| 摘要 |
<p>IN SITU LEACH METHOD FOR RECOVERING URANIUM AND RELATED VALUES An in situ leaching process for recovering uranium values from a subterranean formation containing calcium-based clays wherein the lixiviant used has a cationic composition essentially the same as that of the formation connate water with only minute quantities of innocuous leaching chemicals, i.e., CO2, and an oxidant, e.g., O2, present therein. The pH of the lixiviant at the injection well is maintained at a value approximately equal to that of the formation connate water, i.e., 7.5 to 8.0. The pH control to this level is achieved by addition of limes without introducing additional cations to the leaching circuit. This lime addition also serves the purpose of calcium removal (water softening) from the lixiviant. Since there are no cations, e.g., NH4+, added to the lixiviant, there is no problem of contaminating the formation water and altering the nature of the formation, itself, thereby eliminating the need to restore the formation after the leach. Further, since the lixiviant is essentially of the same cationic composition as the formation water, swelling of clay in the formation is minimized.</p> |
