Shielding process for the effect of anions on uranium selective recovery and heavy metal removal from simulated mine effluents

The selective separation of uranium from uranium tailing wastewater is of great importance for environmental protection and nuclear energy development. The complexation of Cl − , SO 4 2− , NO 3 – , and PO 4 3− with UO 2 2+ seriously hindered the achievement of this goal. Herein, a process for achieving it with the coexistence of anions and cations by shielding the influence of anions was designed. Thermodynamic calculations indicated that CO 3 2– could enhance the retention of uranium in the solution by complexing with UO 2 2+ and capturing UO 2 2+ in UO 2 SO 4 and UO 2 HPO 4 to form water-soluble uranyl-carbonate. The capturing ability of CO 3 2– was not diminished by the increase in anion concentration. And the electrochemical experiments revealed the high efficiency of uranium electrochemical extraction in the above system. In addition, the results showed that uranium could be separated from Co 2+ , Cd 2+ , and Ni 2+ ions under the coexistence of Cl − , SO 4 2− , NO 3 – , and PO 4 3− , thus achieving the selective separation of uranium in the wastewater. And the retention ratio of impurity cations in the liquid phase after separation was less than 0.003. Overall, this method provides new insights into the selective separation of uranium and heavy metal removal in real uranium tailings wastewater.