The production of high-quality electrolytic manganese (Mn) and electrolytic manganese dioxide (EMD) is crucial for numerous advanced applications, including battery technology and high-performance alloys. Achieving the desired purity and crystal morphology often relies on sophisticated chemical additives. While selenious acid (H2SeO3) has traditionally played a key role in enhancing manganese electrodeposition, research is increasingly focusing on how to optimize its use, often through synergistic combinations with other compounds. NINGBO INNO PHARMCHEM CO.,LTD. is actively involved in promoting these advancements for superior product outcomes.

The process of co-electrolysis, which aims to produce both metallic manganese and EMD simultaneously, presents unique challenges in controlling product quality. Additives are essential for managing reaction rates, suppressing unwanted side reactions like hydrogen evolution, and influencing the final crystalline structure of the deposited metals. Selenium compounds, including selenious acid, have been effective in improving current efficiency and refining the manganese deposit. However, the industry is keen on reducing selenium content due to environmental and health considerations.

The synergistic combination of selenious acid with sodium sulfite (Na2SO3) has emerged as a highly promising strategy. Studies have revealed that a precise ratio, such as 0.0175 g/L of H2SeO3 and 1.5 g/L of Na2SO3, can yield exceptional results. This composite additive system not only maintains high current efficiencies but also significantly enhances the quality of the deposited manganese. The resulting manganese exhibits a smooth surface, a bright metallic luster, and a uniform thickness, characteristic of the desired α-Mn crystal phase. Similarly, the co-produced EMD shows improved morphology, appearing as a uniform powder with consistent particle size and the advantageous ε-type crystal structure.

The mechanism behind this quality enhancement involves several factors. Sodium sulfite acts as a stabilizer and contributes to better control over the deposition process. It helps to further suppress the hydrogen evolution reaction, allowing the selenious acid to function more effectively at lower concentrations. This reduction in selenium usage is a key benefit, contributing to a cleaner product and a more environmentally benign process. The combined additives also appear to influence the nucleation and growth mechanisms of the manganese crystals, favoring the formation of dense, well-structured deposits over dendritic or rough formations.

Electrochemical analyses, such as cyclic voltammetry and linear sweep voltammetry, provide crucial validation for these observations. These techniques demonstrate that the presence of the composite additive shifts the deposition potentials favorably, indicating a more efficient electrochemical pathway for manganese reduction. This enhanced efficiency in deposition directly correlates with the improved quality and consistency of the final manganese product.

At NINGBO INNO PHARMCHEM CO.,LTD., we are committed to providing high-quality chemical solutions that drive innovation in industrial processes. The strategic use of composite additives like sodium sulfite in conjunction with selenious acid represents a significant advancement in achieving superior quality electrolytic manganese and EMD, offering a pathway to cleaner, more efficient, and higher-performing metal production.