The quest for optimizing industrial chemical processes is an ongoing journey. In the production of electrolytic manganese (Mn) and electrolytic manganese dioxide (EMD), achieving superior product quality and high operational efficiency is paramount. For years, additives have played a crucial role, with selenium dioxide (SeO2) being a prominent example. However, a modern approach focusing on composite additives, particularly the synergistic interaction between selenious acid (H2SeO3) and sodium sulfite (Na2SO3), is now setting new benchmarks. NINGBO INNO PHARMCHEM CO.,LTD. recognizes the significance of these advancements in shaping the future of metal refining.

The traditional reliance on SeO2 in electrolytic manganese production stems from its ability to significantly improve current efficiency and reduce energy consumption by suppressing the hydrogen evolution reaction (HER). However, the environmental and health implications of selenium have prompted a search for alternatives or, more effectively, for ways to reduce its usage while maintaining or enhancing performance. This is where the strategic use of composite additives comes into play.

Recent research highlights that when sodium sulfite (Na2SO3) is employed as an auxiliary additive alongside a minimal concentration of selenious acid (H2SeO3), a powerful synergistic effect is observed. Studies have pinpointed an optimal ratio, typically involving 0.0175 g/L of H2SeO3 and 1.5 g/L of Na2SO3, which yields exceptional results in the co-electrolysis process for Mn and EMD. This combination dramatically boosts both cathodic and anodic current efficiencies, leading to a more productive and economical operation. The benefits extend to the quality of the deposited manganese, which becomes denser, smoother, and exhibits a desirable metallic luster, indicative of the α-Mn crystal phase.

The underlying mechanisms are complex yet scientifically sound. Sodium sulfite, beyond its role in enhancing manganese deposition, also acts as an antioxidant, preventing the unwanted oxidation of manganese ions and contributing to a cleaner electrolyte. Its presence helps to refine the crystal structure of the deposited manganese, preventing the formation of brittle or dendritic structures. Furthermore, the reduction in the required concentration of selenious acid contributes to a cleaner final product with lower residual selenium content, which is a critical factor for many high-purity applications.

Electrochemical analysis, including cyclic voltammetry and linear sweep voltammetry, provides compelling evidence for the efficacy of these composite additives. These techniques reveal that the additive combination favorably alters the deposition potential of manganese and increases the overall rate of manganese reduction, indicating improved Faradaic efficiency. This enhancement in efficiency translates directly into lower energy consumption, a vital consideration for large-scale industrial processes. The research suggests that this approach can significantly reduce the reliance on higher concentrations of selenium-based compounds, offering a more sustainable and environmentally conscious manufacturing pathway.

At NINGBO INNO PHARMCHEM CO.,LTD., we believe in the power of advanced chemical formulations to drive industrial progress. The optimized use of composite additives like sodium sulfite in conjunction with selenious acid represents a significant leap forward in electrolytic manganese and EMD production. It is a testament to how targeted chemical engineering can lead to greater efficiency, superior product quality, and a more sustainable industrial footprint.