碱式氧化焙烧-水浸-还原法从电镀污泥中制备三氧化二铬
Preparation of Cr2 O3 from electroplating sludge using combined process of alkaline-oxidizing roasting followed by water leaching and Na2 S reduction
周铭江 1李磊 1肖阳 1吴国东2
作者信息
- 1. 东华大学 环境科学与工程学院,上海 201620
- 2. 昆明理工大学省部共建复杂有色金属资源清洁利用国家重点实验室,云南 昆明 650093
- 折叠
摘要
电镀污泥中铬主要以氧化物或氢氧化物形式存在,氧气气氛中以Na2CO3为添加剂对电镀污泥进行焙烧,并对焙烧渣进行水浸处置,最后加入Na2S还原,可实现铬资源的高效回收.结果显示:O2流量40 mL/min条件下,焙烧过程中控制Na2CO3添加量100%、焙烧温度700℃和焙烧时间90 min,焙烧渣水浸工艺中铬浸出率可达97.8%,一定范围内,增加Na2CO3 添加量、提高焙烧温度和延长焙烧时间,可促进Cr由尖晶石相(FeCr2O4和AlCr2O4)转变为Na2CrO4,使铬浸出率提高;Na2CrO4浸出液Na2S还原工艺中,在60℃条件下,控制还原反应物料比n(CrO2-4)/n(S2-)为8:9,反应80 min,还原工艺中铬回收率可达92.3%,增加Na2S添加量、提高反应温度和延长反应时间,可以促进Na2CrO4转变为Cr2O3,提高铬收率,但过多的Na2S会使体系pH值升高,导致Cr2O3 反溶,造成铬回收率下降.研究实现了电镀污泥中铬的高效回收.
Abstract
The chromium in the electroplating sludge occurred mainly in forms of oxides and/or hydroxides,which could be recovered through a combined process of Na2CO3 assisted oxidizing roasting and water leaching in this research.The results show under the condition of Na2CO3 amount of 100%,roasting temperature of 700℃,and roasting time of 90 min,the Cr recovery rate reached 97.8% in the subsequent water leaching process;in a certain range,the Cr recovery rate increased with the increase of Na2CO3 amount,roasting temperature and time;in the Na2S reduction of Na2CrO4 leaching solution,the chromium yield increased with the increase of the amount of Na2S addition,reaction temperature and reaction time;however,excessive Na2S amount would increase the pH of the leaching solution,resulting in the reverse dissolution of Cr2O3 and the decrease of chromium recovery;under the optimized condition of reaction temperature of 60℃,n(CrO2-4)/n(S2-)of 8:9,and reaction time of 80 min,the chromium recovery reached 92.3%.The study achieved an efficient recovery of chromium from electroplated sludge.
关键词
电镀污泥/碱式氧化焙烧/铬尖晶石/硫化钠还原/三氧化二铬/浸出/铬回收率Key words
electroplating sludge/alkaline oxidizing roasting/Cr-containing spinel/Na2S reduction/Cr2O3/leaching/chromium recovery rate引用本文复制引用
基金项目
国家自然科学基金(51874153)
东华大学励志计划项目(LZB20211003)
出版年
2024
NETL
NSTL
维普
万方数据