Using seed materials for the remediation of fluoride-contaminated wastewater

This study investigates improving the removal of fluoride ions from mineral processing plant wastewater through chemical precipitation. The research focuses on the Lovozero Mining and Processing Plant in the Murmansk region, which produces loparite concentrate. Monitoring revealed fluoride concentrations exceeding regulatory limits by 20–25 times at discharge, 35–37 times at the monitoring site, and 2–4 times at the point where the contaminated stream meets the Sergevan River. Given the environmental risks, there is a need for an effective and sustainable treatment method for removing fluoride ions. Existing technologies have significant limitations. We propose a novel approach combining calcium salts with seed materials derived from industrial by-products to enhance chemical precipitation. Experiments have shown that coating seed materials with CaF2 significantly accelerates sedimentation and achieves fluoride removal efficiencies up to 98.4 %. A multi-criteria evaluation was developed to select optimal seed materials based on cost, sedimentation rate, availability, and required dosage. This study highlights the potential of using enrichment tailings and waste rock as seed materials for the removal of fluoride ions from wastewater at the Lovozero Mining and Processing Plant. This approach reduces reagent use and treatment costs, while promoting the reuse of industrial waste, thus lowering environmental impact and disposal fees, which are increasing annually. Overall, the use of such seed materials presents a promising, cost-effective solution for remediating fluoride-contaminated mining wastewater. This research was carried out under the state assignment from the Ministry of Science and Higher Education of the Russian Federation (FSRW-2024-0005), titled «New approaches to environmental monitoring of Arctic ecosystems affected by mineral resources facilities and the development of technologies for their integrated restoration».