从碱渣中提取碲的工艺研究

碱渣是从铅阳极泥中提取贵金属过程中产出的中间物料,其中富集了大量的碲,碱渣中碲主要以亚碲酸钠形态存在.从碱渣的组成和性质出发,利用亚碲酸钠易溶于水、pH值处于中性附近时可转化为二氧化碲的特点,采取碱性湿法冶金技术原理提取碲,其基本路线采用碱渣破碎、球磨、浸出、净化、中和、煅烧、碱溶、电积来得到纯碲.重点研究了浸出时NaOH浓度、浸出时间对碲浸出率的影响,Na2S和CaCl2对Cu,Pb和Si杂质的去除效果,中和沉碲的最佳pH值,煅烧除Se的效果,电积电流密度对电积碲纯度的影响.试验表明,浸出时NaOH最佳浓度为浓度25 g·L-1,最佳浸出时间为4 h,用Na2s,CaCl2除去浸出液中的杂质Cu2+,pb2+和SiO2可以取得理想效果,中和沉碲的最佳pH值为5.0～6.0,最理想的电流密度为50～60 A·m-2.通过对提取碲各阶段试验的数据分析,提出各工艺阶段的控制关键,证实所采用的工艺流程可以从碱渣中成功提取纯碲.

Extracting Tellurium from Alkaline Residue

Alkaline residue was one kind of media matter which came from metallurgy purifying precious metals from lead anode silt,which concentrated a large amount of tellurium,and in which tellurium existed as Na2TeO3.Based on constituent and property of alkaline residue,in which Na2TeO3 and Na2TeO3 was easy to dissolve in water could be turned into TeO2 when pH was 7 or so,alkali hydrometallurgy was chosen to extract tellurium,which included crushing,ball-milling,leach,purification,neutralization,incineration,alkal...