The flow and solidification of grouting slurry are highly temperature sensitive, limiting ambient temperature grouting schemes under high temperature conditions. This study developed a physical simulation method for grouting in filled fractures under high temperature dynamic water conditions. First, the time dependent viscosity of slurry at different temperatures was characterized. Grouting experiments were then conducted to reveal the slurry blocking behavior in filled fractures under dynamic water and temperature effects. The results show that: 1) Under ambient temperature conditions, lower permeability increases the grouting pressure. The grouting pressures of the cement slurry and cement – sodium silicate (C–S) slurry increased by up to 32.26
This study investigates the acoustic field distribution and attenuation characteristics of ultrasonic waves in unclassified tailings slurry under an ultrasonic energy concentrator, aiming to establish an acoustics-based theoretical foundation for ultrasonic-assisted tailings thickening and settling in cemented backfill mining. Experimental tests were conducted to examine the effects of ultrasonic power (100 W, 200 W, 400 W) and slurry concentration (30
Large-scale stockpiling of phosphogypsum (PG) causes severe soil and water contamination, posing a global ecological threat. Despite diverse attempts to reuse PG in engineering construction, agricultural amendment, chemical preparation, and high-value resource recovery, its large-scale application remains limited by inherent impurities, insufficient stability, and potential secondary contamination. This review systematically summarizes PG generation status and environmental hazards, analyzes the technical bottlenecks of current PG utilization approaches, and highlights an innovative PG soilization method that enables large-scale sustainable consumption of PG. The key restrictive factors and future research directions are further proposed, aiming to promote PG resource recycling and provide theoretical references for solid waste ecological remediation.
Accurate in situ acoustic parameters of deep reservoir cores are essential for the reliable inversion of key reservoir properties such as porosity and elastic modulus. The in situ pressure-preserved coring technology enables the acquisition of core samples from deep reservoirs under in situ conditions. Building on this capability, this study proposes an in situ ultrasonic testing method for cores inside a pressure-retaining corer. The method addresses the long-standing problem that the metallic wall of the corer causes strong acoustic interference and prevents effective wave penetration into the core. To overcome this limitation, a metallic waveguide module was developed and integrated into an opening in the simulated corer wall, and a waveguide plug was used to transmit acoustic energy into the core. Ultrasonic experiments were conducted on rock samples under different test conditions to systematically compare the acoustic transmission performance of three waveguide-plug geometries, namely planar, curved, and conical configurations. In parallel, a three-dimensional transient pressure acoustics model was established in COMSOL Multiphysics 6.3 to simulate wave propagation in the multilayer waveguide-core medium and to reveal the evolution of the wave field under different contact conditions. The results show that the composite waveguide-plug structure successfully establishes the intended acoustic transmission path and enables valid measurements of core P-wave velocity, thereby confirming the technical feasibility of the proposed method. Among the three contact modes, the curved-fit configuration performed best. For sandstone, the measured wave velocity was 3.889 km/s, with a deviation of only 2.21
To enable the low-temperature and highly efficient extraction of lithium and valuable metals from spent LiNi0.5Co0.2Mn0.3O2 batteries, the reaction mechanism of the spent battery powder-sulfamic acid system was systematically investigated. The activation energy values of each reaction stage were calculated using different non-model fitting methods. The results indicate a two-stage reaction process, with apparent activation energies of 137.99 kJ/mol for the first stage and 89.08 kJ/mol for the second. Moreover, the reaction mechanisms were determined using the Z (α) master plot method, confirming that distinct kinetic models controlled different stages. Simultaneously, the alloying process of valuable metals in this roasting system was studied using different characterization techniques. This research provided theoretical guidance for the extraction of valuable metals from LiNi0.5Co0.2Mn0.3O2 battery powder.
