The Preparation Process Of Oxalate And Its Catalytic Performance For Thermal Decomposition Of Ammonium Perchlorate

It can effectively solve the shortage of petroleum resources in China by using the gas generator stimulation technique.The control of combustion performance of gas generator propellant charge is the key of charging technology.The effect of catalyst on the propellant burning rate can be predicted by the effect of catalyst on the thermal decomposition property of main component of the gas generator.Metal oxides as a kind of heterogeneous catalysts,the change of their size and morphology can influence their catalytic performance to a great extent.The main content of this paper is divided into two aspects.The first aspect is making alkaline-earth metals with different extractant concentrations and different extraction agitation rates,transition metal and coprecipitation metal oxalate by reverse precipitation method,and then discussing the effect of extractant concentration and extraction agitation rate on size and morphology of metal oxalates.Another aspect is exploring these metal oxides' the catalytic activities on Ammonium perchlorate(AP)thermal decomposition,so as to provide further experimental and theoretical support for the selection of the gas generator catalyst.Under the conditions of different extractant concentration(20~50%)and different stirring rate(100~500 r/min),we made Ca,Sr,Cu,Pb,four kinds of single metal oxalate and a series of oxalate coprecipitation salts like Ca/Sr's oxalate coprecipitation salts and Cu/Pb's oxalate coprecipitation salts by precipitation stripping method.And we represented the structure and morphology of oxalate particles by XRD and SEM.The results show that the particle size of oxalate particles decreases and the degree of decrease is obvious with the increase of extraction agitation rate;with the increase of extractant concentration,the effects of different metal ions are different,but the sizes are not changed greatly.It can be seen that the extraction rate can affect the particle size more than the extractant concentration.The prepared oxalate was mixed with AP at a mass ratio of 3%,and the thermal decomposition catalytic performance of AP was investigated by DTA/TG technique.The results show that calcium oxalate,strontium oxalate,lead oxalate and calcium-strontium oxalic acid coprecipitated salt can increase the peak temperature of AP decomposition at low temperature.The strontium Oxalate Particles whose particle size is 28 nm can make the AP low temperature decomposition peak temperature increase to 325.3 ?,compared to pure AP low temperature decomposition peak temperature increased by 37.9 ?.Compared with the traditional ammonium oxalate descender,the effect is more obvious,so the most obvious effect on slowing down AP decomposition is made by these strontium oxalate particles,which can be considered to be applied to the formulation of the inhibitor of the gas generator.The copper oxalate particles can combine the two decomposition stages of AP into one phase,and accelerate the decomposition process of AP,so it can be considered to be applied to the formulation of the accelerating agent of the gas generator.In view of the different catalytic effects of copper oxalate and lead oxalate on AP,when the ratio of copper and lead in copper-lead oxalic acid coprecipitated salt is not the same,heterogeneous catalysis is produced on AP.When the ratio of copper is larger AP can quickly complete the decomposition process,and when the ratio of lead is larger,it can improve the peak temperature of AP decomposition and delay the decomposition of AP.Therefore,the different catalytic effects of copper-lead oxalic acid coprecipitated salt on the AP can be achieved by adjusting the distribution ratio of copper and lead in it.