Dynamics Mechanism Of Supercritical CO₂Fluid Leaching Of Uranium From Sandstone Type Ores

Currently irrational use of energy causes serious environmental pollution, thedevelopment of nuclear energy as an effective means to reduce emissions pollutionprevention. Uranium is the basic raw material to develop nuclear energy, uranium miningtraditional methods of uranium mining due to the limitations of their own, prone to "waste",causing secondary pollution and increasing environmental and economic costs ofextraction of uranium.This paper creative studied a kind of method leaching uranium from low-gradesandstone uranium deposits by supercritical CO2.That is able to efficiently extract uraniumore, but also avoid secondary pollution. In the experiment we designed the multi-functiondevice of leaching of uranium by ourselves, against a sandstone type uranium deposits inXinjiang, conducted extensive laboratory tests. Firstly, a preliminary experiment provesthe feasibility of leaching of uranium in supercritical carbon dioxide fluid; then through theoptimization experiments, changes the pressure and time, measures the best of thepressure.The final test results are as follows:(1)On the basis of ferric chloride as a reactant， the supercritical carbon dioxide inFeCl3can effectively extract the low-grade uranium ore in sandstone uranium, andcompared with other oxidants and carrying agents better.(2)At a temperature of45℃, the results indicate that leaching efficiency first increaseand then decrease with the increase of pressure under the constant time; it has the sametrend with the increase of time and finally reaches a stable state under constant pressure.The optimum leaching conditions is8-12MPa, and the leaching efficiency could reach to90%.(3)By dynamics simulation, the result shows that the chemical reactions insupercritical carbon dioxide extraction of uranium in uranium play a leading role.