Investigating corrosion mechanisms and the electrochemical performance of ferrosilicon for dense medium separation operations in Botswana

IF 3.7 Q2 MULTIDISCIPLINARY SCIENCES

Scientific African Pub Date : 2026-09-01 Epub Date: 2026-09-02 DOI:10.1016/j.sciaf.2026.e03615

Phemo T. Sebobi, Babatunde Abiodun Obadele, Prasad Raghupatruni

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Abstract

Ferrosilicon (FeSi) is widely used in dense medium separation (DMS) processes for mineral beneficiation, however, its degradation due to corrosion presents significant operational challenges. Despite its industrial importance, limited research has addressed the electrochemical behavior of FeSi under the conditions specific to Botswana’s mining operations. This study investigates the corrosion mechanisms and electrochemical performance of three milled FeSi grades (100D, 150D, and 270D) using open circuit potential (OCP), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS), and surface characterization techniques (SEM-EDS, XRD, Raman Spectroscopy, and particle size distribution). The results reveal that 270D demonstrated the best overall corrosion resistance, exhibiting the highest charge transfer resistance (R_ct = 139,370 Ω·cm²), followed by 100D (R_ct = 139,700 Ω·cm²), and lastly 150D (R_ct = 51,020 Ω·cm²), which consistently exhibited the poorest corrosion resistance across all techniques. 150D showed the highest corrosion current density (I_corr = 1.57 × 10⁻³ A/cm², while 100D; I_corr = 1.94 × 10⁻⁴ A/cm², and 270D; I_corr = 1.50 × 10⁻⁴ A/cm²) and the most negative corrosion potential (E_corr), indicating poorest corrosion resistance. OCP measurement confirmed that 150D exhibited more frequent electrochemical fluctuations, indicative of lower surface stability. Particle size distribution shifted from unimodal to bimodal in all corroded samples, suggesting corrosion-induced particle fragmentation and agglomeration. These finding contribute to material selection and process optimization for more cost-effective and sustainable DMS operations in Botswana.

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研究博茨瓦纳重介质分离操作中硅铁的腐蚀机制和电化学性能

硅铁（FeSi）广泛应用于矿物选矿的重介质分离（DMS）过程，但其腐蚀降解给操作带来了重大挑战。尽管具有重要的工业意义，但有限的研究已经解决了在博茨瓦纳采矿作业特定条件下FeSi的电化学行为。本研究利用开路电位（OCP）、动电位极化（PDP）、电化学阻抗谱（EIS）和表面表征技术（SEM-EDS、XRD、拉曼光谱和粒度分布）研究了三种磨矿FeSi等级（100D、150D和270D）的腐蚀机理和电化学性能。结果表明，270D的整体耐蚀性能最好，电荷转移电阻最高（Rct = 139,370 Ω·cm2），其次是100D (Rct = 139,700 Ω·cm2)，最后是150D (Rct = 51,020 Ω·cm2)，在所有技术中均表现出最差的耐蚀性能。150D腐蚀电流密度最高（Icorr = 1.57 × 10−3 A/cm2）， 100D; Icorr = 1.94 × 10−4 A/cm2, 270D; Icorr = 1.50 × 10−4 A/cm2)，负腐蚀电位最大（Ecorr），耐蚀性最差。OCP测量证实150D表现出更频繁的电化学波动，表明其表面稳定性较低。所有腐蚀样品的粒径分布由单峰型向双峰型转变，表明腐蚀引起了颗粒破碎和团聚。这些发现有助于材料选择和工艺优化，使博茨瓦纳的DMS业务更具成本效益和可持续性。

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