Search Results (45)

Electrostatic separation is a promising technology for the recovery of valuable metals from electronic waste, particularly from printed circuit boards (PCBs). This study explores the application of electrostatic separation for the selective recovery of metallic and non-metallic fractions from crushed PCBs (PCBs). The process exploits the differences in electrical properties between conductive metals and non-conductive polymers and ceramics, facilitating their separation through applied electric fields. The raw materials were pre-treated via mechanical comminution using shredders and hammer mills to achieve an optimal particle size distribution (<3 mm), which enhances separation efficiency. Ferrous materials were removed prior to electrostatic separation to improve process selectivity. Key operational parameters, including particle size, charge accumulation, environmental conditions, and separation efficiency, were systematically analysed. The results demonstrate that electrostatic separation effectively recovers high-value metals such as copper and gold while minimizing material losses. Additionally, the process contributes to the sustainability of e-waste recycling by enabling the recovery of non-metallic fractions for potential secondary applications. This work underscores the significance of electrostatic separation as a viable technique for e-waste management and highlights optimization strategies for enhancing its performance in large-scale recycling operations. Full article

This study investigates a lithium-ion battery failure in heating insoles that ignited during normal walking while powered off. Through comprehensive material characterization, electrical testing, thermal analysis, and mechanical gait simulation, we systematically excluded electrical or thermal abuse as failure causes. X-ray/CT imaging localized the ignition source to the lateral heel edge of the pouch cell, correlating precisely with peak mechanical stress identified through gait analysis. Remarkably, the cyclic load was less than 10% of the single crush load threshold specified in safety standards. Key findings reveal multiple contributing factors as follows: the uncoated polyethylene separator’s inability to prevent stress-induced internal short circuits, the circuit design’s lack of battery health monitoring functionality that permitted undetected degradation, and the hazardous placement inside clothing that exacerbated burn injuries. These findings necessitate a multi-level safety framework for lithium-ion battery products, encompassing enhanced cell design to prevent internal short circuit, improved circuit protection with health monitoring capabilities, optimized product integration to mitigate mechanical and environmental impact, and effective post-failure containment measures. This case study exposes a critical need for product-specific safety standards that address the unique demands of wearable lithium-ion batteries, where existing certification requirements fail to prevent real-use failure scenarios. Full article

The tungsten deposits in Mongolia have the potential to be exploited as an alternative source to alleviate the risk due to the monopolization in the global production of such a critical metal. However, it is challenging to develop an efficient mineral processing method that can complement the supply based on the currently available energy resources in Mongolia. Therefore, the present study investigated the range of energy required for the beneficiation of tungsten ores, including theoretical assumptions and practical evaluation for two processes in Mongolia. The range of energy consumption was 0.12 to 2.21 kWh/t for crushing and 0.29 to 4.62 kWh/t for grinding regarding the range of Kick’s constant 0.2–0.6 kWh/t and Bond work index 7–17 kWh/t, respectively. The most dominant impact factor in the comminution was the product size. The evaluation of 18 different comminution–flotation circuits indicated a range of required energy from 362 kWh to 8298 kWh. The maximum values of energy consumption for mineral processing of Erdene-soum and Khovd Aimag tungsten ore were 6280 and 6355 kWh. An estimation regarding the energy demand (6355 kWh) and supply energy for the process of Khovd Aimag ore was conducted to propose a suitable system of renewable energy resources using the power pinch analysis method. Full article

Narrow-vein deposits have historically been valuable in producing gold, tin, copper, silver, lead, and zinc. Developing these mineral resources is sometimes challenging due to economic and safety concerns. Given the small to medium scale of production, narrow-vein mining could be labor-intensive with increased exposure of the miners to hazardous conditions. A safe, mechanized, efficient, and sustainable method can be invaluable to operators looking to develop narrow-vein mineral resources. The comminution circuit (consisting of crushing and grinding) is downstream of most mineral resources’ extraction processes. Comminution is significantly energy-intensive, consuming almost half of the energy supplied to a mineral-processing activity. Thus, several engineers have investigated the continued development of sustainable narrow-vein mining and comminution technologies. This journal article focuses on a developed innovative, safe, mechanized, and continuous narrow-vein mining technology that has further made accessing narrow-vein deposits more economically feasible and efficient while reducing dilution of ores. The article also extensively presents the impact of this new mining approach on the daily production of the operation and the observed particle size distributions of the day-to-day operational output. Subsequently, the article evaluates and presents the impact of the new procedure of mineral extraction on the resultant size of the cuttings generated as well as the expected energy input of the comminution process downstream of the mining operation. The novelty of the mining method upon which this work is based is improved capital expenditure and reduced dilution. With the new mining method, otherwise-uneconomic narrow-vein deposits can be accessed. Full article

To enhance the performance of the combined high-pressure grinding roller (HPGR) and tower mill (TM) process for −1 mm particle size, this study addresses the key technical challenges of insufficient material quantity (<100 kg) and complex experimental procedures in HPGR closed-circuit crushing tests by proposing a novel circulating load prediction method based on the principle of mass balance and first-order crushing kinetics. Using a side-flanged HPGR WGM 6020 installation, systematic −1 mm HPGR closed-circuit crushing tests were conducted on seven different ore samples under three specific pressing forces, with detailed characterization of the dynamic variations in product size distribution, specific energy consumption, and circulating load during each cycle. The results demonstrate that within the specific pressing force range of 3.5 N/mm² to 4.5 N/mm² when the crushing process reaches equilibrium, the circulating load stabilizes between 100% and 200%, while the specific energy consumption is maintained within 1–2.5 kWh/t. Notably, at the specific pressing force of 4.5 N/mm², both the circulating load and specific energy consumption rapidly achieve stable states, with ore characteristics showing no significant influence on the number of cycles. To validate the model accuracy, additional samples were tested for comparative analysis, revealing that the deviations between the model-predicted −1 mm product content and circulating load and the experimental results were less than ±5%, confirming the reliability of the proposed method. Full article

Lithium-ion battery cells are the fundamental components of all Energy Storage Systems (ESSs) used in electric vehicles (EVs). Increasing concerns about safety issues, particularly the response of battery cells to mechanical crushes that can lead to internal short circuits (ISCs) and potential thermal runaway (TR), necessitate detailed investigation. To evaluate the response of a battery under abuse conditions, a homogeneous finite element (FE) model of a battery cell was developed. This model employs a simplified representation of a battery cell where the internal properties are assumed to be uniform throughout the entire cell. A full factorial approach was utilized to determine the homogenized jellyroll material characteristics. A detailed FEM serves as a benchmark for validating the homogeneous battery model. While requiring less computational effort, the homogeneous model maintains sufficient accuracy, making it suitable for modelling entire battery packs, thanks to the reduced number of elements. Full article

This article refers to the aspects of energy consumption and comminution effectiveness in the mineral processing sector through the evaluation of limestone crushing in a high-pressure grinding roll. The investigative program included a series of crushing tests on limestone samples in a laboratory High Pressure Grinding Rolls (HPGR) press device. The tests were carried out in the scheme of factorial experiment with three levels of pressure (Fsp) and three levels of material moisture (M). The major finding was to determine energetic models referring to consumption of energy and reduction in Bond work index Wi, designed as a function of operational pressure in HPGR and material moisture. The other investigative results encompassed models on fineness effectiveness and throughput. The models appeared statistically significant and showed relationships both with pressure and moisture. The results of the investigations showed that Bond work index Wi decreases when the Fsp increases, but Wi increases as the moisture content decreases. The calculated models also showed an increase in unit energy consumption in the press together with increasing of Fsp and moisture. The models for throughput and finest particle content in HPGR product showed in turn that increasing of Fsp and M results in decreasing of the productivity. Full article

Open-pit mining remains the dominant method for copper extraction in current operations, with blasting playing a pivotal role in the efficiency of downstream processes such as loading, hauling, crushing, and milling. This study assesses the impact of surface blast design parameters on the performance of a comminution circuit processing a copper-bearing ore. The analysis focuses on important design parameters such as burden, spacing, stemming, and powder factor, evaluating their influence on the fragment size distribution and downstream comminution circuit performance. Using the Kuz-Ram model, four novel blast designs are compared against a baseline to predict the size distribution of rock fragments (X80). Key performance indicators throughput and specific energy consumption are calculated to evaluate the comminution circuit performance. Results demonstrated that reducing the X80 from 500 mm to 120 mm led up to a 20% increase in throughput and a 29% reduction in total specific energy consumption. Furthermore, achieving finer particle sizes through more intensive blasting contributed to a reduction in total operating costs by up to 12%. These findings provide valuable insights for optimizing blast design to improve comminution circuit performance, contributing to sustainable mining practices by reducing energy consumption, operating costs, and the environmental footprint of mining operations. Full article

The Mine-to-Mill (M2M) approach aims to enhance efficiency and reduce costs in the mineral processing industry by optimizing the mining and processing stages. M2M integrates orebody characterization, blasting, and downstream processes, such as grinding and flotation, demonstrating that material fragmentation directly impacts downstream efficiency. This review studies the development and applications of fragmentation models in M2M integration and optimization, finding that their study is divided into three phases. In the first, the potential of M2M is investigated through simulation models that improve fragmentation in blasting to optimize grinding. The second focuses on the practical application of these models in mines, while the third phase integrates geometallurgical data into mine block models, enhancing production planning and selective ore extraction. The M2M integration has demonstrated significant improvements in plant performance, particularly in increasing grinding efficiency through optimized blast fragmentation. The literature also emphasizes the role of optimizing crushing and grinding conditions through models and circuit adjustments to enhance performance and reducing energy consumption. Geometallurgy plays a crucial role in plant optimization by identifying areas with better processing characteristics and adjusting operating parameters to maximize efficiency. Recent studies have shown how the implementation of integrated models can increase the profitability and sustainability of mining operations. Full article

This study presents a hydrometallurgical process for the leaching and recovery of tin from waste-printed circuit boards (wPCBs). The process aims to separate and recover tin from filter dust produced during the crushing of wPCBs in a recycling facility. The separation of the metallic and non-metallic fractions was carried out by gravimetric separation. The metallic fraction consisted mainly of Cu (23.8%), Fe (17.8%), Sn (12.7%), Pb (6.3%), and Zn (3.4%). During the leaching tests, the effects of (a) HCl concentration (2, 4, 6 M), (b) pulp density (0.1, 0.2, 0.3 g/mL), and (c) the addition of NaCl (no addition, 1 M, 3 M) were investigated. All tests were conducted at an ambient temperature without agitation. A leaching efficiency of 78.2% was obtained during leaching with 6 M HCl and 0.3 g/mL pulp density, while 94.8% of tin was leached under the same conditions with the addition of 3 M NaCl. Tin was recovered from the pregnant solution by addition of 2 M NaOH at pH = 3.0, with an efficiency of 97.4%. The precipitate, despite being amorphous, was easily filtered and it consisted of 64.7% Sn and less than 2% of impurities. The proposed process consists of a leaching stage with 6 M HCl, 3 M NaCl, 0.3 g/mL pulp density, and a contact time of 24 h, and a recovery stage by chemical precipitation at pH = 3.0. The total tin recovery of the suggested process was 92.3%. Full article

Cone crushers have a central role in the processing of quarry rocks, besides coarser ore preparation in several mineral processing plants. This is particularly true in the case of Itabirite iron ore preparation plants in Brazil, so optimizing their performance is of central importance for reaching maximum productivity of the circuit. The work presents results of modeling the HP500 cone crusher in operation in an industrial plant in Brazil (Minas Rio), from surveys carried out over a few years with different feeds and crushing conditions. A version of the Andersen–Whiten cone crusher model was implemented in the Integrated Extraction Simulator featuring a non-normalizable breakage response and a fit-for-purpose throughput model. The results demonstrate the good ability of the model to predict crusher performance when dealing with different closed-side settings and feed size distributions. Full article

The gyratory crusher is one of the most important mineral processing assets in the comminution circuit, and its production performance directly impacts the circuit throughput. Due to its higher energy utilisation rate for rock breakage than semi-autogenous (SAG/AG) milling, it is a common practice in operations to promote and optimise primary crushing before the downstream capacity can be enhanced. This study aims to develop a discrete element modelling (DEM) and multibody dynamics (MBD) cosimulation framework to optimise the performance of the gyratory crusher. An MBD model was initially established to simulate the gyratory crusher’s drivetrain system. A GPU-based DEM was also developed with a parallel bond model incorporated to simulate the particle breakage behaviour. Coupling of the MBD and GPU-based DEM resulted in a cosimulation framework based on the Function Mock-up Interface. An industrial-scale gyratory crusher was selected to test the developed numerical framework, and results indicated that the developed method was capable of modelling normal and choked working conditions. The outcome of this study enabled more realistic gyratory crusher improvement and optimisation strategies for enhanced production. Full article

The dynamics of milling circuits, particularly those involving Semi-Autogenous Grinding (SAG) mills, are not adequately studied, despite their critical importance in mineral processing. This paper aims to investigate the dynamic behavior of an SAG mill pebble recycling circuit under varying feed ore conditions, focusing on both uncontrollable parameters (such as ore hardness) and controllable parameters (including circuit layout and pebble crusher configurations). The study is carried out with Simulink dynamic simulations. Our findings reveal several key insights. Firstly, plant designs based solely on static simulations may not be adequate for large or complex circuits, as they fail to account for the dynamic nature of milling processes. Second, incorporating stockpiles after pebble crushing can effectively mitigate the impact of dynamic fluctuations, leading to more stable circuit performance. Third, different circuit layouts can facilitate easier maintenance and operational flexibility. Notably, finer pebble crushing can enhance circuit throughput by 5% to 10%. Full article

Crushing is a critical operation in mineral processing, and its efficient performance is vital for minimizing energy consumption, maximizing productivity, and maintaining product quality. However, due to variations in feed material characteristics and safety constraints, achieving the intended circuit performance can be challenging. In this study, a centralized control strategy based on a finite state machine (FSM) is developed to improve the operations of an iron ore crushing circuit. The aim is to increase productivity by manipulating the closed-side-setting (CSS) of cone crushers and the speed of an apron feeder while considering intermediate storage silo levels and cone crusher power limits, as well as product quality. A dynamic simulation was conducted to compare the proposed control strategy with the usual practice of setting CSS to a constant value. Four scenarios were analyzed based on variations in bond work index (BWI) and particle size distribution. The simulation results demonstrate that the proposed control strategy increased average productivity by 6.88% and 48.77% when compared to the operation with a constant CSS of 38 mm and 41 mm, respectively. The proposed strategy resulted in smoother oscillation without interlocking, and it maintained constant flow rates. This ultimately improved circuit reliability and predictability, leading to reduced maintenance costs. Full article

The plastic properties for the jellyroll of lithium-ion batteries showed different behavior in tension and compression, showing the yield strength in compression being several times higher than in tension. The crushable foam models were widely used to predict the mechanical responses to compressive loadings. However, since the compressive characteristic is dominant in this model, it is difficult to identify distributions of the yield strength in tension. In this study, a simplified jellyroll model consisting of double-layer windings was devised to reflect different plastic characteristics of a jellyroll, and the proposed model was applied to an 18650 cylindrical battery under compressive loading conditions. One winding adopted the crushable foam model for representing the compressive plastic behavior, and the other winding adopted the elastoplastic models for tracking the tensile plastic behavior. The material parameters in the crushable foam model were calibrated by comparing the simulated force–displacement curve with the experimental one for the case where the cell was crushed between two plates when the punch was displaced by 7 mm. A specific cut-off value (10 MPa) was assigned to a yield stress limit in the elastoplastic model. Further, the computational model was validated with two more loading cases, a cylindrical rod indentation and a spherical punch indentation, as the punch was displaced by 6.3 mm and 6.5 mm, respectively. For three loading cases, deformed configurations and plastic strain distributions were investigated by finite element analysis. It was found that the proposed model clearly provides the plastic behavior both in compression and tension. For the crush simulation, the maximum compressive stress approached 222 MPa in the middle of the jellyroll, and the maximum effective plastic strain approached 60% in the middle of the layered roll. For indentation with the cylindrical and the spherical punch, the maximum effective plastic strain approached 52% and 277% in the layered roll, respectively. The local crack or location of a short circuit could be predicted from the maximum effective plastic strain. Full article