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: , i.e., . A semi-empirical formula for critical velocity was obtained by fitting the simulation data, . Attachment efficiency was defined and formulated as , establishing relationships between attachment efficiency and the physicochemical properties of RCMD and water droplets.

中文翻译：

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理化性质对可吸入煤矿粉尘撞击水面临界沉降和附着的影响


自20世纪90年代中期以来，吸入煤矿粉尘（RCMD）被认为是煤工尘肺（CWP）死灰复燃的主要原因。目前，最主要的抑尘技术是喷水系统。但在实际应用中，该技术对RCMD的捕获效率较低。为了了解捕获机制并制定改进策略，本研究重点使用动态模型研究 RCMD 的表面化学及其对水面的影响。使用工业分析仪、电感耦合等离子体质谱 (ICP-MS) 和 X 射线衍射 (XRD) 对来自阿巴拉契亚地区的原矿 (ROM) 煤样进行工业分析、化学和矿物成分分析，分别。使用沃什伯恩方程通过毛细管上升测试测量接触角。基于动力学模型，研究了颗粒尺寸、密度、接触角和表面张力对临界下沉的影响。这项工作指出，降低表面张力反过来会降低接触角，这一点在文献中被忽视了。创建了不同矿物的区域图，并显示有机物由于其低密度和高接触角而具有最高的临界速度。将水表面张力降低至煤的临界固体表面张力 30 mN/m 左右可以最大限度地提高附着效率。由力平衡构建的缩放定律导致了临界下沉的标准： ，即 。通过拟合模拟数据，得到了临界速度的半经验公式。附着效率被定义并表述为 ，建立附着效率与 RCMD 和水滴的物理化学性质之间的关系。