Mine Waste Research Articles

Novel Use of Concentrated Solar Thermal Energy for Producing Highly Thermal Activated Materials for CCUS via Mineral Carbonation of Mine Waste

An assessment of the levelised cost and associated CO2-eq emissions for the thermal activation of serpentine mine tailings to be used as activated feedstock for CCUS processes via mineral carbonation, is reported here for the first time. Two main technological scenarios were assessed, based on either direct fuel sources heating (natural gas and hydrogen) or indirect, CST-based heating with a back-up burner and storage to provide continuous operations, for a 200 ton/hr of processed ore and a targeted roasting ore temperature of 700°C. For CST-based systems, 3 different solar input scales, namely 50, 150 and 450 MWth, were considered, and simulations performed over a year timeline with a 10 minutes time step, using Mt Keith Nickel mine in Western Australia as the reference location. The analysis highlighted that the proposed CST-hybrid plant layout can achieve similar cost to that of fuel-only cases with current Australian fuel prices for natural gas and hydrogen, with lower CO2-eq emissions, and a parity cost with fuel-only scenarios of some 16 USD/GJ. The proposed CST-hybrid plant layout was also identified as the potential, preferred route over direct CST routes to achieve 24/7 continuous heat supply while retaining fine tuning of activation temperature, given a very narrow temperature window of activation for the chosen mine tailings for mineral carbonation processes.

On The Potential Use of Copper-Modified Geopolymer Incorporating Lead-Smelter Slag for Thermal Energy Storage

Thermal energy storage (TES) system has been widely employed in concentrated solar power (CSP) plants to ensure the system efficiency. With excellent thermal characteristics, electrolytic copper powder (ECP), graphene oxide (GO) and lead-smelter slag (LSS) aggregate – a mining waste material, have been utilised in this study, aiming to fabricate metallurgical geopolymer material as a storage medium in the TES system. This paper investigated the effect of ECP contents (0, 5%, 10%, 15%, 20%) on the strength, specific heat, thermal conductivity and thermal stability of GO-engineered geopolymer mixes incorporating LSS aggregate. With 10% ECP inclusion, the flow rate and compressive strength improved significantly. Increasing ECP content improved the thermal conductivity but reduce specific heat of geopolymers. The results revealed that ECP was a promising component to be incorporated into geopolymer to enhance its physio-mechanical characteristics and thermal stability. The combination of ECP, GO and LSS to produce geopolymer materials for TES system can provide an eco-friendly solution to the CSP plants and the industry waste recovery.

Deep Learning-Based Calculation Method for the Dry Beach Length in Tailing Ponds Using Satellite Images

The dry beach length determines the hydraulic boundary of tailings impoundments and significantly impacts the infiltration line, which is crucial for the tailings dam. A deep learning method utilizing satellite images is presented to recognize the dry beach area and accurately measure the length of dry beaches in tailing ponds. Firstly, satellite images of various tailing ponds were gathered and the collection was enlarged to create a dataset of satellite images of tailing ponds. Then, a deep learning method was created using YOLOv5-seg to identify the dry beach area of tailing ponds from satellite images. The mask of the dry beach region was segmented and contour extraction was then carried out. Finally, the beach crest line was fitted based on the extracted contour. The pixel distance between the beach crest line and the dry beach boundary was measured and then translated into real distance by ground resolution. This paper’s case study compared the calculated length of dry beach with the real length obtained by field monitoring. The results of the case study showed that the minimum error of the method was 2.10%, the maximum error was 3.46%, and the average error was 2.70%, indicating high precision for calculating dry beach length in tailing ponds.

Initial pedogenic processes, mineral and chemical transformations and mobility of trace elements in Technosols on dumps of the former copper mines in Miedziana Góra and Miedzianka, the Świętokrzyskie Mts., south-central Poland

Technosols develop, among others, on dumps of former copper mines which became overgrown in spontaneous plant succession. The aim of the study was to determine the effect of pedogenesis on soil properties, mineral and geochemical composition, as well as operationally defined forms of As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn in Technosols developed on former mine dumps of the Miedziana Góra and Miedzianka former mining areas in south-central Poland. The studied Technosols were weakly developed soils with a simple soil profile comprising (1) C horizons in the subsoil and (2) O and A (or AC) horizons in the topsoil. The pHH2O of soils was 5.5–8.1. High soil pHH2O values were due to occurrence of carbonates (up to 25 %). The highest content of total organic carbon (TOC) and total nitrogen (TN) was found in O horizons as well as in A and AC horizons including buried A horizon. Soil magnetic susceptibility (χ) was 6.0–171.3 × 10–8 m3 kg−1. In each profile, the highest χ values were typical of A horizons including the buried A horizon. The most common minerals present in all profiles were quartz, kaolinite and mica. There were also admixtures of carbonates (dolomite, calcite), feldspars (orthoclase and albite), jarosite, goethite and traces of Fe sulphides. SEM-EDS analyses showed that soil substrate was subject to transformations of sulphides into Fe oxides. Moreover, pedogenic Cu carbonates were found in pores and on coarse materials. Technosols were enriched in Ag, As, Cd, Co, Cu, Hg, Mo, Ni, Pb, Sb, Zn, U and Th. The most mobile trace elements in the studied Technosols were Cd, Cu and Zn. Topsoil horizons of the studied soils contained a considerable share of Pb, Cu, Zn and Ni bound with soil organic matter. Arsenic was mostly bound with Fe oxides. First indicators of pedogenesis in the studied Technosols are (1) accumulation of soil organic matter in the topsoil followed by the decrease of soil pH and leaching of carbonates, (2) mineral transformations in the soil substrate (alteration of sulphides into Fe oxides and jarosite; origin of pedogenic Cu carbonates due to crystallization from soil solutions), (3) increase of magnetic susceptibility in the topsoil which may be an effect of atmospheric dust fall out or pedogenic transformation of Fe oxides into the phases with higher magnetic susceptibility and (4) the effect of soil properties, mineral composition and soil organic matter on geochemical forms of potentially toxic trace elements. The novelty value of the study lies in the identification of pedogenic Cu carbonates and the potential effect of soil-forming processes on the increase of topsoil magnetic susceptibility.

Study on the Evolution Characteristics of Dam Failure Due to Flood Overtopping of Tailings Ponds

There has been a frequent occurrence of tailing dam failures in recent years, leading to severe repercussions. Flood overtopping is an important element contributing to these failures. Nevertheless, there is a scarcity of studies about the evolutionary mechanisms of dam breaches resulting from flood overtopping. In order to fill this knowledge vacuum, this study focused on the evolutionary characteristics and triggering mechanisms of overtopping failures, utilizing the Heshangyu tailings pond as a prototype. The process of overtopping breach evolution was revealed by the conduction of small-scale model testing. A scaled-down replica of the tailings pond was constructed at a ratio of 1:150, and a controlled experiment was conducted to simulate a breach in the dam caused by water overflowing. Based on the results, the following conclusions were drawn: (1) The rise in water level in the pond caused the tailings to become saturated, leading to liquefaction flow and local slope sliding at the initial dam. If the sediment-carrying capacity of the overflowing water exceeded the shear strength of the tailings, water erosion would accelerate landslides on the slope, generating a sand-laden water flow. (2) The breach was primarily influenced by water erosion, which subsequently resulted in both laterally widened and longitudinally deepened breach. As the breach expanded, the sand-carrying capacity of the water flow increased, leading to a faster rate of failure. The breach process of overtopping can be categorized into four distinct stages: gully formation stage, lateral broadening stage of gully, cracks and collapse on the slope surface, and stable stage of collapse. (3) The tailings from the outflow spread downstream in a radial pattern, forming an alluvial fan. Additionally, the depth of the deposited mud first increased and subsequently declined as the distance from the breach grew. The findings of this research provide an important basis for the prevention and control of tailings dam breach disasters due to overtopping.

Multi-Level Characterization of Lignite Mine Waste by the Integration of Wide Wavelength Range Infrared Spectroscopy

Both the mineralogy and geochemistry of coal mine waste presents environmental and social challenges while simultaneously offering the potential source for recovery of metals, including critical raw materials (CRMs). Assessing these challenges and opportunities requires effective waste management strategies and comprehensive material characterization. This study deals with the integration of analytical data obtained from various portable sensor technologies. Infrared reflection spectroscopy (covering a wide wavelength range of 0.4 to 15 µm), and geochemical x-ray fluorescence (XRF) were utilized to differentiate between samples belonging to various geological lithologies and quantify elements of interest. Therefore, we developed a methodological framework that encompasses data integration and machine learning techniques. The model developed using the infrared data predicts the Sr concentration with a model accuracy of R2 = 0.77 for the testing dataset; however, the model performances decreased for predicting other elements such as Pb, Zn, Y, and Th. Despite these limitations, the approach demonstrates better performance in discriminating materials based on both mineralogical and geochemical compositions. Overall, the developed methodology, enables rapid and in-situ determination of coal mine waste composition, providing insights into waste composition that are directly linked to potential environmental impact, and the possible recovery of economically valuable metals.

Traceability and dispersion of highly toxic soluble phases from historical mine tailings: insights from Pb isotope systematics

Dispersion of potentially toxic elements associated with efflorescent crusts and mine tailings materials from historical mine sites threaten the environment and human health. Limited research has been done on traceability from historical mining sites in arid and semi-arid regions. Pb isotope systematics was applied to decipher the importance of identifying the mixing of lead sources involved in forming efflorescent salts and the repercussions on traceability. This research assessed mine waste (sulfide-rich and oxide-rich tailings material and efflorescent salts) and street dust from surrounding settlements at a historical mining site in northwestern Mexico, focusing on Pb isotope composition. The isotope data of tailings materials defined a trending line (R2 = 0.9); the sulfide-rich tailings materials and respective efflorescent salts yielded less radiogenic Pb composition, whereas the oxide-rich tailings and respective efflorescent salts yielded relatively more radiogenic compositions, similar to the geogenic component. The isotope composition of street dust suggests the dispersion of tailings materials into the surroundings. This investigation found that the variability of Pb isotope composition in tailings materials because of the geochemical heterogeneity, ranging from less radiogenic to more radiogenic, can add complexity during environmental assessments because the composition of oxidized materials and efflorescent salts can mask the geogenic component, potentially underestimating the influence on the environmental media.

Statistical Prediction of Liquefaction Potential in Mining Dump Areas of the Nagpur Region Using Standard Penetration Test (SPT) Data

Liquefaction could be a complicated and questionable but critical subject in ground building, particularly in places that are inclined to seismic tremors. Since of the visit seismic tremors in Nagpur, the developing mining industry makes it difficult to construct successful strategies for getting freed of mine squander. Seismic tremors are a major reason why structures fall flat, for the most part since of liquefaction, which does a parcel of harm to framework. This consider is for the most part approximately Nagpur, which is the third-largest city in Maharashtra and is growing very rapidly. The most objective is to form a arrange of the Nagpur mine dump ranges, figure out how likely it is that the dumps will liquefy, and make the information accessible for future investigate. The think about looks at soil liquefaction within the mine zone utilizing an SPT-N-based strategy. The liquefaction potential is measured utilizing the factor of security (FS) at distinctive soil levels that were found amid the think about. Standard Entrance Testing (SPT) was exhausted 11 test spots around the mine dumping range, and the comes about were composed down in boreholes. Modern investigate shows that the affectability to liquefaction is influenced by the number of SPT blows and the most extreme ground movement. The SPT-N esteem is balanced for the Cyclic Resistance Ratio (CRR), which appears that the soil's qualities and water table levels alter, and higher N values are ordinarily display. This implies that the soil contains a much lower chance of liquefying.

Application of sensing techniques for quantifying CO2 flux and dynamics in environments affected by the fundão dam collapse, mariana, Brazil

The District of Mariana in Minas Gerais, Brazil, witnessed one of the largest natural disasters in history. It involved the deposition of thousands of cubic meters of mining waste on soils near tributaries of the Doce River, resulting in degraded areas and a new environmental landscape. Numerous studies have focused on changes in soil microbiota and physical-chemical attributes. However, studies quantifying and analyzing carbon flux (FCO2) dynamics in the field using proximal sensors under varying temperatures, humidity conditions, and vegetation cover are scarce and nearly nonexistent. These studies could aid in monitoring the recovery of degraded areas and in understanding FCO2 dynamics in such environments. The aim of this study was to quantify and assess FCO2 dynamics using combined sensing techniques in diverse mining-affected areas, comparing different stages of recovery and their vegetation impact, and linking the results to pedoenvironmental factors. To achieve this, four areas were carefully selected and evaluated: affected pasture (AP), pasture (P) (non-affected), mix (MIX), and native trees (NT). In each area, readings were taken using an Infrared gas analyzer (IRGA) sensor, and temperature and soil moisture were measured. Additionally, soil samples were collected for chemical, physical, and biological characterization. Normalized Difference Vegetation Index (NDVI) assessments were conducted using satellites to evaluate vegetation cover. Non-parametric tests (Kruskal Wallis and Principal Component Analyses - PCA) were employed to evaluate differences between the areas and to assess the correlation among the environmental variables. The P area had the highest FCO2 and total organic carbon (TOC), differing significantly from the other site areas. Conversely, AP had the lowest FCO2 and was distinct from other sites. The MIX and NT areas had intermediate FCO2 and TOC values, which were statistically similar to each other. PCA identified distinct patterns in FCO2, soil temperature, and moisture. FCO2 was positively correlated with soil temperature and negatively correlated with moisture. There was a relationship between the biological variables microbial quotient (qMic), metabolic quotient (qCO2), COT, and FCO2. qMic reached the highest values in the MIX area, decreasing linearly from NT to P. Conversely, AP had the lowest qMic. qCO2 had the highest value in AP and NT. The proximal IRGA sensor effectively quantified FCO2 and differentiated mining tailing-affected areas. This assessment incorporated soil temperature, moisture sensors, vegetation index, and soil attribute data. The FCO2 levels were higher in P areas and lower in AP areas. Elevated FCO2 levels were correlated with a high soil temperature and low humidity. In AP, qMic was low, and qCO2 was high, indicating lower FCO2 levels. Conversely, P exhibited a higher FCO2. Higher NDVI values were correlated with elevated FCO2 in areas with specific vegetation cover during environmental recovery, while lower NDVI areas had lower FCO2 levels.

Remote sensing reveals trends in vegetative recovery and land cover transformation post-reclamation at tar creek superfund site

The harmful effects of mining waste on human and ecosystem health make reclamation of former mine sites an environmental management priority. However, field-based monitoring of reclamation requires significant investments of time, labor, and money. Remote sensing offers a less expensive alternative to field-based monitoring, but work is still needed to determine which metrics can be reliably estimated using remote sensing techniques. This study uses remote sensing to examine over 20 years of reclamation efforts at Tar Creek Superfund Site and to assess revegetation after site restoration. Using the Normalized Difference Vegetation Index (NDVI), we quantify key factors affecting vegetation recovery and stability after reclamation across 123 surface mining waste cleanup locations within Tar Creek. Leveraging long-term imagery from Landsat and high-resolution PlanetScope imagery, we combine time series analysis of vegetation regrowth and landcover change detection for a comprehensive picture of recovery at each site. Across all reclamation sites, the average recovery duration was 3.5 years, and average recovery rate was 0.1 NDVI year−1. After vegetative growth had plateaued, reclaimed sites had an average NDVI of 0.70. All reclamation areas were converted from majority barren landcover to vegetated landcover classes after reclamation, and vegetative stability at reclamation sites was high (70% of reclaimed area saw continuous vegetative cover from 2017 to 2023). These results demonstrate a strong potential for multi-method remote sensing techniques in tracking and explaining vegetation recovery after reclamation and represent a cost-effective approach for real-time monitoring of reclamation progress and outcomes.

Nature-Based Secondary Resource Recovery under Climate Change Uncertainty: A Robust Multi-Objective Optimisation Methodology

The management of high-volume (HV) waste poses a persistent challenge in sustainable materials management and represents an untapped opportunity in circular economy models. This study proposes a conceptual decision-making framework to operationalise a novel circular economy strategy for HV waste, involving temporary storage to facilitate nature-based secondary resource recovery. Using an illustrative case study of a candidate HV waste (legacy mining waste), we apply a robust multi-objective spatial optimisation approach at a national scale, employing an exact solution approach. Our methodology integrates mixed-integer linear programming to evaluate the economic viability, social benefits, and impacts of climate change uncertainties on nature-based solutions (NbS) implementation across diverse scenarios. The results demonstrate that NbS can enhance economic feasibility by incorporating carbon sequestration and employment benefits while demonstrating resilience against climate change projections to ensure long-term sustainability. The findings suggest that although NbS can improve the circular economy of HV nationally, it is essential to assess additional ecosystem services and address multiple uncertainties for effective macro-level sustainability assessment of HV management. This study offers a robust decision-making framework for policymakers and stakeholders to plan and implement nature-based circular economy strategies for HV waste streams at a national level while effectively managing long-term planning uncertainties.

Valorization of ladle furnace slag and functional enhancement of post-adsorption materials

Carbonating metallurgical slags plays a pivotal role in achieving efficient mineral CO2 sequestration and waste valorization.This research introduces a novel integrated approach that combines the carbonation of Ladle Furnace Slag (LFS) with the simultaneous degradation of Methyl Orange (MO) in synthetic water. The comprehensive characterization of LFS was conducted using X-ray Diffraction (XRD), X-ray Fluorescence (XRF), Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), Brunauer-Emmett-Teller (BET) analysis, and Scanning Electron Microscopy (SEM). The adsorption experiments reveal the high LSF capacity for MO degradation (149.25 mg/g) following pseudo-second-order kinetics (R2 = 0.99) and Langmuir isotherm (R2 = 0.98). The adsorption process was primarily governed by chemical and electrostatic interactions. Analysis of LFS-loaded MO indicated a reduction in Ca(OH)2phases, responsible for CO2mineralization and the formation of calcite (CaCO3). Furthermore, the study explored the reusability of LFS-MO composites through chemical and thermal modifications. Pyrolysis of carbonated LFS with KOH impregnation exhibited potential for regenerating Ca(OH)2phases, while thermal modification induced significant mineral and microstructural changes, creating new active sites at various temperatures. Additionally, the Fenton-like reaction followed by thermal modification resulted in a highly organized and microporous LFS structure with enhanced surface area and porosity. Moreover, modification with ZnSO4followed by thermal activation promoted the formation of ZnO nanoxides on the LFS surface. This research proposes an innovative carbonating approach for metallurgical slags and wastewater treatment, extending their utility and enhancing industrial sustainability. Carbonated LFS-MO composites hold promise for applications in construction, CO2capture, and wastewater treatment, thereby fostering sustainable industrial practices with ongoing research and development efforts.

Mechanical behavior, petrography and microstructural analysis of mining waste recycled bricks

Mechanical behavior, petrography and microstructural analysis of mining waste recycled bricks

Petrography and geomechanical properties of some mine waste rocks from the Tarkwaian Group in Ghana: implications for their use as aggregates in general engineering works

This research investigated some mine waste rocks from the southwestern part of the Tarkwaian Group in Ghana to check their suitability for general engineering works using petrography and geomechanical characteristics of the rocks. The rocks were subjected to a total of ten (10) tests, including Aggregate impact value (AIV), Aggregate crushing value (ACV), Loss Angeles abrasion (LAA), Specific gravity (SG), and Water absorption (WA), as well as flakiness and elongation index, slake durability (SD), chloride test (CT), sulphate test (ST), and ten percent fines (TPF). The tests were carried out per the American Society for Testing and Materials guidelines (ASTM). The following average test results were obtained: AIV (7.12%), ACV (15.60%), LAA (23.16%), TPF (269.7 kN), sulphate (0.0215%), chloride (0.00123%), flakiness (39.5%) and elongation (39.4%). The mine waste rocks are dominated by quartz and sericite, according to the petrographic examination and thus, can be classified as quartzites. Except for the flakiness and elongation index tests, all the results were consistent with the ASTM standards. The analysis carried out on the selected mine waste rocks from the southwestern part of the Tarkwaian Group could be catastrophic for heavy engineering works such as roads, bridges, and heavy buildings but can be used for pavements, lightweight buildings, monuments, and decoratives due to the percentage of quartz present to compensate for the weakness posed by the sericite.

Experimental Study on Influence of Lime on Cross-Scale Characteristics of Cemented Backfill with Multiple Solid Wastes.

The utilization of industrial solid waste in mines is an important approach to resource utilization. The backfill material in mines is mainly composed of solid waste, which plays a supporting role. The excitation effect of lime on phosphogypsum and fly ash in backfill was studied in this paper. The macroscopic and microscopic characteristics of the backfill material were tested using uniaxial compression, nuclear magnetic resonance, scanning electron microscopy, and electrochemical techniques, and a relationship model was established between them. Furthermore, the influence of industrial solid waste on the properties of the backfill material under the action of lime and the hydration mechanism between different industrial solid wastes were studied. The results show that (1) under the action of lime, fly ash reacts with lime to produce C-S-H and C-A-H, and then C-A-H reacts with phosphogypsum to produce AFt. (2) The excess phosphogypsum also fills the pores. Therefore, 1.8% lime reduces the porosity of the backfill by 17.88% and increases the strength by 21.57%. (3) The cross-scale relationship shows that strength is inversely proportional to each type of pore content and fractal dimension, and it logarithmically increases with impedance at different frequencies. The lower the frequency, the stronger the relationship is. (4) This study indicates that industrial solid waste is a suitable cement replacement.

Analysis of heavy metal content and microbial characteristics in the pioneer plant soil system of typical manganese tailing ponds in Guangxi

Analysis of heavy metal content and microbial characteristics in the pioneer plant soil system of typical manganese tailing ponds in Guangxi

Optimal Machine Learning Model to Predict Demolition Waste Generation for a Circular Economy

A suitable waste-management strategy is crucial for a sustainable and efficient circular economy in the construction sector, and it requires precise data on the volume of demolition waste (DW) generated. Therefore, we developed an optimal machine learning model to forecast the quantity of recycling and landfill waste based on the characteristics of DW. We constructed a dataset comprising information on the characteristics of 150 buildings, demolition equipment utilized, and volume of five waste types generated (i.e., recyclable mineral, recyclable combustible, landfill specified, landfill mix waste, and recyclable minerals). We applied an artificial neural network, decision tree, gradient boosting machine, k-nearest neighbors, linear regression, random forest, and support vector regression. Further, we derived the optimal model through data preprocessing, input variable selection, and hyperparameter tuning. In both the validation and test phases, the “recyclable mineral waste” and “recyclable combustible waste” models achieved accuracies (R2) of 0.987 and 0.972, respectively. The “recyclable metals” and “landfill specified waste” models achieved accuracies (R2) of 0.953 and 0.858 or higher, respectively. Moreover, the “landfill mix waste” model exhibited an accuracy of 0.984 or higher. This study confirmed through Shapley Additive exPlanations analysis that the floor area is the most important input variable in the four models (i.e., recyclable mineral waste, recyclable combustible waste, recyclable metals, and landfill mix waste). Additionally, the type of equipment employed in demolition emerged as another crucial input variable impacting the volume of recycling and landfill waste generated. The results of this study can provide more detailed information on the generation of recycling and landfill waste. The developed model can provide precise data on waste management, thereby facilitating the decision-making process for industry professionals.

Evaluation of Mechanical Properties and Hydrophilicity of Alkaline and Plasma Treated Abaca Fiber Epoxy Composite with Mineral Waste as Fillers

Evaluation of Mechanical Properties and Hydrophilicity of Alkaline and Plasma Treated Abaca Fiber Epoxy Composite with Mineral Waste as Fillers

A novel alkali-slag cemented tailings backfill: Recycling of soda residue and calcium carbide slag

In order to address the safety and environmental concerns associated with high disposal cost and low disposal rate associated with mine tailings, low-cost cemented paste backfills (CPBs) were prepared from solid wastes such as calcium carbide slag (CS), soda residue (SR), ground granulated blast-furnace slag (GGBS) and iron tailings (TA) in this study. The effects of mass concentration of filling slurry, GGBS content, activator dosage, and SR proportion on the mechanical properties of CPBs were studied. The results showed that a flow of 235.8 mm and 28-d compressive strength of 2.3 MPa for the freshly mixed slurry could be attained with 75 % mass concentration, 14 % GGBS content, an activator-to-binder ratio of 0.4, and a CS-to-SR ratio of 3:7. The strength of CPBs first increased and then decreased with the increasing of activator dosage or SR proportion contents, and reached the optimal value for the activator-to-binder ratio of 0.4 and SR of 70 % – 75 %. Microstructural analyses by TG-DTG, FTIR, SEM-EDS, and XRD revealed that mainly C-(A)-S-H gel, hydrotalcite (HT), and Friedel's salt (FS) were formed as the hydration products in CS-SR synergistically-activated GGBS paste. The Ca2+ dissolved from CS facilitated GGBS hydration to generate the C-(A)-S-H gels and further reacted with Cl− in SR and [Al(OH)6]3− dissolved from GGBS to generate FS. The combined effect of C-(A)-S-H gel and FS enhances the strength of CPBs. When the percentage of SR is in the range of 70–75 %, the synergistic excitation of slag by alkali slag and calcium carbide slag is superior, and the matrix structure is denser.

Respiratory Changes in Children Exposed to Mining Waste Dust in Brumadinho, Minas Gerais, Brazil. Bruminha Project

Respiratory Changes in Children Exposed to Mining Waste Dust in Brumadinho, Minas Gerais, Brazil. Bruminha Project