Leaching manganese nodules with iron-reducing agents – A critical review

Toro, Norman; Rodríguez, Freddy; Rojas, Ãnyelo; Robles, Pedro; Ghorbani, Yousef

doi:10.1016/j.mineng.2020.106748

Cited by 28 publications

(19 citation statements)

References 63 publications

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“…Figure 5 shows the potential and pH values during the dissolution of manganese nodules and black copper minerals when working at a concentration of 1 mol/L sulfuric acid and changing the ratios of MnO2/Fe3O4 (Figures 3 and 4). According to Senanayake [27], potential and pH values must be between -0.4 and 1.4 V and -2 and 0.1 in an acidreducing dissolution of MnO2, using Fe-reducing agents [28]. This is consistent with the results presented in Figure 5.…”

Section: Effect Of Acid Concentration In the Systemsupporting

confidence: 86%

Comparative Study of MnO2 Dissolution from Black Copper Minerals and Manganese Nodules in an Acid Medium

Moraga

Cerecedo‐Sáenz

González

et al. 2021

Metals

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The low grade of copper deposits and the use of the froth flotation process have caused excessive tailing production. In recent years, experts have looked for new alternative methods to improve this situation. Black copper minerals are abundant resources not exploited by large-scale copper mining and possess high Mn concentrations. On the other hand, manganese nodules are submarine resources and show high concentrations of Cu, Ni, Fe, and, mainly, Mn. However, both mineral resources are refractory to conventional leaching processes, and so a reducing agent is necessary for their treatment. We studied the use of tailings obtained from the flotation of foundry slags with a high content of Fe3O4 as reducing agents at different MnO2/tailings ratios and H2SO4 concentrations. Mn dissolution was compared in marine nodule and black copper minerals samples. It was found that higher Mn dissolutions are obtained from marine nodules, likely due to the acid consumption created by Cu dissolution from black copper minerals. The remnant elements in manganese nodules were leached under an oxidant condition.

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Section: Effect Of Acid Concentration In the Systemsupporting

confidence: 86%

Comparative Study of MnO2 Dissolution from Black Copper Minerals and Manganese Nodules in an Acid Medium

Moraga

Cerecedo‐Sáenz

González

et al. 2021

Metals

Self Cite

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“…In Table , the R 2 values fitted by diffusion control reaction kinetics are all above 0.98, which is closer to 1.0 than those fitted by liquid film diffusion control and chemical reaction control. The result indicated that the reduction leaching process of EMAS can be explained by the diffusion control model and is mainly limited by the diffusion of Fe 2+ and Mn 2+ through the ash layers Figure d shows the Arrhenius curve of the EMAS leaching process.…”

Section: Resultsmentioning

confidence: 98%

“…The result indicated that the reduction leaching process of EMAS can be explained by the diffusion control model and is mainly limited by the diffusion of Fe 2+ and Mn 2+ through the ash layers. 32 Figure 4d shows the Arrhenius curve of the EMAS leaching process. According to the calculation of the Arrhenius curve (ln K − T −1 ) equation, the apparent activation energy E a of the EMAS reduction leaching process is 38.38 kJ/mol.…”

Section: Resultsmentioning

confidence: 99%

Enhanced Leaching of Mn from Electrolytic Manganese Anode Slime via an Electric Field

et al. 2021

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Electrolytic manganese anode slime (EMAS) contains many Mn resources, and efficient Mn leaching is the key to realizing its high-value utilization. In this study, the effects of Fe2+ concentration, H2SO4 concentration, liquid–solid mass ratio, reaction temperature, and current density on Mn leaching efficiency were investigated. The enhanced leaching kinetics and mechanism of Mn from EMAS were analyzed. The results showed that the leaching efficiency of Mn in EMAS was 97.5%, the Pb content in the leaching residue was 42.24 wt % at a current density of 120 mA/cm2, the concentration of Fe2+ was 0.7 mol/L, the concentration of H2SO4 was 1.6 mol/L, the mass ratio of liquid–solid was 6 mL/g, and the reaction time and temperature were 150 min and 333 K. The leaching mechanism showed that the closed-cycle system of Fe2+–Fe3+–Fe2+ was formed in the process of electric field leaching, and Fe2+ and Fe3+ became the electron transport media, which realized the oxidation–reduction leaching of MnO2 and Fe2+ in EMAS. Leaching kinetics indicated that the apparent activation energy is 38.38 kJ/mol and the apparent efficiency equation is 1–2/3X – (1 – X)2/3 = A exp(−38.38/RT)t. This study provides a new method for resource utilization of EMAS.

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“…Because in pure ammonia solution, the manganese leaching efficiency is very low, by adding ammonium carbamate and ammonia to form a buffer solution to adjust the pH value of the solution, the pH value of the solution was suitable for the formation of a manganese-ammonia complex in this paper. The leaching reaction is shown as Equation (1). The specific steps of the ammonia immersion test are as follows: (1) A roasted lowgrade rhodochrosite calcine sample for reserve, weighing 10 g; (2) the desired concentration of leaching agent was prepared using a 25% mass fraction of ammonia and analytical pure ammonium carbamate and added to a three-mouth flask (when the required ammonia concentration was greater than 13 mol/L, 25% of the ammonia solution was continuously injected with ammonia to achieve the desired ammonia concentration); (3) after the water bath temperature was set and the leaching agent reached the specified temperature, the low-grade rhodochrosite calcine sample was added; (4) the electric stirring paddle was opened and the sample of low-grade rhodochrosite calcine was dissolved at a certain stirring rate; (5) after leaching for a certain period of time, the solution was taken out and the solid and liquid were separated by vacuum extraction and filtration; (6) the volume of filtrate was measured and the content of manganese in filtrate was determined by ICP, and the phase of leaching residue was determined by XRD.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…Manganese (Mn) is one of the 12 most abundant elements (it comprises approximately 0.1% of the earth's crust), and can be associated in different ways, finding oxides, sulfides, carbonates, and silicates with greater abundance. Besides, some recent studies mention that the largest manganese reserves in the world (high-grade deposits) are found on the seabed [1]. At present, 95% of the manganese produced annually is being consumed by the steel industry, and the remaining 5% is being used by other industries, such as the chemical, paint, fertilizer, and battery industries [2].…”

Section: Introductionmentioning

confidence: 99%

Study on Adding Ammonium Hydrogen Fluoride to Improve Manganese Leaching Efficiency of Ammonia Leaching Low-Grade Rhodochrosite

Yang

Liang

et al. 2021

Metals

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The ammonia leaching method for treating low-grade rhodochrosite has the advantages of a good impurity removal effect and low environmental pollution. In this paper, aiming at the low leaching efficiency of low-grade rhodochrosite treated by the ammonia leaching method, studies on enhancing the leaching efficiency of manganese by using ammonium hydrogen fluoride as an additive are carried out. The effects of different ammonia concentrations, leaching temperatures, leaching times, liquid-solid ratios, stirring rates, and the addition of ammonium hydrogen fluoride on the leaching efficiency of manganese with and without ammonium hydrogen fluoride as an additive were comparatively studied, and the parameters of ammonia concentration, ammonia leaching temperature, and ammonium hydrogen fluoride dosage were optimized in the experimental study. The results indicated that ammonium hydrogen fluoride as an additive in the treatment of low-grade rhodochrosite by the ammonia leaching method could effectively increase the leaching efficiency of manganese, and the optimal process parameters were obtained. Meanwhile, the addition of ammonium hydrogen fluoride didn’t affect the quality of the steamed ammonia product.

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Leaching manganese nodules with iron-reducing agents – A critical review

Cited by 28 publications

References 63 publications

Comparative Study of MnO2 Dissolution from Black Copper Minerals and Manganese Nodules in an Acid Medium

Comparative Study of MnO2 Dissolution from Black Copper Minerals and Manganese Nodules in an Acid Medium

Enhanced Leaching of Mn from Electrolytic Manganese Anode Slime via an Electric Field

Study on Adding Ammonium Hydrogen Fluoride to Improve Manganese Leaching Efficiency of Ammonia Leaching Low-Grade Rhodochrosite

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