1. Extraction of Uranium From Alkali Residue With Supercritical Carbon Dioxide Fluid
- Author
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GANG Fa-yuan, SONG Zhi-jun, DING You-qian, WANG Xiu-feng, YU Zhen-hua, SUN Xue-jie, and BAI Long
- Subjects
alkali residue ,supercritical co2 fluid extraction ,uranium ,Nuclear engineering. Atomic power ,TK9001-9401 ,Chemical technology ,TP1-1185 - Abstract
Alkali residue was dissolved by the ammonium hydrogen fluoride method, in which the uranium content is determined to be (16.7±0.3)%(n=6) by inductively coupled plasma optical emission spectrometry(ICP-AES). By means of XRD and SEM-EDS, the main uranium occurrence form of alkali residue was determined. It includes UO3, fluoride(CaF2, NaF, MgF2, UF4, etc), SiO2-P2O5-UO3, Cr2O3-Fe2O3 and other solid melts, and the forms of UO3 being wrapped by the above solid melts. Using TBP-HNO3 as complexing agent, the effects of various parameters were investigated on the lab-scale supercritical CO2 fluid extraction facility. The extraction parameters are optimized: the particle size is 0.250-0.420 mm, saturated Al(NO3)3 solution of w=25% alkali residue is used as salting agent, the mole ratio of TBP-HNO3/U is ≥50, the extraction temperature is 50 ℃ and the pressure is 20 MPa. Under these conditions, the extraction rate of uranium in the alkali residue reaches as high as 98.5% within 2 h. This work provides a new method for the recovery of uranium in alkali residue.
- Published
- 2023
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