Poojari, M.Vardhan, H.Hanumanthappa, H.Jathanna, H.M.Reddy, D.G.2026-02-032025JOM, 2025, 77, 5, pp. 3736-374710474838https://doi.org/10.1007/s11837-025-07280-8https://idr.nitk.ac.in/handle/123456789/20286This paper discusses zeta potential as an indicator of enhanced stability and in turn quality of lean-grade iron ore from Karnataka following physical pretreatments such as microwave (MW) and ultrasonic (US). Throughout the study, a set of 16 samples, designated S1–S16, was investigated, with S1 representing the untreated sample, S2–S4, US-treated samples, S5–S7, MW-treated samples, and S8–S16 representing samples that received MW and US combined pretreatment at different time intervals. The increased ore stability was confirmed by assessing multiple parameters such as electrophoretic mobility, optical density (OD), conductivity, and transmittance. Samples S12, S13, and S16 had higher conductivity, while S5, S7–S9, and S15–S16 had higher transmittance, proving that they had better inter-particle repulsions and thus stronger stability. Ore quality improvement was further verified using x-ray diffraction (XRD), which revealed gangue reduction in the aforementioned samples compared to ore that had other treatments or was left untreated. These findings show the importance of MW and US pretreatments in increasing ore quality and its stability in subsequent processing steps. © The Minerals, Metals & Materials Society 2025.Iron ore reductionIron ore treatmentUltrasonic applicationsCombined pre treatmentsDispersive behaviorsEnhanced stabilityHigh conductivityKarnatakaMultiple parametersOptical-Ore qualityPhysical pre-treatmentTime intervalIron ores