Effective Utilization of Coal Processing Waste: Separation of Low Ash Clean Coal from Washery Rejects by Hydrothermal Treatment

Sriramoju, Santosh Kumar and Babu, Varahala and Dash, Pratik Swarup and Majumdar, Saptarshi and Shee, Debaprasad (2020) Effective Utilization of Coal Processing Waste: Separation of Low Ash Clean Coal from Washery Rejects by Hydrothermal Treatment. Mineral Processing and Extractive Metallurgy Review. pp. 1-17. ISSN 0882-7508

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Handling and disposal of high volume of fine coal tailings is a biggest challenge for coal washeries. Separation of clean coal by density separation and flotation shows limited yields of 23–28% and 13–14% respectively. Chemical leaching process has a challenge with the formation of insoluble salts. The present investigation aimed to separate clean coal by a combination of chemical-physical separation technique, i.e. alkaline hydrothermal process followed by density separation. Hydrothermal extraction of humic substance causes dissociation of coal aggregated structure (Mineral-Maceral-Pore structure), thus improves the separation. Experiments performed as per design of experiments and reduced design of experiments, where 100 µ particle size, 50% (w/w) pulp density, 4.5% KOH (w/w), and 140°C reaction temperature found to be optimum, at which 16.2% ash clean coal at 40.7% yield and humic acid by-product at 18.3% yield were obtained. Use of swelling agent such as tetrahydrofuran shown negative impact on clean coal recovery. Material balance and cost data were presented to show the techno-commercial viability of this technology.

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IITH Creators:
IITH CreatorsORCiD
Majumdar, SaptarshiUNSPECIFIED
Shee, DebaprasadUNSPECIFIED
Item Type: Article
Uncontrolled Keywords: Aggregated structure; Chemical leaching; Commercial viability; Density separation; Hydrothermal process; Hydrothermal treatments; Physical separation; Reaction temperature
Subjects: Chemical Engineering
Divisions: Department of Chemical Engineering
Depositing User: . LibTrainee 2021
Date Deposited: 19 Jul 2021 05:31
Last Modified: 24 Feb 2022 11:02
URI: http://raiith.iith.ac.in/id/eprint/8416
Publisher URL: http://doi.org/10.1080/08827508.2020.1833196
OA policy: https://v2.sherpa.ac.uk/id/publication/5861
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