摘要
传统的浓酸浸出对电镀污泥中重金属进行提取,会导致多种重金属同时溶解,不利于它们的逐步回收。为了克服传统浓酸浸出的非选择性,对电镀污泥中的Cr进行选择性提取,采用了添加剂焙烧和稀酸浸出的方法。在电镀污泥中添加Na_(2)SiO_(3)焙烧,使大部分Cr转化为高酸溶动力学的Na_(2)CrO_(4),Ni和Cu转化为低酸溶动力学的NiO和CuO,通过稀酸浸出选择性提取其中的Cr。通过对不同提取条件的探索得出,在电镀污泥中加入添加剂Na_(2)SiO_(3)于500℃下焙烧6h后,用0.1mol·L^(-1)的H2SO4以10∶1的液固比进行浸出实验,浸出液中Cr的纯度(渗滤液中相对浓度)可达99.9%,同时Cr提取率也达到最大,为82.6%。本研究在含多金属的混合质电镀污泥中选择性提取了高纯度的Cr,为其他含多金属危废中Cr的选择性提取提供了参考。
The extraction of heavy metals from electroplating sludge by traditional concentrated acid leaching will lead to simultaneous dissolution of various heavy metals,which is not conducive to their gradual recovery.In order to overcome the non selectivity of traditional concentrated acid leaching,we combine the additive roasting with dilute acid leaching methods to explore the best conditions for Cr extraction.By means of roasting electroplating sludge with Na_(2)SiO_(3) as additive,most Cr is transformed into Na2CrO4 with high acid dissolution kinetics,and Ni and Cu are transformed into NiO and CuO with low acid dissolution kinetics.Furthermore,the heavy metal Cr can be selectively extracted from the roasted electroplating sludge by dilute acid leaching.After exploring different extraction conditions,we found that when the electroplating sludge was roasted with Na_(2)SiO_(3) additive at 500℃for 6h and leached with 0.1mol·L^(-1) H_(2)SO_(4) at a liquid-solid ratio of 10∶1,the extraction rate and purity(relative concentration in leachate)of Cr reached the maximum,which were 82.6%and 99.9%respectively.In this study,high purity Cr is selectively extracted from the mixed electroplating sludge containing polymetals,which provides a reference for the selective extraction of Cr from other hazardous wastes containing polymetals.
作者
肖豪
XIAO Hao(College of Chemistry,Fuzhou University,Fuzhou 350108,China)
出处
《化学工程师》
CAS
2023年第1期75-80,33,共7页
Chemical Engineer
基金
国家重点研发计划(2019YFA0210402)。
关键词
电镀污泥
重金属
铬
选择性提取
硅酸钠
electroplating sludge
heavy metals
chromium
selective extraction
sodium silicate
