Abstract:To investigate how deformation localization develops in sandstone during failure under acidification,we conducted triaxial compression tests on sandstone samples exposed to acidic chemical corrosion.The experiments used a visual servo-controlled triaxial compression system and employed three-dimensional digital image correlation(3D-DIC)technology to analyze spatiotemporal patterns of deformation.The results revealed several key findings:(1)Under triaxial compression,deformation localization in sandstone develops progressively,with strain values gradually concentrating along the main fracture surface,particularly at the initial 5%strain points.(2)At a constant confining pressure,the width of the deformation localization band on the sandstone surface first increases and then decreases as immersion time in acid solution increases.(3)Using 3D-DIC,we obtained detailed surface deformation data in three dimensions.Analysis of the spatial and temporal evolution of the largest 5%strain points during loading showed that the angle between the deformation localization zone and the specimen's axial direction decreases as immersion time increases.Additionally,with longer immersion,the fracture surface evolves from a surface feature to a planar one.

Abstract:In order to solve the problem of low permeability and difficult pumping in deep coal seams and significantly improve the permeability of coal seams and the efficiency of gas extraction,a pulsating air blast high-efficiency permeability enhancement technology was proposed.The mechanism of high-pressure pulsating air burst flushing and pressure relief was expounded.The numerical simulation was carried out under the conditions of different coal strengths,buried depth,initiation pressure and pulsation times by using LS-DYNA software.The cracking effect of high-pressure pulsating air burst was analyzed.The results indicate that through theoretical research and calculations of the parameters of the p-a equation of state and the RHT constitutive equation in the RHT model,the parameters of the RHT model are derived,allowing the RHT damage constitutive model to better reflect the dynamic deformation and failure process of coal.For fracture caused by pulsating air blasts,with controlling a single variable,it was found that the effective fracturing range is generally negatively correlated with coal strength.The best fracturing effect was observed in medium-hard coal and effective fracturing range is 2.52 m.The effective fracturing range is negatively correlated with coal seam depth.With a depth of 300 m,the effective fracturing range for hard coal is 0.47 m.The effective fracturing range is positively correlated with coal initiation pressure.With an initiation pressure of 100 MPa,the effective fracturing range for hard coal is 2.83 m.The effective fracturing range is positively correlated with the number of pulses.At three pulses,the effective fracturing range for hard coal is 2.72 m.Regression models were established for each factor affecting the effective fracturing range,and the correlation of the influence of different factors on the effective fracturing range was further analyzed.

Abstract:The controlled electrical pulse technology can effectively improve the pore and fracture structure of coal and rock,and enhance the permeability of coal seams.This technology has a promising application prospect in the field of coal seam enhancement.In this study,a self-built controlled electric pulse cracking and enhancing permeability of coal rock test system is utilized to carry out impact test of coal and rock samples under varying capacitance conditions of 2 μF,4 μF,6 μF and 8 μF.The shock wave propagation laws and structural damage characteristics of coal and rock are studied.Additionally,the microstructure of coal samples is examined and analyzed using scanning electron microscopy and low-temperature N2(77 K)adsorption methods.The results show that the duration of the shock pressure exerted on the coal rock by controlled electric pulse action is several microseconds.The peak pressure of the shock wave generated at the same position of the specimen increases significantly with the increase of capacitance,and the maximum peak pressure increases by 6.23 times.The crack densities of coal rock specimens under controlled electric pulse action with capacitance of 2 μF,4 μF,6 μF and 8 μF are 1.407 72 m-1,2.064 64 m-1,9.123 04 m-1,and 16.700 19 m-1,respectively.These datasets indicated that there is an exponential function correlation between the crack density of coal rock specimens and the capacitance.With the increase of capacitance,a large number of pores and fracture appear in the coal body.The total pore volume and specific surface area of the coal body increase by 2.3 times and 3.6 times,respectively,and the pore fractal characteristics are significant.The controlled electric pulse has a significant improvement effect on the micro-pore and fissure structure of coal after penetration,thereby providing a good channel for the migration of coal seam gas.

Abstract:The oil and gas development in the Luzhou Area of the Sichuan Basin has entered a mature stage,charactericed by a large number of abandoned wells with high warter-cut.Research on the redevelopment of its geothermal resources holds strategic significance for achieving the region's"dual carbon"goals.The study area located on the Indosinian Luzhou-Kaijiang paleo-uplift,hosts the Qixia-Maokou Formation of the Permian,recognized as the region's most significant karst-type geothermal reservoir.This formation exhibits the typical features of a basin-type,stratabound,medium-to low-temperature geothermal system.Drawing on geological,seismic,drilling,and logging data,this study analyzes the reservoir-caprock assemblages,temperature distribution,and structural characteristics of the area.Findings reveal that geothermal heat accumulation in the paleo-uplift zone results from a combined mechanism of heat conduction,concealed fault-driven heat convection,and thermal radiation reflection.A volumetric approach was used to quantitatively assess geothermal resource reserves.The results indicate that crustal uplift from the Indosinian Luzhou paleo-uplift,together with fault development caused by Himalayan and Yanshan tectonic movements,facilitated the accumulation of deep geothermal fluids in the Luzhou area,forming a distinctive tectonic heat accumulation system.The estimated geothermal resources in the Qixia-Maokou Formation total 2.894×1020 J,equivalent to 9.87×109 tons of standard coal,demonstrating substantial potential for geothermal development in the region.

Abstract:To identify a more effective method for predicting water inflow in production mines,this study first examines the"large well"conceptual model.The formation of"large wells"in coal mines typically requires several decades,making it difficult to obtain time-dependent groundwater parameters.Additionally,the Gal empirical formula relies on limited parameters and is prone to overextension,resulting in high prediction errors ranging from 84%to 398%.Recognizing that mine water inflow over time reflects the site's hydrogeological conditions,this study introduces the potential line method for water inflow prediction.By calculating the water-rich coefficient based on updated inflow data,the accuracy of predictions improves compared to traditional methods.Using a case study of a single mine,water inflow was predicted using both the water-rich coefficient method and the trend line method.The relative errors for these approaches ranged from 14.2%to 17.3%.Overall,the large well method is best suited for the early stages of mine design and initial production.For ongoing operations,the water-rich coefficient method or trend line method is recommended,provided that water inflow data is collected continuously and comprehensively.

Abstract:Aiming at the problems of poor recognition effect and low efficiency of the coal gangue sorting task in the coal mining industry,a recognition and detection model of coal gangue is proposed based on improved YOLOv8n.Firstly,the standard convolution in YOLOv8n is replaced by Ghost convolution,and the Ghost convolution is integrated into C2f module to construct a C2fGhost module,which reduced the number of network parameters.Secondly,a multi-scale adaptive fusion module is designed to replace the splicing module of YOLOv8n,which optimized the multi-scale feature fusion strategy and improved the overall quality of feature integration as well as recognition accuracy.Finally,a dynamic detection head is adopted to enhance the model's processing capabilities in the dimensions of scale,spatiality,and task.The experimental results show that compared to the YOLOv8n model,the improved model achieves a 3%increase in average accuracy mean P,an 8.4 FPS improvement in detection frame rate,a 24%reduction in parameter count,a 16%decrease in computational load,and a 25%reduction in model size.

Abstract:To examine how the permeability of surrounding rock and fault-related water conduction evolve during mining-induced disturbances,this study adopts theoretical analysis methods.The Mohr-Coulomb and maximum tensile criteria were used to develop a mathematical model that describes sudden changes in permeability caused by stress and water pressure.This model was integrated into FLAC3D simulation software to create a dynamic characterization of permeability mutations.A case study in a Shandong mining area employed this numerical simulation approach to simulate the activation of floor faults and the subsequent formation of water inrush events.The simulations revealed the staged evolution of fault permeability and the elevation of pressure-driven water conduction during mining.Key findings include:the elevation of pressure-driven water conduction lags significantly behind fault activation,with hydraulic fracturing effects persisting even after mining stops.Conduction velocity increases with burial depth and initial fault permeability.Shallower faults exhibit smaller permeability changes and slower water conduction,while higher initial permeability reduces energy loss and accelerates water movement.These results offer valuable insights for preventing water hazards in mining operations,particularly in areas prone to fault activation and delayed water inrush.

Abstract:Under the framework of the new Mineral Resources Law,advancing the deep participation of social capital in mine ecological restoration in an orderly manner is essential for transitioning from a traditional government-led approach to a multi-dimensional model that integrates policy guidance,legal safeguards,market operations,and capital participation.This transition is driven by multiple factors,including ecological value realization,green financial innovation,and the development of transaction technologies,collectively promoting the industrialization,marketization,and capitalization of mine ecological restoration.This study systematically explores market-oriented models of mine ecological restoration,delves into the core driving forces of the restoration process,and scientifically implements the specific provisions of the new Mineral Resources Law concerning ecological restoration.Furthermore,it systematically outlines a market-based approach for mine ecological restoration:(i)constructing a multi-perspective market guidance system encompassing"policy tool innovation,resource optimization,and governance standard benchmarking";(ii)developing a multi-dimensional market operation framework that integrates"trading platform development,transaction mechanism innovation,transaction supply optimization,and transaction monitoring and supervision";(iii)establishing a multi-level social capital support framework for mine ecological restoration,including"capital guidance,financial innovation,and industrial integration";(iv)formulating a multi-domain ecological product value transformation mechanism covering"resource assessment,market conversion,and industrial clustering".This transition continuously propels mine ecological restoration from a traditionally administratively dominated,single-governance model to an integrated,synergistic approach that combines"mandatory legal constraints,flexible policy guidance,and adaptive market mechanisms".Consequently,mine ecological restoration evolves from an"end-of-pipe comprehensive treatment"approach toward an"eco-economy-society"co-benefit paradigm,thereby providing a sound reference for achieving the deep integration of ecological civilization construction in mining areas with the high-quality development of the mining economy.

Abstract:This study summarizes the mechanisms of alkali-activated materials in solidifying salt ions in mine water with high TDS and the research progress of novel technologies,while also analyzing relevant domestic application scenarios and key technical challenges.Alkali-activated cementitious backfill materials were prepared using mine water with high TDS,coal gangue,fly ash,ordinary portland cement,and additives.By investigating the content of different additives,the compressive strength of test specimens and the ion concentration in the soaking solution were measured.The results indicated that the test specimens with the addition of 4.8%industrial water glass demonstrated the optimal compressive strength.Based on this,calcium oxide was additionally introduced as an additive,while high-temperature pretreatment was applied to fly ash.Ultimately,the solidification rate of chloride ions reached 87.54%,and the solidification rate of sulfate ions was greater than or equal to 98.72%.Experimental results demonstrate that alkali-activated materials based on coal-based solid waste can effectively solidify salt ions in mine water.Under coexisting conditions of Cl-and SO2-4,the priority of ion solidification must be considered,and aluminum sources should be rationally allocated through mix proportion optimization.Pretreatment of fly ash is an effective method to enhance the performance of alkali-activated materials,significantly improving ion solidification efficiency and resource utilization rates.For mine water with varying water quality characteristics,customized formulation schemes should be developed and combined with pretreatment processes to achieve efficient solidification and resource utilization of salt ions.

Abstract:This study aims to scientifically quantify the carbon emission intensity of various open-pit mining techniques and clarify their differences in carbon emissions,and thereby support the selection of low-carbon alternatives in open-pit coal mining.Based on the Life Cycle Assessment(LCA)method,carbon emission sources across the full life cycle of different open-pit coal mining techniques were identified.Taking each production stage as the research subject,Analysis of Variance(ANOVA)was systematically employed to analyze the carbon emission intensity characteristics of five mining techniques:the single-bucket truck discontinuous process,the single-bucket truck semi-mobile crushing station semi-continuous process,the bucket-wheel continuous process,the single-bucket self-moving crusher semi-continuous process,and the cast blasting-dragline stripping process.The research results indicate that the carbon emission intensities of the five mining techniques differ significantly.The carbon emissions of these techniques,in descending order from highest to lowest,are:the single-bucket truck discontinuous process,the single-bucket truck semi-mobile crushing station semi-continuous process(approximately equal to the single-bucket self-moving crusher semi-continuous process),the bucket-wheel continuous process,and the cast blasting-dragline stripping process.The transportation and disposal stage is the core emission source for most mining techniques,accounting for 47.06%to 87.49%of total carbon emissions.In terms of carbon emission composition,the single-bucket truck discontinuous process is primarily driven by diesel consumption,accounting for 82.55%to 87.49%,while the single-bucket truck semi-mobile crushing station semi-continuous process is mainly driven by electricity consumption,accounting for 42.41%to 69.47%.Comprehensive optimization and configuration of mining techniques can significantly reduce carbon emissions.For the single-bucket truck semi-mobile crushing station semi-continuous process,adopting a large-bandwidth conveyor system can lower carbon emissions by 12%to 15%.For the single-bucket truck process,scaling up equipment in the transportation stage can reduce carbon emission intensity by 18%,while replacing diesel-powered equipment with electric-powered alternatives can cut carbon emission intensity by 80%.

Abstract:A deep understanding of the erosion loss effect induced by coal mining subsidence on the slope scale is an important scientific basis for the accurate prevention and control of erosion loss in the coal mining area in the middle reaches of the Yellow River.Taking the typical loess mining subsidence basin in Northern Shaanxi as the research area,through FLAC3D numerical simulation,the deformation characteristics of concave loess slope on the main cross-section of the mining subsidence basin are revealed from the perspective of the triadic coupling of"slope position(slope edge,center,margin),natural slope gradient(5°,15°,25°,35°,45°),and slope aspect(downslope,upslope)".Based on the CSLE model and the empirical model,the soil erosion effect of the concave loess subsidence slope is clarified.The results show that under the triadic coupling of"slope position,natural slope gradient,and slope aspect",coal mining subsidence leads to an increase in the gradient of concave loess slopes,with slope position being the key controlling factor.The increase of slope gradient increases first and then decreases with the transition of slope position from margin to center,and reaches the maximum of 11.85%under the conditions of"slope edge position+natural slope gradient of 5°+downslope aspect".Whether in the scale of annual erosion rainfall or typical field erosion rainfall,coal mining subsidence will lead to the increase of soil erosion modulus of concave loess slope,and the increase will reach the maximum under the condition of"slope edge position+natural slope gradient of 5°+downslope aspect",which is 11.40%and 10.14%respectively.Slope position is still the key control factor.It is suggested that the layout of underground coal mining face should be adjusted and optimized according to the relative position relationship of surface concave loess slope in coal mining subsidence area as the pre-mining precise prevention and control strategy of erosion loss effect in loess mining subsidence area of Northern Shaanxi in the middle reaches of the Yellow River.

Abstract:Grouting filling is the key technology to solve the large-scale collapse of large and high goaf under water filling conditions.The law of slurry diffusion is of great significance for engineering design.The influence of water cement ratio,particle size of injection medium and grouting pressure on slurry diffusion radius and pressure stability value was studied by orthogonal test method,and the variation law of slurry diffusion shape and slurry pressure was discussed in depth.The results show that the influence of each factor on the diffusion radius of the slurry is in the following order:the particle size of the injection medium,the water-cement ratio and the grouting pressure.The particle size of the injection medium has a significant effect on the diffusion radius of the slurry.The influence of various factors on the stable value of slurry pressure is water-cement ratio,particle size of the injection medium and grouting pressure in turn,among which water-cement ratio and particle size of the injection medium have significant influence on the stable value of slurry pressure.During the grouting process,the slurry flow experienced three stages:vertical settlement,lateral diffusion and upward penetration.The overall pressure change shows the dynamic characteristics of dynamic peak,drainage pressure relief,step-by-step growth and stabilization.The results can provide reference for grouting filling design.

Abstract:Land use changes driven by mining activities have profound impacts on the"carbon source-sink balance"in mining areas.Investigating their evolution patterns is critical for advancing regional green development.Taking the Huainan Mining Area as an example,this study extracted land use data from Landsat satellite images from 2000 to 2024.By integrating energy consumption and nighttime light data,the InVEST model and the Intergovernmental Panel on Climate Change(IPCC)carbon emission coefficient method were employed to conduct a quantitative assessment of carbon storage,carbon budget,and the carbon reduction benefits of floating photovoltaic systems in mining areas.The results reveal significant changes in Huainan Mining Area land use structure,characterized by expansion of mining and construction land along with reduction of arable land,leading to a continuous decline in carbon storage.The carbon budget exhibited distinct spatiotemporal heterogeneity,as coal mining activities not only increased carbon emissions but also enhanced carbon sink capacity due to the formation of subsidence water areas.The photovoltaic power plants achieved an average annual CO2 emission reduction of approximately 670 000 tons,with the cumulative reduction over their lifecycle equivalent to four years of total carbon emissions in the region.Based on on the research findings,differentiated zoning-based governance strategies were proposed to support the low-carbon transition of resource-based regions.

Abstract:In order to solve the space-time contradiction between mining and filling processes of most filling mining technologies,the existing problems of various filling mining technologies were discussed by comprehensively analyzing the application status of filling mining technologies in domestic coal mines.Based on this,combined with the self-designed independent and composite hydraulic support for mining and filling,the technical conception of non-destructive filling mining in coal mine was put forward.The technical ways of non-destructive filling mining were categorized to realize the near-zero damage of ecological environment,mining efficiency and working space in the process of coal mining.Based on the relevant results of the research team,an enhanced filling method suitable for non-destructive filling mining was proposed,and its process flow was refined,which can realize the accurate adaptation of the strength of the filling body to the difference of movement in different regions during the roof breaking process.Based on the above research,the future development direction of non-destructive backfill mining technology in coal mines is proposed,focusing on integrated technologies for lightweight and high-efficiency equipment,intelligent mining and filling equipment,and diversified utilization of gangue-based materials.

Abstract:Ecological restoration of historically left abandoned mines constitutes an important component and a key priority area of ecological conservation and restoration in territorial spaces.Its restoration effectiveness directly determines the"degree to which the weaknesses"are addressed in the territorial space ecosystem.Under the new circumstances,it is urgent to systematically address the problem of abandoned mines through new concepts,new technologies,and new standard,and promote the integrated development of the ecological restoration service industry."Nature-based Solutions(NbS)"is regarded as a core means to achieve sustainable development.By expounding on its connection with the ecological restoration of historically left abandoned mines,a full-cycle nature-coordinated ecological restoration technology system has been established,which features"multi-dimensional base diagnosis-nature-adapted scheme design-modular collaborative and targeted implementation-long-term monitoring and dynamic optimization-ecological value transformation and long-term management".This study also analyzes the multi-dimensional challenges it faces in terms of natural base,policy mechanism,technology adaptation,economic sustainability,social coordination,and monitoring and evaluation,and puts forward practical paths including continuous theoretical research,strengthened technical practice,promotion of long-term monitoring,improvement of policies and regulations,and emphasis on public participation.The study also explores the practical significance of the thought on ecological civilization for NbS in the ecological restoration of historically left abandoned mines,and summarizes the experience and insights from the application of NbS in this field,with the aim of aligning ecological restoration efforts with the local natural characteristics of the mines.These efforts aim to make the ecological restoration work conform to the local natural characteristics of mines,and ultimately achieve a new pattern of self-sufficiency and self-circulation in the ecological restoration of historically left abandoned mines.

Abstract:As an important coal production base in China,the long-term exploitation of mineral resources in the Northern Shaanxi Coal Mining Area has given rise to a series of ecological and environmental problems,including surface subsidence,vegetation degradation,and water resource damage.To achieve precise management,control,and restoration of the mining area's ecological environment,and in response to the issues that existing technologies are insufficient to meet the requirements for dynamic and precise monitoring,a comprehensive monitoring system framework integrating the"Air-Space-Ground"integrated monitoring technology is proposed.This system combines multiple technical means such as satellite remote sensing,UAV remote sensing,ground sensor networks,and manual field surveys,covering five major monitoring themes:geological hazards,vegetation ecology,water environment,atmospheric environment,and soil environment.By designing a multi-level monitoring index system,the monitoring content,technical methods,and early warning thresholds are clearly defined.Finally,an application practice was conducted in a production coal mine within the Northern Shaanxi Coal Mining Area.The results show that during the period from January to December 2024:the surface deformation in the mining area reached the millimeter level(the cumulative deformation of Areas A-D ranged from-45.49 mm to-23.60 mm);land damage was mainly characterized by subsidence(1 254.70 hm2)and occupation(12.33 hm2);vegetation coverage was dominated by medium coverage(20.36%)and medium-high+high coverage(33.49%);groundwater was classified as Class V water;soil heavy metals generally met the risk control standards for soil pollution in agricultural land.A mine ecological environment monitoring system was developed based on the monitoring data,realizing the closed-loop management of"perception-analysis-early warning-decision-making".The research indicates that this system can achieve dynamic,real-time,and quantitative monitoring of the ecological environment in large-scale mining areas,providing effective data support and a decision-making basis for the ecological environment supervision of mining areas.

Abstract:The continuous evolution of land use structure in mining areas exerts a significant impact on ecosystem carbon storage.Quantifying the response mechanisms of carbon storage to land-use transitions under different development scenarios in coal mining regions is essential for achieving ecological restoration of energy bases and the goals of"carbon peak and carbon neutrality".Taking the Yushenfu Mining Area as the study region,based on remote sensing image data from 1990 to 2021,the InVEST model was used to quantitatively evaluate the characteristics of carbon storage changes across different periods.The PLUS model was applied to simulate land-use patterns in 2035 under three development scenarios—natural development,farmland protection,and ecological protection—while the Geodetector model was used to identify the dominant driving factors and their interactions influencing the spatial heterogeneity of carbon storage.The results indicate that:(1)From 1990 to 2021,the land-use pattern in the mining area underwent significant changes.The continuous expansion of construction land and the notable reduction in unused land,coupled with the increase in grassland and forest area,contributed to an overall upward trend in carbon storage.(2)Carbon storage responses varied considerably under different development scenarios,with the ecological protection scenario showing the highest increase(13.94%),whereas the farmland protection scenario showed a slight decline,indicating that the explicit parameterization of policy constraints plays a key regulatory role in simulations.(3)The spatial differentiation of carbon storage was jointly driven by natural and anthropogenic factors.In loess regions,it is primarily dominated by the intensity of human activities,whereas in sand-covered areas,it is constrained by natural factors such as precipitation.The study constructed a"policy-scenario-land-carbon storage"chain-coupled framework,revealing the natural-social synergistic mechanisms driving the evolution of carbon storage in semi-arid energy bases.This provides scientific support for ecological restoration,spatial planning optimization,and regional carbon management in coal resource development areas.

Abstract:Night light remote sensing can directly reflect the intensity of human activities and the trajectory of urban expansion in resource-exhausted cities,which is conducive to promoting the green and low-carbon transformation and development of resource-exhausted cities.This study takes Jiaozuo City,a typical resource-exhausted city in the Yellow River Basin,as the research object.Based on NPP/VIIRS-like night light remote sensing data,the identification of the built-up area of the city is carried out,the expansion and spatial structure evolution of the built-up area of Jiaozuo City from 2000 to 2024 are analyzed.The results show that:(1)The built-up area of Jiaozuo City has increased from 52 km2 to 119 km2.The expansion process presents three stages:"rapid expansion-fluctuating development-internal optimization",reflecting that the spatial structure of resource-exhausted cities has shifted from extensive outward expansion to intensive internal development.(2)The overall urban center of gravity shows a trend of shifting from"northwest to southeast",indicating the leading role of functional new areas in the reconstruction of urban structure under policy guidance.(3)SPSS univariate analysis shows that the expansion of built-up areas is highly positively correlated with permanent resident population,primary industry,GDP,and urbanization rate,and negatively correlated with raw coal output.(4)Geographic detector analysis indicates that natural condition factors are gradually weakening,and policy guidance,infrastructure construction and the aggregation of new industries have become the core driving forces for urban expansion and functional reconstruction.This study reveals the transformation path of typical resource-exhausted city from resource-driven to green and low-carbon development,providing a scientific basis for the green and low-carbon transformation and development of resource-exhausted cities.

Abstract:Red mud,as an alkaline solid waste,can achieve CO2 mineralization and storage through carbonation reactions.To investigate the wet carbonation characteristics of Bayer process red mud under the three factors of liquid-solid ratio,temperature,and CO2 flow rate,and to evaluate the carbon sequestration performance under various conditions,the loss on ignition and variation in pH value of the carbonated red mud were used as criteria to evaluate its carbon sequestration capacity.Kinetic fitting was applied to analyze the influence of different variables on the carbonation modification of red mud.The evolution patterns of carbonation products in red mud were investigated using techniques such as XRD,FT-IR,N 2 adsorption,and SEM,and the mechanism of wet carbonation in red mud was explored.The results show that under the optimal conditions of a liquid-solid ratio of 2.0∶1,a CO2 flow rate of 100 mL/min,and a reaction temperature of 30℃,the carbon sequestration rate of red mud can reach 5.68%,while the pH value of the red mud slurry gradually decreases from 9 and stabilizes at 6.45.Kinetic fitting results indicated that the degree of influence of variables on carbonation modification followed the order:liquid-solid ratio>CO2 flow rate>temperature.Characterization of carbonation products revealed an increase in the content of cancrinite and CaCO3.This is attributed to the participation of hydrogennet and AlO(OH)in the red mud during the carbonation modification process,releasing Ca2+,Na+,and OH-.Some Ca2+reacted with CO2 dissolved in water to form CaCO3,while the remaining Ca2+,Al3+,and Na+served as ion sources for the formation of cancrinite.Additionally,the carbonation reaction corrodes the alkaline minerals in red mud and generates carbonation products,resulting in an increased specific surface area of carbonated red mud compared to uncarbonated red mud.

Abstract:Coal mining subsidence wetlands are crucial to farmland ecosystems in Eastern China plains,serving as important water conservation areas and biodiversity reservoirs in agricultural regions.How to perform their ecological functions is essential to the regional farmland ecosystems.High-throughput sequencing technology and microbial co-occurrence network analysis were employed to investigate coal-mining subsidence wetlands of three different formation ages,including Quanrun(QR),Jiuli(JL)and Pan'an(PA),revealing the network characteristics and functions of abundant and rare microbial communities.The results show that the α-diversity indices(Shannon and Richness)of rare bacterial and abundant fungal taxa exhibited consistent trends,significantly increasing with wetland formation age(JL>QR>PA,P<0.05).The Jiuli group,representing the longest-formed coal-mining subsidence wetland,exhibited the significant network connectivity and other topological properties,indicating the highest network stability and complexity.The proportion of positive relationships among network nodes exceeded 50%,suggesting a cooperative trend among microbial taxa in the wetland.In the abundant bacterial networks,Proteobacteria accounted for 48.4%to 57.3%of the composition,serving as the dominant phylum.In the abundant fungal network,Ascomycota was the dominant phylum,accounting for 42.4%to 55.9%.Functional prediction based on FAPROTAX revealed that the sediment bacteria in coal-mining subsidence wetlands exhibited strong metabolic functions,which increased with wetland age.The dominant functional groups included chemoheterotrophy(11.78%to 17.27%),aerobic chemoheterotrophy(11.74%to 16.24%),and aromatic compound degradation(10.64%to 12.27%).Using Funguild to predict the functional roles of fungi in wetland sediments,the main functional group was found to be saprotrophs,with undefined saprotrophs accounting for approximately 20%relative abundance across all three wetland age groups.The high complex microbial networks and its multifunction of coal mining subsidence wetlands can facilitate ecological function restoration and reuse of these wetlands,holding significant importance for ensuring national food security and maintaining regional ecological safety.