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With the exploitation of uranium–beryllium ore, the waste and wastewater produced have received extensive attention. There are a lot of toxic and harmful substances in uranium–beryllium ore, among which beryllium has not been widely concerned. This paper used hydrochloric acid (HCl) pretreatment activated carbon (H-AC) to study the removal of beryllium from uranium beryllium ore wastewater. This experiment explored the influence of reaction time, reaction temperature, and other conditions on the adsorption effect. It concluded that the adsorption efficiency was 99% when pH = 5, the amount of adsorbent was 2 g/L, and the temperature was 25 °C. The effects of Be–U, Be–Mn, Be–Zn, Be–Fe and, Be–Al binary systems on the adsorption of beryllium by H-AC were analyzed. The results show that the adsorption capacity of H-AC to beryllium is not affected by the coexisting ions. According to thermodynamics, the adsorption process is a spontaneous endothermic single-layer adsorption, and the maximum adsorption capacity fitted by thermodynamics is 30.63 mg/g. Kinetic fitting showed that chemical adsorption was the primary process, and the reaction was intense in the early stage. This study provides a new idea for removing beryllium from uranium beryllium ore wastewater, and H-AC can be considered a potential adsorbent for removing beryllium from industrial wastewater. [ABSTRACT FROM AUTHOR]

According to the difficult problem of disposal and recovery of uranium-containing waste slag, the leaching experiment was conducted by using the secondary countercurrent leaching process. The results showed that under conditions particle size of 1 mm, reaction time of 120 min, leaching temperature of 90 °C, nitric acid concentration of 429 g/L, liquid–solid ratio of 2.2:1, hydrogen peroxide dosage of 30 mL/L in primary leaching, then the temperature was switched to 130 °C during the secondary leaching. The leaching rate of uranium in alkali slag was 99.73% and the content of the uranium in insoluble slag was 0.788%. [ABSTRACT FROM AUTHOR]

In this study, a new type of phosphorylated chitosan-supported nano iron (CSP/Fe0) composite material. CSP/Fe0 had a high adsorption rate (99.25%) and a maximum adsorption capacity (627.34 mg g−1) when the conditions were pH = 6, 308.15 K and 12 h. CSP/Fe0 had a specific surface area of CSP/Fe0 was 6.02 m2 g−1, and has a mesoporous structure with more active sites (average pore size is 9.67 nm). The primary mechanism may be the complexation of U(VI) with abundant –OH, –NH2, P=O on the surface of the material and the reduction of nanoscale zero-valent iron. Therefore, it is indicated that the material has good potential in remediation of uranium-contaminated groundwater environment. [ABSTRACT FROM AUTHOR]

The oxidation efficiency and leaching rate of ozone micro-nano bubbles (OMNBs) on UO2 and sandstone uranium ore were explored and evaluated through a batch oxidation experiment of sandstone uranium ore and a continuous flow oxidation experiment of UO2. OMNBs can accelerate the rate of oxidative leaching. Oxidation mainly relies on ozone oxidation. Oxidation of sandstone uranium ore by OMNBs was feasible, and OMNBs may solve current problems encountered in production practice. The continuous flow experiment verified the feasibility of the large-scale experiment and provided a new method for CO2 + O2 ISL of uranium under normal pressure in the future. [ABSTRACT FROM AUTHOR]

Low-grade uranium ore, which was challenging to be treated economically by conventional methods, can be treated by uranium leaching by bacteria. However, high uranium concentration will lead to the death of bacteria. This work researched the oxidative leaching performance of bacteria (Acidithiobacillus ferrivorans with uranium resistance) under different iron valence conditions. Oxidative leaching of UO2 by bacteria from energy substrates with varying states of the valence of iron ions was studied through an Acidithiobacillus ferrivorans oxidation model. The results showed that the probability of pyrite being oxidized by the Acidithiobacillus ferrivorans system was 98.05% under the condition of Fe2+, while it was 87.30% exposed to Fe3+. In addition, the leaching rate of UO2 by the Acidithiobacillus ferrivorans & Fe2+ system was 94.70%. Under the same conditions, while adding 1 g/L pyrite, the leaching rate of UO2 increased to 99.96%. This study revealed the oxidative leaching mechanism of UO2 and provided a new theoretical basis for the bacterial leaching of uranium. [ABSTRACT FROM AUTHOR]

Uranium mining, smelting, and nuclear industries generate a considerable amount of wastewater containing uranium. To treat this wastewater effectively and inexpensively, a novel hydrogel material (cUiO-66/CA) was developed by co-immobilizing UiO-66 with calcium alginate and hydrothermal carbon. Batch tests were conducted to determine the optimal adsorption conditions for uranium using cUiO-66/CA, and the adsorption behavior was spontaneous and endothermic, confirming the quasi-second-order dynamics model and the Langmuir model. At a temperature of 308.15 K and pH = 4, the maximum adsorption capacity of uranium was 337.77 mg g−1. The surface appearance and interior structure of the material were analyzed using SEM, FTIR, XPS, BET, and XRD techniques. The results indicated two possible uranium adsorption processes of cUiO-66/CA: (1) Ca2+ and UO 2 2+ ion exchange process and (2) coordination of uranyl ions with hydroxyl and carboxyl ions to form complexes. cUiO-66/CA exhibited strong selectivity for U (VI) in a multicomponent mixed solution and uranium-containing wastewater, with uranium removal rates of 99.03 % and 81.45 %, respectively. The hydrogel material demonstrated excellent acid resistance, and the uranium adsorption rate exceeded 98 % in the pH range of 3–8. Therefore, this study suggests that cUiO-66/CA has the potential to treat uranium-containing wastewater in a broad pH range. [Display omitted] [ABSTRACT FROM AUTHOR]