The contaminated solvent from the Purex process is washed with alkaline detergents such as sodium carbonate, which generates a large amount of secondary wastes. Therefore, hydrazine carbonate as a salt-free reagent deserves to be studied in depth. In this study, the Ce(IV), U(VI), and Zr(IV) metal ions in organic phases containing dibutyl phosphate (HDBP) of 30% tributyl phosphate (TBP)–dodecane were washed with hydrazine carbonate. The effects of the oscillation time (1 to 15 min); temperature (25°C to 85°C); cumulative number of washes (one to four times); mass fraction of hydrazine carbonate (0.1% to 20%); volume ratio of the aqueous phase to the organic phase (0.2 to 5); HDBP concentration (0 to 0.4 M); HNO3 concentration (0.05 to 8 M); and concentration of Ce(IV), U(VI), and Zr(IV) metal ions on the removal percentages of Ce(IV), U(VI), and Zr(IV) metal ions in polluted solvents were studied. The results showed that when the organic phase containing 0.02 M HDBP was washed three times with 5% hydrazine carbonate at 25°C, the removal percentages of the Ce(IV), U(VI), and Zr(IV) ions were 96%, 98%, and 94%, respectively. Meanwhile, the retention concentrations of the three in the organic phase were 35, 28, and 78 mg/L, respectively. The increase of the mass fraction of hydrazine carbonate enhances the removal of the metal ions from the organic phase into the aqueous phase. High acid is not conducive to alkaline washing of metal ions. The increase of HDBP concentration not only promotes extraction but also increases the retention capacity of the organic phase and has the most significant effect on Zr(IV). U(VI) promotes the preferential washing of Zr(IV) while Ce(IV) increases the metal retention concentration of Zr(IV) in the organic phase.
NTAamide(C8) exhibits high selectivity for the extraction of Pu(IV) across a wide range of nitric acid concentrations. To separate trace Pu(IV) from radioactive liquid stream generated during the PUREX process in spent nuclear fuel reprocessing, a novel silica-polymer-based adsorbent, NTAamide(C8)/SiO 2 -P, was synthesized via vacuum impregnation using NTAamide(C8) as the extractant and SiO 2 -P as the support. The adsorption performance of Pu(IV) were systematically evaluated. Batch experiments revealed that adsorption equilibrium was achieved within 2 h, with a maximum adsorption capacity of 143.2 mg/g for Pu(IV). The material demonstrated high selectivity for Pu(IV) and exhibited excellent radiation resistance and hydrolytic stability. The adsorption mechanisms were further elucidated using X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations, confirming the formation of 1:1 complexes between NTAamide(C8) and the metal ions. Column experiments using actual uranium product solution from the PUREX process verified the material's performance in trace Pu(IV) removal. After column treatment, the Pu content in the uranium product solution was reduced to below 10 Bq/gU, with no significant loss of uranium. These results demonstrate that NTAamide(C8)/SiO 2 -P is a promising adsorbent for the efficient and selective separation of Pu(IV) from radioactive liquid stream under a wide range of nitric acid concentrations.
Jing Ma,Jingyu Zhao,Tiejun Liu,Cuiling Yang,Yeyun Wang,Jinghui Zhang,Mingfu Li,Yufan Sun
This project designed and created a large-scale pyrolysis incineration system that decomposes waste tributyl phosphate/kerosene (TBP/OK) solvent from the plutonium/uranium process (PU-REX) in the nuclear industry. This system consists of a suspension preparation system (SPS), a pyrolysis and ash discharge system (PADS), and a combustion furnace and gas treatment system (CGS). The preparation of a waste TBP/OK emulsified suspension in the SPS, continuous operation experiments of the PADS and CGS, and pyrolysis incineration experiments were conducted. The results show that the SPS achieved the automatic preparation and feeding of emulsified suspensions at 30 kg/h. The PADS decomposed 99.99% of the TBP/OK emulsified suspensions and fixed more than 99% of phosphorus. The CGS burned the pyrolysis gas without diesel oil and purified more than 99.995% of the radioactive nuclides. This system showed great feasibility, stability, continuity, and safety, proving the compatibility between multiple systems of this new design. This paper marks a significant step in pyrolysis incineration technology for the nuclear industry.Keywords:pyrolysis incineration;TBP/OK;PUREX
危险品化学品经营许可证（带存储）