Work

Innovative solution for the recovery of clean water and high-purity minerals from the coal mine sector

Year: 2025

Type: article

Abstract: Coal mining activities generate massive volumes of highly saline wastewater that cause significant ecological damage once they end up in the environment. Saline discharges contribute to the salinization of soil, the disruption of the aquatic flora and fauna, and the degradation of surface water quality. To address this issue, a near-zero liquid discharge (near-ZLD) system has been designed and constructed to treat coal mine wastewater before its discharge into the environment. The pilot system comprised membrane, precipitation, and thermal technologies to desalinate the water and recover valuable products, including Europe’s critical material, magnesium, as magnesium hydroxide with more than 84% purity. Calcium carbonate, calcium sulphate, and sodium chloride were also recovered from the wastewater with high purity: over 96% for CaCO3 and CaSO4, and more than 99.9% for NaCl. The recovered water exhibited high purity with a conductivity below 400 μS/cm. The pilot system energy consumption was 421 kWh/t of salt with more than 90% overall waster recovery. The results show that the proposed technology, if implemented in a much larger scale, has a potential to decrease the salt load discharged into surface water.

Source: Desalination

DOI: 10.1016/j.desal.2025.119121