Study On The Inhibition Mechanism Of LDHs On Spontaneous Combustion Of Coal

In this paper,the inhibition effect of LDHs on the spontaneous combustion of coal was studied,and its mechanism was explored.The results of this study were of great significance to the development of the inhibition technology of coal spontaneous combustion.In this paper,rare earth hydrotalcite(LDHs)were prepared by co-precipitation method.The composition,structure and microscopic morphology of LDHs were studied by XRD and SEM.Based on the thermogravimetric analysis technology,the inhibition effect of LDHs on coal spontaneous combustion was explored.Based on the in situ diffuse Reflectance Infrared Spectroscopy(DIR),the mechanism of preventing coal spontaneous combustion by LDHs has been explored.The results shows that:It has shown that the LDHs were successfully prepared,but the micro structure and morphology of LDHs were destroyed to some extent after the addition of lanthanum ions.LDHs have an inhibitory effect on the spontaneous combustion of coal,and the inhibition effects of the five kinds of LDHs follow the order of:LDHs-5>LDHs-3>LDHs-2>LDHs-1>LDHs-4.The adsorption and thermal effect Coupling Mechanism of LDHs and Coal was proposed.Due to the existence of binding water and anions adsorbed between layers,when LDHs is covered on the coal surface,the contact between oxygen and coal is blocked and the reaction between oxygen and coal is prevented.Oxygen-containing functional groups such as-COO-in coal can form a weak hydrogen bond with-OH on LDHs,which in turn inhibits the continuation of low-temperature oxidation of the more active-COO-functional groups in coal.At the same time,LDHs can also absorb the heat released from the low temperature oxidation stage of coal and produce CO2,H2O and other gases,thus slowing down the rate of coal temperature rising.In the process of coal spontaneous combustion,the compound SL-LDHs after blending with coal can form a tight barrier layer,prevent the further oxidation reaction of coal,and thus play a certain role in inhibiting the spontaneous combustion of coal.