酸法地浸采铀中孔隙度及铀浸出迁移的时空演化

在酸法地浸采铀过程中,铀在溶解—沉淀—再溶解的过程中会生成石膏堵塞空隙,导致孔隙度及铀浸出迁移的变化。为探明酸法浸铀过程中因石膏沉淀堵塞产生的变化,以某实际地浸采铀过程为例,通过模型概化构建孔隙度变化下的不同模型进行对比分析。结果表明:1)模拟过程结束后(600d),整个模型孔隙度均发生不同程度的变化,在注液孔2与注液孔5所在截面内,0m处孔隙度增幅最大,增大了3.66%,8m处孔隙度降幅最大,减少了1.66%。2)铀矿的浸出速率与该处孔隙度呈正相关,t=8d时,0m处生产模型孔隙度达到最大,理想模型与生产模型在该处的铀矿剩余量差值也达到最大,理想模型沥青铀矿剩余量为54.84%,生产模型沥青铀矿剩余量为54.74%。t8d时,0m处生产模型孔隙度开始减小,铀矿浸出速率下降,t=18d时,理想模型与生产模型铀矿剩余量相等。3)孔隙度减少的矿层直接影响到溶浸液在其中的迁移,降低了铀浸出迁移的效果。t=600d时,8m处生产模型孔隙度达到最小值,溶浸液运移阻碍影响达到最大时,理想模型与生产模型中10m处沥青铀矿剩余量差值也达到最大,理想模型为9.65%,生产模型为13.34%。

Spatial-Temporal Evolution of Porosity and Leaching Migration in In-situ Acidic Leaching of Uranium

In process of uranium extraction by acid leaching, gypsum will be formed during dissolution, precipitation and redissolution of uranium, which will lead to change of porosity and uranium leaching migration. Taking an actual uranium leaching process as an example, a comparative analysis of different models under porosity change by model generalization was constructed to explore these changes. The results show that: 1) After simulation process (600 days), porosity of the whole model changes to different degrees. Within cross sections of pore 2 and pore 5, porosity at 0 m rises the most with an increase of 3.66%, and that at 8 m drops the most with a drop of 1.66%. 2) Leaching rate of uranium ore positively correlates with porosity of the site. When t=8 d, the porosity of production model at 0 m reaches the maximum, and the difference between uranium residue of ideal model and production model also reaches the maximum. Uranium residue of ideal model and production model is 54.84% and 54.74% respectively. At t>8 d, porosity and uranium leaching rate of production model at 0 m begin to drop. At t=18 d, uranium surplus of ideal model and production model is equal. 3) Ore bed with reduced porosity directly affects migration of leaching solution in it, reducing effect of uranium leaching migration. When t=600 d, porosity of production model at 8 m reaches the minimum value, and influence of leaching solution migration obstacle reaches the maximum. Difference of pitchblende residue between ideal model and production model at 10 m also reaches the maximum value, the ideal model is 9.65%, and the production model is 13.34%.