Effect of Physicochemical Properties on Critical Sinking and Attachment of Respirable Coal Mine Dust Impacting on a Water Surface

Details

• Personal Author:
  Han S ; Rezaee M ; Roghanchi P
• Description:
  Respirable coal mine dust (RCMD) inhalation is identified as the main cause of the resurgence of coal worker's pneumoconiosis (CWP) since the mid-1990s. At present, the predominant dust control technology is the water spray system. However, in practice, the capture efficiency of RCMD by this technology is relatively low. To understand the capturing mechanism and develop improvement strategies, this research is focused on the surface chemistry study of RCMD and its impact on a water surface using a dynamic model. Proximate analysis, chemical, and mineral composition of a run-of-mine (ROM) coal sample from Appalachian region were analyzed using a proximate analyzer, Inductively Coupled Plasma Mass Spectrometry (ICP-MS), and X-ray Diffraction (XRD), respectively. Contact angles were measured by capillary rise test using the Washburn equation. Based on the dynamic model, the effects of particle size, density, contact angle, and surface tension on the critical sinking were investigated. It was pointed out in this work that reducing surface tension, in turn, decreases contact angle, which has been neglected in the literature. Regime maps for different minerals were created and showed that organic matter has the highest critical velocity due to its low density and high contact angle. Reducing water surface tension to the critical solid surface tension of coal around 30 mN/m could maximize the attachment efficiency. Scaling laws, constructed by force balance, led to the criteria of critical sinking: Ucr[Formula presented][Formula presented], i.e., Wecr[Formula presented]. A semi-empirical formula for critical velocity was obtained by fitting the simulation data, Ucr=1.09[Formula presented][Formula presented]. Attachment efficiency was defined and formulated as Pa=[Formula presented]=[Formula presented], establishing relationships between attachment efficiency and the physicochemical properties of RCMD and water droplets. [Description provided by NIOSH]
• Subjects:
  Dust Occupational Health Safety
• Keywords:
  Author Keywords: Attachment Efficiency Coal Dust Contact Angle Critical Velocity Dust Control Equipment Dust Inhalation Physical Properties Respirable Coal Mine Dust Respirable Dust Surface Properties Surface Tension Water Surface

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• ISSN:
  0009-2509
• Document Type:
  Text
• Funding:
  Contract
• Genre:
  Journal Article
• Place as Subject:
  Birmingham Region [OSHA] ; Dallas Region [OSHA] ; Kentucky ; New Mexico ; Pennsylvania ; Philadelphia Region [OSHA]
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  300
• NIOSHTIC Number:
  nn:20070055
• Citation:
  Chem Eng Sci 2024 Dec; 300:120588
• Contact Point Address:
  Mohammad Rezaee, John and Willie Leone Family Department of Energy and Mineral Engineering, College of Earth and Mineral Sciences, The Pennsylvania State University, University Park, PA 16802, USA
• Email:
  m.rezaee@psu.edu
• Federal Fiscal Year:
  2025
• Performing Organization:
  New Mexico Institute of Mining and Technology
• Peer Reviewed:
  True
• Start Date:
  20190915
• Source Full Name:
  Chemical Engineering Science
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:4fd37812dc147c0c0d97e030804661c950b1eaab03d5bc16f4bbfcdd3efcb4c4d63cfe014cf048884d397775aff79084c43a4ac1a931b9365e465dc9c706fcae
• Download URL:
  https://stacks.cdc.gov/view/cdc/208353/cdc_208353_DS1.pdf
• File Type:
  [PDF - 1.85 MB ]