Experimental Study on the Influence of Pyrite Oxidation Products on Coal Spontaneous Combustion

ABSTRACT

In order to study the effect of pyrite oxidation products on the spontaneous combustion of coal, five kinds of compounds of pyrite oxidation products with 6% of a mass fraction were added to the coal sample of Yangmei No. 5 Mine. The analysis shows that the weightlessness and ignition activation energy of coal samples after adding Fe³⁺, Fe²⁺, and H⁺ are reduced compared with YM. Fe³⁺ and Fe²⁺ catalyze the free radical chain reaction during the spontaneous combustion of coal, promote the development of C = O and -CO-O-, and accelerate the oxidation reaction of -CH₃, -CH₂- and -OH. H⁺ reduces the content of Si-O-Si structure. After adding Fe(OH)₃ and S⁰, the activation energy of coal samples is higher than that of YM. Through the adiabatic oxidation experiment, it can be seen that Fe³⁺, Fe²⁺, H⁺ shorten the shortest ignition time of YM coal samples 40.7 h, 32 h, 4.6 h. Fe(OH)₃ and S⁰ prolong the shortest ignition time of YM coal samples by 7.1 h and 21.8 h, respectively. This shows that the oxidation products of FeS₂ play an important role in promoting low-temperature oxidation of coal.

KEYWORDS:

• Oxidation products
• the characteristic temperature points
• the shortest ignition time
• the weightlessness activation energy
• the ignition activation energy

Acknowledgments

The authors greatly acknowledge the financial support from the National Natural Science Foundation of China (51574143).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the the National Natural Science Foundation of China [52074147].