Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

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中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第29卷    第7期    总第244期    2019年7月

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文章编号:1004-0609(2019)-07-1528-08
优先络合-水解沉淀法分离铬铁机理
李金辉1,徐志峰1,高 岩2,剧智华1,陈志峰1,李德顺1

(1. 江西理工大学 冶金与化学工程学院,赣州 341000;
2. 河南省冶金研究所有限责任公司,郑州 450053
)

摘 要: 针对电镀污泥硫酸浸出液中铬铁分离的难题,本文提出“优先络合-水解沉淀”的方法分离铬铁,在去除铁的同时减少铬的损失。采用紫外分光光度法、质谱法对甲酸钠与硫酸铁、硫酸铬以及硫酸铁、硫酸铬混合液的配位机理进行研究,结果表明:铬、铁离子与甲酸钠都可以生成配合物,但相同条件下水溶液中Fe3+优先于Cr3+与甲酸钠形成配合物,反应热效应计算表明该反应都是吸热反应,高温有利于反应的正向移动尤其是铁的络合。通过对甲酸钠用量、反应温度及保温时间等对分离效果的影响进行研究。按HCOO-/Cr3+摩尔比为5.5的量加入甲酸钠,在温度90 ℃下反应6 h后,加碱调节溶液pH值为2.5并搅拌反应30 min,铁沉淀率达93.65%,铬沉淀率仅为13.37%,Cr3+、Fe3+分离效果良好。

 

关键词: 铬铁分离;电镀污泥;络合;水解;沉淀

Mechanism of ferro-chrome separation by prior complexing-hydrolysis precipitation method
LI Jin-hui1, XU Zhi-feng1, GAO Yan2, JU Zhi-hua1, CHEN Zhi-feng1, LI De-shun1

1. School of Metallurgical and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, China;
2. Henan Institute of Metallurgy Co., Ltd., Zhengzhou 450053, China

Abstract:Aiming at the separation problem of iron and chromium in sulfuric acid leaching solution of electroplating sludge, this paper presented a method of “preferential complexing-hydrolysis precipitation” to separate ferro-chrome and reduce the loss of chromium while removing iron. The complexing mechanism of sodium formate with ferric sulfate, chromium sulfate, mixed solution of ferric sulfate and chromium sulfate was studied comprehensively by UV spectrophotometry and mass spectrometry. The results show that both chromium and ferric ions can form complexes with sodium formate. But under the same conditions, the complexing of Fe3+ and sodium formate in aqueous solution is prior to that of Cr3+. The calculation of reaction heat effect shows that these reactions are endothermic and the high temperature is favorable for these reactions especially ferric than chromium. The effects of amount of sodium formate, reaction temperature and holding time on the separation efficiency between iron and chromium were studied. The results show that when the molar ratio of HCOO-/Cr3+ is 5.5, reaction temperature is 90 ℃, holding time is 6 h, the pH value of the solution is adjusted to 2.5 with addition of alkali and the reaction time is 30 min, the iron precipitation rate is 93.65%, the chromium precipitation rate is only 13.37%. The separation effect of Cr3+ and Fe3+ is good.

 

Key words: separation of iron and chromium; electroplating sludge; complexing; hydrolysis; precipitation

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

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