Laboratory Ball Mill Research Articles

Comparison of surface physicochemical properties of spodumene and feldspar using different grinding media: Implications for flotation separation

Grinding processing after crushing is a common practice in mineral processing circuits involving flotation, and achieving selective liberation of target minerals by grinding is a prerequisite for successful flotation. In this study, the surface characteristics and the floatability of spodumene and feldspar particles produced by laboratory ball and short cylinder mills were determined by XRD, SEM, AFM, XPS analysis, DFT calculation, and flotation experiment. Compared with ball-milled particles, spodumene ground with short cylinder media had more exposed {110} cleavage planes, while feldspar under the same condition had more exposed {110} and {201} cleavage planes. Additionally, the amount of Al sites and the roughness of spodumene and feldspar after grinding by short cylinder media were higher than those of ball-milled particles. Micro-flotation experiments and XPS analysis further indicated that, although the co-adsorption of NaOL/DDA on the surface of spodumene is stronger than feldspar under both milling media, the flotation separation efficiency of spodumene and feldspar remained higher with short cylinder grinding media. Therefore, this study is expected to provide more reference value and theoretical guidance for the development of selective flotation separation of spodumene and feldspar from the perspective of grinding.

Scaling Energy Transfer in Ball Mills: A Scale-Agnostic Approach through a Universal Scaling Constant

Ball mills are widely used for size reduction in mineral processing, but effective scaling from laboratory to industrial scale remains challenging. This study introduces a novel scaling constant approach to replicate energy transfer to ore during milling across different scales by adjusting rotational speed and grinding medium size distribution. The scaling constant encapsulates parameters like the number of balls per working area, rotational speed, and an average ball’s maximum potential and kinetic energies. Experiments were conducted using a laboratory ball mill with interchangeable drum sizes (300, 400, and 500 mm) and a Design of Experiments methodology. Statistical analysis revealed that the scaling constant was more effective at maintaining consistent specific energy and energy per rotation across scales than size reduction, especially in dry milling. Wet milling results showed no significant differences in all metrics across scales. The dominant charge motion shifted from centrifuging to cascading as the mill diameter increased, highlighting the complex scaling dynamics. While the scaling constant shows promise for maintaining energy utilization, additional factors like charge motion and particle breakage mechanisms should be considered. The findings provide insights for improving ball mill design and optimization in mineral processing.

Calibrating the Digital Twin of a Laboratory Ball Mill for Copper Ore Milling: Integrating Computer Vision and Discrete Element Method and Smoothed Particle Hydrodynamics (DEM-SPH) Simulations

This article presents a novel approach to calibrating the digital twin of a laboratory mill used for copper ore milling. By integrating computer vision techniques for real-time data extraction and employing DualSPHysics simulations for various milling scenarios, including balls only, balls with ore, and balls with slurry, we achieve a high degree of accuracy in matching the digital twin’s behavior with actual mill operations. The calibration process is detailed for mills with three different diameters, highlighting the adjustments in simulation parameters necessary to account for the absence of ore. Understanding the dynamics between the suspension within the mill and the operation of the grinders is crucial for the future improvement of the grinding process. This knowledge paves the way for optimizing the process, not only in terms of the quality of the end product but primarily in terms of energy efficiency. A profound understanding of these interactions will enable engineers and technologists to design mills and grinding processes in a way that maximizes efficiency while minimizing energy consumption.

Some aspects on grindability of feldspar ore using ball mill

Egyptian feldspar ores are usually of low grade and need beneficiation to improve their grade for industrial applications. Therefore, feldspar should be ground to a reasonable liberation degree prior to beneficiation processes. Mineralogical studies showed that a good degree of liberation is below 0.25 mm. This work aims to optimize the grinding parameters for an Egyptian feldspar ore that ensures maximum production of size −250 + 45 µm and minimum % − 45 µm. Grinding was performed using a laboratory ball mill. The results displayed that the grinding performance was increased with decreasing the solid content with U between 0.5 and 1. A high milling rate was achieved at ball filling 20–30%. The ideal ball-filling ratio was determined to be 25%, with less production of fines. Hence, it was decided to crush the feed to less than 2 mm before grinding with 36.6 mm balls to reduce fines.

Production of a sustainable cement through the usage of clay as binding element

The formulation of a calcined clay-based hydraulic binder is an innovative solution for reducing the carbon footprint in the construction industry. This binder is made from calcined clay, a natural and abundant material that does not require high-temperature firing in the 400C to 950C range. In our study, we worked respectively under the following temperatures: 550C, 650C, 750C and 850C, unlike traditional binders whose clinker is fired at a temperature of around 1450C. The blaine tests showed that the binder had been well ground, resulting in a much finer binder. We then obtained various blaines varying between 5000 and 8000 Cm2/g, unlike the blaine of the traditional binder, which is 3800 Cm2/g; the residue rate is very high compared with that of the traditional binder, due to the grinding carried out in a laboratory ball mill. The results of resistance tests at 30% gave 34.8, 48.8, 36.5 and 46 respectively; those at 40% gave 42.7, 45.4, 44.4 and 44.8, while the resistance of traditional binder gave 42.5. In other words, we obtained strengths comparable to those of the traditional binder. In addition, it was found that the manufacture of calcined clay-based hydraulic binders reduces CO2 emissions compared with traditional binders, which emit very high levels of CO2, making the production of calcined clay-based binders a more environmentally-friendly option for the cement industry. The financial assessment carried out at the end of this study shows that the production of a calcined clay-based binder is more economical than that of a traditional binder (Portland cement).

Multi-source unsupervised domain adaptive mill load forecasting method based on deep learning and fusion features

In the grinding industry, accurate prediction of the mill load is the key to enhancing plant profitability and reducing mill failures. After the condition changes, the model is usually mismatched, and the true label cannot be obtained in time. To solve this problem, we propose a multi-source unsupervised domain adaptation model based on deep learning and fusion features (MUDA_DF), which is suitable for predicting multiple mill load parameters. Considering that the information contained in the data of a single working condition is insufficient to completely cover the information of the unmodeled working condition, we introduce multiple source domains into the model, which can improve the generalization of the model. Since the special features of the source domain also contain useful information, we use the features after the fusion of special features and common features for regression prediction. By designing multiple loss functions, we achieve the prediction of three mill load parameters in unknown operating conditions: material-to-ball volume ratio (MBVR), pulp density (PD), and charge volume ratio (CVR). Experiments were carried out on data sets collected by a laboratory ball mill. Compared with the traditional mill load soft measurement method, the R2 of this method can reach above 0.9 and the highest can reach 0.99, which proves the effectiveness of this method.

Developing a digital twin for a laboratory ball mill operation – a step towards mining metaverse

Digital twins (DTs) are transforming business operations across industries through accurate replication of physical entities using the Internet of Things and big data analytics. Despite booming progress in the manufacturing, aerospace and buildings sectors, the adoption of DTs in the minerals industry has been slow, and integration with efficient visualisation and user interactions has not been fully optimised to achieve maximum fidelity and usability. One promising avenue for enhancing DT capabilities is the utilisation of extended reality (XR) technologies, which also hold great potential for realising an industrial metaverse where real-world business activities can be conducted in a virtual space. This article proposes a cost-effective and scalable approach to developing a DT with real-time monitoring and control capabilities for a ball mill operation, a widely used processing equipment in the minerals industry. The case study showcases two approaches with different levels of system integration by leveraging serious game development platforms, toolkits and workflows.

Determination of parameters for wet grinding of phosphates in a laboratory ball mill and classification in a hydrocyclone

Determination of parameters for wet grinding of phosphates in a laboratory ball mill and classification in a hydrocyclone

An Improved Understanding of Chalcopyrite Leaching Mechanisms: The Influence of Anisotropic Crystal Planes

Chalcopyrite (CuFeS2) particles, exposing anisotropic crystal planes during the grinding process, possess comprehensive surface properties that affect their leaching behaviors. In order to investigate the influence of anisotropic crystal planes on the leaching mechanisms, CuFeS2 particles with anisotropic crystal planes were produced by employing three-head laboratory grinder mill (TM), rod mill (RM), and ball mill (BM) and were then leached in a sulfuric acid solution at pH = 1. Based on the XRD, SEM, XPS, and simulation results, (112), (102), (312), (110), (116), (100), and (001) planes were mainly exposed on the CuFeS2 surface during the crushing and grinding process. In addition, fewer (112), (102), (312), and (110) planes but more (116), (100), and (001) planes were exposed on the CuFeS2 samples in the TM method than in the RM and BM methods. Since the leaching rates were in the order of (001) > (100) > (116) > (110) > (312) > (102) > (112) planes, the Cu extractions followed an order of TM > RM > BM. This study, therefore, provides an excellent theoretical basis for the effect of anisotropic crystal planes on CuFeS2 leaching, further improving the understanding of CuFeS2 leaching mechanisms.

Concrete Modification for Hot Weather Using Crushed Dolomite Stone

Crushed dolomite stone can be used as a part of concrete for hot weather. Fine dolomite as a filler is not commonly included in Portland cement. In this paper, the properties of a blended binder based on Portland cement and dolomite filler are presented. Dolomite filler was obtained from dust grains by mechanical activation in a laboratory ball mill to increase the specific surface area and its chemical activity. It is shown that the impact of mechanical activation allows to obtain dolomite filler with a median particle size of 1.4 μm and a specific surface area of 639.9 m2/kg. The content of dolomite filler in Portland cement was 10, 30 and 50%. The main properties of blended cements, i.e., the standard consistency, setting time, compressive strength, average density, and drying shrinkage, were determined on pastes. The mineralogical composition of the hydrated pastes was determined by XRD at 28 days. The presence of dolomite filler at levels higher than 10% decreases the compressive strength of blended cements. The dolomite filler decreases the water demand, shortens the setting time, and mitigates the development of drying shrinkage in the blended binder. To prevent concrete cracking, the application of dolomite filler in blended cement is relevant in hot weather due to its reduced drying shrinkage.

Effect of duration and type of grinding on the particle size distribution and microstructure of natural pumice with low pozzolanic reactivity

Pumice, with low pozzolanic reactivity, was ground for 1, 3, and 6 h with a laboratory ball mill in dry conditions and it was ground for 1 h in wet conditions via an industrial-scale ball mill. Based on derivative particle distribution, grinding for longer periods led to the disappearance of bimodal distribution and the development of unimodal distribution. Furthermore, the phase characterization, assessed through XRD, demonstrated appreciable changes in intensities of the peaks of quartz and dachiardite. The extension of grinding time resulted in a significant uptake at the early-age lime consumption and evolution of hydration heat. According to SEM images, the number of particles between 10 and 20 μm was less in the powder ground for 3 and 6 h. Moreover, it was found that the prismatic shapes of raw pumice tended to transform to spheroid shapes after prolonged grinding, and the smooth surfaces of pumice particles became more rugged.

Assessing the Effects of Material Properties on Load Behavior in Dry Ball Mills Using DEM

Understanding how the mill load behaves is crucial for enhancing ball mill effectiveness. This study aimed to create a discrete element method (DEM) model to simulate the motion charge in ball mills and to analyze how the simulation material properties affected the load behavior. The steel balls were modelled as a collection of distinct particles, each of which was subject to Newton’s laws of motion and tracked in a Lagrangian manner. Hertzian contact law was used to describe inter-particle collisions. Then, this numerical model was coded using the open-source C++ program LAMMPS Improved for General Granular and Granular Heat Transfer Simulation (LIGGGHTS) to mimic laboratory and pilot-scale ball mills. The load positions measured from the DEM simulations were compared to the published experimental data and empirical models of comparable laboratory and pilot-scale experiments to validate the findings. The angular shoulder position ranged between 137° to 154° for the range of Young’s modulus of 0.5 to 1000 MN/mm2. Angular shoulder and toe positions had a variation of less than 10% from the laboratory and pilot-scale experimental data. The outcomes demonstrated a significant relationship between load position and material characteristics such as Young's modulus in DEM simulation. This preliminary model can be used for choosing the appropriate material parameters for ball mills both with DEM and coupled CFD–DEM multiphase simulations. This assessment concluded that material properties affect the load behavior in computer simulations of ball mills.

Mechanocomposites based on 1(10)β-epoxy-5,7α(Н),6β(Н)-guai-3(4),11(13)-diene-6,12-olide

Current paper discusses the results of complex formation of 1(10)β-epoxy-5,7α(Н),6β(Н)-guai-3(4),11(13)-dien-6,12-olide with polyvinylpyrrolidone, disodium salt of glycyrrhizin acid and magnesium carbonate. Inclusion complexes with disodium salt of glycyrrhizic acid were obtained by mechanochemical treatment into micelles formed by the associated molecules of glycyrrhizic acid. Polyvinylpyrrolidone and magnesium carbonate form host-guest type complexes with 1(10)β-epoxy-5,7α(Н),6β(Н)-guai-3(4),11(13)-diene-6,12-olide. Mechanocomposites were obtained in Itomak laboratory ball mill MSHL-1 with 1 to 6 hours processing time. Studies on water solubility of obtained mechanocomposites demonstrate that water solubility of 1(10)β-epoxy-5,7α(Н),6β(Н)-guai-3(4),11(13)-diene-6,12-olide in a mechanocomplex with disodium salt of glycyrrhizic acid after 2-hour mechanochemical treatment increased by 4.61 times, in the mechanocomplex with polyvinylpyrrolidone by 4.42 times, and with magnesium carbonate by 1.66 times. The surface morphology of the obtained mechanocomposites was studied by scanning electron microscopy (magnification x500). After mechanochemical treatment, the original shape of the particles of the initial components has changed and it is impossible to isolate individual components, except for the formed agglomerates. The resulting substances are polydisperse powders with particles (5-20 µm in size) and their aggregates. The results obtained indicate that the increase in the water solubility of the substance based on 1(10)β-epoxy-5,7α(Н),6β(Н)-guai-3(4),11(13)-diene-6,12-olide has been achieved by the formation of supramolecular complexes after mechanochemical treatment with polyvinylpyrrolidone, disodium salt of glycyrrhizic acid and magnesium carbonate

Influence of milling parameters on the properties of ground coal bottom ash and its blended cement

Coal bottom ash (CBA), a by-product of the coal thermal power plant, can be classified as pozzolanic material according to ASTM C618. Therefore, it is a suitable supplementary cementitious material (SCM) in concrete. In recent developments, it was established that the pulverization of CBA enhanced the pozzolanic properties. Numerous prior studies on utilising the ground CBA (GCBA) as SCM was conducted by milling CBA in a laboratory ball mill. However, the optimisation of the milling parameters was not investigated to achieve the optimum output rate and quality of GCBA. Hence, the present work is aimed to establish optimised milling parameters for producing high-quality GCBA in a ball mill for use as a constituent binder in binary and ternary blended cement. The raw CBA was pulverised at various retention times, the angular velocity of the mill (in revolution per minute, RPM) and CBA to instantaneous media ratio. The physical and pore properties of the resulting GCBA were characterized by Blaine fineness, laser particle and Bruneur Emmer Teller analysis. Besides, the workability and mechanical strength of mortar made with the GCBA blended cement were also examined. Subsequently, statistical analysis of test results was conducted by analysis of variance (ANOVA). It was observed that the CBA ground for 5 hours (5H-GCBA) exhibited optimum performance in physical and mechanical properties. Subsequently, the 5H-GCBA was pulverised at an angular velocity of 50 – 80 revolutions per minute (RPM) with a CBA to instantaneous media ratio of 1:10 – 2:10. The statistical analysis revealed that the retention time and the angular velocity of mill and CBA to instantaneous media ratio significantly influenced the workability, flexural and compressive strength of GCBA-blended mortar. In conclusion, the blended cement containing GCBA pulverised at 70 RPM with a CBA to instantaneous media ratio of 1.5:10 for 5 hours exhibits optimum performance.

Evaluation of the Relationship between the Milling Breakage Parameters and Mineralogical Data: A Case Study of Three Copper Ores from a Multi-Mineralised Deposit

The study evaluated the milling kinetics of three copper ores, from a multi-mineralised deposit, which were identified as sulphide 1 (with bornite as a dominant copper mineral), sulphide 2 (mainly composed of chalcopyrite) and oxide (with malachite as a dominant copper mineral) and related the breakage parameters to the mineral composition data. Five mono-size fractions between 1000 µm and 212 µm were dry milled for short grinding times in the laboratory ball mill in order to obtain data for predicting breakage rate parameters. The analytical and mineralogical characterisation of the ores were performed using X-ray fluorescence (XRF) analysis, scanning electron microscopy energy dispersive spectroscopy (SEM-EDS) analysis, optical microscopy analysis and X-ray diffractometer (XRD). The mineralogy data showed that quartz was the abundant gangue mineral (average for each ore was above 60% (w/w)), followed by K-feldspar minerals (orthoclase and microcline) which constituted between 4% (w/w) and 6% (w/w) and the remainder are the minor calcite and dolomite minerals which are also in the host rock. The experimental milling kinetics parameters and mineralogical data were used to assess the robustness of the heterogeneous (two-component) and homogeneous (single-component) first-order rate breakage models. The mineral composition data were used for setting up the predictions of breakage parameters in the two-component and single-component first-order breakage models. The experimental data fitted better on the two-component breakage model than the single-component breakage model. These results highlighted the influence of two groups of minerals (generally classed as valuable and gangue minerals). The breakage data showed that the selection function for the hard component (the gangue minerals) has a dominant contribution to the overall selection function of the ores, with SiA correlating fairly well with experimental Si. The parameter a in the Austin empirical breakage model was relatively similar (approximately 1) for all three ores, which confirms similar milling conditions to which the ores were subjected to. The data suggests that there is a relationship between breakage parameter α (material-specific parameter) in the Austin empirical breakage model and brittleness index βi (calculated from the mineralogical composition of the gangue phase). No clear trends could be deduced from the cumulative breakage distributions of the three ores. This highlights the complexity of developing relationships between the mineralogical composition data and breakage distributions of the ores which are extracted from the same deposit and with comparable gangue composition.

Kinetics of dolomite grinding in a laboratory ball mill

Kinetics of dolomite grinding in a laboratory ball mill

Application of artificial neural network method to predict the breakage properties of PGE bearing chromite ore

In the present investigation, systematic grinding experiments were conducted in a laboratory ball mill to determine the breakage properties of low-grade PGE bearing chromite ore. The population balance modeling technique was used to study the breakage parameters such as primary breakage distribution (Bi, j) and the specific rates of breakage (Si). The breakage and selection function values were determined for six feed sizes. The results stated that the breakage follows the first-order grinding kinetics for all the feed sizes. It was observed that the coarser feed sizes exhibit higher selection function values than the finer feed size. Further, an artificial neural network was used to predict breakage characteristics of low-grade PGE bearing chromite ore. The predicted results obtained from the neural network modeling were close to the experimental results with a correlation of determination R2 = 0.99 for both product size and selection function.

Effect of Grinding Media Size on Ferronickel Slag Ball Milling Efficiency and Energy Requirements Using Kinetics and Attainable Region Approaches

The aim of this study is to evaluate the effect that the size of grinding media exerts on ferronickel slag milling efficiency and energy savings. A series of tests were performed in a laboratory ball mill using (i) three loads of single size media, i.e., 40, 25.4, and 12.7 mm and (ii) a mixed load of balls with varying sizes. In order to simulate the industrial ball milling operation, the feed to the mill consisted of slag with natural size distribution less than 850 μm. Grinding kinetic modeling and the attainable region (AR) approach were used as tools to evaluate the data obtained during the ball milling of slag. Particular importance was given to the determination of the specific surface area of the grinding products, the identification of the grinding limit, and the maximum specific surface area which could be achieved when different grinding media sizes were used. The results showed that, in general, the breakage rates of particles obey non-first-order kinetics and coarse particles are ground more efficiently than fines. The AR approach proved that there is an optimal grinding time (or specific energy input) dependent on the ball size used for which the volume fraction of the desired size class is maximized. The use of either 25.4 mm balls or a mixed load of balls with varying sizes results in 31 and 24% decrease in energy requirements, compared to the use of balls with small size (12.7 mm).

ВПЛИВ МЕХАНІЧНОЇ АКТИВАЦІЇ НА РОЗМІРНІ ХАРАКТЕРИСТИКИ ТА ФОРМУ ЧАСТИНОК ГЛИНОПОРОШКІВ РІЗНОГО ТИПУ

Purpose. Determination of the influence of the process of preliminary mechanical activation on the dimensional characteristics and shape of particles of different types of clay powders.Methodology. Clay powders of montmorillonite and palygorskite type were chosen as the objects of research in this work. The process of mechanical activation of clay powders was carried out using a laboratory ball mill. For microanalysis of sample particles, the method of optical polarizing microscopy was used. Morphometric analysis of clay powder particles was performed by image analysis using the ImageJ software. At the same time, the area and perimeter were determined, and the equivalent diameter and also the shape index of the particles of the samples were calculated. The experimental data were statistically processed using the Statistica and Excel software packages.Results. The paper investigates the effect of the process of mechanical activation on the dimensional characteristics and shape of particles of montmorillonite and palygorskite type clay powders. It was found that the decrease in the average values of the equivalent particle diameter in the process of mechanical action (~14–15%) is realized mainly due to the destruction of their largest aggregates. Moreover, the intensity of this process is noticeably higher for clay of the montmorillonite type. It is shown that for both studied samples, the process of mechanical activation leads to an increase in the average values of the particle shape index (~ by 9–10%) and an increase in the uniformity of their distribution by this index.Scientific novelty. Using a detailed morphometric analysis of particles of various types of clay powders, the regularities of the influence of the mechanical activation process on the quantitative statistical characteristics of their distribution over the equivalent diameter and shape index have been established.Practical value. The results obtained will make it possible to reasonably approach the choice of pretreatment methods for clay powders intended for the production of polymer filled nanocomposite materials.

Investigating grinding mechanisms and scaling criteria in a ball mill by dimensional analysis

A dimensional analysis of the ball mill process is carried out through the Buckingham-Pi method. The dimensionless quantities identified are discussed and used in order to suggest scaling criteria for ball mills. The flowability and the particle size distribution of an alumina powder ground in laboratory ball mills of various dimensions are compared in order to discuss the influence and the relevance of each dimensionless numbers. Some geometrical, kinetics and dynamic similitudes are highlighted both theoretically and experimentally. In particular, the conservation of the Froude number and the fragmentation number lead to relevant scaling criteria for mills of 1, 2 and 7 L inner volumes. The importance of the ratio between the pebble size and the vessel diameter is also discussed. Finally, the preponderance of the fragmentation number over the number of revolutions of the vessel is interpreted in terms of particle fragmentation mechanisms.