Experimental Study On The Prevention And Cure Of Anthracite Spontaneous Combustion In Goaf By Ferrocene-potassium Salt Ultrafine Particle Aerosol

Coal fires caused by the spontaneous combustion of coal are one of the main mine disasters in the process of coal mining,storage and transportation.Once a fire occurs in a coal mine,it will cause a lot of waste of resources,severely damage the surrounding environment,and put a huge threat to the safety of coal mine production.Compared with general solid fires,spontaneous coal fires in coal mines have the characteristics of unobvious source location,easy re-ignition,and difficulty to prevent.Although the mainstream goaf fire-fighting technology at this stage is effective in ensuring the safe production process of coal mines,some problems cannot be ignored,such as short life span,easy loss,weak diffusion ability,and high cost.Therefore,the prevention and control technology of coal spontaneous combustion in goaf needs to be further improved.In this paper,through the study of coal spontaneous combustion mechanism,the advantages and disadvantages of traditional fire-fighting technologies are analyzed and compared,and the feasibility of ultra-fine particle aerosol fire-fighting technology to prevent and control coal spontaneous combustion disasters in goafs.This paper uses potassium dihydrogen phosphate（KH₂PO₄）as the base material and ferrocene（Fe（C₅H₅）₂）as the additive to develop a new type of ferrocene-potassium dihydrogen phosphate ultrafine particle aerosol fire extinguishing agent.A planetary ball mill is used to grind and prepare aerosol materials,and the test results of particle size,bulk density,moisture absorption,and fluidity are analyzed.After that,the fire extinguishing performance of the material was tested through synchronous thermal analysis,Fourier infrared spectroscopy test and physical simulation experiment.The experiment selects potassium dihydrogen phosphate（KH₂PO₄）,potassium bicarbonate（KHCO₃）,potassium nitrate（KNO₃）,potassium oxalate（C₂H₂K₂O₅）,and potassium chloride（KCl）as the five potassium salts as candidate materials.After comparative analysis,phosphoric acid is preferred.Potassium dihydrogen（KH₂PO₄）is used as a base material,and ferrocene（Fe（C₅H₅）₂）is used as an additive for experimental research.Analyze the concentration changes of coal spontaneous combustion oxidation products and the speed of extinguishing coal fires by gas chromatography,study the fire-fighting effects of aerosol materials under different ratios,and clarify the scientific ratio of aerosol materials.It was determined that when the content of ferrocene was 0.9 wt%,the performance of the inhibited coal sample with ultrafine particle aerosol was the best.Through simultaneous thermal analysis experiments,the effects of ferrocene-potassium dihydrogen phosphate ultrafine particle aerosol materials on coal combustion point,heat release,heat release rate,weight loss rate and other parameters are studied.The results show:The ferrocene-potassium dihydrogen phosphate ultrafine particle aerosol material can effectively increase the burning point of coal by 16-19℃.Reduce the weight loss rate,the maximum weight loss rate,the maximum heat release rate,and the maximum heat release rate of coal samples by 15.2～20%,1.91～2.5%/min,2.22～3.21 m W/mg,1299.91～2189.1 J/g;Among the differen coal samples,when the ferrocene-potassium dihydrogen phosphate ultrafine particle aerosol material content is 15 wt%,the inhibition effect on the oxidation and heating process of the coal sample is the best.Through Fourier infrared spectroscopy experiments,the effect of ferrocene-potassium dihydrogen phosphate ultrafine particle aerosol materials on the changes of different types of active groups in coal molecules such as hydroxyl,aliphatic hydrocarbons,and oxygen-containing functional groups during the oxidation and heating process of coal was studied.The results show that the ultrafine particle aerosol material can effectively accelerate the reduction of the hydroxyl（-OH）content in the coal body,and at the same time reduce the reaction consumption of aliphatic hydrocarbons（-CH₃,-CH₂-）in the oxidation heating stage,and reduce the oxygen content The increase of functional groups（C=O,C-O,-COO-）interrupts the chain reaction of active groups and effectively delays the oxidation and heating process of coal.Finally,by constructing a physical simulation experiment platform for coal spontaneous combustion,the fire extinguishing performance of ferrocene-potassium dihydrogen phosphate ultrafine particle aerosol materials was studied.The results showed that the fire extinguishing time of ultrafine particle aerosol materials was about that of yellow mud under the same conditions 1/2;When using ferrocene-potassium dihydrogen phosphate ultrafine particle aerosol to extinguish coal fires,spraying 15 wt%aerosol can not only ensure a large coal body cooling rate,but also ensure that ferrocene-Effective utilization of potassium dihydrogen phosphate ultrafine particle aerosol.