The adsorption/desorption characteristics for light and heavy rare earth elements (REEs) on halloysite and illite (which are beneficial for the utilization of ion-adsorption RE ore) were systematically investigated and compared. Additionally, halloysite and illite were fully charactered by XRD, SEM, microscope, zeta potential, nitrogen adsorption–desorption isotherms and buffer pH to build the relationship between adsorption/desorption mechanisms and the minerals’ properties. The results of experiments show that the adsorption rate of halloysite is higher than illite, although they are both very fast and follow the pseudo-second-order kinetic model. The adsorption capacity of halloysite and illite increases with an increase in adsorption pH and remains constant when pH is higher than 4. Due to the narrow interlamellar spacing of halloysite and the fact that it is a nanotube, RE ions are adsorbed only through electrostatic attraction, whereas the adsorption and desorption pH have a significant effect on the recovery of RE ions from illite, because of the diverse adsorption mechanism. The results illustrated that the structure and surface properties of clays are also the key factors that affect RE ions leaching.

Kaolinite is the primary mineral in ion-adsorption rare earth ores, and improving our understanding of the adsorption state of REEs on kaolinite will benefit efforts to leach REEs from these ores. In order to explain why Eu³⁺ ions exhibit stronger pH-dependent desorption behavior than Lu³⁺, molecular dynamics simulations were applied to investigate the adsorption mechanism of Eu³⁺ and Lu³⁺ on a deprotonated kaolinite (001) surface. The simulation results show that the hydration numbers of Eu³⁺ and Lu³⁺ are comparable, whereas the ordering degree of water molecules around Eu³⁺ is higher than that of Lu³⁺, which is beneficial to the movement of Eu³⁺ to preferentially occupy favorable adsorption sites on the kaolinite surface, following which coordination bonds are formed between Eu³⁺ and the surface. As a result, the desorption rate of Eu³⁺ decreases sharply with the increase in leaching pH, while the desorption rate of Lu³⁺ is only slightly affected by pH.

In this work, we applied the technology of magnetic treatment to the flotation of chalcopyrite. The mechanism of the effect of pre-magnetized butyl xanthate on chalcopyrite flotation was studied using monomineral flotation tests, adsorption tests, conductivity tests, Fourier transform infrared spectroscopy (FTIR), etc. The monomineral flotation test results showed that, after the magnetization pretreatment of butyl xanthate solution, the chalcopyrite flotation recovery was increased by nearly two percentage points, and the dosage was reduced by 4–10 mg/L at the same recovery. The adsorption, FTIR, dissolved oxygen, and conductivity test results all showed that the magnetization pretreatment increased the dissolved oxygen content and promoted the oxidation of butyl xanthate to double xanthate with better selectivity to chalcopyrite. An electrochemical analysis showed that the magnetization pretreatment of butyl xanthate reduced the corrosion potential and corrosion current density of chalcopyrite surface and inhibited the self-corrosion process of chalcopyrite surface. The flotation test results of actual copper sulfide ore showed that pre-magnetized butyl xanthate could increase the copper recovery of copper concentrate by 3.06 percentage points and the sulfur recovery of sulfur concentrate by nearly 3 percentage points, and effectively reduce the mutual content of copper and sulfur concentrates.