Search Results (3)

Electrolytic manganese metal (EMM) produced from recyclable resources has recently gained increasing attention due to the scarcity of high-quality manganese natural resources and its broad range of applications. This review has summarised recent progress in manganese recovery techniques, including pyrometallurgy and hydrometallurgy. It has also critically assessed the processes and mechanisms involved in manganese electrodeposition for the Mn chloride- and Mn sulphate-based systems, with a major focus on electrode reactions and Mn nucleation growth. The key optimisation factors influencing manganese electrodeposition, such as electrolytes, power consumption, additives, cell structures, and electrode materials, were analysed, with particular attention to their impact on current efficiency, specific energy consumption, and product quality. The recent research directions were also highlighted to address practical challenges and enhance the sustainability of the EMM process, which mainly includes improving the ecological outcomes and reducing both the operating and investment costs. Promising strategies for the simultaneous production of EMM and electrolytic manganese dioxide (EMD) were also identified, which mainly comprised applying membrane technology, electrodeposition from ionic liquids, recycling and reusing waste materials, and exploring hybrid techniques. The results of this study showed that the prospective optimisation approaches for EMM are mainly driven by the need to enhance efficiency, reduce costs, and improve product quality through sustainable technological advancements. This review can be used as a comprehensive guide for manganese electrodeposition approaches for both practical and scientific research communities. Full article

The ferromanganese (FeMn) alloy is produced through the smelting-reduction of manganese ores in submerged arc furnaces. This process generates large amounts of furnace dust that is environmentally problematic for storage. Due to its fineness and high volatile content, this furnace dust cannot be recirculated through the process, either. Conventional MnO₂ production requires the pre-reduction of low-grade ores at around 900 °C to convert the manganese oxides present in the ore into their respective acid-soluble forms; however, the furnace dust is a partly reduced by-product. In this study, a hydrometallurgical route is proposed to valorize the waste dust for the production of battery-grade MnO₂. By using dextrin, a cheap organic reductant, the direct and complete dissolution of the manganese in the furnace dust is possible without any need for high-temperature pre-reduction. The leachate is then purified through pH adjustment followed by direct electrowinning for electrolytic manganese dioxide (EMD) production. An overall manganese recovery rate of >90% is achieved. Full article

In this work, we present the electrochemical deposition of manganese dioxide (MnO₂) thin films on carbon-coated TiN/Si micro-pillars. The carbon buffer layer, grown by plasma enhanced chemical vapor deposition (PECVD), is used as a protective coating for the underlying TiN current collector from oxidation, during the film deposition, while improving the electrical conductivity of the stack. A conformal electrolytic MnO₂ (EMD) coating is successfully achieved on high aspect ratio C/TiN/Si pillar arrays by tailoring the deposition process. Lithiation/Delithiation cycling tests have been performed. Reversible insertion and extraction of Li⁺ through EMD structure are observed. The fabricated stack is thus considered as a good candidate not only for 3D micorbatteries but also for other energy storage applications. Full article