醋酐法制备奥克托今过程中废液的回收利用

On the reclaim of waste liquid in the procedure of HMX preparation with the acetic anhydride method

为了处理醋酐法制备奥克托今（HMX）产生的废液，采用蒸馏的方式，在处理废液的同时回收硝酸铵和醋酸。经两步过滤对废液进行预处理，加热废液至115℃，馏出约占65％废液总量、质量分数为70％左右的乙酸溶液，釜底液冷却结晶，理论上可回收约88．9％硝酸铵。分别利用回收的硝酸铵与原料硝酸铵制备HMX，所得HMX无明显差异。

The present paper is concerned about the way for reutilization of the ammonium nitrate and acetic acid in the waste liquid of HMX preparing process by distillation. The experimental operation procedure can be shown in the following steps： First of all, the waste liquid can be filtered through the next two steps （the ordinary filtration and the activated carbon filtration）, and then the bottom liquid should be subjected to cooling and crystallization, so as to be able to remove the impurities and dry out the ammonium nitrate in preparing for the HMX. Furthermore, the prepared HMX has to be examined and characterized through a certain technical procedure. The simulated waste liquid can be found consisting of 62% acetic acid, 27% water and 1 t % ammonium nitrate. The results of the simulated experiment may show that the recovery rate of ammonium nitrate tends to increase at first and then decrease with the increase of temperature. Practically speaking, when the heating temperature reaches 115 ℃, the recovery rate of ammonium nitrate is likely to be made to reach the highest rate （88.9%）. However, the decomposition of am- monium nitrate is aggravated beyond the said temperature, the amount of the ammonium nitrate dissolved in the water would only be increased below the said temperature. And so, neither of the aforementioned situations tends to be favorable for the recovery of ammonium nitrate. In the recovery experiment of the authentic waste liquid, the maximum recovery rate of ammonium nitrate can be found to reach 26. 6%, which is lower than the simulated re- covery experiment. On the other hand, there may be other uni- dentified reactions accompanying the process of nitrification, which may lead to the recovery rate of the ammonium nitrate lower than the theoretical indicated value. In that case, HMX can be prepared by the recovery ammonium nitrate and the raw ammoni- um nitrate, then the ready-made products can be identified and characterized by using the high power electron microscope, the melting point instrument and the infrared spectrometer. The resuits of the above said experiments show that, both of the products area - HMX, with their average melting point being about 277 ℃, and the average yield being 53.1% , and the infrared spectrum may fail to show any obvious difference. Therefore, the recovery of the ammonium nitrate can be used for preparing HMX, and the yield and performance of HMX would not have been affected by the use of the recycled raw materials.