scholarly journals Recovery of clean coal from blast furnace dusts by flotation column

2020 ◽  
Vol 61 (1) ◽  
pp. 124-131 ◽  
Author(s):  
Tran Van Duoc ◽  
Nguyen Hoang Son ◽  
Nhu Thi Kim Dung ◽  
Vu Thi Chinh ◽  

The paper presents the results of the study on recovery of clean coals from blast furnace dusts of the Cao Bang Iron Steel plant. The study has explored the effects of the most important operating parameters on the coal flotation performance including flotation reagent dosage, solid concentration, froth wash-water rate, flotation time and the froth thickness. The results of the study showed that using a combination of a rougher and a cleaning flotation operations at respectively collector dosage, solid concentration, flotation time, froth wash-water rate and froth thickness of 1000 g/t, 100 g/l, 10 minutes and 1.5 l/minute and 450 mm, has obtained a clean coal product with the yield, ash content and combustible matter recovery respectively of 44.90%, 19.15% and 77.63%. The clean coal has met the quality strandards requirements of the fuel for sintering.

2014 ◽  
Vol 1010-1012 ◽  
pp. 1603-1608 ◽  
Author(s):  
Jian Zhong Wang ◽  
Xian Bo Zhang ◽  
Hai Bin Qin ◽  
Li Tan

Coal slime in Zhongcheng coal preparation plant in Baotou, Inner Mongolia, was analyzed. It is found that this coal sample is with high inner ash content and very difficult to float. It is hard to obtain low ash concentrate and high ash tailing with primary flotation. The live scale required ash content is 12.00% for total clean coal, 15.00% for flotation concentrate. It is found that the lowest concentrate ash content is 29.24% through exploring flotation experiments, which can not meet the producing requirement. Results of timed release flotation experiment show that when concentrate ash content is 15.00%, the theoretical concentrate yield is 24.36%, with 50.03% of flotation tailing ash content and 35.49% of combustible matter recovery. It can be concluded that the floatable grade of this coal sample is Very Difficult to Float. So flotation column is taken into account. The lowest concentrate ash content of roughing flotation by flotation column is 18.94%, which does not meet the requirement, either. Results of cleaning flotation of roughing flotation concentrate show that when the recycling pressure is 0.14 MPa, the concentrate ash content is 14.15% with a yield of 30.39%, which is satisfactory and can be referred to direct industrial production.


2021 ◽  
Vol 58 (1) ◽  
pp. 51-58
Author(s):  
Rawya Gamal ◽  
Nader A.A. Edress ◽  
Khaled A. Abuhasel ◽  
Ayman A. El-Midany ◽  
Salah E. El-Mofty

Abstract The most frequently investigated salts in coal flotation are chlorides. However, seawater contains additional salts such as sulfates. In coal flotation, magnesium chlorides showed the best results in terms of higher yield and lower ash content compared to the other magnesium salts studied. Therefore, two magnesium salts were tested in this investigation, namely magnesium chloride and magnesium sulfate. The effect of the magnesium salts as well as the optimization of coal flotation were investigated by statistical design of experiments in terms of pulp density, particle size, conditioning time and different dosages of MgCl2 and MgSO4. The flotation results obtained by statistical design show that the ash content was lowest at 8.2% when a mixture of 2 kg/t MgSO4 and 2 kg/t MgCl2 has been used, with pulp density 20%, particle size 400 lm and conditioning time 15 min. The particle size plays an important role in reducing the ash content when the conditioning time has been extended and pulp density has been reduced. The strong interaction between the salts hinders the reduction of the ash content to less than 8.2%.


2015 ◽  
Vol 35 (6) ◽  
pp. 281-294 ◽  
Author(s):  
Chao Ni ◽  
Guangyuan Xie ◽  
Bo Liu ◽  
Yaoli Peng ◽  
Jie Sha ◽  
...  

2014 ◽  
Vol 1010-1012 ◽  
pp. 1636-1639 ◽  
Author(s):  
Ji Hui Li ◽  
Li Qiang Ma ◽  
Yan Zhao Li ◽  
Wen Jing Li ◽  
Jian Wei Yue

The properties analyzing of flotation feed sample told that this fine coal sample is high-ash and hard-to-float coal slime. The ash reduction comparison of the step-by-step release flotation test with high intensity conditioning (HIC) or not, and the comparison of flotation test with HIC and adding depressant were made. The results showed that HIC can significantly improve the flotation effect for high-ash and hard-to-float coal slime. Comparing with the traditional step-by-step flotation process, if it meets the demand of ash content is 10.00% and 8.00%, the clean coal yield with HIC will increase 18 and 29 percentage points respectively; comparing with the effect of floatation adding depressant, HIC has more help to reduce the ash content and increase the yield of clean coal. In addition, HIC will save a lot of flotation reagents.


Processes ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 500 ◽  
Author(s):  
Shen ◽  
Min ◽  
Liu ◽  
Xue ◽  
Zhu

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.


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