Research On Separating And Recycling Main Solid Components From Obsolete Propellant

Obsolete solid propellants, as a kind of particular dangerous article, must be properly treated. For many of these ammunition items the traditional method of disposal is open burning/open detonation which makes no profit and causes pollution. To recycle obsolete propellant by solvent extraction method has profound significance considering environment protection and resource recovery. Therefore, the solvent extraction method is used in experiment for the first time to reclaim the main materials from two kinds of thermoplastic elastomer propellants in the process of investigation. The expensive substances in the obsolete propellant can be reclaimed to reuse in producing explosives.In this thesis, the experiments include two parts. Firstly, the solubility of the main propellant substances including nitrocellulose (NC), nitroglycerin(NG), thermoplastic polyurethane elastomer (TPU) and hexogen(RDX) in proper solvents were measured under different temperature. Secondly, the suitable solvents were selected and used to separate the mixture through solvent extraction. According to the effect of mixture separation, the better extraction conditions were determined and the reclaimed materials were characterized by GC, LC, IR, UV spectra and melting point measurement.The extraction experimental results for typeⅡpropellant show that NG could be removed with ether by the mean of 2h extraction under the water bath of 56.0～58.5℃; RDX recovery rate could be more than 80 percent by using recycled aniline to extract RDX under 80℃which was then precipitated at lower temperature; under the conditions:dichloromethane, 20℃,1h solution time, TPU recovery rate was more than 66%; NC was reclaimed totally and aluminum powder(Al) recovery rate was more than 88% using acetonitrile under 40℃by means of 1h solution. The main recovery amount of RDX, TPU, NC and A1 was up to the 80% of solid material in the type II solid propellant.The optimum extraction condition of type I propellant was that, acetonitrile,50.0℃, 8min solution time. RDX in the sample could be totally reclaimed; the recovery rates of Al and TPU were more than 90% immersed 2h in chloroform under 20.0℃and filtered twice with type 60-8(130) cloth, or under the other condition:85%, 1h, dimethylsulfoxide,80.0℃. The main recovery amount of RDX, TPU and Al was up to 93% of the solid material in the type I solid propellant.The IR test results show that the wave number of the reclaimed RDX,NC and TPU were similar contrast to there pristine substances. The purity of reclaimed RDX can reach above 99.0% measured by LC and UV spectra method, and the reclaimed RDX's melting point approaches the purity's.