摘要
本文选取四川某地富稀土粉煤灰,利用逐级化学提取查明了稀土元素的赋存状态,研究了稀土元素在物理分选(筛分、浮沉及磁选)中的分布规律,考察了NaOH溶液脱硅和盐酸浸出对稀土元素富集提取的效果,最后利用X射线光电子能谱(XPS)及扫描电子显微镜(SEM)分析了固体表面特征.研究结果表明:该粉煤灰中稀土元素含量为782μg/g,68%的稀土元素赋存于铝硅化合物态中;稀土元素主要分布在非磁性的小颗粒组分中,颗粒越小、磁性越弱稀土含量越高;NaOH溶液预处理对稀土元素具有良好的富集效果,稀土元素的提取率可从31%提高至75%(一步碱溶)和94%(分步碱溶);XPS和SEM研究结果证实碱溶后粉煤灰活性得到有效激发,有利于稀土的浸出,酸浸残渣为更稳定的硅酸聚合物.最终形成了“物理分选—分步脱硅—酸法浸出”的粉煤灰中稀土元素的提取流程,实现脱硅后粉煤灰中稀土元素达到占比为2135μg/g的富集效果,保证了稀土的有效浸出.
Coal fly ash(CFA)was collected from Sichuan province to facilize the recovery of rare earth elements and yttrium(REY)in this paper.The modes of occurrence and distribution of REY in CFA were investigated using sequential chemical extraction and physical separation(sieving,float-sink,magnetic separation).The effect of desilication by NaOH solution and REY extraction by hydrochloric acid were evaluated.The mechanism of alkali treatment-acid leaching was analyzed via X-ray Photoelectron Spectroscopy(XPS)and Scanning Electron Microscope(SEM).The REY content is 782μg/g in CFA and majority(68%)was associated with aluminosilicate form.The content of REY in non-magnetic fine particle fraction is higher than that in other fractions.The REY recovery increases from 31%to 75%,and 94%,respectively,resulting from the silicon removal by one step and multistep alkali treatment.The XPS anslysis and SEM obsertation showed CFA was activated after desilication,and it is easier for REY leaching than before.The residue after acid leaching was very stable.Finally,the integrated process of physical separation—multistep desilication—acid leaching was designed with the REY content of 2135μg/g in midproduct after desilication and efficient leaching rate.
作者
潘金禾
周长春
温智平
聂天成
张宁宁
PAN Jinhe;ZHOU Changchun;WEN Zhiping;NIE Tiancheng;ZHANG Ningning(School of Chemical Engineering and Technology,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;College of Chemistry and Chemical Engineering,Xi’an University of Science and Technology,Xi’an,Shaanxi 710054,China)
出处
《中国矿业大学学报》
EI
CAS
CSCD
北大核心
2022年第5期998-1006,共9页
Journal of China University of Mining & Technology
基金
国家自然科学基金项目(51974309,92062109)
国家重点研发计划资助(2021YFC2902601)
博士后创新人才支持计划(BX2021362)
关键词
粉煤灰
稀土元素
赋存状态
物理分选
脱硅
酸浸
coal fly ash
rare earth elements
mode of occurrence
physical separation
desilication
acid leaching
作者简介
通信作者:周长春(1972—),男,山东省滕州市人,教授,博士生导师,工学博士,从事煤系稀有金属高效分离理论与技术、煤基固废资源利用等方面的研究.E-mail:cczhoucumt@126.com,Tel:13912009173
