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This research assesses the effect of carbonated pyrolysis oil (CPO) derived from scrap car tires on the metallurgical efficiency of coal flotation as a flotation additive. Using a statistical experimental design, the influence of various operational variables, including solid percent of feed pulp and dosages of reagents, i.e., CPO as an additive, diesel oil as a collector, and pine oil as a frother, on the ash content and yield of the final concentrate were investigated. Experimental data vary significantly based on operational conditions, ranging from 6.6% ash content with a 15% yield to 19.1% ash content with a 76.8% yield. The composition of the pyrolysis oil was identified by using Fourier transform infrared spectroscopy (FTIR). The analysis of variance (ANOVA) of experimental results demonstrated that almost all variables had a substantial effect on the flotation responses, positive or negative, depending on the variable or variable interaction. It was discovered that the usage of CPO intensified the total yield and ash content of concentrate in a nonlinear fashion in a range of 15% and 4%, respectively. The results revealed a non-selective interaction effect between CPO and pine oil, as well as competitive adsorption between diesel oil and CPO, which contributed to the curved behavior of flotation measurements. The detrimental effect of CPO on the flotation response of the studied coal sample was also related to the interaction of the hydrophilic groups in the CPO structure and the oxide groups of ash material in coal particles. This work shows the potential of carbonated pyrolysis oil to enhance coal flotation performance and sheds light on the underlying mechanisms. [ABSTRACT FROM AUTHOR]

Many reagents are used as frother in flotation process, however, a general reference for their identification and characterization is not available. The present work categorizes the commonly used frothers and evaluates the available methodologies to determine their properties. In this paper, frothers properties such as molecular weight, viscosity, boiling and freezing point, hydrophile-lipophile balance number, solubility, surface activity and critical micelle concentration were discussed. The commonly used measurement methods for froth structure and dynamic and static frothability were also presented along with water recovery index and critical coalescence concentration (CCC). Results showed that the practical identification of frothers properties has not been thoroughly evaluated and therefore, there is a need for developing novel and easy-to-apply experimental methods in this area. For example, it was found that there is no promising single process to measure the CCC value. This review revealed that the 2D froth structure measurement methods are associated with a considerable bias, while 3D techniques can effectively represent the actual froth properties. It was also found that the potential interactions between various frothers properties and how they can influence the flotation performance in an industrial environment are not yet understood and needs further investigation. It was also identified that there is no standard instruction to provide a reliable connection between both manufactures and frothers consumers. In our opinion, the current review paves the path for the elaboration of knowledge and technology to provide promising methods for determining conventionally used and complex frothers properties. [ABSTRACT FROM AUTHOR]

In this paper, an extended Historical Data (HD) design was applied for evaluating the effect of an acetonized pyrolysis oil (PO) produced by pyrolysis of spent-car tires in coal. Experimental and statistical analyses were applied for examining the influence of some operating variables such as concentration of diesel oil (0, 10, and 20 L/t), pine oil (0.55, 0.1, and 1 L/t), and the pyrolysis oil (0, 10, and 20 L/t) as well as solid content of pulp (5, 10, and 15% (w/w)) on the yield and ash content of final concentrate. Fourier Transform Infrared Spectroscopy (FTIR) measurements showed that PO contained hydroxyl, aldehyde, aliphatic, and aromatic compounds. Based on the results of Analysis of Variance (ANOVA), the main effect of all variables, except concentration of pine oil, on the flotation responses were found significant. Batch flotation experimental results indicated that using pyrolysis oil resulted in a 2% increase in ash content and a 35% decrease of the yield, through a nonlinear trend. The curved behavior of flotation measures was due to the possible competitive adsorption between PO and diesel oil and nonselective interaction between pyrolysis oil and other reagents. The negative effect of PO on coal flotation efficiency was also ascribed to the interaction between hydrophilic groups in PO structure and the oxide nature of non-combustible materials of coal particles. [ABSTRACT FROM AUTHOR]

In this research work, the role of a pyrolitic oil (PO) produced by pyrolysis of used car tires in coal flotation was evaluated using an extended full factorial design. Effects of operating parameters including pulp solid content and the concentration of pine oil, diesel oil, and pyrolitic oil on ash content and yield of final concentrate as process responses were assessed using experimental and statistical analyses. Fourier Transform Infrared Spectroscopy (FTIR) technique revealed that PO consists of hydrocarbons and their hydrophilic oxides. Analysis of variance (ANOVA) results indicated that the main effect of all parameters on flotation responses was significant. Experimental results showed that pyrolitic oil increased both the ash content and total yield through a nonlinear trend in ranges of 5% and 40%, respectively. Nonselective interaction between pyrolitic oil and pine oil molecules, and competitive adsorption of PO and diesel oil on the surface of coal particles were found to be the chief reasons behind the observed curved behavior of flotation measures. The negative effect of PO on ash content of final concentrate was also ascribed to the interaction between hydrophilic groups in PO structure and the oxide nature of noncombustible materials in coal particles. [ABSTRACT FROM AUTHOR]

The present study investigates the optimization and advanced simulation of the flotation process of coarse particles (–425 + 106) using micro-nanobubbles (MNBs). For this purpose, flotation experiments in the presence and absence of MNBs were performed on coarse quartz particles, and the results were statistically analyzed. Methyl isobutyl carbinol (MIBC) was employed as a frother for generating MNBs through hydrodynamic cavitation. The significance of the operating variables, including impeller speed, air flow rate, together with the bubble size, and particle size on the flotation recovery was assessed using historical data (HD) design and analysis of variance (ANOVA). The correlation between the flotation parameters and process response in the presence and absence of MNBs was modeled using hybrid convolutional neural networks (CNNs) and recurrent neural networks (RNNs) as the deep learning (DL) frameworks to automatically extract features from input data using a CNN as the base layer. The ANOVA results indicated that all variables affect process responses statistically and meaningfully. Significant interactions were found between air flow rate and particle size as well as impeller speed and MNB size. It was found that a CNN-RNN model could finally be used to model the process based on the intelligent simulation results. Based on Pearson correlation coefficients (PCCs), it was evident that particle size had a strong linear relationship with recovery. However, Shapley additive explanations (SHAP) was considerably more accurate in predicting relationships than Pearson correlations, even though the model outputs agreed well. [ABSTRACT FROM AUTHOR]

This research work introduces a novel hybrid geometallurgical approach to develop a deep and comprehensive relationship between geological and mining characteristics with metallurgical parameters in a mineral processing plant. This technique involves statistically screening mineralogical and operational parameters using the Historical Data (HD) method. Further, it creates an intelligent bridge between effective parameters and metallurgical responses by the Deep Learning (DL) simulation method. In the HD method, the time and cost of common approaches in geometallurgical studies were minimized through the use of available archived data. Then, the generated DL-based predictive model was enabled to accurately forecast the process behavior in the mineral processing units. The efficiency of the proposed method for a copper ore sample was practically evaluated. For this purpose, six representative samples from different active mining zone were collected and used for flotation tests organized using a randomizing code. The experimental results were then statistically analyzed using HD method to assess the significance of mineralogical and operational parameters, including the proportions of effective minerals, particle size, collector and frother concentration, solid content and pH. Based on the HD analysis, the metallurgical responses including the copper grade and recovery, copper kinetics constant and iron grade in concentrate were modeled with an accuracy of about 90%. Next, the geometallurgical model of the process was developed using the long short-term memory neural network (LSTM) algorithm. The results showed that the studied metallurgical responses could be predicted with more than 95% accuracy. The results of this study showed that the hybrid geometallurgy approach can be used as a promising tool to achieve a reliable relationship between the mining and mineral processing sectors, and sustainable and predictable production. [ABSTRACT FROM AUTHOR]

This paper reviews recent developments in the fundamental understating of ultrafine (nano) bubbles (NBs) and presents technological advances and reagent types used for their generation in flotation. The generation of NBs using various approaches including ultrasonication, solvent exchange, temperature change, hydrodynamic cavitation, and electrolysis was assessed. Most importantly, restrictions and opportunities with respect to the detection of NBs were comprehensively reviewed, focusing on various characterization techniques such as the laser particle size analyzer (LPSA), nanoparticle tracking (NTA), dynamic light scattering (DLS), zeta-phase light scattering (ZPALS), and zeta sizer. As a key feature, types and possible mechanisms of surfactants applied to stabilize NBs were also explored. Furthermore, flotation-assisted nano-bubbles was reported as an efficient method for recovering minerals, with a special focus on flotation kinetics. It was found that most researchers reported the existence and formation of NBs by different techniques, but there is not enough information on an accurate measurement of their size distribution and their commonly used reagents. It was also recognized that a suitable method for generating NBs, at a high rate and with a low cost, remains a technical challenge in flotation. The application of hydrodynamic cavitation based on a venturi tube and using the LPSA and NTA in laboratory scales were identified as the most predominant approaches for the generation and detection of NBs, respectively. In this regard, neither pilot- nor industrial-scale case studies were found in the literature; they were only highlighted as future works. Although the NB-stabilizing effects of electrolytes have been well-explored, the mechanisms related to surfactants remain the issue of further investigation. The effectiveness of the NB-assisted flotation processes has been mostly addressed for single minerals, and only a few works have been reported for bulk materials. Finally, we believe that the current review paves the way for an appropriate selection of generating and detecting ultrafine bubbles and shines the light on a profound understanding of its effectiveness. [ABSTRACT FROM AUTHOR]

Although column flotation cells have been extensively studied in the literature, the hydrodynamic impact of orifice properties has not been adequately addressed yet. This paper initially investigates the effect of sparger orifice diameter on hydrodynamic behavior of coal particles in a pilot-scale column flotation. The metallurgical responses (i.e., ash, yield and recovery contents) were evaluated for four different sparger orifice sizes including 1, 3, 5, and 7 mm under constant operating conditions by experimental measurements associated with computational fluid dynamics (CFD) simulations. A numerical model of a two-phase air-water flow in the column (3 m × 0.5 m) was chosen and the turbulence patterns inside the collection zone and at the pulp-froth interface were simulated by employing the Volume-Of-Fluid (VOF) model. The experimental results indicated that desiring concentrated product i.e., ash content of 8.8% and yield of 57.2% could be obtained using the 3 mm orifice size. Simulation results revealed that as the sparger orifice size decreased to 1 mm, the reduced carrying capacity of the bubbly regime led to the poor flotation performance. In contrast, the turbulence condition intensified as the sparger orifice size was increased to 7 mm. Another negative consequence of the 7 mm orifice was attributed to the exceeded entrainment of high ash fines due to a bubble swarm mechanism. The 7 mm sparger orifice diameter showed a concentrate of 17.1% ash and 12.5% yield. Finally, according to the obtained results in this work and literature studies, several necessary highlights were suggested for future works in this scope. [ABSTRACT FROM AUTHOR]

In the present research study, the efficient removal of hexavalent chromium from aqueous solutions by precipitate flotation method was investigated. The experiments were carried out with the use of ferrous sulfate as a precipitating agent for chromium and rhamnolipid bio surfactant (RL) as a precipitate collector. The effects of rhamnolipid and co-precipitate concentrations, aeration rate, solution pH, and salt addition on the chromium removal were studied using a full factorial design. The chromium removal and water recovery to foam products were analyzed as process responses. Statistical analyses showed that the effects of all factors on the chromium removal followed a non-linear trend with a peak at the middle level. After the process optimization, the maximum chromium removal of 96.75±0.3% was obtained at pH value of 8, RL/Cr ratio of 0.01, Fe/Cr ratio of 3, and aeration rate of 50 cm³/min. Addition of salt with different cationic and anionic groups negatively influenced the removal efficiency. Kinetic studies suggested that the process of chromium removal by the precipitate flotation followed the first-order process with a rate constant of about 0.018 sec-1. Given the good removal capacity and kinetics, rhamnolipid biosurfactants can be a promising environmental-friendly bio collector for the removal of chromium ions from aqueous solutions. [ABSTRACT FROM AUTHOR]

Inthis research, the potential of cadmium removal from aqueous solutionby foam flotation with a rhamnolipid biosurfactant sample was studied.The effects of different major operating conditions, such as rhamnolipidand cadmium concentrations, solution pH, aeration rate, and frothertype and concentration, on the cadmium removal were investigated.The selectivity coefficients in the presence of rhamnolipid maintaineddefinite orders as follows: cadmium > zinc, cadmium > copper,and zinc > copper. The selectivity coefficient of cadmium overcopper was the highest one. The maximum removals of Cd from cleanand Zn- and Cu-contaminated solutions were about 57%, 36%, and 48%,respectively. Kinetic studies indicated that ion flotation of cadmiumfollows a first-order equation with a kinetic rate of 0.0071 min–1. Although the removals are rather low, it seems thatthe use of rhamnolipid biosurfactant can be promising in heavy-metalremoval from wastewaters by foam flotation with some modifications. [ABSTRACT FROM AUTHOR]

Abstract: The effect of a concentrated rhamnolipid biosurfactant (purity > 97%) produced by Pseudomonas aeruginosa MA01 on flotation performance of coal and minerals was studied and compared with those from synthetic flotation reagents in both single and mixed systems. Results of phosphate flotation tests showed that phosphate content in the floated product decreased by rhamnolipid concentration. However, final recovery of phosphate at appropriate dosage of reagent was insignificant. This could be ascribed to the increase of iron recovery to final concentrate likely due to collecting action of rhamnolipid for iron minerals. In coal flotation, the increase of rhamnolipid concentration in mixture with pine oil reduced both ash content and coal yield of concentrates. In desulfurization of a sample iron concentrate using reverse flotation, rhamnolipid addition successfully decreased the sulfur content of the iron concentrate. The flotation responses of the studied sample ores showed that rhamnolipid can be used as a promising frother or co-frother in mineral processing practices. [Copyright &y& Elsevier]

[Display omitted] • Impact of hydrophobic groups of four surfactants on the floatability of anode-active materials was studied. • Particle surface charge became more negative by adding surfactants at acidic and neutral pHs. • Contact angles and recoveries increased from 70 ± 1° to 120 ± 2° and 0 to 85% in the absence and presence of 2-octanol. • Anode active material recovery increased with the order of 2-octanol≫terpenic oil > SDBS > MIBC. In the present paper, the effect of surface activity and the role of hydrophobic groups of four different frothers (2-octanol, terpenic oil, methyl isobutyl carbinol (MIBC), and sodium dodecyl benzene sulfonate (SDBS)) on the collector-less floatability of anode-active materials were studied. Fourier-transform infrared spectroscopy (FTIR) and zeta potential analyses were applied to detect functional groups and particle surface charge, respectively. The floatability of the material was examined using an XFG flotation cell in the absence and presence of these frothers. The experimental results showed that the functional groups on the surface of anode active materials (AAM) including CH 3 , C-O-O, and aromatic rings reacted with a frother and increased the recovery of the particles by 15%. Also, the presence of phenolic resin on the particle surface caused the functional groups on the surface of the particles to interact with frother molecules and improved the recovery of the particles by acting as a collector. Furthermore, the zeta potential of the particles after the addition of surfactant (at pH 7) showed a negative shift because of the particle hydrophobicity and agglomeration of particles. In addition, the results of contact angle and FTIR analyses showed that materials had a greater contact angle after using various surfactants and successful interaction occurred between the AAM surface and the hydrocarbon tail of the surfactants. The flotation results demonstrated that the recovery of AAM without any surfactants was zero but it was increased as the following order of 2-octanol ≫ terpenic oil > SDBS > MIBC. [ABSTRACT FROM AUTHOR]

In recent years, there has been a growing emphasis on the recovery of cathode and anode active constituents extracted from spent lithium-ion batteries (LIBs) due to their significant value and technological importance. Prior to the flotation separation of spent LIBs, pyrolysis pretreatment plays a critical role in the removal of organic binding components from the particle surface. However, the presence of residual impurities on the material's surface can hinder the flotation process. This study proposes an environmentally friendly approach to recycling spent LIBs by combining pyrolysis with grinding, ultrasonic treatment, and micro-nanobubbles (MNBs), utilizing the electrode active materials from the batteries as raw materials. Various analytical techniques, including X-ray Diffractometer (XRD), Field-emission Scanning Electron Microscope with Energy Disperse Spectroscopy (FSEM-EDS), X-ray Photoelectron Spectroscopy (XPS), and contact angle measurements, are employed to analyze the samples. The experimental results reveal that the flotation performance is enhanced through the use of pyrolysis-grinding and pyrolysis-ultrasonic techniques combined with MNBs, resulting in improved recovery and metal content. The most optimal flotation performance is achieved with the pyrolysis-ultrasonic-MNBs method at a pyrolysis temperature and duration of 350 °C and 15 min, respectively, leading to an increase in the metal content of cathode materials from 65 ± 3 % to 95 ± 2 %. • Effect of pyrolysis and MNBs on the performance of spent LIBs flotation was studied. • Surface properties of pyrolytic materials were analyzed. • Elimination of organic binders was achieved through pyrolysis at 350 °C for 15 min. • Improved flotation performance was observed with using of PGM and PUM. • Two-stage flotation processes with MNBs upgraded the grade of CMs up to 95 ± 2 %. [ABSTRACT FROM AUTHOR]

The present research study investigates the performance of pyrolysis oils recycled from waste tires as a collector in coal flotation. Three different types of pyrolysis oils (namely, POT 1 , POT 2 , and POT 3) were produced through a two-step pressure pyrolysis method followed by an oil rolling process. The characteristics of POTs were adjusted using various oil-modifying additives such as mineral salts and organic solvents. The chemical structure of POTs was explored by employing necessary instrumental analysis techniques, including microwave-assisted acid digestion (MAD), inductively coupled plasma atomic emission spectroscopy (ICP-AES), Fourier-transform infrared spectroscopy (FT-IR), and gas chromatography-mass spectrometry (GC-MS). The collecting performance of POTs in coal flotation was evaluated using an experimental design based on Response Surface Methodology (RSM), considering the ash content and yield of the final concentrate. The effect of the type and dosage of POTs was evaluated in conjunction with other important operating variables, including the dosage of frother, dosage of depressant, and the type of coal. Results of POTs characterization revealed that the pyrolysis oils were a complex composition of light and heavy hydrocarbon molecules, including naphthalene, biphenyl, acenaphthylene, fluorene, and pyrene. Statistical analysis of experimental results showed that among different POTs, POT 1 exhibited remarkable superiority, achieving not only a 15% higher coal recovery but also a 12% lower ash content. The outstanding performance of POT 1 was attributed to its unique composition, which includes a concentrated presence of carbon chains within the optimal range for efficient flotation. Additionally, the FT-IR spectra of POT 1 reveal specific functional groups, including aromatic and aliphatic compounds, greatly enhancing its interaction with coal surfaces, as confirmed by contact angle measurement. This research provides valuable insights into the specific carbon chains and functional groups that contribute to the effectiveness of POT as a collector, facilitating the optimization of coal flotation processes and underscoring the environmental advantages of employing pyrolysis oils as sustainable alternatives in the mining industry. [Display omitted] • Enhanced Flotation Performance: Pyrolysis oil derived from waste tire outperforms commercial collectors in yield. • Unique Composition Boosts Interaction: The distinctive composition of POT 1 enhances its interaction with coal, contributing to improved flotation efficiency. • Favorable PAH Concentration: POT 1 contains PAHs that enhance flotation efficiency. • Hydrophobic Surface Modification: POT 1 effectively modifies coal surfaces, increasing their hydrophobicity and optimizing the flotation process. • Optimized Flotation Conditions: Identification of optimal conditions for enhanced yield and reduced ash content, providing valuable insights for practical application. [ABSTRACT FROM AUTHOR]

[Display omitted] • Froth flotation of fine and coarse particles is studied, focusing on cell designs. • Generating micro-bubbles, intensive turbulence, and high gas hold-up are advantages of intensified cells. • Scaling up/down procedures for the intensified cells are found unclear. • Positioning the optimum location of discussed cells in flotation circuits is found challenging. After more than a century applying flotation to the mining industry, two completely different strategies have been introduced for processing purposes. One is the classical approach viz. grinding ores to a certain extent (fine particles) and floating them via conventional mechanical and pneumatic cells i.e., Jameson, Imhoflot™ and Reflux™. This strategy continues because mines face declining cut-off grades, complex and poly-mineralized ores, and they are required to achieve an acceptable degree of mineral liberation. The other school of thought deals with coarse particle processes mainly owing to the low energy requirements, that includes SkimAir® flash, fluidized bed and HydroFloat™ cells. There is no study in the literature to comparatively present the recent developments of flotation apparatuses versus the conventional mechanical cells. To cover this knowledge gap in the literature, the present paper endeavors to critically evaluate these concepts from several points of view, including existing technological advancements, water and energy usage, kinetics, and circuit design. A brief introduction of advanced technologies, along with their applications is presented. The data from literature and case studies showed that the Jameson, Imhoflot™ and recently developed Reflux™ flotation cells can be very effective for recovering fine particles owing to their specific hydrodynamic designs, intensive energy dissipation rate and generation of micron-sized bubbles (100–700 µm). Very low (less than a few minutes) mean particle residence time, high gas-hold up (ca. 50–70 %), no agitation and high efficiency of particle-bubble collision were identified as their main advantages compared to traditional mechanical flotation cells. In addition to their common applications in cleaner stage, these cells were used in pre-flotation and scalping (producing final concentrate from the rougher feed) duties. Their main challenges were recognized as relatively unclear procedure on their scale up/down, optimization and simulation. The HydroFloat™ cell was indicated as a promising technology for recovering coarse particle fraction sizes by taking advantage of the fluidized-bed concept with plug-flow dispersion regime, high particle residence time, and limited cell turbulence. We finally concluded that fine particle flotation may remain as the main focus of re-processing tailings dams, while coarse particle treatment should be the focus of this century to reduce total energy consumptions. [ABSTRACT FROM AUTHOR]