类铀矿岩材料制备及氡扩散系数测定的实验研究

The experimental study on the preparation of quasi-uranium ore material and the measurement of radon diffusion coefficient

扩散过程是主导氡在铀矿岩中运移与析出的主要方式。铀矿原岩辐射较大且取样困难,不利于开展有关室内实验。为了解决以上问题,依据相似理论,以某花岗岩为原型,选取石英砂、铀尾砂、水泥、精铁粉和微硅粉等为原材料,制备了3种不同材料配比的圆柱形类铀矿岩试样,并测定了原型和试样的物理力学参数;然后采用密闭腔体法测量了原型和试样在不同包裹方式下的累积氡浓度,推导氡的扩散性能参数的计算公式,通过计算获得了原型和试样的氡扩散长度和扩散系数。实验结果表明:花岗岩原型与所制备的类铀矿岩的颗粒密度、抗压强度、抗拉强度、内聚力和内摩擦角相似比的均值分别为1.09∶1、3.93∶1、4.28∶1、3.47∶1和1.00∶1;花岗岩原型的扩散系数为0.146×10^(-6)m^2·s^(-1),类铀矿岩的扩散系数介于0.114×10^(-6)~0.594×10^(-6)m^2·s^(-1)之间,两者的相似比介于0.25∶1~1.28∶1之间。研究认为所制备的试样3在一定程度上可用来模拟花岗岩型铀矿岩,以满足室内实验的需求。

Diffusion process is the main factor that leads to the migration and exhalation of radon in uranium ore. Taking into account the fact that the hazard exists in underground uranium mine and field sampling are rather difficult,it is not conducive to do the laboratory test. In order to solve the above problems,based on the similarity theory,a kind of typical granite was taken as the prototypical model,and the quartz sand,uranium tailings,cement,fine iron powder and silicon powder as the raw materials,three cylindrical uranium-like rock samples with different material ratios were prepared,and the physical and mechanical parameters were then measured. In addition,these samples were sealed in different ways and the corresponding cumulative radon concentrations were measured by closed chamber method. The formula for calculating the diffusion performance of radon is deduced,and the radon diffusion length and diffusion coefficient of the prototype and the samples were calculated. The results showed that the mean similarity ratios of the particle density,compressive strength,tensile strength,cohesion and internal friction angle of the granite rock and quasi-uranium ore were respectively1. 09 ∶ 1,3. 93 ∶ 1,4. 28 ∶ 1,3. 47 ∶ 1 and 1. 00 ∶ 1,the diffusion coefficient of granite prototype was 0. 146 ×10^（-6） m^2·s^（-1）,the diffusion coefficient of quasi-uranium ore was between 0. 114 × 10^（-6） m^2·s^（-1） and 0. 594 ×10^（-6） m^2·s^（-1）,and the similarity ratio was between 0. 25∶ 1 and 1. 28∶ 1. Therefore,the third sample of similar materials to some extent can be used to simulate the granite-type uranium rock and can meet the needs of laboratory experiments.