简介概要

粗锑电解精炼除铋

来源期刊:中国有色金属学报2008年增刊第1期

论文作者:林艳 谢刚 杨大锦 李荣兴

文章页码:106 - 111

关键词:锑;电解精炼;铋;草酸

Key words:antimony; electro refining; bismuth; oxalic acid

摘    要:针对粗锑精炼过程中锑铋难以分离的技术难点,采用H2SO4-NH4F-SbF3电解液体系进行高铋粗锑电解精炼除铋,考察温度、电流密度及添加剂对除铋的影响。通过扫描电镜(SEM)分析,研究添加剂对阴极锑沉积形貌的影响。获得水溶液电解精炼除铋的最佳工艺条件为:室温(25 ℃),电流密度为400 A/m2,异极距为50 mm,草酸加入量为10 g/L,电解周期为24 h。实验结果表明,锑电结晶按螺旋位错生长机理进行,其晶体呈三角棱锥结构;当草酸含量在适当范围之内时,锑镀层的生长机理无明显变化。

Abstract: It is difficult to separate bismuth and antimony in the process of crude refining. The electro refining of high-bismuth antimony was studied by using ammonium fluoride-antimony sulphate electrolyte system. The influences of temperature, current density and additives on bismuth removal from crude antimony were discussed. The effect of additives on morphologies of cathodic deposition layer was investigated by scanning electron microscopy (SEM). Optimum process parameters, namely, temperature of 25 ℃, current density of 400 A/m2, distance between anode and cathode of 50 mm, oxalic acid dosage of 10 g/L and electrolytic period of 24 h, were ascertained. The result shows that electrocrystallization of antimony follows the screw dislocation growth mechanism with a trigonal pyramids structure, and addition of oxalic acid to electrolyte has no remarkable change in it if the dosage is appropriate.

基金信息:云南省科技攻关项目



详情信息展示

文章编号:1004-0609(2008)S1-0106-06

粗锑电解精炼除铋

林  艳1,谢  刚1,杨大锦2,李荣兴1

(1. 昆明理工大学 材料与冶金工程学院, 昆明 650093;

2. 云南冶金集团总公司技术中心,昆明 650031)

摘  要:针对粗锑精炼过程中锑铋难以分离的技术难点,采用H2SO4-NH4F-SbF3电解液体系进行高铋粗锑电解精炼除铋,考察温度、电流密度及添加剂对除铋的影响。通过扫描电镜(SEM)分析,研究添加剂对阴极锑沉积形貌的影响。获得水溶液电解精炼除铋的最佳工艺条件为:室温(25 ℃),电流密度为400 A/m2,异极距为50 mm,草酸加入量为10 g/L,电解周期为24 h。实验结果表明,锑电结晶按螺旋位错生长机理进行,其晶体呈三角棱锥结构;当草酸含量在适当范围之内时,锑镀层的生长机理无明显变化。

关键词:锑;电解精炼;铋;草酸

中图分类号:TB 331; TH 117.3       文献标识码:B

Bismuth removal from crude antimony by electro refining

LIN Yan1, XIE Gang1, YANG Da-jin2, LI Rong-xing1

(1. Faculty of Materials and Metallurgical Engineering, Kunming University of Science and Technology,Kunming 650093, China;

2. Technique Center of Yunnan Metallurgy Co. Ltd, Kunming 650031, China)

Abstract: It is difficult to separate bismuth and antimony in the process of crude refining. The electro refining of high-bismuth antimony was studied by using ammonium fluoride-antimony sulphate electrolyte system. The influences of temperature, current density and additives on bismuth removal from crude antimony were discussed. The effect of additives on morphologies of cathodic deposition layer was investigated by scanning electron microscopy (SEM). Optimum process parameters, namely, temperature of 25 ℃, current density of 400 A/m2, distance between anode and cathode of 50 mm, oxalic acid dosage of 10 g/L and electrolytic period of 24 h, were ascertained. The result shows that electrocrystallization of antimony follows the screw dislocation growth mechanism with a trigonal pyramids structure, and addition of oxalic acid to electrolyte has no remarkable change in it if the dosage is appropriate.

Key words: antimony; electro refining; bismuth; oxalic acid

                    

铋是粗锑中较常见的杂质之一,对锑的性能影响很大。在锑精炼标准中,要求铋含量低于0.005%[1]。现有的粗锑火法精炼工艺中,前人尚未针对粗锑脱铋进行专门研究 [2-3]。锑的熔盐电解精炼阴极法能够较好地脱除铋,但由于其具有一些无法克服的缺点,如操作温度高、脱除的杂质品种少、电解槽结构复杂、电解质的净化和循环利用难等,在工业上推广应用还需进一步改进[4]

粗锑水溶液电解精炼所采用的电解液体系分为碱性体系和酸性体系两大类[5]。碱性体系主要是碳酸钠-氢氧化钠体系和锑的硫化碱体系。由于碱性体系缺点较多,如阴极只能得到海绵锑[6]、沉积层薄、不能用于含贵金属粗锑的电解等,未能得到推广。目前,工    业生产中主要采用氢氟酸-硫酸体系[7]。酒石酸体系[8]和柠檬酸体系由于价格昂贵,应用范围小。针对盐酸体系电解液再生困难,阴极易产生爆锑等缺点,北京矿冶研究总院在复杂锑铅精矿矿浆电解过程中采用盐 酸-氯化铵体系代替盐酸体系,较好地实现了锑铅分离,有效地避免了阴极上爆锑的生成[9-10]。但该体系阳极易产生氯气,对电解车间的环境不利。

由于锑铋的标准电极电位相近[11],传统的水溶液电解精炼理论认为锑铋在电解中彼此不容易完全分 离[12]。因此,本文作者针对从铅阳极泥产出的金属锑具有含铅铋高、贵金属富集等特点,进行水溶液电解精炼除铋的试验研究。在室温和高电流密度的条件下,采用H2SO4-NH4F-SbF3电解液体系,草酸以添加剂形式加入到电解液体系中,能够有效脱除杂质铋,获得的精锑达到国标一号。粗锑中As、Pb、Bi、Fe和Ag等杂质均能够有效被脱除,并通过阳极泥的处理得到回收。

1  试验

1.1  粗锑阳极的成分分析

阳极采用云南蒙自某冶炼厂所产粗锑浇铸而成,质量为300 g,主要成分见表1。

表1  锑阳极的化学分析结果

Table 1  Composition of antimony anode (mass fraction, %)

1.2  电解液组成

采用H2SO4-NH4F-SbF3电解液体系,电解液由蒸馏水配制,其成分见表2。

表2  电解液基本成分

Table 2  Basic composition of electrolyte (g/L)

1.3  仪器及试剂

仪器为:WYJ-1550型可调式直流稳压稳流电源,DT-1000型电子天平,C59-A型电流表,HH-6型数显恒温水浴锅,医用蒸馏水机,EPMA-100型扫描电子显微镜。

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