LAUSR

Spontaneous combustion of oxidized coal occurs frequently in mining and utilization process, which is influenced by the first oxidation conditions significantly. With a focus on the influence of pre-oxidation temperature on spontaneous combustibility of oxidized coal, oxidized coal samples were prepared by heating at preset temperature of 50 °C, 70 °C, 90 °C, 110 °C and 130 °C. Programmed heating tests on oxidized coal and raw coal samples were carried out in air atmosphere of 120 mL min−1, with the heating rate of 0.3 °C min−1. The gaseous mixture of O2, CO and CO2 at the outlet was identified by gas chromatography to analyze oxidizability and exothermicity of experimental coal samples. The results showed that, with the increasing pre-oxidation temperature, the oxidizability and exothermicity of oxidized coals decreased first and increased later, which were related with change of oxygen consumption rate, emission rate of CO and CO2 gas. The spontaneous combustibility order by pre-oxidation temperatures was 130 °C, raw, 50 °C, 110 °C, 90 °C and 70 °C. Being oxidized at 130 °C could promote coal to self-heat, and being oxidized below 110 °C would inhibit coal self-heating.