摘要
以氟碳铈矿-独居石混合稀土矿为研究对象,采用分步选择性碳热氯化-化学气相传输反应(SC-CVT),实现钍与其它稀土元素的分离。当氯化反应温度为500℃,以活性炭为还原剂、SiCl4为脱氟剂,在Cl2气氛下稀土矿反应2h时,钍的氯化产物(ThCl4)挥发量小于1%;继而以AlCl3作配位体,800℃、Cl2气氛下传输反应0.5h,ThCl4与配位体反应形成气态配合物ThAlCl7;温度降低时,ThAlCl7分解并沉积在600℃左右的温区内,AlCl3沉积在温度低于200℃的温区内,FeCl3主要沉积在200~350℃的温区内,从而实现放射性元素Th的分离和回收。
A stepwise carbochlorination-chemical vapor transport (SC-CVT) technique is proposed for separation of thorium from mixed bastnaesite-monazite concentrate. Mixed bastnaesite-monazite concentrate is first isothermally carbochlorinated for 2 h in a Cl2 atmosphere with activated carbon as a reductant and SiCl4 as a fluorine scavenger at a temperature as low as 500℃, only about 1 percent of the total thorium contained in the bastnaesite-monazite concentrate is evaporated. CVT processing is then undertaken at 800℃ for 0.5 h in a Cl2 SiCl4-AlCl3 atmosphere. During this stage thorium is converted to a volatile complex ThAlCl7, and is driven to transport to a temperature-gradient collection system, where thorium is deposited around 600℃, while FeCl3 and AlCl3 are deposited in the range of 200~350℃ and at even lower temperature(〈200℃), respectively. By using this technique the pollution caused by thorium radioactivity could be significantly alleviated.
出处
《核化学与放射化学》
EI
CAS
CSCD
北大核心
2006年第1期61-64,共4页
Journal of Nuclear and Radiochemistry
基金
国家自然科学基金资助项目(59874008)
辽宁省教育厅资助项目(20040294)