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    Wyświetlanie 1-11 z 11
    Tytuł:
    Enhanced separation efficiency of low–rank coal using waste engine oil as a flotation collector
    Autorzy:
    Li, Ming
    Xia, Yangchao
    Guo, Fangyu
    Rong, Guoqiang
    Li, Guosheng
    Xu, Baolin
    Xing, Yaowen
    Gui, Xiahui
    Powiązania:
    https://bibliotekanauki.pl/articles/109613.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    low rank coal
    engine oil
    waste engine oil
    flotation
    Opis:
    Because of the rich oxygen-containing functional groups and developed pores on the Surface of low-rank coal, it is difficult to realize efficient separation during low-rank coal flotation using common oil collectors. Waste engine oil (WEO) is abundant in polar oxygen-containing functional groups and could be an alternative collector. In this study, the effect of WEO on low-rank coal floatation was assessed and engine oil (EO) was also used for comparison. The results show that the separation efficiency of low-rank coal can be significantly improved using WEO; additionally, 96.73% of the clean coal yield can be obtained when the WEO dosage was only 4 kg/t. Compared with EO, the bubble–particle induction time in the presence of WEO shortened from 430 to 220 ms. Moreover, more low-rank coal particles were captured and adhered to the bubble surface using WEO, which indicated a higher probability of bubble–particle attachment. Nonpolar components, polar components and metal ions synergistically promote the flotation separation enhancement of low-rank coal using WEO.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2020, 56, 2; 252-263
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Kinetic modelling and optimization of flotation process of electrum
    Autorzy:
    Aydın, Ş. Beste
    Gül, Alim
    Powiązania:
    https://bibliotekanauki.pl/articles/2146860.pdf
    Data publikacji:
    2021
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    electrum
    flotation
    separation efficiency
    kinetic models
    Opis:
    The investigation of flotation as an alternative method to cyanide leaching of gold ores is significant in terms of economic and environmental aspects. In this study, a gold ore sample containing 4.79 ppm Au and 7.72 ppm Ag was used. Gold and silver were observed to be present as liberated electrum or associated with or within quartz, galena, and sphalerite. Initially, five-stage rougher flotation tests were conducted, and then three-stage scavenger circuits and four-stage cleaning flotation circuits were performed in order to obtain high-content gold concentrate and decrease losses of Au and Ag in tailings. As a result of tests, the flotation concentrate assayed as 437 ppm Au and 511 ppm Ag was obtained with recoveries of 76.3% and 58.5%, respectively. This study reveals that the concentrates ready for direct smelting without any additional process can be obtained with flotation. In order to determine kinetic characteristic of electrum in the sample, the tests were conducted using firstorder model, first-order model with rectangular distribution of rate constants, second-order model and second-order model with rectangular distribution of rate constant. The second-order model was considered as most reasonable for fitting the recoveries of gold as a function of flotation time during the flotation process.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2021, 57, 6; 80--94
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Improving separation efficiency of 6-1 mm coal by introducing vibration energy to dense medium gas-solid fluidized bed
    Autorzy:
    He, J.
    Zhao, Y.
    Luo, Z.
    Zhao, J.
    Duan, C.
    He, Y.
    Powiązania:
    https://bibliotekanauki.pl/articles/110018.pdf
    Data publikacji:
    2015
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    vibration energy
    dense medium gas-solid fluidized bed
    fluidization quality
    density uniformity
    separation efficiency
    Opis:
    Effects of the vibration energy on the fluidization quality and separation performance of dense medium gas-solid fluidized bed were investigated experimentally. The magnetite powder with a wide size range of 0.3-0.074 mm was utilized as the basic medium solids. 6-1 mm fine coal sample from Yongcheng (China) was used to perform the separation experiments. The results indicate that the vibration amplitude A and superficial gas velocity U are greatly significant to the fluidization stability and the density distribution uniformity. Comparing with the bed without vibration, the optimal SP and Sρ values of 0.034 kPa and 0.018 g/cm3 are acquired in vibration bed with the operating factors of A = 1 mm, U = 1.8Umf, f = 15 Hz and Hs = 150 mm. The coal ash content was reduced from 27.84% to 9.50% at a separating density of 1.68 g/cm3 with a probable error E value of 0.505. The separation efficiency of 6-1mm fine coal is effectively improved by introducing vibration energy to dense medium gas-solid fluidized bed. The technology provides a novel approach to achieve high-efficiency separation of 6-1 mm fine coal in the arid and water-shortage areas.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2015, 51, 1; 95-108
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    QSAR study of amine collectors for iron ore reverse flotation
    Autorzy:
    Wang, Benying
    Xu, Xinyang
    Duan, Hao
    Wang, Xinyang
    Powiązania:
    https://bibliotekanauki.pl/articles/110929.pdf
    Data publikacji:
    2019
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    QSAR
    separation efficiency
    reverse flotation
    amine collectors
    Opis:
    In order to reveal the relationship between flotation behaviors of collectors and their structures, quantitative structure–activity relationship (QSAR) study about separation efficiency of quartz from hematite using amine collectors was performed. The genetic function approximation (GFA) algorithm was applied to generate the correlation models and model with acceptable R2 and Rcv2 (cross validated R-squared) correlation coefficients (R2=0.9666, Rcv2=0.9201) was developed. The model revealed that the Lowest Unoccupied Molecular Orbital (LUMO) energy of the molecule, the charge of nitrogen and the electronegativity of polar group were the major factors that affected the separation efficiency of collectors. The higher nitrogen charge, the larger electronegativity of polar group and the more positive of LUMO energy of amine collectors were, the higher separation efficiency would be.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2019, 55, 5; 1059-1069
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of microwave system location on floatability of chalcopyrite and pyrite in a copper ore processing circuit
    Autorzy:
    Gholami, Hamed
    Rezai, Bahram
    Mehdilo, Akbar
    Hassanzadeh, Ahmad
    Yarahmadi, Mohammadreza
    Powiązania:
    https://bibliotekanauki.pl/articles/109728.pdf
    Data publikacji:
    2020
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    microwave technology
    chalcopyrite
    pyrite
    comminution circuits
    separation efficiency
    Opis:
    The present work aims at investigating the effect of microwave local positions (i.e. before crushing (BC), after crushing (AC) and after milling (AM)) on microwave-assisted flotation of chalcopyrite and pyrite in a porphyry copper complex deposit. Individual given samples for each state were pre-treated with a variable power microwave at a power level of 90 to 900W for 15, 30, and 60s. Furthermore, froth floatation experiments were carried out using a laboratory mechanical Denver flotation cell on both microwave-treated and untreated samples. Particle surface properties were characterized by a scanning electron microscopy (SEM) and an energy-dispersive X-ray spectroscopy (EDX) analysis. The results showed that the chalcopyrite and pyrite floatabilities increased monotonically by rising the exposure time and power level for the uncrushed preconditioned samples (BC) due to the enhancement of mineral liberation degrees together with the formation of sulphide species and polysulphides on the mineral surfaces. However, flotation results of treated samples for the crushed one (AC) revealed an optimum range. Formation of intensive oxide layers on the mineral surfaces of milled samples (AM) led to a substantial reduction in their recoveries by increasing the microwave’s power level and the sample’s exposure time. The results obtained from mineral’s floatabilities in recleaner stage showed that the microwave-assisted sample at 900W for 30s at BC state favourably provided 5% higher S.E.’s than that of the untreated sample. Finally, it was concluded that the microwave pretreatment of samples induced the best floatability responses if it located before the crusher.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2020, 56, 3; 432-448
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study on pre-concentration efficiency of wolframite from tungsten ore using gravity and magnetic separations
    Autorzy:
    Lu, D.
    Wang, Y.
    Jiang, T.
    Sun, W.
    Hu, Y.
    Powiązania:
    https://bibliotekanauki.pl/articles/109597.pdf
    Data publikacji:
    2016
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    tungsten ore
    pre-concentration
    separation efficiency
    gravity separation
    magnetic separation
    Opis:
    Pre-concentration is effectively applied in recovering wolframite from tungsten ore, due to its benefits of further upgrading tungsten ore and improving separation efficiency. The most important pre-concentration techniques for tungsten ore include gravity separation and magnetic separation, based on the fact that there are appreciable differences, between the desired wolframite and the gangue minerals, in density and magnetic susceptibility. This study investigated the separation efficiency of gravity pre-concentration (Falcon Concentrator) and high-gradient magnetic pre-concentration (SLon VPHGMS) for the beneficiation of a Canada tungsten ore. It is a low-grade type of ore with high silica and arsenic content, and an average content of WO3 is about 0.45%. The optimum conditions for different operational parameters of two pre-concentration separators were studied on this low-grade material. The results presented in this paper suggested that although both pre-concentration techniques were effective for producing pre-concentrates containing high WO3, magnetic pre-concentration showed significantly better separation efficiency. Over 90% of the feed was rejected as the final tailings, meanwhile, over 85% of arsenic minerals were removed with tailings, while the WO3 loss was less than 15%.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2016, 52, 2; 718-728
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The influence of micro-morphology and micro-structure on fly ash triboelectrostatic beneficiation
    Autorzy:
    Wang, Wenping
    Chen, Yinghua
    Haisheng, Li
    Dong, Haoran
    Wang, Guanghui
    Powiązania:
    https://bibliotekanauki.pl/articles/1448347.pdf
    Data publikacji:
    2021
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    fly ash
    triboelectrostatic beneficiation
    micro-structure
    micromorphology
    separation efficiency
    Opis:
    Fly ash is a complex system with a variety of fine particles. The complex relationship between unburned carbon and ash particles has an important influence on the efficiency of fly ash triboelectrostatic beneficiation. The particles adhered to the two electrode plates are collected through the triboelectrostatic beneficiation experiment. The scanning electron microscopy and X-ray fluorescence are used to detect the microscopic differences between the particles of positive and negative plates. The results show that the flaky carbon particles in the raw ash and the ash particles larger than 4µm are more easily separated, while it is converse for the ash particles with particle size less than 4µm. With the particle size less than 4µm, it is gradually more obvious for the influence of adhesion caused by the roughness surface of spherical unburned carbon particles, and the surface pores structure of porous carbon particles. The binding structure between unburned carbon and ash particles is complex and changeable. It is not beneficial to improve the separation efficiency. Therefore, the micro-structure and micro-morphology have an important effect on fly ash triboelectrostatic beneficiation. Some suggestions were proposed from the microscopic point to improve the efficiency of fly ash triboelectrostatic beneficiation.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2021, 57, 1; 53-63
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A new approach in separation process evaluation. Efficiency ratio and upgrading curves
    Autorzy:
    Irannajad, M.
    Nuri, O. S.
    Allahkarami, E.
    Powiązania:
    https://bibliotekanauki.pl/articles/110189.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    separation efficiency
    mineral processing
    selectivity index
    process evaluation
    efficiency ratio
    operation efficiency
    Separation Process
    Opis:
    In mineral processing separation efficiency (SE), operation efficiency (OE), selectivity index (SI) and other indices have been used to evaluate the separation process. Up to now, no study has been conducted on the relationship between the SE, OE and SI indices. In this research, two upgrading curves are proposed based on the above indices for process and selectivity evaluation. The first upgrading curve is based on recovery R, SE, and OE as a function of concentrate grade. This curve has three background lines, including no upgrading line, ideal upgrading line and the ideal mixing line. The proposed upgrading curve is applicable not only for process evaluation by specification of OE and SE, but also for selectivity evaluation with the lowest difference between SE and OE. The curve showed that the recovery value is always greater than the SE and OE values. The parameters of OE, SE and R were used for plotting the upgrading curve as a function of concentrate grade taking into consideration all of them at a time. A new selectivity indicator, namely Efficiency Ratio (ER) as the selectivity parameter, is proposed as the ratio of OE to SE. The ER values fluctuate between 1 and . It can be presented as a function of concentrate and tailing grades (ER = [c(1-t)]/[1(c-t)]). The results showed that ER is insensitive to the feed grade and has the inverse relationship with SI. To measure the separation selectivity, another upgrading curve is proposed based on ER and SI parameters. This curve is divided into seven separation classes for evaluation the class of a separation process from ideal class to no separation one. The results of this research can be useful for separation process evaluation.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2018, 54, 3; 847-857
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Evaluation of the efficiency of metal recovery from printed circuit boards using gravity processes
    Autorzy:
    Franke, Dawid M.
    Suponik, Tomasz
    Nuckowski, Paweł M.
    Dubaj, Justyna
    Powiązania:
    https://bibliotekanauki.pl/articles/1445935.pdf
    Data publikacji:
    2021
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    metals recovery
    printed circuit board
    gravity separation
    ICP-AES
    SEM-EDS
    Opis:
    This paper evaluates the efficiency of metal recovery from printed circuit boards (PCBs) using two gravity separation devices: a shaking table and a cyclofluid separator. The test results were compared with the results obtained from previous research, where an electrostatic separation process was used for an identically prepared feed. The feed for the separators consisted of PCBs shredded in a knife mill at cryogenic temperatures. The separation efficiency and purity of the products were evaluated based on microscopic analysis, ICP-AES, SEM-EDS, XRD, and specific density. The yield of concentrates (valuable metals) obtained from the shaking table and the cyclofluid separator amounted to 25.7% and 18.9%, respectively. However, the concentrate obtained from the cyclofluid separator was characterised by much higher purity, amounting to ~88% of valuable metals, compared to ~72% for the shaking table. In both cases, middlings formed a significant share, their yield amounting to ~25%, with the share of valuable metals of ~15%. The yield of waste obtained from the shaking table and the cyclofluid separator were 42.6% and 52.5%, respectively. In both cases, as a result of the applied process, the waste was divided into two homogeneous groups differing in grain size and shape. The recovery of metals through gravity separation is possible, in particular, by using a shaking table. These processes can also be applied to separate waste (plastics) into two groups to be selectively processed to produce new materials in line with a circular economy.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2021, 57, 4; 63-77
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Evaluation of flotation reagents by normalization procedures
    Autorzy:
    Drzymala, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/109804.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    flotation
    separation
    foam
    froth
    frother
    selectivity
    efficiency
    normalization
    generic reagents
    selective reagents
    internal parameter
    external parameter
    Opis:
    Froth flotation is a dynamic multiphase process in which particulate matter is separated with the help of chemical reagents by gas bubbles immersed in water. The original flotation results are usually presented in the form of kinetic curves relating recovered particulate matter mass (yield ) or mass of a selected component (recovery ), both shortly denoted as y, versus process time t at different concentrations c (g/dm3) of the applied reagents. The kinetic curves can be modified into three: incentive (maximum yield or recovery ymax vs c), limits (ymax vs kinetic constant k or specific rate) and half-life of flotation (t1/2 vs c) curves. The original and modified curves can be normalized by taking into account either an external parameter such as molecular mass (MW), critical coalesce concentration (CCC), critical concentration at the minimum bubble velocity (CMV), dynamic foaming index (DFI), and many other parameters or an internal parameter such as time, concentration needed to achieve certain yield, recovery (y) or kinetic constant. Normalization leads to new flotation curves and provides additional useful information about flotation performance. Normalization can be fully effective, partial or ineffective. Normalization of the original flotation kinetic curves usually is ineffective. Also, normalization of the incentive curve with external parameters such as frother molecular mass, which changes reagent concentration from c (g/dm3) to C (mol/dm3), is also ineffective. Partially effective are normalizations with other external parameters such as CCC and CMV, usually within the same class of regents, for instance alcohols. Only DFI seems to be a universal external normalization parameter for flotation results because it provides fully effective normalization and thus predicts the flotation results. Limited data on DFI restrict a full verification of this hypothesis. Normalization of the modified flotation curves with internal parameters such as k50 (value of 1st order kinetic constant when recovery or yield is 50% after a given flotation time), Ct1/2 (frother concentration in mol/dm3 at which the flotation half-life has an arbitrarily chosen value) and cy75 (frother concentration in g/dm3 at which recovery or yield is 75% after a given flotation time) is a good base for practical classification of flotation reagents.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2018, 54, 1; 182-192
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of crushing type on the efficiency of flowing film separation
    Autorzy:
    Sirkeci, A. A.
    Gul, A.
    Bulut, G.
    Ozer, M.
    Guven, O.
    Perek, K. T.
    Powiązania:
    https://bibliotekanauki.pl/articles/109918.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    particle shape characteristics
    liberation degree
    chromite
    shaking table
    Opis:
    In recent years, the influence of different crushing systems (compression, impact, attrition) has been receiving more attention due to their significant role on particle liberation and shape of particles. The objective of this study was to investigate the effects of different crushing systems on both liberation degree and shape factors of chromite particles along with their enrichment conditions by shaking table. The tests were conducted on -1+0.5, -0.5+0.212 and -0.212 mm size fractions using the Wilfley type shaking table. The results of these tests showed that concentrates with higher metal contents were obtained by impact crushing of chromite in proportion to higher liberation degree and roundness of particles. Therefore, it was found that selective breakage can well be obtained by impact crushing in all fractions. The results of this study demonstrated the importance of crushing type on the liberation and enrichment processes.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2018, 54, 2; 601-608
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-11 z 11

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