One-step method for electrokinetic uranium extraction and separation from sandstone-type uranium deposit

Abstract

A one-step method for electrokinetic uranium extraction and separation from sandstone-type uranium deposit is provided, including: using an activating leaching agent to adjust pH of activation environment as pH≤3, converting uranium elements in sandstone-type uranium deposit into positively charged uranyl and its complexes; applying direct current (DC) electric field with voltage gradient of 0.1 V/cm to 2 V/cm between cathode and anode, and allowing the uranium elements to move toward a cathode chamber under the action of the electric field and to undergo selective reduction by receiving electrons to produce a low-valent insoluble uranium-containing substance precipitated on the cathode surface. The present invention, through activating leaching, allows the formation of positively charged uranium ions and their complexes only, and electrophysical effects such as electromigration and electroosmosis promote directional movement of uranium toward cathode, thereby achieving uranium extraction from a sandstone-type uranium deposit.

What is claimed is: 
     
         1 . A one-step method for electrokinetic uranium extraction and separation from a sandstone-type uranium deposit, the method comprising:
 uranium activation: using an activating leaching agent to adjust a pH of an activation environment as pH≤3, converting uranium elements in the sandstone-type uranium deposit into positively charged uranyl and its complexes; wherein the activating leaching agent is a mixture of FeCl 3  and a chlorine-containing inorganic acid; a solid-liquid ratio of the sandstone-type uranium deposit to the activating leaching agent is 1 kg: 1-10 L, and a concentration of FeCl 3  in the activating leaching agent is 10 g/L to 20 g/L;   electric field drive: introducing an activated sandstone-type uranium deposit into a direct current (DC) electric field, applying a DC electric field with a voltage gradient of 0.1 V/cm to 0.5 V/cm between a cathode and an anode, and allowing the uranium elements to move toward a cathode chamber ( 4 ) under an action of the electric field and thus to be directionally enriched in the cathode chamber ( 4 );   electrode selective reduction and fixation of uranium: both the cathode and the anode being conductive plastic electrodes, allowing selective reduction of the positively charged uranium elements on a surface of the cathode conductive plastic electrode ( 2 ) by electrochemically reducing them to a low-valent insoluble uranium-containing substance and precipitating it on the surface of the cathode conductive plastic electrode ( 2 ), such that the uranium-containing precipitate is collected on the surface of the cathode conductive plastic electrode ( 2 ).   
     
     
         2 . The one-step method for electrokinetic uranium extraction and separation from the sandstone-type uranium deposit according to  claim 1 , wherein the solid-liquid ratio of the sandstone-type uranium deposit to the activating leaching agent 1 kg: 5-10 L. 
     
     
         3 . The one-step method for electrokinetic uranium extraction and separation from the sandstone-type uranium deposit according to  claim 1 , wherein a pH of the activating leaching agent is 0.5-3. 
     
     
         4 . The one-step method for electrokinetic uranium extraction and separation from the sandstone-type uranium deposit according to  claim 3 , wherein the pH of the activating leaching agent is 0.5-1. 
     
     
         5 . The one-step method for electrokinetic uranium extraction and separation from the sandstone-type uranium deposit according to  claim 1 , wherein the chlorine-containing inorganic acid is selected from any one or more of HCl, HClO, and HClO 4 . 
     
     
         6 . The one-step method for electrokinetic uranium extraction and separation from the sandstone-type uranium deposit according to  claim 1 , wherein after adding the activating leaching agent, the sandstone-type uranium deposit is activated at a temperature of 0-40° C. for 1-24 hours, and then a direct current with a voltage gradient of 0.1 V/cm to 0.5 V/cm is applied between the cathode and the anode for 1-24 hours. 
     
     
         7 . The one-step method for electrokinetic uranium extraction and separation from the sandstone-type uranium deposit according to  claim 1 , wherein the sandstone-type uranium deposit is separated from the cathode conductive plastic electrode ( 2 ) and the anode conductive plastic electrode ( 3 ) by a cathode filter ( 6 ) and a anode filter ( 7 ) respectively to form the cathode chamber ( 4 ) and an anode chamber ( 5 ), and the uranium elements enter the cathode chamber through the cathode filter ( 6 );
 and, the cathode filter ( 6 ) and the anode filter ( 7 ) are both nylon filters;   and, a mesh size of the cathode filter ( 6 ) and a mesh size of the anode filter ( 7 ) are both 400 mesh.   
     
     
         8 . The one-step method for electrokinetic uranium extraction and separation from the sandstone-type uranium deposit according to  claim 2 , wherein the sandstone-type uranium deposit is separated from the cathode conductive plastic electrode ( 2 ) and the anode conductive plastic electrode ( 3 ) by a cathode filter ( 6 ) and a anode filter ( 7 ) respectively to form the cathode chamber ( 4 ) and an anode chamber ( 5 ), and the uranium elements enter the cathode chamber through the cathode filter ( 6 );
 and, the cathode filter ( 6 ) and the anode filter ( 7 ) are both nylon filters;   and, a mesh size of the cathode filter ( 6 ) and a mesh size of the anode filter ( 7 ) are both 400 mesh.   
     
     
         9 . The one-step method for electrokinetic uranium extraction and separation from the sandstone-type uranium deposit according to  claim 3 , wherein the sandstone-type uranium deposit is separated from the cathode conductive plastic electrode ( 2 ) and the anode conductive plastic electrode ( 3 ) by a cathode filter ( 6 ) and a anode filter ( 7 ) respectively to form the cathode chamber ( 4 ) and an anode chamber ( 5 ), and the uranium elements enter the cathode chamber through the cathode filter ( 6 );
 and, the cathode filter ( 6 ) and the anode filter ( 7 ) are both nylon filters;   and, a mesh size of the cathode filter ( 6 ) and a mesh size of the anode filter ( 7 ) are both 400 mesh.   
     
     
         10 . The one-step method for electrokinetic uranium extraction and separation from the sandstone-type uranium deposit according to  claim 4 , wherein the sandstone-type uranium deposit is separated from the cathode conductive plastic electrode ( 2 ) and the anode conductive plastic electrode ( 3 ) by a cathode filter ( 6 ) and a anode filter ( 7 ) respectively to form the cathode chamber ( 4 ) and an anode chamber ( 5 ), and the uranium elements enter the cathode chamber through the cathode filter ( 6 );
 and, the cathode filter ( 6 ) and the anode filter ( 7 ) are both nylon filters;   and, a mesh size of the cathode filter ( 6 ) and a mesh size of the anode filter ( 7 ) are both 400 mesh.   
     
     
         11 . The one-step method for electrokinetic uranium extraction and separation from the sandstone-type uranium deposit according to  claim 5 , wherein the sandstone-type uranium deposit is separated from the cathode conductive plastic electrode ( 2 ) and the anode conductive plastic electrode ( 3 ) by a cathode filter ( 6 ) and a anode filter ( 7 ) respectively to form the cathode chamber ( 4 ) and an anode chamber ( 5 ), and the uranium elements enter the cathode chamber through the cathode filter ( 6 );
 and, the cathode filter ( 6 ) and the anode filter ( 7 ) are both nylon filters;   and, a mesh size of the cathode filter ( 6 ) and a mesh size of the anode filter ( 7 ) are both 400 mesh.   
     
     
         12 . The one-step method for electrokinetic uranium extraction and separation from the sandstone-type uranium deposit according to  claim 6 , wherein the sandstone-type uranium deposit is separated from the cathode conductive plastic electrode ( 2 ) and the anode conductive plastic electrode ( 3 ) by a cathode filter ( 6 ) and a anode filter ( 7 ) respectively to form the cathode chamber ( 4 ) and an anode chamber ( 5 ), and the uranium elements enter the cathode chamber through the cathode filter ( 6 );
 and, the cathode filter ( 6 ) and the anode filter ( 7 ) are both nylon filters;   and, a mesh size of the cathode filter ( 6 ) and a mesh size of the anode filter ( 7 ) are both 400 mesh.