高铋铅阳极泥脱砷锑工艺研究

发布时间：2018-03-03 15:50

  本文选题：高铋铅阳极泥　切入点：焙烧预氧化　出处：《昆明理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：高铋铅阳极泥是粗铅电解精炼过程中在阳极区产生的一种副产品,含铋、砷、锑、铅、锡及贵金属等多种元素,也是回收金属铋的重要原料。由于砷及其化合物具有挥发性,采用传统的火法工艺处理铅阳极泥时容易产生含砷烟尘给环境带来砷害,湿法处理工艺流程长,容易造成砷的分散及二次污染。锑与铋的电极电位接近,采用电解法进行铋的提取时,阴极上会出现锑和铋的共析,给阴极铋的质量带来影响。本文针对高铋铅阳极泥砷锑含量高的特点,提出了“焙烧预氧化—碱性浸出脱砷”和“加压氧化碱性浸出脱砷锑”工艺来处理高铋铅阳极泥,为后续金属铋及有价金属的富集与提取奠定基础。本研究所用的原料是铋含量45%、Bi/As为4.9、Bi/Sb为4.3的铅阳极泥。首先进行了铅阳极泥脱砷方案的实验初探,包括常压水溶液氧化浸出和预氧化—碱性水溶液浸出,分别对氧化剂的种类、浸出剂及预氧化方式对脱砷效果的影响进行了实验探索,确定了以亚硝酸钠作氧化剂,采用焙烧预氧化—碱性浸出工艺进行铅阳极泥脱砷处理的技术路线。详细考察了焙烧预氧化—碱性浸出过程中焙烧温度、液固比、碳酸钠用量、氧化剂用量及氢氧化钠浓度对脱砷率的影响,获得了较佳工艺条件：焙烧温度400℃,焙烧时间2h、液固比5：1,碳酸钠用量为铅阳极泥质量的40%、氧化剂(NaNO2)用量为铅阳极泥质量的15%,氢氧化钠浓度120g/L,碱浸温度80℃,碱浸时间1h,该工艺条件下,砷的浸出率达到了95%以上,脱砷效果较好,但锑的浸出率仅在4%左右,因此还需进行脱锑研究。采用加压氧化碱性浸出工艺对铅阳极泥进行了一步法脱除砷锑的实验研究,确定了以硝酸钠作氧化剂,氢氧化钠体系加压氧化浸出处理铅阳极泥的技术方案。对实验中影响脱砷锑的各因素,如氧化剂用量、氢氧化钠浓度、液固比、浸出温度及反应时间进行了详细考察,获得了较佳的工艺条件：氧化剂用量为铅阳极泥质量的15%、NaOH浓度150g/L、液固比7：1、浸出温度180℃、反应时间2h,该工艺条件下,砷、锑的浸出率分别达到了95.16%和80.51%,浸出渣中Bi/As、Bi/Sb分别达到了72和25,金银含量也由原来的24.30g/t、3408g/t富集到了38.20g/t和5878g/t,达到了预期的效果。分别采用静置冷却沉砷及向沉砷后液中加双氧水沉锑的方法进行碱浸液的净化处理,砷、锑、铅分别以砷酸钠、焦锑酸钠和锑酸铅的形式予以回收,净化后液经补加定量的氢氧化钠能够返回浸出工序。在小实验的基础上,进行了公斤级实验,实验重复性好,渣率、金属浸出率、碱浸液净化效果及循环利用率稳定可靠。
[Abstract]:High bismuth lead anode slime is a by-product produced in the anode region in the process of coarse lead electrorefining. It contains many elements, such as bismuth, arsenic, antimony, lead, tin and precious metal, and is also an important raw material for recovering metal bismuth. It is easy to produce arsenic-containing dust in the treatment of lead anode slime by traditional pyrotechnics. The wet treatment process is long, and it is easy to cause arsenic dispersion and secondary pollution. The electrode potential of antimony and bismuth is close to that of bismuth. When bismuth is extracted by electrolysis, antimony and bismuth eutectoid will appear on the cathode, which will affect the quality of bismuth cathode. The processes of "calcination preoxidation-alkaline leaching for arsenic removal" and "pressure-oxidized alkaline leaching for arsenic and antimony removal" were proposed to treat high bismuth lead anode slime. In this study, the raw material used in this study is the lead anode slime with bismuth content of 45% and Bi / as = 4.9% SB = 4.3. First, the experiment of arsenic removal from lead anode slime was carried out. Including atmospheric pressure aqueous solution oxidation leaching and preoxidation alkaline aqueous solution leaching, the effects of oxidizing agent, leaching agent and pre-oxidation method on arsenic removal efficiency were investigated respectively. Sodium nitrite was used as oxidant, and sodium nitrite was used as oxidant. The technological route of removing arsenic from lead anode slime by roasting preoxidation and alkaline leaching process was introduced. The calcination temperature, the ratio of liquid to solid, the amount of sodium carbonate in the process of roasting preoxidation and alkaline leaching were investigated in detail. The effect of the amount of oxidant and the concentration of sodium hydroxide on the arsenic removal rate was studied. The optimum technological conditions were obtained as follows: calcination temperature 400 鈩，

本文编号：1561682