Study on thermal and flame retardant properties of hydrated phase change materials for preventing coal spontaneous combustion

doi:10.16265/j.cnki.issn1003-3033.2025.12.0064

Abstract

Abstract:

To effectively suppress the transition of coal spontaneous combustion oxidation in goaf areas into the accelerated stage, a stable and high-heat-storage PCM was prepared using ammonium aluminum sulfate dodecahydrate and magnesium sulfate heptahydrate as raw materials. Through differential scanning calorimetry tests, solid-liquid transition tests, programmed heating tests, infrared spectroscopy, thermal insulation tests, and microscopic analysis, PCM thermal properties, the driving mechanism of solid-liquid transition, heat storage capacity, and coal oxidation inhibitory performance were studied. The test results show that the developed material has a phase transition temperature of 66.8℃, a latent heat of phase transition of 300.708 J/g, and a relatively low specific heat capacity during the heating process. The melting time exhibits an exponential decrease with increasing temperature, and a dense covering film forms after melting. When the material is added at a mass fraction of 15%, the inhibitory rate reaches 41%. Under a 500℃ heat source, with a material thickness of 30 mm, the effective thermal insulation time reaches 65 minutes.

Key words: coal spontaneous combustion, hydrated phase change materials (PCM), inhibition, insulation, infrared spectra.

CLC Number:

X936

LI Jingjing, LU Yi, SHAO Shuzhen, SHI Shiliang, SHI Zhengjing, YU Bo. Study on thermal and flame retardant properties of hydrated phase change materials for preventing coal spontaneous combustion[J]. China Safety Science Journal, 2025, 35(12): 164-171.

Figures/Tables 13

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温度/ ℃	融化现象所需时间/min
温度/ ℃	t₁	t₂	t₃	t₄
90	1	3	7	12
85	3	5	10	20
80	5	9	20	50
75	15	65	85	135
70	100	190	210	290
65	290始终未融化
60	290始终未融化

主要官能团	原煤		50 ℃处理抑制煤样		70 ℃处理抑制煤样		90 ℃处理抑制煤样
主要官能团	峰面积	面积占比/%	峰面积	面积占比/%	峰面积	面积占比/%	峰面积	面积占比/%
C-O-C伸缩振动	11.488 1	55.361 4	6.526 1	50.266 5	2.973 9	54.735 7	7.388 3	47.635 4
Ar-CO伸缩振动	1.489 4	7.177 5	1.177 8	9.071 9	0.148 7	2.736 9	0.528 3	3.406 2
-CH₃对称变形振动	0.875 0	4.216 6	0.704 5	5.426 3	0.258 9	4.765 1	1.565 6	10.094 1
-CH₂、-CH₃不对称变形振动	1.415 3	6.820 4	0.924 2	7.118 5	0.457 8	8.426 0	2.740 2	17.667 2
C=C伸缩振动	2.837 2	13.672 5	2.385 9	18.377 1	0.965 3	17.766 7	0.789 1	5.087 7
-COOH伸缩振动	2.646 1	12.751 6	1.264 5	9.739 7	0.627 6	11.551 2	2.498 6	16.109 5