Wyniki wyszukiwania - Biblioteka Nauki

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Dynamic analysis of a dashpots equipped vibrating screen using finite element method

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Khoshdast H. , Jalilifard S. , Khoshdast H.

Physicochemical Problems of Mineral Processing

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2021

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tom Vol. 57, iss. 1

112--126

EN

Even though vibrating screens have been used in mining industries for over a century, their use has often been cited as challenging in terms of understanding its dynamic responses to different operating factors, particularly those that affect the structural aspects. Among the various aspects of screen design, the control of vibrational energies imposed on various parts of the screen is of particular importance because these vibrations directly affect the separation efficiency and useful life of the screen. This study proposes the use of vibration absorbers to control the adverse effects of severe screen vibrations. The dynamic behavior of a medium-sized vibrating screen utilized in the aggregate industry was investigated using the finite element method for both spring/dashpots and conventional solely spring systems. The modeling process was performed in loaded and unloaded conditions and in three frequencies of 15, 23, and 27 rad/s. Numerical simulation results showed that the use of dashpots can significantly reduce the maximum stress in the screen, such that the maximum stress in the center of gravity of the screen at the optimal frequency of 23 decreased from 237 to about 97 MPa. Also, sieve modal analysis showed that the stress in the sieve equipped with the spring/dashpots system had a more uniform distribution. The results revealed that the use of vibration absorbers can be a promising solution to prevent damage caused by high vibrational energies in screens.

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A hybrid geometallurgical study using coupled Historical Data (HD) and Deep Learning (DL) techniques on a copper ore mine

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Gholami A. , Asgari K. , Khoshdast H. , Hassanzadeh A.

Physicochemical Problems of Mineral Processing

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2022

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tom Vol. 58, iss. 3

art. no. 147841

EN

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.

3

Coupled fuzzy logic and experimental design application for simulation of a coal classifier in an industrial environment

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Khoshdast H. , Soflaeian A. , Shojaei V.

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2019

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tom Vol. 55, iss. 2

504--515

EN

Design of experiments (DOE) is an effective method providing useful information about the interaction of operating variables and the way the total system works by using statistical analyses. However, its industrial application is limited because it is almost difficult to maintain variables in DOE matrix at desired constant levels in industrial environment. Thus, this paper aims to present a new mixed modeling method which is a combination of fuzzy logic and design of experiments methods to overcome such practical limitations. The method first uses a fuzzy model which is trained by practical data gathered from industry to predict DOE response corresponding to each run in DOE matrix. Then, a statistical parametric model is constructed for the prediction of process response to any change of operating parameters under real industrial conditions. The proposed mixed method was successfully validated by using data obtained from a coal hydraulic classifier at Zarand Coal Washing Plant (Kerman, Iran). The method also seems to be a promising tool for modeling all devices and processes in real industrial environment and allows researchers to benefit from all the advantages of experimental design and fuzzy logic methods simultaneously.

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Effect of an acetonized pyrolysis oil recycled from spent-car tires on coal flotation performance

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Hasanizadeh I. , Khoshdast H. , Rahmanian A. , Asgari K. , Hassanzadeh A.

Physicochemical Problems of Mineral Processing

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2023

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tom Vol. 59, iss. 2

art. no. 163109

EN

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.

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Metallurgical evaluation of copper ore flotation performance in the presence of Rhamnolipid biosurfactant produced from Pseudomonas aeruginosa. Part 1: Copper-bearing minerals

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Biniaz G. , Khoshdast H. , Garmsiri M. R. , Maleki-Moghaddam M. , Hassanzadeh A.

Physicochemical Problems of Mineral Processing

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2023

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tom Vol. 59, iss. 5

art. no. 183176

EN

The present research work studies the effect of rhamnolipid biosurfactant (RL) produced from Pseudomonas aeruginosa bacteria on the metallurgical response of a copper ore sample flotation through an extensive full factorial experimental design. Key influential factors including feed particle size, pulp solid content, pH, and dosages of collector, frother and RL biosurfactant were considered. The surface activity of the RL biosurfactant was also studied based on a D-optimal experimental design. Surface activity results revealed that increasing pH and electrolyte concentrations negatively impacted the RL surface activity, while the effect of electrolyte source was dependent on their ionic strength. Metallurgical investigations showed that operating parameters significantly influence the copper grade and recovery with considerable interaction among various parameters. RL biosurfactant was found to negatively decrease the copper grade (~0.5%) and positively enhance the recovery (~3%). Effect of RL was attributed to two potential mechanisms, i.e., being ineffective on copper minerals and/or interaction with gangue minerals, as well as increasing the rate of entrainment due to high foamability, both of which increased non-selective recovery of gangue minerals. Interestingly, regardless of the structural similarities, no interaction between the flotation reagents and rhamnolipid was observed. Fourier-transform infrared (FTIR) spectroscopic analysis of copper minerals, both pure and RL-exposed, showed that there was actually no molecular interaction between RL molecules and particle surface.

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Introducing key advantages of intensified flotation cells over conventionally used mechanical and column cells

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Hassanzadeh A. , Safari M. , Khoshdast H. , Güner M. K. , Hoang D. H. , Sambrook T. , Kowalczuk P. B.

Physicochemical Problems of Mineral Processing

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2022

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tom Vol. 58, iss. 5

art. no. 155101

EN

The present paper introduces the key advantages of ImhoflotTM, JamesonTM, and RefluxTM flotation cells over the conventionally used mechanical and column cells from different perspectives. The impact of slurry mean retention time, bubble size distribution, and energy input was studied for all cell types. The mean retention time of laboratory scale ImhoflotTM (V030-cell) and RefluxTM flotation cells (RFC100) were measured experimentally using KCl as a tracer. Also, initially a statistical and practical overview of previously installed ImhoflotTM, and JamesonTM cells was presented in this work. It was found that more industrial data is available for the JamesonTM cell. The diagnostic results showed that RefluxTM, JamesonTM, and ImhoflotTM functionally operate similarly based on providing intensive turbulence in the downcomer. They were initially applied to the Australian and the UK coal industries and installed in the cleaning stage of flotation circuits, while there are now more applications in a wide variety of minerals across the world in different flotation stages. First pilot trials on a Russian gold ore were reported operating both JamesonTM and ImhoflotTM cells at the rougher-scalper and cleaner stages providing superior results using the ImhoflotTM cell as rougher-scalper and the JamesonTM at the cleaner. Formation of sub-micron and micron-sized bubbles, effective hydrodynamic characteristics, and low capital and operating costs were reported as major advantages of intensified flotation cells over the conventionally used ones in improving the recoverability of ultra-fine particles. Literature data showed that these cells provide greater gas-hold-up values (40-60%) over the mechanical (5-20%) and column cells (5-25%) with substantially lower power inputs. It was indicated that low mean slurry retention time could lead to a potential enhancement in their throughputs, but further industrial measurements are required to prove this statement. The RefluxTM cell showed a plug-flow mixing regime, while ImhoflotTM V-Cell followed the trend of perfect mixing and plug-flow dispersion regimes.

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Effect of different process water sources on rougher flotation efficiency of a copper ore : A case study at Sarcheshmeh Copper Complex (Iran)

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Soufiabadi A. M. , Nejadaria M. , Dehghan R. , Safari M. , Hassanzadeh A. , Khoshdast H.

Physicochemical Problems of Mineral Processing

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2023

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tom Vol. 59, iss. 5

art. no. 184087

EN

In this research, the effect of different sources of process water on the flotation efficiency of copper sulfide ore prepared from the Sarcheshmeh copper mine was investigated. For this purpose, samples of fresh water to the plant, overflows of copper-molybdenum concentrate thickener, copper concentrate thickener, and recycled water pool as well as a mixture of fresh water and recycled water were prepared and characterized. Flotation tests were performed under the same conditions as the plant’s rougher circuit and were kept constant during all experiments. Grade and recovery of copper, iron, molybdenum, and silica were selected as the metallurgical response of flotation tests. The results were subjected to statistical analysis to assess the relative significance of which water source affects the flotation performance as evaluated from the experimental results. The results showed that the copper concentrate thickener overflow had the greatest effect on the flotation efficiency, so the grade and recovery decreased by about 10% and 75% for copper, and 10% and 6% for iron in the concentrate, respectively, while the grade and recovery increased up to 0.1% and 12% for silica, and 3% and 25% for molybdenum, respectively. The reason for this effect was attributed to the high content of suspended solid particles, and Cu2+, Mo2+, and Fe2+ cations in this water source that increased the coating effect over gangue minerals and entrainment rate. The improvement of molybdenum flotation was also ascribed to the possible presence of residual diesel oil from the flotation process in the plant. Due to the relatively equal amount in all sources of process water, the effect of anions and ions of dissolved salts was difficult.

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Studying on mineralogical and petrological characteristics of Gara Djebilet oolitic iron ore, Tindouf (Algeria)

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Chebel N. , Nettour D. , Chettibi M. , Rachid C. , Khoshdast H. , Hassanzadeh A.

Physicochemical Problems of Mineral Processing

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2023

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tom Vol. 59, iss. 5

art. no. 178382

EN

Demand for iron ore worldwide has been steadily increasing which leads to the extraction of iron ore deposits with more complex mineralogies and higher levels of silicon and phosphorus impurities. This is the case in Algeria with the iron ore deposit of Gara Djebilet, Tindouf; where it has recently been exploited to ensure the sufficiency of iron ore required to produce iron and steel products. This deposit has remained unexploited for several decades due to inadequate knowledge of its mineralogy, treatment, and economic assessments. This study aims to find out the microstructure, chemical composition, and mineralogical distribution of valuable minerals and impurities, to understand the efficient processing methods for this specific iron ore. The characterization of representative ironstone samples taken from the studied area was carried out using optical microscopy, X-ray fluorescence spectrometer (XRF), petrographic microscope, X-ray diffractometer (XRD), and scanning electron microscope (SEM) coupled with energy dispersive X-ray spectroscopy (EDS). The results of the mineralogical analyses confirmed that it is an oolitic fine-grained ore consisting of gangue minerals principally composed of quartz, apatite, and iron-rich concentric cored structures. Chemical analyses of the ore indicated that it contains 56.58 wt% Fe with 7.98 wt% SiO2, 7.09 wt% Al2O3, and minor amounts of P2O5, CaO, MgO, and TiO2 compounds. The phosphorus associated was present in both ooids and groundmass, indicating that the ore has a complex texture with very rich and diverse mineralogy. For that, two conceptual scenarios were potentially proposed for processing the studied iron ore, while further detailed automated mineralogical information was required to make sure about the processing units from a practical perspective.