Study on the nucleation crystallization pelleting process for manganese ion recovery from hydrometallurgical tailings water

The recovery of high-concentrations manganese (Mn) ion (tens of thousands of milligrams per liter) from hydrometallurgical tailing water poses considerable challenges, leading to resource wastage and environmental concerns. To address this, this study proposes the nucleation crystallization pelleting process, a technique that facilitates the adherence of Mn ion onto the surface of specialized seeds, enabling the formation of nucleation pellets for recovery. A multistage series reactor was used under optimized conditions (particle sizes of 60–80 mesh, sodium carbonate dosage of 2500 mg/L influent pH of 3, and upflow velocity of 50 m/h). A stable and continuous operation of the reactor resulted in a Mn ion removal rate of > 99%. Laser particle size analysis and scanning electron microscopy results revealed that seeds growth occurred progressively, forming a loose and porous surface structure that enhanced the attachment of manganese carbonate (MnCO₃) particles. X-ray diffraction, X-ray photoelectron spectroscopy and zeta potential analyses results demonstrated that Mn ion predominantly adhered to seed surface in the form of MnCO₃ with purity detection confirming nucleation pellets achieving a content of > 95 %. This study demonstrates the high efficiency and practical applicability of this nucleation crystallization pelleting process and highlights its potential to significantly reduce resource wastage and environmental impacts, offering a practical and effective solution for recovering high-concentrated Mn ion from hydrometallurgical tailing water.