scholarly journals Enhanced Flotation Recovery of Fine Molybdenite Particles Using a Coal Tar-Based Collector

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1439
Author(s):  
Yande Chao ◽  
Shulei Li ◽  
Lihui Gao ◽  
Lijuan Sun ◽  
Lingni Li ◽  
...  
Keyword(s):  
Rate Constant ◽  
Surface Coverage ◽  
Coal Tar ◽  
Low Grade ◽  
Industrial Practice ◽  
Crystal Anisotropy ◽  
Flotation Recovery

Low flotation efficiency has always been a problem in the separation of low-grade molybdenum ores because of the finely disseminated nature and crystal anisotropy of molybdenite. In this study, a novel kerosene–coal tar collector (KCTC) was prepared and used to explore the feasibility of improving the recovery of fine molybdenite particles. The results showed that KCTC achieved better attaching performance than that shown by kerosene, and the surface coverage and attaching rate constant were improved significantly, especially for finer particles of −38 + 20 μm. Compared with kerosene, KCTC showed more affinity for molybdenite particles and greater adsorbed amounts of KCTC on molybdenite particles were achieved. Moreover, the composite collector was shown to float single molybdenite particles of different sizes, and it was found that the recovery of molybdenite particles of different sizes, particularly in the case of those at −20 μm, was improved dramatically by KCTC. The flotation results of actual molybdenum ores further confirmed that KCTC was beneficial to flotation recovery and the selectivity of molybdenite. This indicated that KCTC is a potential collector for the effective flotation of low-grade deposits of molybdenum ores, and more studies should be conducted on further use in industrial practice.

scholarly journals Investigation on Component Separation and Structure Characterization of Medium-Low Temperature Coal Tar

2019 ◽  
Vol 9 (20) ◽  
pp. 4335
Author(s):  
Ning Zhao ◽  
Dong Liu ◽  
Hui Du ◽  
Congcong Wang ◽  
Fushan Wen ◽  
...  
Keyword(s):  
Low Temperature ◽  
Coal Tar ◽  
Molecular Composition ◽  
Structure Characterization ◽  
Low Rank ◽  
Proton Nuclear Magnetic Resonance ◽  
Composition Analysis ◽  
Low Grade ◽  
Distillate Fraction ◽  
Distillate Fractions

Two medium-low temperature coal tars (MLCTs) derived from the pyrolysis of low-grade bituminous coal were separated into 11 narrow fractions by true boiling distillation. The primary property and chemical composition analysis of MLCTs and their distillate narrow fractions were investigated at the macroscopic and molecular level by gas chromatography-mass spectrometer (GC-MS) and proton nuclear magnetic resonance (1H NMR). The two MLCTs show obvious characteristics of medium-low temperature coal tar, including a high H/C, high-oxygen and nitrogen, low-sulfur, low-density, and low viscosity. As the boiling point increases, the molecular weight of each distillate fraction increases continuously. Meanwhile, the yield of each distillate fraction increases gradually, except for the 270–300 °C distillate fractions. The oxygen content in the 170–230 °C distillate fractions is much higher than that of the other distillate fractions. The dominant groups of compounds in the MLCTs were saturates, aromatics, and resins, and the resin content was above 24.5 wt%. The molecular composition of the below 170 °C fractions mainly consists of benzene, toluene, and xylene, and the main phenolic compounds in the 170–230 °C distillate fraction are low-rank phenols, such as phenol, cresol, and xylenol. Although the macroscopic properties of the MLCT-Z and MLCT-S were quite similar, the molecular composition, the group composition and hydrogen distribution in each MLCT and its narrow distillate fractions are still different. The present work has contributed to our present understanding of the composition of MLCTs and to the guiding of the efficient processing of MLCTs.

scholarly journals Thermokinetic parameters of the primary coal tars destruction in the presence of catalysts and polymeric materials

2021 ◽  
Vol 102 (2) ◽  
pp. 89-95
Author(s):  
N.Zh. Balpanova ◽  
◽  
M.I. Baikenov ◽  
A.M. Gyulmaliev ◽  
Z.B. Absat ◽  
...  
Keyword(s):  
Activation Energy ◽  
Nickel Oxide ◽  
Rate Constant ◽  
Thermal Destruction ◽  
Coal Tar ◽  
Magnetic Microspheres ◽  
Thermokinetic Parameters ◽  
Isothermal Kinetics ◽  
Organic Mass ◽  
Oxide Particles

The hydrogen-donor abilities of polymers and the activity of catalysts in the process of thermal destruction of the organic mass of primary coal tar (PCT) are studied by non-isothermal kinetics methods. PCT,magnetic microspheres, nickel-deposited chrysotilechrysotile and Fe3O4nanocatalysts were used as initial raw materials. Рolymers such as polyethylene (PE), polystyrene(PS) and polyethylene glycol (PEG) were selected as a hy-drogen donor. The phases Mg3[OH]4{Si2O5} and NiO were determined by X-ray phase analysis (XRD) in the obtained catalyst (nickel-deposited chrysotile), and the presence of highly dispersed nickel oxide particles on the surface and inside the nanotubes was shown by the transmission electron microscope (TEM). Nickel oxide particles of 8–11 nmand 30–37 nmwere evenly distributed on the surface and inside the chrysotile nanotubes. The kinetic parameters of the thermal destruction of a mixture of PCT, catalyst and polymer material were determined on the basis of thermogravimetric analysis using the integral method and the method for determin-ing the thermokinetic parameters by the inflection point on the thermogravimetric curve(TG). The change in the activation energy, rate constant and pre-exponential factor with an increase in the degree of destruction of the organic mass of the PCT is established. It was shown that the nature of polymers and catalysts significantly affects the value of the rate constant and the activation energy. The calculated activation energies of the thermal destruction of a mixture of coal tar with PS and PE in the presence of a catalyst (nickel-deposited chrysotile) by the first method are 47.6 kJ/mol and 40.4 kJ/mol, and by the second method are 47.3 kJ/mol and 86.5kJ/mol respectively.

scholarly journals The Effect of Hydrodynamic Conditions on the Selective Flotation of Fully Liberated Low Grade Copper-Nickel Ore

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 328
Author(s):  
Haresh Kumar ◽  
Kirsi Luolavirta ◽  
Saad Ullah Akram ◽  
Hassan Mehmood ◽  
Saija Luukkanen
Keyword(s):  
Rate Constant ◽  
Nickel Particle ◽  
Bubble Surface ◽  
Low Grade ◽  
Hydrodynamic Conditions ◽  
Gas Velocity ◽  
Selective Flotation ◽  
Fine Grained ◽  
Superficial Gas Velocity ◽  
Bubble Surface Area Flux

Low grade sulfide ores are difficult to process due to their composite mineralogy and their fine grained dissemination with gangue minerals. Therefore, fine grinding of such ores becomes essential to liberate valuable minerals. In this research, selective flotation was carried out using two pitched blade turbine impellers with diameters of 6 cm and 7 cm to float copper and nickel. The main focus of this research was to generate optimum hydrodynamic conditions that can effectively separate nickel and copper from gangue minerals. In addition, we investigated the effects of superficial gas velocity, impeller speed, bubble size distribution, and bubble surface area flux on the flotation recovery and rate constant. The results demonstrated that a 7 cm impeller comparatively produced optimum hydrodynamic conditions that improved Cu-Ni recovery and the rate constant. The maximum copper and nickel recoveries in the 7 cm impeller tests were observed at 93.1% and 72.5%, respectively. However, a significant decrease in the flotation rate of nickel was observed, due to entrainment of nickel in copper concentrate and the slime coating of gangue minerals on the nickel particle surfaces.

Catalytic coal-tar decomposition to enhance reactivity of low-grade iron ore

2013 ◽  
Vol 113 ◽  
pp. 84-89 ◽  
Author(s):  
Rochim B. Cahyono ◽  
Alya N. Rozhan ◽  
Naoto Yasuda ◽  
Takahiro Nomura ◽  
Sou Hosokai ◽  
...  
Keyword(s):  
Iron Ore ◽  
Coal Tar ◽  
Low Grade

Flotation recovery of vanadium from low-grade stone coal

2014 ◽  
Vol 24 (4) ◽  
pp. 1145-1151 ◽  
Author(s):  
Li WANG ◽  
Wei SUN ◽  
Run-qing LIU ◽  
Xiao-chuan GU
Keyword(s):  
Low Grade ◽  
Stone Coal ◽  
Flotation Recovery

Concentration effect of copper loading on the reductive dechlorination of tetrachloroethylene by zerovalent silicon

2010 ◽  
Vol 62 (1) ◽  
pp. 28-35 ◽  
Author(s):  
Chun-chi Lee ◽  
Ruey-an Doong
Keyword(s):  
Rate Constant ◽  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Surface Coverage ◽  
Metal Layer ◽  
Chemical Species ◽  
Distribution Patterns ◽  
Order Rate Constant ◽  
High Concentration ◽  
Low Concentration

The dechlorination of tetrachloroethylene (PCE) by zerovalent silicon (Si(0)) in the presence of low concentration of Cu(II) ion was investigated under anaerobic conditions. The mass loadings of Cu(II) in the Si(0)-H2O system were in the range 0.06–3 wt% (0.02–1 mM). In addition, the X-ray photoelectron spectroscopy (XPS) and electron probe microanalysis (EPMA) were used to characterize the change in chemical species and distribution patterns of metals, respectively. Results showed that the pre-incubation time of 3 d was needed to activate the reactive sites of Si(0) before the dechlorination of PCE. Addition of low concentration of Cu(II) at 0.06 wt% significantly enhanced the dechlorination of PCE, while high concentration of Cu(II) would occupy the reactive sites of Si(0), and subsequently decreased the dechlorination efficiency and rate of PCE. The pseudo first-order rate constant (kobs) for PCE dechlorination by 0.06 wt% Cu/Si was 0.028 h−1, which was 2.8 times higher than that by Si(0) alone. However, the kobs for PCE dechlorination decreased to 0.0016 h−1 when the loading of Cu(II) increased to 3 wt%. The EPMA results showed that the distribution of 0.06 wt% Cu on the Si(0) surface was homogeneous without any aggregation, which means that the maximum rate constant was observed before the total coverage of the active sites on the reductive metal by the catalytic metal layer. The surface coverage of Cu to Si(0) can theoretically calculate by estimation of the lowest energy fcc(111) crystallographic orientation. The calculated surface coverage of 0.06 wt% Cu onto Si(0) was approximately 43%, which is consistent with the experimental results obtained in this study.

Beneficiation of a Low-Grade Flaky Graphite Ore from Australia by Flotation

2015 ◽  
Vol 1090 ◽  
pp. 188-192
Author(s):  
Xin Zhang ◽  
Ling Yan Zhang ◽  
Yang Shuai Qiu ◽  
Xin Qu
Keyword(s):  
Recovery Rate ◽  
Closed Circuit ◽  
Low Grade ◽  
Flotation Reagents ◽  
Pine Oil ◽  
Flotation Recovery ◽  
Flotation Method

The graphite ore from Australia is a sort of the low-grade and fine-scaled graphite ore. On the basis of the optimum rough grinding fineness, an open and a closed circuit tests were conducted which consist of one rougher, one scavenging, then four-time-regrinding and five-time-cleaning to the rough concentrate, one grinding and scavenging to the mixture of middling1~3, and the middling4~6 returned to the rougher, cleaning1 and cleaning2 respectively. Taking the kerosene, pine oil, lime as flotation reagents, the concentrate with grade improvement from 12.78% to 90.5% was achieved through the routine flotation method, as the flotation recovery rate reached to 92.46%.

scholarly journals Effect of Binders on the Crushing Strength of Ferro-Coke

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 850
Author(s):  
Runsheng Xu ◽  
Shuliang Deng ◽  
Wei Wang ◽  
Heng Zheng ◽  
Shaopeng Chen ◽  
...  
Keyword(s):  
Iron Ore ◽  
Corn Starch ◽  
Coal Tar ◽  
Carbon Matrix ◽  
Coal Tar Pitch ◽  
Low Grade ◽  
X Ray Diffraction ◽  
Crushing Strength ◽  
Bonding Effect ◽  
Cold Crushing Strength

Ferro-coke, as a new burden of blast furnace (BF), can not only greatly reduce the energy consumption and CO2 emission, but also promote the resource utilization by using the low-quality iron ore and low-grade coal. However, the strength of ferro-coke decreased with the increasing amount of iron ore powder. In order to maintain the strength of ferro-coke while increasing the amount of iron ore powder, it is necessary to add binder during the coking process to enhance the strength of ferro-coke. In this paper, phenolic resin, silicon metal powder, corn starch, and coal tar pitch were used as binder for the fabrication of ferro-coke. I-type drum machine (I 600), scanning electron microscope (SEM), and X-ray diffraction (XRD) were applied to test the crushing strength, morphology, and microcrystalline structure of the ferro-coke. The results showed that the increasing amount of iron ore powder resulted in lower crushing strength, higher porosity, and the worse macroscopic morphology of ferro-coke. When the amount of iron ore powder reached 40%, obvious cracks appeared on the surface of ferro-coke. When the amount of iron ore was 30%, the crushing strength of ferro-coke dropped to 18.15%. Among the four binders, coal tar pitch could significantly enhance the cold crushing strength of ferro-coke through decreasing the porosity of ferro-coke and improving the bonding effect between carbon matrix particles. In the case of the 10% coal tar pitch addition, the cold crushing strength of ferro-coke was increased from 18.15% to 76.41%; meanwhile, its hot compression strength during gasification improved by 100N.

scholarly journals Composition of phenolic compounds in wastewater from the fixed-bed gasification of Baishihu coal

2021 ◽  
Author(s):  
Yuan Zhao
Keyword(s):  
Phenolic Compounds ◽  
Water Solubility ◽  
Coal Tar ◽  
Fixed Bed ◽  
Value Added ◽  
Total Content ◽  
Raw Material ◽  
Low Grade ◽  
Distillation Range ◽  
Range Analysis

AbstractCrude phenols extracted using organic solvent from the wastewater of a typical fixed-bed gasification process was used as a raw material, and the distillation range was analyzed. The wide and narrow fractions of the raw material derived from distillation range analysis were cut using a real boiling point distillation device. The phenolic compounds in the different fractions were then qualitatively and quantitatively analyzed by gas chromatography after derivatization pretreatment. The yield of the < 290 °C fraction was 68.50% (mass fraction). A total of 33 effective phenolic compounds were identified in this fraction, and the percentage of identified phenols was nearly 80%. The contents of eight phenolic compounds were high, with phenol being the most abundant (26.34%) followed by catechol (13.44%). The contents of the remaining six abundant phenols ranged from 4% to 8%. The sum of the contents of m-cresol and p-cresol exceeded 12%, and the content of 5-indenol was nearly 8%. The yield of the fraction rich in low-grade phenols (< 230 °C) was 35.40%. The content of phenol in this fraction was more than 40%, the total content of cresol was over 23%, and the total content of m-cresol and p-cresol was nearly 20%. At room temperature, the 235–245 °C and 245–260 °C fractions were white crystals in which the catechol content was approximately 50%, and the 5-indenol content was more than 10%. The contents of these two high-value-added phenolic compounds are low in typical coal tar, making them difficult to extract. However, due to their strong polarity and good water solubility, catechol and 5-indenol are enriched in gasification wastewater by water selection, allowing their further extraction.

The Influence of Cetane Additive on Diesel Oil Performance

2014 ◽  
Vol 513-517 ◽  
pp. 343-346
Author(s):  
Chao Liang ◽  
Ya Xu Chu ◽  
Jian Zhang
Keyword(s):  
Diesel Engine ◽  
Thermal Efficiency ◽  
Coal Tar ◽  
Cetane Number ◽  
Diesel Oil ◽  
Heavy Fraction ◽  
Low Grade ◽  
Engine Fuel ◽  
Boiler Fuel ◽  
Oil Performance

The production of mesothermal coal tar dutrey oil cetane number is low grade, heavy fraction is too much, and will affect the use of the product range. Generally only used as a boiler fuel, not as a diesel engine fuel. By adding a cetane number of Heavy Dutrex by join cetane additive, can increase the cetane number of Heavy Dutrex oil and accelerate the burning rate of Heavy Dutrex, improve thermal efficiency and emissions of combustion quality, the use of diesel engines to meet the needs.

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