Очищення феронікелю методами електролізу та осадження для виробництва високочистого нікелю

This study investigates the purification of ferronickel through electrolysis and precipitation processes to produce high-purity nickel. Ferronickel has yet to find extensive applications in industries requiring high-purity nickel. So, it is imperative to develop technologies that can upgrade ferronickel through electrolytic processes. Ferronickel, consisting of approximately 18% Ni and 80% Fe, represents an abundant but underutilized resource for high-grade nickel applications. Electrolysis was conducted using ferronickel anodes and graphite cathodes in 2 M HCl, followed by oxidation with H2O2 and precipitation with NaOH under varying pH (4.4 and 4.7) and temperature (40–70°C) conditions. Results demonstrated that the Ni concentration increased linearly from 5.36 g/L to 32.57 g/L over 8 hours of electrolysis, while Fe concentration rapidly increased and stabilized around 84.8 g/L after 3 hours. XRD analysis revealed improved crystallinity at higher temperatures, predominantly forming FeO2 and NiO phases at 70°C. XRF analysis confirmed effective iron removal, achieving 78.91% Fe precipitation at pH 4.4 and 70°C, while nickel recovery was maximized at 14.60% at pH 4.7 and 70°C, but this pH is not favorable due to the Ni loss. SEM indicated finer, more homogeneous precipitate morphology at elevated temperatures. SEM imaging revealed that at pH 4.4 the precipitate formed at 40°C had a coarse, loosely packed structure with large, irregular particles (average size ≈6.50 µm). By contrast, at 70°C the precipitate was much finer and more homogeneous, with particles ~916.8 nm. The findings highlight that electrolysis follow by optimized precipitation enables efficient separation of nickel from iron, offering a promising alternative route for upgrading ferronickel without relying on HPAL or matte processes. This approach contributes to diversifying nickel supply chains and promoting sustainable raw material utilization using local content