低频振动下铀尾砂氡析出机理研究

Study on the Mechanism of Radon Exhalation from Uranium Tailings Under Low Frequency Vibration

为探究铀尾砂氡析出内在机理,以铀尾砂为研究对象,针对振动频率、振幅、试验温度、试样含水率四个因素,采用控制变量法,以开环的形式进行振动氡析出试验。结果表明:振动作用加剧了铀尾砂氡析出。振动频率加快,铀尾砂愈发疏松、颗粒裂隙增多,加剧氡析出;振幅小于A时,振动作用导致铀尾砂堆松散程度增加,利于氡原子从颗粒间隙中逸出;振幅大于A小于5A时,振动导致铀尾砂颗粒反复摩擦,愈发光滑,促使颗粒间愈发密实,填堵了原有的气流通道,氡析出减弱;振动下温度升高,铀尾砂颗粒内外形成孔隙压、浓度差,氡热运动加剧,致使氡析出加剧;含水率小于15%时,孔隙水增强氡射气成为主导,捕获更多的氡原子,随着含水率增大,氡析出加剧;含水率大于15%时,孔隙水阻碍氡扩散成为主导,抑制氡析出,随着含水率增大,氡析出减弱。

In order to explore the internal mechanism of radon exhalation from uranium tailings,the uranium tailings are taken as the research object,and the vibrational radon exhalation test is carried out in an open-loop form by using the controlled variable method according to the four factors of vibration frequency,amplitude,test temperature,and sample moisture content.The results show that:vibration intensifies the exhalation of radon from uranium tailings.The vibration frequency is accelerated,the uranium tailings become loo-ser,the adsorbed radon is desorbed,and the particle cracks increase,which intensifies the radon exhalation;When the amplitude is less than A,the vibration will lead to an in-crease in the loosening of the uranium tailings pile,which is conducive to the escape of ra-don atoms from the particle gap;When the amplitude is greater than A and less than 5A,the vibration causes the uranium tailings particles to rub repeatedly and become smoother,making the particles more dense,filling the original airflow channel,and weakening the radon exhalation;When the temperature rises under vibration,the pore pressure and con-centration difference are formed inside and outside the uranium tailings particles,which weaken the physical adsorption capacity of radon,reduce the solubility of radon in pore water,increase the thermal movement of radon,and increase the exhalation of radon;When the humidity is less than 15%,the pore water enhances the radon emission to be-come the dominant,capturing more radon atoms.As the humidity increase,the exhalation of radon increase;When the humidity is greater than 15%,the pore water hinders the dif-fusion of radon and becomes the dominant one,which inhibits the precipitation of radon.As the humidity increases,the radon exhalation decreases.