摘要
含汞金矿在堆浸喷淋提金过程中汞与金一起被氰化浸出。为消除后续解吸、电解、冶炼以及活性炭再生过程中的汞污染问题,拟对堆浸富液进行除汞预处理,即采用沉淀-絮凝法选择性去除富液中的汞杂质。考察絮凝剂种类(即FeSO4、明矾、AlCl3和PAM)、Na2S加入量、沉淀pH值调节及其氢氧化物沉淀预分离对除汞效果和金损失率的影响。结果表明:(1)堆浸富液中除了Hg2+外,还存在较多会消耗Na2S的离子,如Ag+、Fe2+、Cu2+、Zn2+、Mn2+和Pb2+等,因而Na2S实际加入量显著增大,较佳Na2S/Hg质量比为12左右。(2)采用FeSO4+PAM作为絮凝剂,能显著加快硫化物沉淀物的沉降,极有利于其工业化应用。(3)适当提高堆浸富液的pH值(11左右),并将产生的氢氧化物沉淀倾滤分离。可以适当降低Na2S加入量,而不影响汞的去除率。
In the course of extracting gold from gold ore containing mercury by heap leaching process, mercury is also solubilized in the process. In order to reduce mercury pollution in the succeeding gold stripping, electrowinning, retorting and regeneration of the mercury-laden AC steps, the leachate is demercurated previously, i.e. mercury in the leachate solution is selectively removed by precipitation-flocculation process. The effect of flocculant type （i.e. FeSO4, alaum, AlCl3 and PAM）, Na2S dosage, precipitating pH ajustment and pre-separation of its hydroxide precipitation on the mercury removal and gold loss respectively was investigated. The results showed that, （1） the suitable Na2S/Hg mass ratio was 12, greater than that in theory, which is due to the co-existence of Ag^＋, Fe^2＋, Cu^2＋, Zn^2＋, Mn^2＋, Pb^2＋, etc. and Hg^2＋, in the heap leachate, consuming Na2S; （2） the sedimentation of the sulfide precipitation was ar,,celvrated significantly using FeSO4 and PAM as flocculant, which is favorable for its industrial application,（3） the pH of heap leachate was adjusted from 8 to I I and the hydroxide precipitation formed was separated by decantation. Thus the removal rate of mercury is not affected significantly due to the decrease of Na2S dosage.
出处
《水处理技术》
CAS
CSCD
北大核心
2007年第12期73-76,共4页
Technology of Water Treatment
关键词
堆浸富液
汞污染
沉淀-絮凝法
选择性
除汞
heap leachate solution
mercury pollution
precipitation-flocculation method
selective
mercury removal
