Challenges of closing water loops at mineral processing sites

Challenges of closing water loops at mineral processing sites

Paper Draft for Sustainable Minerals ‘23 Conference Falmouth, Cornwall, UK | June 7-9, 2023

Diana Kasymova 1,2,*, Eija Saari 1, Kari Heiskanen 1, Benjamin Musuku 2,3, Olli Dahl 2

1 Metso Outotec

2 Aalto University

3 Boliden Kevitsa

* Correspondence: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract: Resilient conversion of mineral resources is required from the mining industry while minimizing the use of resources needed. Based on extensive several-year research at a medium-sized Cu-Ni flotation plant, the common practice of a single closed water loop with recycling from a TSF being of sub-optimal nature became apparent. The results show a highly dynamic nature of water quality, where the build-up of ions, their reactions, temperature, and changes in mineralogy make it impossible to attribute single variable impacts on flotation performance. Effects and reasons for a varying oxidation potential in the pulp will be discussed as well as some subtle issues of colloid-forming reactions. As the mine is north of the Polar circle, substantial seasonal variations are also discussed, and explanations are proposed. Based on these industrial findings, the paper proposes a paradigm shift of how to move towards a more resilient mineral resource conversion.

Keywords: closed water loops, water recycling, sulfide minerals, surface oxidation, physicochemical interactions, seasonal variations, plant survey, water chemistry, grinding