Thermal shock is common in fire disaster and blasting of rock engineering; moreover, the rock mass bears dynamic mechanical disturbance frequently. In order to study the damage characteristics of thermal shock on physical and dynamic compressive properties, the thermal shock damage of granite treated to different temperatures at different heating rates was obtained by measure the ultrasonic wave velocity, and the internal structures were obtained by scanning electron microscopy experiments. By using split Hopkinson pressure bar, the dynamic experiments on granite treated to 400°C and 600°C at heating rates of 1, 2, 4, 6, 10, 20, 30, and 40°C/min were carried out. Thereby, the damage characteristics of thermal shock on the physical and dynamic compressive properties of granite were obtained. The results show that there is a heating rate threshold value between 6 and 10°C/min, which divides the thermal shock damage. Before the threshold value, the thermal shock does not appear. The dynamic compressive strength, dynamic elastic modulus, and density decrease; however, peak strain increases as the thermal shock damage increases. The researches of thermal effect on granite by heating with the heating rate below or equal to 6°C/min could avoid thermal shock. The research could provide a theoretical foundation for rock engineering suffered thermal shock, such as geothermal reservoir.

Rock mass is frequently subjected to rapid cooling in geothermal reservoir during water injection and reinjection. In this paper, to understand the effects of cooling treatments on heated granite, heat conduction tests, magnetic resonance imaging tests and numerical investigations were carried out to evaluate variations of thermal damage. The test results reveal that the heat flux and the heat transfer coefficient increases to a maximum within a few seconds and then gradually decreases. The maximum heat transfer coefficient of the samples treated with the initial temperature of 500, 400, 300, 200 and 100 °C is 2.3, 2.15, 1.9, 1.22 and 1.86 W·m⁻²K⁻¹, respectively. The edge area with drastic temperature changes is accompanied by the densely distributed microcracks; in contrast, the internal cracks of the specimen with gentle temperature are relatively sparse. The thermal damage contributed by the heating cracks occurs at a continuous decrease, and the thermal damage contributed by cooling occurs at a continuous increase, with the increasing heating temperature. The damage caused by heating is the result of the uneven thermal expansion of the local particles, the propagation of cooling cracks is strongly affected by heating cracks, and stress concentration induced by thermal shock promotes the coalescence of the pre-existing heating cracks.

Montmorillonite is a major mineral present in ion-adsorption rare earth ores, and the microscopic adsorption states of rare earth ions on its surface are of a great significance for the efficient exploitation of ion-adsorption rare earth ores. In this article, density functional theory calculations were used to investigate the adsorption mechanisms and bonding characteristics of hydrated Pr, Mg and NH₄ ions on the (001) surface of montmorillonite. Pr³⁺ exhibited a directed tendency geometry with Pr(H₂O)₁₀³⁺, which was adsorbed onto montmorillonite by hydrogen bonding with an adsorption energy of −1182 kJ/mol, and one coordinated H₂O ligand was separated from the first hydration layer of Pr. Both hydrated Mg and NH₄ ions were adsorbed onto the montmorillonite surface through hydrogen bonds, and the adsorption energies were −206 and −188 kJ/mol, respectively, indicating that the adsorption stability of the hydrated Mg ion was slightly higher than that of the hydrated NH₄ ion, but both were lower than that of hydrated Pr (−1182 kJ/mol). Hence, higher concentrations of Mg and NH₄ ions than rare earth ions would be necessary in the leaching process of ion-adsorption rare earth ores. Additionally, desorption experiments revealed that the recovery of Pr³⁺ by Mg²⁺ with a concentration of 38 mmol/L is 80%, while it is only 65% with the same concentration of NH₄⁺, and the concentrations of Mg²⁺ and NH₄⁺ were much higher than that of Pr³⁺ in lixivium, which is consistent with the DFT calculations.

A polyamine special ion exchange resin was used to adsorb Mo from ammonium tungstate solutions. The effects of adsorption time, S²⁻ concentration, adsorption temperature, CO₃²⁻ concentration, mass ratio of WO₃ to Mo, and Mo concentration on the Mo and WO₃ adsorption capacities were investigated. Energy dispersive spectrometer plane scans were used to study the distributions of Mo, W, S, and Na on the loaded polyamine special ion exchange resin and the desorbed polyamine special ion exchange resin. The results showed that the polyamine special ion exchange resin performed well during adsorption and desorption. Under the optimum conditions for the static adsorption experiments, the adsorption capacities for Mo and WO₃ were 99.29 mg/mL and 31.97 mg/mL, respectively, and the desorption rates for Mo and WO₃ were 99.35% and 99.43%, respectively. Adsorption and desorption of molybdenum and tungsten on the polyamine special ion exchange resin were investigated by dynamic adsorption experiments with an ammonium tungstate solution containing 125.0 g/L WO₃, 12.50 g/L Mo, 15.65 g/L S²⁻, and 0 g/L CO₃²⁻. The adsorption capacities for Mo and WO₃ were 53.48 mg/mL and 9.79 mg/mL, and the adsorption rates for Mo and WO₃ were 99.05% and 1.81%, respectively. The loaded polyamine special resin was desorbed with a 45 g/L sodium hydroxide solution, and the dynamic desorption rates for Mo and WO₃ were 99.02% and 99.29%, respectively.

It is important to recover La³⁺ from metallurgical solutions or wastewater. However, the recovery rate of La³⁺ is usually less than 1% and the recovery methods are not environmentally friendly or user-friendly. Therefore, a straightforward, efficient, clean, and economically friendly method is needed. In this investigation, a modified adsorbent, COSAC-Na₂EDTA-15, which was made from the Camellia oleifera shell (COS) and disodium ethylenediaminetetraacetic acid (Na₂EDTA), was invented. In addition, characterization of the COSAC-Na₂EDTA-15 adsorbent was conducted using SEM and XPS, and the principle of adsorption was revealed. The adsorption kinetics followed P-S-O KM, while the isotherm of COS-activated carbon (COSAC) aligned more closely with the Langmuir model. Compared to COSAC, the maximum La³⁺ adsorption capacity of COSAC-Na₂EDTA-15 increased from 50 to 162.43 mg/g, and the content of O and N changed from 7.31% and 1.48% to 12.64% and 4.15%, respectively. The surface of the COSAC-Na₂EDTA-15 exhibited abundant C, N, and O elements, and La³⁺ was detected on the sample surface after adsorption. The test and analysis results fully indicate that La³⁺ can be successfully adsorbed on the surface of COSAC-Na₂EDTA-15. Because of its easy preparation, low cost, and superior performance, activated carbon made from COS finds extensive applications in the adsorption and recovery of rare earth elements.