Under the new development philosophy of carbon peaking and carbon neutrality,CO_(2)and O_(2)in situ leaching(ISL)has been identified as a promising technique for uranium mining in China,not only because it solves carb...Under the new development philosophy of carbon peaking and carbon neutrality,CO_(2)and O_(2)in situ leaching(ISL)has been identified as a promising technique for uranium mining in China,not only because it solves carbon dioxide utilization and sequestration,but it also alleviates the environmental burden.However,significant challenges exist in assessment of CO_(2)footprint and water-rock interactions,due to complex geochemical processes.Herein this study conducts a three-dimensional,multicomponent reactive transport model(RTM)of a field-scale CO_(2)and O_(2)ISL process at a typical sandstone-hosted uranium deposit in Songliao Basin,China.Numerical simulations are performed to provide new insight into quantitative interpretation of the greenhouse gas(CO_(2))footprint and environmental impact(SO_(4)^(2–))of the CO_(2)and O_(2)ISL,considering the potential chemical reaction network for uranium recovery at the field scale.RTM results demonstrate that the fate of the CO_(2)could be summarized as injected CO_(2)dissolution,dissolved CO_(2)mineralization and storage of CO_(2)as a gas phase during the CO_(2)and O_(2)ISL process.Furthermore,compared to acid ISL,CO_(2)and O_(2)ISL has a potentially smaller environmental footprint,with 20%of SO_(4)^(2–)concentration in the aquifer.The findings improve our fundamental understanding of carbon utilization in a long-term CO_(2)and O_(2)ISL system and provide important environmental implications when considering complex geochemical processes.展开更多
The Shihongtan uranium deposit in northwest China is a sandstone-type deposit suitable for alkaline in-situ leaching exploitation of uranium. Alkaline leaching tends to result in CaCO3 precipitation there by affecting...The Shihongtan uranium deposit in northwest China is a sandstone-type deposit suitable for alkaline in-situ leaching exploitation of uranium. Alkaline leaching tends to result in CaCO3 precipitation there by affecting the porosity of the ore-bearing aquifer. CaCO3 deposits can also block pumping and injection holes if the formulation parameters of the leaching solution are not well controlled. However, controlling these parameters to operate the in-situ leaching process is challenging. Our study demonstrates that the dissolved uranium concentration in the leaching solution increases as HCO3-concentration increases. Therefore, the most suitable HCO3-concentration to use as leaching solution is defined by the boundary value of the HCO3-concentration that controls CaCO3 dissolution-precipitation. That is, the dissolution and precipitation of calcite is closely related to pH, Ca2+ and HCO3-concentration. The pH and Ca2+ concentration are the main factors limiting HCO3-concentration in the leaching solution. The higher the pH and Ca2+ concentration, the lower the boundary value of HCO3-concentration, and therefore the more unfavorable to in-situ leaching of uranium.展开更多
The development of industry of uranium mining and metallurgy in China has been reviewed generally,emphasizing on investigation approaches and application levels of uranium mining technologies such as in-situ leaching,...The development of industry of uranium mining and metallurgy in China has been reviewed generally,emphasizing on investigation approaches and application levels of uranium mining technologies such as in-situ leaching,heap leaching,stope leaching:on the basis of analysis on status of uranium mining and metallurgy and problems existed,also considering the specific features of deposit resources,the development orientation of uranium mining and metallurgy in China is pointed out.The industry of China uranium mining and metallurgy is faced to new opportunity of development and challenge in 21st century,the only way to realize sustainable development of uranium mining and metallurgy and harmonious development between economy and environment is to develop new technology on mining,ore beneficiation and metallurgy,increase the utilization level of uranium resources,low down impact on environment caused by mining and metallurgy.展开更多
[ Objectivel The study aims to discuss the impact factors of COD （chemical oxygen demand） throughput in corncob extract. [ Method ] Firstly, as the variations of the mass concentration of corncob, temperature, time ...[ Objectivel The study aims to discuss the impact factors of COD （chemical oxygen demand） throughput in corncob extract. [ Method ] Firstly, as the variations of the mass concentration of corncob, temperature, time and pH, the throughput of COD in corncob extract were analyzed respectively. Afterwards, through the orthogonal test, the best conditions for extracting organic matter from corncob were determined. [ Result] The single-factor tests showed that there was a linear relationship between the mass concentration of corncob and COD of corncob extract when the mass concentration of the corncob was lower than 50 g/L; COD of corncob extract was higher under acidic or alkaline conditions. The optimum con- ditions for extracting organic compounds from corncob were as follows： temperature was 35 ℃, mass concentration was 40 g/L, pH =3, and ex- tracting time was 3 hours; under this conditions, the mass of COD released from a unit mass of corncob reached 0.056 2 g. [ Conclusien] The re- search could decrease the treatment cost of wastewater from uranium mining in mines and make corncob more useful.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.U2167212)。
文摘Under the new development philosophy of carbon peaking and carbon neutrality,CO_(2)and O_(2)in situ leaching(ISL)has been identified as a promising technique for uranium mining in China,not only because it solves carbon dioxide utilization and sequestration,but it also alleviates the environmental burden.However,significant challenges exist in assessment of CO_(2)footprint and water-rock interactions,due to complex geochemical processes.Herein this study conducts a three-dimensional,multicomponent reactive transport model(RTM)of a field-scale CO_(2)and O_(2)ISL process at a typical sandstone-hosted uranium deposit in Songliao Basin,China.Numerical simulations are performed to provide new insight into quantitative interpretation of the greenhouse gas(CO_(2))footprint and environmental impact(SO_(4)^(2–))of the CO_(2)and O_(2)ISL,considering the potential chemical reaction network for uranium recovery at the field scale.RTM results demonstrate that the fate of the CO_(2)could be summarized as injected CO_(2)dissolution,dissolved CO_(2)mineralization and storage of CO_(2)as a gas phase during the CO_(2)and O_(2)ISL process.Furthermore,compared to acid ISL,CO_(2)and O_(2)ISL has a potentially smaller environmental footprint,with 20%of SO_(4)^(2–)concentration in the aquifer.The findings improve our fundamental understanding of carbon utilization in a long-term CO_(2)and O_(2)ISL system and provide important environmental implications when considering complex geochemical processes.
基金supported by the basic science research project (A3420060142) from China National Defence Science and Technology Industry BureauChina National Natural Science Fund Project (40872165)
文摘The Shihongtan uranium deposit in northwest China is a sandstone-type deposit suitable for alkaline in-situ leaching exploitation of uranium. Alkaline leaching tends to result in CaCO3 precipitation there by affecting the porosity of the ore-bearing aquifer. CaCO3 deposits can also block pumping and injection holes if the formulation parameters of the leaching solution are not well controlled. However, controlling these parameters to operate the in-situ leaching process is challenging. Our study demonstrates that the dissolved uranium concentration in the leaching solution increases as HCO3-concentration increases. Therefore, the most suitable HCO3-concentration to use as leaching solution is defined by the boundary value of the HCO3-concentration that controls CaCO3 dissolution-precipitation. That is, the dissolution and precipitation of calcite is closely related to pH, Ca2+ and HCO3-concentration. The pH and Ca2+ concentration are the main factors limiting HCO3-concentration in the leaching solution. The higher the pH and Ca2+ concentration, the lower the boundary value of HCO3-concentration, and therefore the more unfavorable to in-situ leaching of uranium.
文摘The development of industry of uranium mining and metallurgy in China has been reviewed generally,emphasizing on investigation approaches and application levels of uranium mining technologies such as in-situ leaching,heap leaching,stope leaching:on the basis of analysis on status of uranium mining and metallurgy and problems existed,also considering the specific features of deposit resources,the development orientation of uranium mining and metallurgy in China is pointed out.The industry of China uranium mining and metallurgy is faced to new opportunity of development and challenge in 21st century,the only way to realize sustainable development of uranium mining and metallurgy and harmonious development between economy and environment is to develop new technology on mining,ore beneficiation and metallurgy,increase the utilization level of uranium resources,low down impact on environment caused by mining and metallurgy.
基金Supported by National Natural Science Foundation of China (51154003,50774047) Educational Commission of Hunan Province,China (09c864)
文摘[ Objectivel The study aims to discuss the impact factors of COD （chemical oxygen demand） throughput in corncob extract. [ Method ] Firstly, as the variations of the mass concentration of corncob, temperature, time and pH, the throughput of COD in corncob extract were analyzed respectively. Afterwards, through the orthogonal test, the best conditions for extracting organic matter from corncob were determined. [ Result] The single-factor tests showed that there was a linear relationship between the mass concentration of corncob and COD of corncob extract when the mass concentration of the corncob was lower than 50 g/L; COD of corncob extract was higher under acidic or alkaline conditions. The optimum con- ditions for extracting organic compounds from corncob were as follows： temperature was 35 ℃, mass concentration was 40 g/L, pH =3, and ex- tracting time was 3 hours; under this conditions, the mass of COD released from a unit mass of corncob reached 0.056 2 g. [ Conclusien] The re- search could decrease the treatment cost of wastewater from uranium mining in mines and make corncob more useful.
