# A Review of Recent Progress of Carbon Capture, Utilization, and Storage (CCUS) in China
## 4 Progress of CO\({}_{2}\) Utilization in China
### Development Status of CO\({}_{2}\) Geological Utilization in China
#### 4.3.4 CO\({}_{2}\) for In-Situ Leach Uranium Mining in China  
Uranium resources are not only a strategic national resource and an important energy resource, but also an important raw material for the nuclear military industry and nuclear power [157]. Sandstone-type uranium resources contribute 41.57% of all the proven uranium resources in China. More than 70% of these complex sandstone-type uranium resources have high salinity, high carbonate, low permeability and low grade, making them difficult to mine using the traditional acid or alkali in situ leach method. In response to this actual situation, the Beijing Research Institute of Chemical Engineering and Metallurgy of China National Nuclear Corporation (CNNC) has carried out a series of theoretical research and technological innovations since 2002. China has successfully mastered and industrialized the technology of CO\({}_{2}\) and O\({}_{2}\) in-situ leach uranium mining through three generations of improvement in mining and metallurgical technology, becoming the second nation after the United States to accomplish this advancement in the world.  
In this technology, CO\({}_{2}\) and O\({}_{2}\) are added to the groundwater to form a leaching agent, which is then introduced into the uranium ore. In the reaction between the leaching agent and uranium ore, O\({}_{2}\) oxidizes tetravalent uranium into hexavalent uranium, while CO\({}_{2}\) reacts with groundwater to form bicarbonate ions. Then, bicarbonate and hexavalent uranium combine to form uranyl ions, which are dissolved in the solution and potently inhibit the precipitation of calcium ions. Finally, the uranium solution is lifted to the ground with a submersible pump for processing, and primary products of uranium can be obtained. The tail solution serves as the leaching agent for cycle use [158].  
Low permeability now has become a major barrier restricting uranium mining in China. The permeability of sandstone-type uranium deposits gradually decreases with increasing mining depth. Therefore, based on the mature technology of CO\({}_{2}\) and O\({}_{2}\) in-situ leach uranium mining, [PERSON] et al. proposed a method of combining CO\({}_{2}\) blasting and CO\({}_{2}\) in-situ leach uranium mining, where CO\({}_{2}\) blasting can create a three-dimensional fracture grid inside the uranium deposit to improve its overall permeability, thereby improving the efficiency of subsequent CO\({}_{2}\) in-situ leach uranium mining [159,160]. [PERSON] et al. put forward a simulation test system for in-situ leach uranium mining in horizontal wells, where horizontal wells are used for liquid injection while vertical wells are used for liquid extraction, to investigate and enhance recovery of CO\({}_{2}\) in-situ leach uranium mining [161].  
At present, there is one CO\({}_{2}\) and O\({}_{2}\) in-situ leach uranium mining project in China, which is operated by CNNC. The improvement of CO\({}_{2}\) and O\({}_{2}\) in-situ leach uranium mining makes \"dead ore\" a lucrative resource that can be economically mined by resolving the technical challenges of excessive acid consumption and easy blockage in the in-situ leach uranium mining of sandstone-type ore. While addressing the issue of CO\({}_{2}\) emissions,  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Project** & **Project Location** & **Operation Start Year** & **Transport** &
\begin{tabular}{c} **CO\({}_{2}\) Injection Capacity** \\ **(Tonnes/Year)** \\ \end{tabular} \\ \hline CUCMC Shizhuang & Shizhuang Block of & & & \\ CO\({}_{2}\)-ECBM project & Qinshui Basin in Shanxi & 2004 & Tanker truck & 1000 \\ CUCMC Liulin & Liulin Block of Ordos & & & \\ CO\({}_{2}\)-ECBM project & Basin in Shanxi & 2012 & Tanker truck & 1000 \\ \hline \hline \end{tabular}
\end{table}
Table 7: CO\({}_{2}\)-ECBM projects in China [50].  
it greatly enhances the usage of sandstone-type uranium resources and effectively solves the problem of difficult groundwater pollution treatment [162].