Liquid injection process for in-situ leaching and extracting ion-adsorption type rare earth elements

Abstract

A liquid injection process for in-situ leaching and extracting an ion-adsorption type rare earth including: setting up a liquid injection network having liquid injection shallow wells and liquid injection deep wells, inputting a leaching agent into the injection shallow wells, then inputting the leaching agent into the deep wells, and finally inputting a pushing water into all of the wells. This process is characterized by a high rare earth mineral-leaching rate, a high mother liquid concentration, a small residue of the mother liquid of the ore earth, a small unit consumption of the leaching agent, simple operation, wide application, and outstanding environmental protection effect. Additionally, the process also can cancel any blind area in mineral leaching, increase stability of side slope in the liquid injection process, and control a flow direction, a flow rate of the leaching agent, and a liquid injection intensity.

1 . A liquid injection process for in-situ leaching and extracting, in particular, ion-adsorption type rare earth, characterized in that, setting up a liquid injection network having liquid injection shallow wells and liquid injection deep wells alternatively distributed at an interval; in the procedure of the liquid injection process, firstly input a leaching agent into the injection shallow wells, then input the leaching agent into the injection deep wells, and in the end jointly input a pushing water into the injection shallow wells and the injection deep wells. 
     
     
         2 . The liquid injection process of  claim 1 , characterized in that, additional liquid injection wells with moderate depth are also set in the liquid injection network. 
     
     
         3 . The liquid injection process of  claim 1 , characterized in that, in the liquid injection network, any liquid injection shallow well is at interval of 2-3 m×2-3 m to its neighbour liquid injection deep wells; when the ore earth is mainly composed of medium or coarse sand, a bigger interval is provided between one injection shallow well and one of its neighbour deep wells; while when the ore earth is mainly composed of clay minerals, a smaller interval is arranged between one injection shallow well and one of its neighbour deep wells. 
     
     
         4 . The liquid injection process of  claims 1  or  2 , characterized in that, the injection shallow well is inputted with the leaching agent under static pressure, while the injection deep well is inputted with the leaching agent under a closed state and injected at moderate depth. 
     
     
         5 . The liquid injection process of  claim 1 , characterized in that, a drainage pipe of the injection shallow wells and the injection deep wells, a corresponding ball valve switch, and a diversion conduit are interconnected with a main extracting pipeline, so as to form a liquid injection system. 
     
     
         6 . The liquid injection process of  claim 1 , characterized in that, a diameter of, the injection shadow well is 3-4 times as much as that of the injection deep well, and a diameter of the injection deep well is 10-12 cm. 
     
     
         7 . The liquid injection process of  claim 1 , characterized in that, the bottom of the injection shallow well is 1-2 m below ore-hearing formation, and the bottom of the injection deep well is 4.5-5.5 m over or above the liquid recovery engineering control surface, or is determined according to the following equation:
   the ore thickness at the injection deep well+(the depth of the engineering control surface at the injection deep well−the ore thickness at the injection deep well)×55%≦the depth of the injection deep well≦the ore thickness at the injection deep well+(the depth of the engineering control surface at the injection deep well−the ore thickness at the injection deep well)×75%.
   
     
     
         8 . The liquid injection process of  claim 7 , characterized in that, when the ore earth is mainly composed of medium or coarse sand (i.e. when the ore earth is with a good permeability), the depth of the injection deep well is selected to be smaller in said calculation equation; while when the ore earth is mainly composed of clay minerals and/or silt (i.e. when the ore earth is with a poor permeability), the depth of the injection deep well is selected to be bigger in said calculation equation. 
     
     
         9 . The liquid injection process of  claim 2 , characterized in that, the depth of the injection well with moderate depth is determined according to the following equation:
   the depth of the injection well with moderate depth=(the depth of the injection deep well−the depth of the adjacent injection shallow/2+the depth of the adjacent injection shallow well, or
   the depth of the injection well with moderate depth is determined according to the following equation:
   the ore thickness at the injection well with moderate depth+(the depth of the engineering control surface at the injection well with moderate depth−the ore thickness at the injection well with moderate depth)×40%≦the depth of the injection well with moderate depth≦the ore thickness at the injection well with moderate depth+(the depth of the engineering control surface at the injection well with moderate depth−the ore thickness at the injection well with moderate depth)×60%.
 
   
     
     
         10 . The liquid injection process of  claim 9 , characterized in that, when the ore earth is mainly composed of medium or coarse sand (i.e. when the ore earth is with a good permeability), the depth of the injection deep well with moderate depth is selected to be smaller in said calculation equation; while when the ore earth is mainly composed of clay minerals and/or silt (i.e. when the ore earth is with a poor permeability), the depth of the injection deep well with moderate depth is selected to be bigger in said calculation equation.