scholarly journals Carrier Flotation of Low-Rank Coal with Polystyrene

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 452
Author(s):  
Gen Huang ◽  
Jiaqi Xu ◽  
Pengyue Geng ◽  
Jihui Li
Keyword(s):  
Fine Particles ◽  
Hydrophobic Interactions ◽  
Ash Content ◽  
Low Rank ◽  
Low Rank Coal ◽  
Fine Coal ◽  
Coal Particles ◽  
Electron Microscopy Analysis ◽  
Flotation Performance ◽  
Oxygenated Functional Groups

The problem of low-rank coal flotation continues to be a challenge due to the poor hydrophobicity and abundant oxygenated functional groups on particle surfaces. In this study, carrier flotation was used to improve the flotation performance of low-rank coal with polystyrene as a carrier material. Kerosene was used as a collector and played a role in the adhesion of fine low-rank coal to polystyrene due to its hydrophobic properties. The carrier feature of polystyrene was demonstrated by Turbiscan Lab Expert stability analysis and scanning electron microscopy analysis. The flotation experiments revealed that the optimum conditions were: collector dosage 5000 g/t, pulp concentration 40 g/L, and the ratio of low-rank coal to polystyrene 100:10. Under these conditions, the combustible recovery by carrier flotation was obtained as 70.59% when the ash content was 12.32%, which increased by 25.68 points compared with the combustible recovery of conventional flotation under almost the same ash content. The fine coal particles coated the coarse polystyrene particles through hydrophobic interactions between the polystyrene and hydrocarbon chains of the kerosene adsorbed on coal particles. The results suggested that the flotation performance of low-rank coal was significantly improved by carrier flotation with polystyrene, especially for fine particles.

Attachment interactions between low-rank coal particles and air/oily bubbles in a microflotation cell

2018 ◽  
Vol 41 (10) ◽  
pp. 1209-1215
Author(s):  
You Zhou ◽  
Boris Albijanic ◽  
Shiwei Wang ◽  
Guosheng Li ◽  
Xiangnan Zhu
Keyword(s):  
Low Rank ◽  
Low Rank Coal ◽  
Coal Particles

scholarly journals Effects of temperature gradient and particle size on self-ignition temperature of low-rank coal excavated from inner Mongolia, China

2019 ◽  
Vol 6 (9) ◽  
pp. 190374 ◽  
Author(s):  
Yongjun Wang ◽  
Xiaoming Zhang ◽  
Hemeng Zhang ◽  
Kyuro Sasaki
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Temperature Gradient ◽  
Ignition Temperature ◽  
Coal Particle ◽  
Critical Value ◽  
Low Rank ◽  
Low Rank Coal ◽  
Coal Particles ◽  
Effects Of Temperature

This study investigates the effects of temperature gradient and coal particle size on the critical self-ignition temperature T CSIT of a coal pile packed with low-rank coal using the wire-mesh basket test to estimate T CSIT based on the Frank–Kamenetskii equation. The values of T CSIT , the temperature gradient and the apparent activation energy of different coal pile volumes packed with coal particles of different sizes are measured. The supercriticality or subcriticality of the coal is assessed using a non-dimensional index I HR based on the temperature gradient at the temperature cross-point between coal and ambient temperatures for coal piles with various volumes and particle sizes. The critical value I HRC at the boundary between supercriticality and subcriticality is determined as a function of pile volume. The coal status of supercritical or subcritical can be separated by critical value of I HR as a function of pile volume. Quantitative effects of coal particle size on T CSIT of coal piles are measured for constant pile volume. It can be concluded that a pile packed with smaller coal particles is more likely to undergo spontaneous combustion, while the chemical activation energy is not sensitive to coal particle size. Finally, the effect of coal particle size on T CSIT is represented by the inclusion of an extra term in the equation giving T CSIT for a coal pile.

Experimental Study on Low-Temperature Carbonization of Low Rank Coal

2013 ◽  
Vol 805-806 ◽  
pp. 1311-1316
Author(s):  
Li Qun Wang ◽  
Zhong Xiang Wei ◽  
Zhong Bo Yi
Keyword(s):  
Experimental Study ◽  
Ash Content ◽  
Carbonization Temperature ◽  
Holding Time ◽  
Low Rank ◽  
Volatile Content ◽  
Low Rank Coal ◽  
Fixed Carbon ◽  
Dry Distillation ◽  
Increasing Trend

In this paper,a research was carried out on the regularities of carbonization temperature,holding time and mass on weightlessness of low rank coal. The experiment showed experiments in a certern range (450°C~700°C,<60min),weightlessness of coal in an increasing trend,the remained volatile content of semi-coke was measured reduce tending to value,ash content increased,fixed carbon gradually increased in the temperature range with the improvement of the carbonization temperature and holding time,also hydrogen and oxygen content of the char decreased,a significant increased in the carbon content,nitrogen and sulfur content was essentially the same. Reactivity of CO2 and semi-coke obtained in different carbonization conditions were better,the response rates are 100% when the temperature exceeded 1000°C. Best condition of dry distillation: carbonization temperature was 500°C~650°C,mass of low rank coal was less than 30g,holding time was between 30 minutes to 40 minutes.

Enhancing flotation performance of low rank coal by improving its hydrophobicity and the property of oily bubbles using 2-ethylhexanol

2017 ◽  
Vol 167 ◽  
pp. 61-67 ◽  
Author(s):  
Songjiang Chen ◽  
Longfei Tang ◽  
Xiuxiang Tao ◽  
Huan He ◽  
Liang Chen ◽  
...  
Keyword(s):  
Low Rank ◽  
Low Rank Coal ◽  
Flotation Performance

scholarly journals Improving Coal Flotation by Gaseous Collector Pretreatment Method and its Potential Application in Preparing Coal Water Slurry

Processes ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 500 ◽  
Author(s):  
Shen ◽  
Min ◽  
Liu ◽  
Xue ◽  
Zhu
Keyword(s):  
Contact Angle ◽  
Coal Sample ◽  
Ash Content ◽  
Low Rank ◽  
Distribution Analysis ◽  
Low Rank Coal ◽  
Clean Coal ◽  
Pretreatment Method ◽  
Water Slurry ◽  
Coal Water Slurry

Low-rank coal is difficult to upgrade using conventional flotation methods due to its high hydrophilic properties. Thus, it is necessary to explore new methods for upgrading and utilizing low-rank coal. In this investigation, a gaseous dodecane pretreatment method was used to enhance the flotation performance of low-rank coal. Pore distribution analysis, FTIR (Fourier Transform Infrared Spectroscopy), and contact angle measurements were used to study the surface properties of the coal sample. Size distribution and float-sink test results indicated that the coal sample contained a lot of clean coal with low ash content, which could be used as a high quality raw material for making coal water slurry. FTIR, pore distribution analysis, and contact angle results showed that the coal was very hydrophilic due to the high concentration of -OH group and the large number of pores and cracks on the coal surface. The hydrophobicity of the coal sample was significantly improved by the gaseous dodecane pretreatment method. Clean coal with 67.2% combustible matter recovery and 10.5% ash content was obtained by gaseous dodecane pretreatment flotation method. Coal water slurry with 60% concentration was prepared using the flotation clean coal.

scholarly journals Effect of Comminution Methods on Low-Rank Coal Bubble–Particle Attachment/Detachment: Implications for Flotation

Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 452 ◽  
Author(s):  
Guoqiang Rong ◽  
Yangchao Xia ◽  
Youfei Zhang ◽  
Fangyu Guo ◽  
Dongyue Wang ◽  
...  
Keyword(s):  
Morphological Characteristics ◽  
Bubble Surface ◽  
Diameter Ratio ◽  
Low Rank ◽  
Low Rank Coal ◽  
Attachment Efficiency ◽  
Coal Flotation ◽  
Coal Particles ◽  
Wrap Angle ◽  
Particle Attachment

The floatability of fine low-rank coal particles can be greatly influenced by their morphological characteristics, such as shape and surface roughness. In this study, the attachment efficiency and detachment amplitude of fine low-rank coal particles produced by various comminution methods onto/from the bubble surface were investigated using homemade bubble–particle wrap angle and bubble–particle attachment/detachment testing systems. Results showed that the length–diameter ratio of rod-milled products was smaller than that of crushed products. The wrap angle of particles obtained by the crushed method was larger than that obtained by the rod-milled method, i.e., particles with greater length–diameter ratio showed higher attachment efficiency onto the bubble surface. Meanwhile, particles with greater length–diameter ratio exhibited a larger detachment amplitude, which suggests that it is more difficult to be detached from the bubble surface. However, rod-milled products showed lower attachment onto the bubble surface. The flotation test confirmed that the floatability ratio of crushed products was higher than that of rod-milled products, consistent with evidence from experimental analyses. This study provides a fundamental understanding of particle shapes for low-rank coal flotation by a novel research method combining the attachment efficiency and detachment amplitude of bubble–particle combinations.

Comparison of flotation performances of low-rank coal with lower ash content using air and oily bubbles

2020 ◽  
Vol 374 ◽  
pp. 443-448
Author(s):  
Shiwei Wang ◽  
Kaifang Liu ◽  
Xiangchuan Ma ◽  
Xiuxiang Tao
Keyword(s):  
Ash Content ◽  
Low Rank ◽  
Low Rank Coal

scholarly journals CHARACTERISTICS AND LIQUEFACTION OF COAL FROM WARUKIN FORMATION, TABALONG AREA, SOUTH KALIMANTAN–INDONESIA

2015 ◽  
Vol 5 (2) ◽  
Author(s):  
Edy Nursanto ◽  
Arifudin Idrus ◽  
Hendra Amijaya ◽  
Subagyo Pramumijoyo
Keyword(s):  
Volatile Matter ◽  
Ash Content ◽  
Coal Liquefaction ◽  
Low Rank ◽  
Coal Rank ◽  
Low Rank Coal ◽  
Coal Seams ◽  
Fixed Carbon ◽  
Time Intervals ◽  
Coal Properties

Since the coal characteristic is the main controlling factors in coal liquefaction, thus five coal seams with different coal rank from Warukin Formation in Tabalong Area, South Kalimantan have been used in this study. Three seams were low rank coal (Wara 110, Wara 120, Wara 200) while two seams were medium rank (Tutupan 210 and Paringin 712). The objectives of this study was to investigate the effect of coal rank on the rate of coal conversion factor. Coal liquefaction was conducted in an autoclave on low pressure (14.7 psi) and temperature 120°C. Experiments were designed with time intervals 30, 60 and 90 minutes, respectively. The average coal properties of seam Wara 110, Wara 120 and Wara 200 were 26.65%, 5.08%, 46.26% and 30.60% for inherent moisture, ash content, volatile matter and. fixed carbon, respectively. In contrast, coal properties for seam Tutupan 210 and Paringin 712 were 18.42%, 1.81%, 23.02% and 35.76% for inherent moisture, ash content, volatile matter and fixed carbon, respectively. The maximum yields for Wara 110, Wara 120 and Wara 200 were 48.60% (30 minutes), 51.27% (60 minutes) and 46.72% (90 minutes). In comparison, Tutupan 210 and Paringin 712 resulted maximum yields of 8.22% (30 minutes), 18.35% (60 minutes), 6.23% (90 minutes). In conclusion, low rank coal has higher yield conversion compared to medium rank coal since it has higher H/C ratio. Keywords: Coal liquefaction, low rank coal, Kalimantan.

Sign in / Sign up

Export Citation Format

Share Document