Preparation and Characterization of a Bentonite-Based Hybrid Gel for Coal Spontaneous Combustion Prevention

Abstract

This paper presents an investigation of the feasibility of intercalating lignocellulose/xanthan gum (XG) and organic polymers into bentonite to obtain an efficient fire extinguishing gel material. The bentonite-based hybrid gel was prepared by adding polyacrylates, Al(OH) 3 , lignocellulose, and XG into a bentonite suspension, and the resulting gel was characterized. The results showed that no cracking and powdering were found on the surface of the hybrid gel due to the formation of the cross-linked network in the bentonite, and a wide mesopore size distribution and good thermal stability were observed. The hybrid gel also exhibits a wide range of water adsorption ratios, excellent water retention, adjustable gelation times, shear thinning characteristics, and improved compressive strength (the yield stress reaches up to 13 MPa). Based on these characterizations, the mechanism of hybrid gel formation is proposed. The inhibition performance of the hybrid gel on coal spontaneous combustion indicates that the addition of the gel slows down the oxygen chemisorption and thus increases the ignition temperature. Due to the presence of the hybrid gel in the coal, the crossing point temperatures were increased and the lowest CO concentration was produced.

Infrared Spectrum Characteristics and Quantification of OH Groups in Coal

“…According to the element analysis (Table ), the oxygen element content of CC, HJ, ST, and NM coal samples is 2.68, 2.37, 5.30, and 14.52% respectively. When the mass content of elements in coal samples is converted into atomic content, the number of oxygen atoms per 100 atoms in CC, HJ, ST, and NM coal samples is 1.69, 1.54, 3.02, and 7.96 respectively. − …”

Study on the Preparation of Montmorillonite-Type Multiple Network Composite Gel for Coal Spontaneous Combustion and Its Firefighting Mechanism

“…Hu et al proposed an anionic polyacrylamide (HPAM)–aluminum citrate gel system for the self-heating and spontaneous combustion of coal, which was found to be effective in controlling the gel formation time and formed a gel barrier in the area of self-heating or gas leakage on the coal body, thus preventing the contact of air with the coal body. However, most of the gel materials have shortcomings in terms of poor structural stability, susceptibility to water loss and cracking, and decomposition by heat and cannot function on the coal body for a longer time. − Moreover, fire prevention and control effect are poor and can even cause reignition of coal mine fire.…”

“…However, most of the gel materials have shortcomings in terms of poor structural stability, susceptibility to water loss and cracking, and decomposition by heat and cannot function on the coal body for a longer time. 19 − 21 Moreover, fire prevention and control effect are poor and can even cause reignition of coal mine fire.…”

Preparation of food active packaging materials based on calcium hydroxide and modified porous medium for reducing carbon dioxide and kimchi odor

“…The predominant odor adsorption materials include activated carbon (El‐Merraoui et al., 2000) and zeolite (Bickel & Gounder, 2022) with micropores (below 2 nm), as well as bentonite (Zhong et al., 2022) and diatomite (Zhou et al., 2022) with mesopores (2–50 nm). These porous materials exhibit large specific surface areas (Lim et al., 2020; Sonwane & Bhatia, 2000) and, owing to their porous structure, can efficiently remove sulfur compounds and carbon dioxide via van der Waals adsorption (Abdulrasheed et al., 2018; Chung et al., 2021; Jeong & Yoo, 2020).…”