Water-retaining properties of NCZ composite dust suppressant and its wetting ability to hydrophobic coal dust

Abstract

Coal dust is a primary threat to underground coal miners. The most common approach to control coal dust is hydraulic methods, such as water spray and coal seam water injection. To improve the dust suppressant efficiency of hydraulic methods, a novel chemical composite dust suppressant, called NCZ, was prepared in this study using calcium chloride (CaCl2), magnesium chloride (MgCl2), and nonionic surfactants using a thermal synthesis method. The water-retaining properties of NCZ powder and its solutions were characterized using the water absorption rate (WAR) and evaporation rate (ER), respectively, and the wetting abilities of the NCZ solutions on coal dust were tested using the initial contact angle (ICA) and sink rate (SR). The results indicate that the NCZ solutions have anti-evaporation effects, and the ER of the solution with a 20.0 wt% NCZ is reduced by 11.7% compared with that of clean water. Furthermore, NCZ solutions have remarkable enhancement effects on the wettability of coal dust. The ICA and SR of clean water and the NCZ solution at 20.0 wt% are 141.9° and 0 mg/s, and 29.3° and 1.46 mg/s, respectively. Finally, quantitative relationships between the solution surface tension and the ICA and IR were established using the least squares method. This study provides a new product for dust suppression in underground mines, which is significant for the optimum applied concentration of dust suppressant in mining operations.

Suppression Characteristics and Mechanism of Molasses Solution on Coal Dust: A Low-Cost and Environment-Friendly Suppression Method in Coal Mines

“…Note that the cumulative number of PM10 particles is the total number of particles with sizes of 0.3, 0.5, 1.0, 2.0, 5.0, and 10.0 µm. It can be computed using Equation (7). c = ∑ pm= pm 0.3 + pm 0.5 + pm 1.0 + pm 2.0 + pm 5.0 + pm 10.0 (7) where c is the cumulative number of PM10 particles; and pm i is the number of particles with a particle size of i (i = 0.3, 0.5, 1.0, 2.0, 5.0, 10.0).…”

“…It can be computed using Equation (7). c = ∑ pm= pm 0.3 + pm 0.5 + pm 1.0 + pm 2.0 + pm 5.0 + pm 10.0 (7) where c is the cumulative number of PM10 particles; and pm i is the number of particles with a particle size of i (i = 0.3, 0.5, 1.0, 2.0, 5.0, 10.0).…”

“…With regard to energy, coal is one of the most widely used energy sources, and this is especially true in developing countries, where coal is the primary source of energy [ 4 , 5 ]. To meet the ever-increasing demands, the mining intensity of coal is increasing yearly, resulting in severe coal dust pollution in underground coal mines [ 6 , 7 ]. In recent years, more than 10,000 cases of pneumoconiosis have been recorded in China each year [ 8 ], and coal workers’ pneumoconiosis (CWP) has also been detected in developed countries such as Australia and the United States [ 9 ].…”

Chemistry and particle size distribution of respirable coal dust in underground mines in Central Eastern Europe

“…Fan et al, 2018;Wu et al, 2019). For this reason, dust monitoring control during the handling of different mining technologies requires extensive investigation, including information on the physicochemical characteristics of the deeply inhalable (particle size below 10 µm) and respirable fractions (particle size below 4 µm and 2.5 µm), both of which could be a key factor in the prevention of coal dust problems in mining, such as diverse authors are contributing (Zhang et al 2020;Szkudlarek and Janas 2021;Jiang and Luo 2021;Liu et al 2021;Reed et al 2021).…”

Special Issue on mine dust research: health effects and control technologies

“…From the perspective of the physical and chemical properties of dust in mines, the wettability of copper mine blasting dust is mainly controlled by particle size and pore structure (Jin et al 2021). A molecular dynamics simulation study indicated that larger coal dust particle has higher wettability (Zhang et al 2021).…”