Abstract
Near Gravity Material (NGM) is classically and by BIS defined as the percentage of material occurring within a range of ±0.1 of the relative density at which separation takes place in coal cleaning operations. NGM is said to affect the separation performance of coal cleaning equipment and is believed to be the primary reason or at least an important reason for misplacement between the products. Therefore, coal producers, coal consumers and the technology providers in India are concerned about the effect of NGM on coal cleaning operations. It is true that Indian coal is one of the most difficult to “wash”. The question is, whether this difficulty to “wash” is getting translated or not into a kind of obsession with NGM while keeping other factors apparently out of consideration?
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References
Atesok G, Boylu F, Sirkeci A A, and Dincer H, Fuel, 81 (2002).
Bandyopadhayay P, Unpublished Lecture Notes, Indian School of Mines Dhanbad (1986).
Bhatnagar A, Personal Communication (2014).
Bhattacharya S, Thermal coal preparation in India: Drivers barriers prospects and challenges, South African Coal Processing Society IV Biennial Coal Preparation Conference, Secunda, South Africa (2011).
Bhattacharya S, Khanna R, and Nath N C, Development of specifications for the procurement of lump magnetite for heavy media use, XIV International Coal Preparation Congress, South African Institute of Mining and Metallurgy, Johannesburg (2002), p 325.
Chen J, Chu K W, Yu A B, Vince A, Barnett G D, and Barnett P J, Particle Scale Modelling of the Multiphase Flow in a Dense Medium Cyclone: Effect of Near Gravity Material, Powders and Grains 2013 AIP Conference Proceedings, doi: 10.1063/1.4812180. p 1308.
Claassen J O, J South Afr Inst Min Metall 113 (2013), p 761.
Deurbrouck A W, and Hudy J Jr, Performance Characteristics of Coal Washing Equipment: Dense Medium Cyclones, US Department of the Interior, RI 7673 (1969).
Feurstenau M C, and Han Kenneth N, Principles of Mineral Processing, SME, Colorado (2003) p 199.
Jyoti D, Bhattacharya S, Anand A, and Saxena V K, Washing of low volatile coking (LVC) coal—is that difficult? Transaction Indian Institute of Metals, published online 21 January (2015).
De Korte G J, Int J Coal Prep Util 28 (2008) p 69.
Konar B B, Banerjee S B, Chaudhuri S G, Chaudhuri A, Das N S, and Sen K, Coal Preparation, Allied Publishers, Calcutta (1997) p 44.
Leonard J W, Coal Preparation, vol. 4, AIME, New York (1979) p. 30.
Magwai M K, and Claassen J O, Near-Gravity material experience at Leeuwpan coal mine, SACPS Bi-annual Conference, Secunda http://s3.amazonaws.com/zanran_storage/www.sacoalprep.co.za/ContentPages/2501426370.pdf. (2013). Accessed 12.03.2015.
Napier-Munn T J, Trans Inst Min Metall Sect C Miner Process Extr Metall 94 (1985) p C98.
Napier-Munn T J, Coal Prep 8 (1990) p 145.
Osborne D J, Coal Preparation, Vol. 1, Graham and Trotman, New York (1988) p 153.
Osborne D G, and Mikhail M W, Coal Prep 8 (1990) p 111.
SACPS, South African Coal Processing Society, Coal Preparation in South Africa, 234 (2002).
SACPS, South African Coal Processing Society, Coal Preparation in South Africa (2011) p 154.
Sanders G J, The Principles of Coal Preparation, 4th edn, Australian Coal Preparation Society, Newcastle, (2007) p 130.
Yadav S, Wash and Go, World Coal, April, (2011) p 39.
Acknowledgments
First author gratefully acknowledges the intellectual input received from Dr Arun Kumar Majumder, IIT Kharagpur and Atul Bhatnagar, Tata Steel in writing this paper.
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Bhattacharya, S., Maheshwari, A. & Panda, M. Coal Cleaning Operations: The Question of Near Gravity Material. Trans Indian Inst Met 69, 157–172 (2016). https://doi.org/10.1007/s12666-015-0737-z
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DOI: https://doi.org/10.1007/s12666-015-0737-z