Inhibition Mechanism of LDHs on Coal Spontaneous Combustion Based on Thermogravimetric Analysis

The technology of preventing and controlling coal spontaneous combustion by paralysant is one of the most important technologies in coal spontaneous combustion prevention and control system, especially the layered double hydroxide (LDHs) developed in recent years is a new type of coal spontaneous combustion inhibitor. In order to study the inhibition effect of LDHs on coal spontaneous combustion and the best ratio (the most economical and efficient addition), this paper uses self-made LDHs inhibitor preparation device to successfully make the LDHs in a variety of metal ion ratios by coprecipitation method. And then, the paper uses the thermal gravimetric analysis to obtain the TD-DTG curves of coal samples at 3 %, 5 %, 10 % and 15 % by 5 kinds of LDHs additive amounts, and then, the inhibition effect of various inhibitors under different adding conditions is investigated. The results show that when the LDHs physical mixing amount is 15 %, it can effectively prevent the spontaneous combustion of coal samples; finally, according to the test results, the hypothesis of LDHs inhibiting coal spontaneous combustion mechanism is put forward, that is, on the one hand, the La3+ in LDHs will have complexation effect with active groups in coal to prevent the reaction of coal and oxygen; on the other hand, the intermediate bound water between rare earth layered double hydroxides will increase with the adding of La3+, so as to restrain the spontaneous combustion of coal by self-heating. The research findings will have better theoretical guidance and reference significance for the study on LDHs new type self-ignition inhibitor and its on-site economical and efficient use.