Rare earth metals sorption recovery from uranium in situ leaching process solutions

Sorption characteristics of ion exchange resins 001 × 7, 005 × 8, D72 regarding rare earth metals （REM） during extraction from barren solution of uranium sorption in dynamic conditions were investigated. It was identified that D72 resin capacity on analyzed REM was 2.46 mg.cm-3 after passing 220 BV （bed volume） of initial solution with 95 % recovery of element of REM with the lowest affinity. Researches on REM desorption in dynamic conditions from investigated ion exchange resins by solution of 1.7 mol.L-1 HNO3 and 8.0 mol.L-1 NHnNO3 with 0.2 mol.L-1 HNO3 passing were carded out. It was identified that using desorption solution based on ammonium nitrate allows to achieve acceptable recovery degree of REM from the resin. The possibility of organization of a circulating desorption solution system increases the perspectives of nitrate ammonium solution usage.

Assessment of the Greenhouse Gas Footprint and Environmental Impact of CO_(2)and O_(2)in situ Uranium Leaching

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.

Wetting front migration model of ion-adsorption rare earth during the multi-hole unsaturated liquid injection

In the process of ion-adsorption rare earth ore leaching,the migration characteristics of the wetting front in multi-hole injection holes and the influence of wetting front intersection effect on the migration distance of wetting fronts are still unclear.Besides,wetting front migration distance and leaching time are usually required to optimize the leaching process.In this study,wetting front migration tests of ionadsorption rare earth ores during the multi-hole fluid injection(the spacing between injection holes was 10 cm,12 cm and 14 cm)and single-hole fluid injection were completed under the constant water head height.At the pre-intersection stage,the wetting front migration laws of ion-adsorption rare earth ores during the multi-hole fluid injection and single-hole fluid injection were identical.At the postintersection stage,the intersection accelerated the wetting front migration.By using the Darcy’s law,the intersection effect of wetting fronts during the multi-hole liquid injection was transformed into the water head height directly above the intersection.Finally,based on the Green-Ampt model,a wetting front migration model of ion-adsorption rare earth ores during the multi-hole unsaturated liquid injection was established.Error analysis results showed that the proposed model can accurately simulate the infiltration process under experimental conditions.The research results enrich the infiltration law and theory of ion-adsorption rare earth ores during the multi-hole liquid injection,and this study provides a scientific basis for optimizing the liquid injection well pattern parameters of ion-adsorption rare earth in situ leaching in the future.

Study on the Impact Factors of COD Throughput in Corncob Extract

[ 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.