited.

In this pre-study we will use residual resources from the forest industry to develop biodegradable flotation reagents, i.e. lignin nanoparticles, for beneficiation of mine tailings. The overall aim is to verify the use of these lignin nanoparticles for the flotation of mine tailings from LKAB to recover high-quality concentrates of phosphate with a potential to be used as a source for P-rich fertilizers.

Purpose and goal

The overall aim of this pre-study is to develop and test the feasibility of novel flotation collectors that can optimize resource use and minimize the environmental impact of the Swedish mining industry. Especially, we will target sustainable recovery of apatite from mine tailings as a source for phosphorous fertilizers. Residual resources from the forest industry will be used to develop low-carbon footprint, biodegradable and non-toxic flotation reagents for the beneficiation of mine waste streams.

Expected results and effects

The potential of lignin-based flotation collectors for selective enrichment of apatite from mine waste has been demonstrated The lignin based flotation collector technology, including the biomass fractionation technology for their preparation, is currently at TRL 5. A full-scale process plan at TRL 7 will be develop by LTU and LKAB as a project delivery.

Planned approach and implementation

The project is carried out for 6 months and is led by Ulrika Rova from Luleå University of Technology. The project concept combines the expertise of LTU and LKAB, which at an early stage provides conditions to identify the future potential of the envisioned technology.