The Study On The Treatment Method Of Waste Residue In Uranium Mine

The exploitation and refine process of uranium mine produce a large quantity ofslag and tailings, in which the componet of uranium is 1-3 10-4g/g, radiation dosage is 77-200 10-3Gy/h. They are larger 5-70 times than the background value of ordinary earth. Because the waste mine stone being open air undergoes drenching and washing out, the uranium in the slag is filtered out. Hence, the uranium mine slag becomes a potential radiation pollution source.At present, there are the following methods treating slag and tailing: for slag, the means include setup of permanent mine pile, backfilling in the mined area, reclaiming uranium in slag; for tailing pile, the means include building mine dam with it, vegetation on it, and physical-chemical treatment of it.In this thesis, the sandstone uranium mine is taken as an example to treat uranium slag from geologic engineering and biogeology.The slag sample from some uranium mine is lixiviated at room temperature with the solution containing Na2CO3-NaHCO3-H2O2- The lixivated solution is enriched at the reduction environment (pH=5,Eh=-1.8V) in the PVC column filling green vitriol, pyrite, lignite (brown coal). After 20 days enrichment experiment, the PVC column is solidified with the cement. The measured radiation dosage is 186.77 10-3Gy/h for lixivated solution, 25.66 10-3 Gy/h for lixivated solution after enriched, 1 30.54 10-3Gy/h for the solidified PVC column. The uranium ion is easily washed away with flowing water at oxidation environment, deposited at the reduction environment. In the nature,the uranium mine is usually enriched in the oxidation-reduction transition zone.The slag is stackd up in the open air and piled under the well. The treatment methods for them are different. The slag in the open air is commonly in the unstable state and easy to coast and fall. The treatment technology is to fill cement slurry in high pressure so as to form the concretion solid with surpport action. The filled materials include pyrite, green vitriol,and cement. The uranium is situated at the center in the solidified and not easy to wash out. The treatment method for the slag under the well is as following. The place easy to landslip is fixed with anchor staff. The mouth of the well is blocked out, so that the path of ground water is return to the original befor the mined, and the geologic environment is resumed. Though the characteristic mine in oxidative-reductive environment, the oxidative,reductive zone can be found. In theoxidation zone in the well alley, the slag pile is solidified with green vitriol, pyrite,lignite,and cementHowever, the reductive or oxidative-reductive transition zone maybe used as the place to conserve the slag containing more uranium. The results have shown that the treatment methods above-mentioned are efficient through the radiation measurement of the crowd around the mine before and after treatment of slag pile.