Ion-adsorption-type rare earth ores (IREOs) are an indispensable strategic resource. Rare earths can be extracted from IREOs by means of in situ leaching, which is strongly influenced by the migration of clay components. In order to clarify the effect of the interaction between mineral particles on the rare earth leaching process, the aggregation of IREO colloids was investigated in suspension after NaCl concentration and pH value were disturbed based on a light scattering method. The results show that IREO colloids are prone to unstable aggregation, which can be affected by salinity and pH in suspension. Combined with the analysis of the surface acid–base properties and the zeta potential of the IREO colloids, the long-range electrostatic attraction between mineral heterogeneous charge surfaces plays a leading role in the interaction between mineral particles. In suspension, electrolyte concentration and pH can adjust the strength of the electrostatic force and the force field overlapping between the surface double electric layers to influence the aggregation of the IREO colloids. The above conclusion can enrich and supplement the rare earth extraction theory, which has a certain guiding significance for green exploitation of IREOs.

To address the technical challenges involved in the resource utilization of hot metal containing high levels of vanadium (V: 2–5%) and chromium (Cr: 1–5%), this study proposes a novel method based on pyrometallurgical selective oxidation for simultaneously extracting vanadium and retaining chromium. Through thermodynamic analysis and high-temperature smelting experiments, the competitive oxidation behaviors of carbon, vanadium, and chromium were revealed, and the synergistic control mechanism of temperature and oxygen partial pressure was clarified. The results indicate that within a temperature range of 1693–1753 K, adjusted over 1 h, vanadium preferentially oxidizes over carbon and chromium, while carbon effectively suppresses chromium oxidation. By optimizing ω(FeO) (10.0–15.7%), we achieved a vanadium oxidation efficiency (η_V) of 72.5–82.2% and maintained a chromium retention efficiency (100−η_Cr) exceeding 57.1%. Compared to traditional methods, which rely on high-oxygen blowing (oxygen supply: 43–195 kg/tFe), multi-stage roasting, and hydrometallurgical refining, this approach eliminates roasting and hydrometallurgical steps (such as sodium/calcium roasting and the associated leaching–precipitation units), shortens the process chain, reduces oxygen consumption (>80 kg/tFe), and lowers environmental risks (Cr oxidation reduced > 40%). This study establishes a theoretical framework for achieving sustainable V/Cr separation, enhancing resource efficiency and minimizing pollution (e.g., Cr(VI)-containing wastewater, high-salinity NH₄⁺/Na⁺ wastewater).

To address the technical challenges in the resource utilization of hot metal containing high levels of vanadium (V: 2–5%) and chromium (Cr: 1–5%), this paper proposes a novel method based on pyrometallurgical selective oxidation for the simultaneous extraction of vanadium and retention of chromium. Through thermodynamic analysis and high-temperature smelting experiments, the competitive oxidation behaviors of carbon, vanadium, and chromium were revealed, and the synergistic control mechanism of temperature and oxygen partial pressure was clarified. The results indicate that within the temperature range of 1693–1753 K, vanadium preferentially oxidizes over carbon and chromium, while carbon effectively suppresses chromium oxidation. By optimizing the ω(FeO) (10.0–15.7%), achieving a vanadium oxidation efficiency (ηV) of 72.5–82.2% and maintaining the chromium retention efficiency (1–ηCr) exceeding 57.1%. Compared to traditional methods—which rely on high-oxygen blowing (oxygen supply: 43–195 kg/tFe), multi-stage roasting, and hydrometallurgical refining—this approach eliminates roasting and hydrometallurgical steps, shortens the process chain, reduces oxygen consumption (> 80 kg/tFe), and lowers environmental risks (Cr oxidation reduced > 40%). The study establishes a theoretical framework for sustainable V/Cr separation, enhancing resource efficiency and minimizing pollution.