Does it Matter How Coals are Cleaned for CWS?

Abstract

Chemical additives utilized to reduce viscosity of coal-water slurries (CWS) operate by making coal surface hydrophilic and by increasing electrical charge of the coal particles. In the preceding stage, coal beneficiation, reduction of the ash content increases coal's hydrophobicity. The reagents used in flotation further modify coal surface properties and render it more hydrophobic. Such a product, especially when flotation reagents also include water-insoluble oils, tends to agglomerate and may require different viscosity reducing additives. It is shown that these two types of additives, flotation reagents and viscosity reducers are not compatible. While production of a clean coal product with a bi-modal particle size distribution may be simple, optimization of these two operations with respect to the surface properties of the coal particles will require more in depth studies.

Keywords:

• Coal wettability
• coal cleaning
• coal flotation
• flotation reagents
• coal-water slurry
• particle size distribution
• dispersants

Additional information

Notes on contributors

J. S. LASKOWSKI

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