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To investigate the impact of hydraulic conditions on the seepage characteristics of loose sandstone, this study employed optimized methods to prepare loose sandstone samples. Subsequently, seepage experiments were conducted under different injection pressures, flow rates, and flow volumes. The permeability, porosity, particle size distribution, and other parameters of the rock samples were obtained. By analyzing the response of seepage characteristics to pore and particle size characteristics, the influence of different hydraulic conditions on the seepage characteristics of loose sandstone was explored. The results indicated that improvements in the parameters of hydraulic conditions had different effects on various rock samples. For rock samples with developed seepage channels, increasing the value of each hydraulic condition parameter could expand the channels and discharge particles, and improve permeability. For rock samples with a larger number of small pores, increasing each hydraulic condition parameter caused particles to crack under pressure, drove particles to block holes, and thus reduced permeability. In this experiment, the permeability parameter had a significant positive response to the proportion of pores larger than 0.1 µm and a significant negative response to the proportion of particles smaller than 150 µm.

This study investigated a typical mining area with overlapping uranium and coal resources within the northern Ordos Basin. Based on the hydrogeologic conditions and spatial overlapping relationship of uranium and coal resources, we analyzed critical constraints on coordinated mining of uranium and coal. Using the Groundwater Modeling System, we established a numerical model of the groundwater flow field for coordinated mining of uranium and coal. Accordingly, we characterized the impacts of coal mining on the groundwater level in the uranium area, followed by quantitative prediction of the relationship between the coal mining avoidance distance and the groundwater level in the uranium mining area. Regarding the impacts on the groundwater level, this study proposed priority zones and their time sequence for coal mining. Additionally, based on the time when coal mining avoidance scenarios would influence the groundwater level in the uranium mining area, this study proposed priority zones and their time sequence for uranium mining. By developing an avoidance scheme for coordinated mining of uranium and coal from temporal and spatial aspects, this study provides a theoretical basis for the scientific, coordinated mining of uranium and coal resources.

A weakly basic anion exchange resin (SLX-D011) with an amino group as the functional group was prepared by an amination reaction using acrylonitrile and divinylbenzene copolymer as a framework. Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM–EDS) were used to characterize the physicochemical structure of the synthetic resin. Contact time, the influence of solution pH, temperature and initial uranium concentration on adsorption behavior were investigated. Adsorption kinetics, adsorption isotherms and adsorption thermodynamics were studied to obtain key parameters of the uranium adsorption mechanism. Furthermore, the effect of pH on the adsorption capacity of the resin for uranium and rhenium showed that the separation coefficient of uranium and rhenium was the largest (β U/Re  = 271.15) at pH 8.0. At this time, the resin showed high selectivity for uranium and can realize the simultaneous recovery of uranium and rhenium from low-grade uranium associated rhenium ore.

In situ leaching (ISL) is an important method for green and efficient development of sandstone‐type uranium ore. It achieves ISL of uranium through the deployment of injection and extraction vertical well patterns. The optimization of parameter matching between injection and extraction wells is key to improving the efficiency of uranium development. However, as the depth of mining and the scale of development increase, the small area controlled by vertical wells leads to a large number of vertical wells and high drilling costs, which severely affect the benefits of mine development. In this paper, taking the development case of the LK mine area in Xinjiang as an example, an extraction method of “horizontal well injection–vertical well extraction” was innovatively proposed for the first time. By using the well‐storage coupling model and particle tracking technology, this study systematically investigated the impact of well types and injection–extraction parameters on the leaching range and the distribution of leaching dead zones. Furthermore, a hybrid multiobjective optimization algorithm was used to complete the parameter optimization of well‐storage coupling for ISL of uranium. The research content of this paper explores the impact of injection–extraction parameters and well spacing on the leaching effect of “horizontal well injection–vertical well extraction,” providing a method and approach for the optimization study of ISL uranium parameters. In addition, the research results of this paper have certain guiding significance for enhancing the leaching and extraction effect of the existing uranium mining plan in the LK mining area.

With the application of electronic detonators, millisecond blasting is regarded as a significant promising approach to improve the rock fragmentation in deep rock blasting. Thus, it is necessary to investigate the fracturing mechanisms of short-delay blasting. In this work, a rectangle model with two circle boreholes is modeled as a particles assembly based on the discrete element method to simulate the shock wave interactions induced by millisecond blasting. The rectangle model has a size of 12 × 6 m (L × W) and two blast holes have the same diameter of 12 cm. The shock waves are simplified as time-varying forces applied at the particles of walls of the two boreholes. Among a series of numerical tests in this study, the spacing between two adjacent boreholes and delay time of millisecond blasting are considered as two primary variables, and the decoupling charge with a coefficient of 1.5 is taken into account in each case. The results show that stress superposition is not a key factor for improving rock fragmentation (tensile stress interactions rather than compressive stress superposition could affect the generation of cracks), whereas collision actions from isolated particles or particles with weakened constraints play a crucial role in creating the fracture network. The delay time has an influence on causing cracks in rock blasting, however, whether it works heavily depends on the distance between the two holes.

In situ leaching (ISL) is becoming the main mining practice for sandstone-type uranium deposits in China. The key to ISL technology is to aid the leaching solution in contacting the ore bed over a large range, which will induce a series of chemical reactions to extract uranium; thus, it is essential to thoroughly understand the reservoir physical properties of uranium deposits. Taking the Qianjiadian sandstone-type uranium deposits (southern Songliao Basin, China) as an example, the mineral composition and pore structure of samples in different layers were measured using X-ray diffraction (XRD), thin section analysis (TSA), low-temperature N2 adsorption (LTN2A), and mercury intrusion porosimetry (MIP), and their influences on the ISL effect were analyzed. The results show that more than 65% of the minerals in the Qianjiadian uranium deposits are felsic minerals, and the carbonate minerals, clay minerals, and augite are auxiliary minerals. The primary intergranular pores, intergranular-dissolved pores, intragranular-dissolved pores, intercrystalline pores, and microfractures are developed in uranium deposits with various lithologies to different degrees. The macropores ( >1000 nm) and mesopores (100-1000 nm) of medium sandstone, argillaceous sandstone, and siltstone are well developed; in contrast, the proportions of micropores ( <10 nm) and transition pores (10-100 nm) in coarse sandstone, fine sandstone, and sandy mudstone are quite high. The heterogeneity of pores in uranium deposits of different lithologies is strong and influences the mineral composition and its fabric mode. Coarse sandstone, fine sandstone, and sandy mudstone are favorable for ISL mining in Qianjiadian uranium deposits because their permeability is above the required permeability threshold of ISL. The uranium deposits with permeability below the threshold are recommended to adopt the blasting-enhanced permeability method to improve their permeability for achieving large-scale and high-efficiency ISL mining. This study can provide guidance for the selection of favorable ore beds for ISL mining and reservoir stimulation methods in low-permeability sandstone-type uranium deposits.

In the present study, an immersion experiment was carried out to examine how N80 steel corrodes when exposed to formation water containing dissolved CO2 and supercritical CO2 (Sc-CO2) along with water vapor. We employed electrochemical and surface analysis methods to examine the influence of various factors, including the temperature and duration of immersion, on the extent of corrosion. The results show that the corrosion patterns of N80 steel in a supercritical CO2 environment and CO2-saturated formation water differed significantly. The presence of similar corrosion features was suggested by the constant structure of the corrosion products identified in the formation water. However, the morphology of the corrosion product was complex in the supercritical CO2 environment, exhibiting features of pitting and localized corrosion. Furthermore, a non-linear trend in the corrosion rate was observed between 40 °C and 120 °C. Specifically, the rate of corrosion declined from 40 °C to 80 °C, but it then resumed its growth from 80 °C to 120 °C. These findings suggest that very high temperatures could lead to the destruction of corrosion products and subsequently enhance the corrosion process.

It is very important to properly treat uranium-containing wastewater scattered in the environment. In this study, we used the hydrothermal method to synthesize carbon-coated magnetic Fe 3 O 4 nanoparticles and then modified by sodium hydroxide to yield magnetic carbon nanomaterials (Fe 3 O 4 @HTC-NaOH). The microstructure and chemistry of the material were characterized by TEM and FTIR. We investigated the adsorption behavior of materials for uranium (VI) under different conditions, including pH, contact time, initial uranium concentration, and temperature. The results indicated that this material adsorbs uranium quickly, achieving equilibrium in static adsorption after approximately 225 min. The adsorption behavior was strongly dependent on pH, and the maximum adsorption capacity (457.83 mg/g) was reached at pH 5.5. The initial concentration also had a role in the adsorption behavior. With the gradual increase of the initial concentration of uranium (VI), the adsorption capacity showed an increasing trend and reached saturation at 100 mg/g. Adsorption isotherm could be well fitted by the Langmuir model and the pseudo-second-order kinetic model. And the results indicated it is a heat-absorbing reaction. Owing to the introduction of Fe 3 O 4 , the material is magnetic and the solid-liquid separation can be rapidly completed by the pairing of magnets. The new material could be regenerated using HNO 3 , and the adsorption rate could maintain above 75% after five adsorption/regeneration cycles, which illustrated its certain practical application value.

For the leaching process of uranium ore, the leaching rate, leaching efficiency, and energy consumption are hot research topics. In order to meet the industry’s demand for natural uranium and ensure the stable supply of uranium products, this article proposes the use of surfactants to improve the leaching efficiency and leaching rate of uranium ore, thereby achieving better leaching results at larger particle sizes and reducing grinding energy consumption. This article focuses on the core samples of a certain mine and adopts a stirring leaching method. Firstly, the acid stirring leaching process conditions were optimized. Based on this, the types and concentrations of surfactants were selected, and the influence of the selected surfactants on the stirring leaching law of the ore was investigated. The results indicate that the addition of cetyltrimethylammonium bromide (CTAB) cationic surfactant has the highest leaching efficiency in the optimal conventional stirring leaching environment for ores. Compared with the stirring leaching effect without CTAB, after adding 50 mg/L CTAB for leaching, the leaching rate of uranium ore increased from 90.79 to 96.34% within the same leaching cycle; By adding 50 mg/L CTAB to leach ore with a particle size of − 60 mesh, the uranium leaching rate increased from 35.09 to 87.79%, achieving effective leaching of uranium ore with coarser particles; Through analysis such as BET and SEM, it was determined that the addition of CTAB promoted the solution to enter the microporous gaps between ores, achieving an increase in leaching rate. Surfactants reduced the thickness of the liquid film formed on the ore surface and the diffusion time of the liquid film, which was the reason for the improvement of uranium leaching effect.

This paper synthesized a stytypyridine (LSL-030-bd) resin with small particle size and uniform distribution to recover molybdenum resources leached during neutral in-situ leaching of uranium. The batch experiment results show that the LSL-030-bd ion exchange resin produced had the highest U(VI) adsorption capacity at pH 7.0, reaching 187.20 mg·g −1 . At pH 3.0, LSL-030-bd resin adsorbed 180.17 mg·g −1 of Mo(VI). At pH 7.0, the resin exhibited the highest separation coefficient for uranium and molybdenum, with a KD value of 9.08. The resin's adsorption of U(VI) is a spontaneous endothermic process involving monolayer adsorption that combines physical and chemical adsorption. The adsorption of Mo(VI) by the resin is an exothermic process that is not spontaneous. It involves monomolecular layer adsorption with hydrogen bonding as the primary chemical force. By desorbing molybdenum with NH 4 SCN, followed by utilizing a mixed solution of NH 4 HCO 3 and (NH 4 ) 2 CO 3 to desorb uranium, a step-by-step desorption process may be achieved to separate and purify uranium and molybdenum.