Study On The Preparationrtion And Properties Of Pillared Hydrotalcite Based On Coal Inhibitor

The coal is the most abundant strategic energy stored in the world,inseparable from the industrial production of human beings.Because of the spontaneous combustion of environmental temperature in the process of coal transportation and storage,coal spontaneous combustion seriously affects the mining of the coal industry and affects the living environment of the residents.Based on the research and analysis of the mechanism of coal spontaneous combustion,many inhibitors have been used to prevent spontaneous combustion of coal at present.The main mechanism of the inhibitor to cut off oxygen and destroy the active group on the surface of the coal,the traditional inhibitor has the disadvantages of unstable effect,certain harm to the environment,short life and so on.In view of the above situation,using magnesium aluminum layered double hydrotalcite(Mg/Al-LDHs)as carrier,a highly efficient and environmentally friendly coal inhibitor was prepared by ammonium polyphosphate(APP)pillared Mg/Al-LDHs.In the paper,the proportion and aging time of synthetic Mg/Al-LDHs are investigated by coprecipitation method,the experimental results show that when the ratio of magnesium to aluminum is 3:1 and the aging time is 24 h,the characteristic crystal structure of the hydrotalcite can be formed.Then the calcination of Mg/Al-LDHs was selected at different temperatures.The change of the characteristic peak and the interlayer crystallization water and hydroxyl groups of hydrotalcite were investigated.According to the analysis,the calcination temperature of Mg/Al-LDHs should be at 500?;The pillared experiment using the calcination reduction method of Mg/Al-LDHs,because of the larger particle size of polyphosphate,directly pillared is unable to obtain the target product.The Mg/Al-LDHs after calcination was pretreated by the selection of twelve alkyl phosphate potassium in the proportion of 1:2.Twelve alkyl phosphate potassium hydrotalcite as a precursor,Under the condition of neutral solution,ammonium polyphosphate and precursor hydrotalcite are mixed by ion exchange method to carry out the pillared experiment.By means of analysis of XRD,FT/IR and XPS:Polyphosphoric acid pillared hydrotalcite forms a typical crystal structure,and the interlayer twelve alkyl phosphate acid roots are replaced by polyphosphoric acid root.The thermal stability of pillared hydrotalcite is reflected by thermo gravimetric analysis,and it is proved that there are polyphosphoric acid ions between layers to achieve the pillared effect.Finally,taking Heilongjiang as the research object of lignite resistance,using hydrogen peroxide and temperature programmed heating experiment test comparison of several traditional coal inhibitor inhibition effect.Experimental results show that ammonium polyphosphate pillared hydrotalcite can delay coal self-heating rate of oxidation.In the heating process,can inhibit the activity of oxygen and coal surface a collision.At the same time,pillared hydrotalcite can decompose the endothermic effect occurred in multi-stage heat,low coal temperature,to prevent and control coal spontaneous combustion.