龚伟 1徐永东 2崔文星 2刘晓娟 2石国升 3吴明红3
作者信息
- 1. 中核四0四有限公司,甘肃嘉峪关 732850||上海大学,上海 200444
- 2. 中核四0四有限公司,甘肃嘉峪关 732850
- 3. 上海大学,上海 200444
- 折叠
摘要
Abstract
In the uranium chemical process,the hydrogen peroxide precipitation method can be used for the purification of uranyl nitrate.The research on the overoxidized uranium crystallization process based on the batch-stirred reactor is relatively in-depth.However,due to the batch precipitation process being batchwise precipitation and using mechanical stirring for mixing,there are problems such as lack of process continuity,dependence on equipment volume,average mass transfer effect,large retention volume,and multiple moving components.To improve the traditional batch precipitation method and strengthen the overoxidized uranium precipitation process,the ultrasonic field and microchannel technology were coupled to study the influence of the combined effect of ultrasonic action and microchannel technology on the precipitation conversion and impurity purification of overoxidized uranium.Firstly,the influence of the coupling of ultrasonic and microchannel technology on the precipitation rate and the crystal size distribution of the precipitate was studied.Then,the influence of the coupling of ultrasonic and microchannel technology on impurity purification was investigated.Finally,the influence of the combined use of ultrasonic and microchannel technology on continuous impurity purification in the precipitation process was verified through a large-flux precipitation test.The results show that the combined action of ultrasonic strengthening technology and micro-mixing technology significantly improves the growth rate of precipitation crystals,thereby accelerating the formation rate of precipitation and significantly increasing the precipitation rate,without aging,ensuring the size of the crystal,achieving uniform,regular,and having a large particle size of overoxidized uranium precipitate crystals,and simultaneously achieving a significant improvement in the impurity purification ability of the precipitation process.Only under the microchannel reaction conditions,the amounts of the five impurities(Al,Fe,Ni,Cu,Cr)in the product UO4·4H2O decrease from 9 178 μg/gU to below 4.89 μg/gU.This indicates that the continuous homogeneous mixing of the micro-mixing process reduces the entrainment of impurities and improves the impurity purification rate.For Zr4+,which has a larger ionic potential,the ultrasonic action accelerates the crystal growth rate,controls the particle size and distribution of the precipitation crystals,reduces the encapsulation of Zr,and the two technologies are combined to achieve a significant improvement in the impurity purification ability of the precipitation process.Under the optimal conditions of the test device with a flux of 298.14 g/h,the total amount of six impurities in the UO4·4H2O crystals is less than 136 μg/gU(while the original solution contains 9 178 μg/gU).The purification coefficients of Fe,Cr,Ni,Zr,Cu,and Al are 969,1 528,1 427,9,1 237,and 131 respectively,far exceeding the average impurity purification efficiency of the original batch precipitation process.关键词
超声/微通道/过氧化铀沉淀/杂质净化Key words
ultrasonic/microchannel/uranium peroxide precipitation/impurity purification分类
能源科技
