Optimization of Parameters for the Dissolution of Mn from Manganese Nodules with the Use of Tailings in An Acid Medium

• Main Authors: Norman Toro, Manuel Saldaña, Edelmira Gálvez, Manuel Cánovas, Emilio Trigueros, Jonathan Castillo, Pía C. Hernández
• Format: Article
• Language: English
• Published: MDPI AG 2019-06-01
• Series: Minerals
• Subjects: leaching; manganese nodules; optimization of parameters; tailings
• Online Access: https://www.mdpi.com/2075-163X/9/7/387

Manganese nodules are an attractive source of base metals and critical and rare elements and are required to meet a high demand of today’s industry. In previous studies, it has been shown that high concentrations of reducing agent (Fe) in the system are beneficial for the rapid extraction of manganese. However, it is necessary to optimize the operational parameters in order to maximize Mn recovery. In this study, a statistical analysis was carried out using factorial experimental design for the main parameters, including time, MnO₂/Fe₂O₃ ratio, and H₂SO₄ concentration. After this, Mn recovery tests were carried out over time at different ratios of MnO₂/Fe₂O₃ and H₂SO₄ concentrations, where the potential and pH of the system were measured. Finally, it is concluded that high concentrations of FeSO₄ in the system allow operating in potential and pH ranges (−0.2 to 1.2 V and −1.8 to 0.1) that favor the formation of Fe²⁺ and Fe³⁺, which enable high extractions of Mn (73%) in short periods of time (5 to 20 min) operating with an optimum MnO₂/Fe₂O₃ ratio of 1:3 and a concentration of 0.1 mol/L of H₂SO₄.