高铁闪锌矿中铟、镉的综合利用研究

发布时间：2018-09-08 20:57

【摘要】：高铁闪锌矿是我国特有的铟锌资源,富含锌、铁、铟、锡、铜、镉、银等多种金属,如何实现其清洁高效综合利用是铟锌冶金行业面临的重要问题。采用湿法冶炼将产出大量的浸出渣和净化渣,金属铟回收率低(In≤60%)。"还原熔炼-常压精馏-综合回收"冶炼工艺实现了锌、铟资源的综合回收,但仍存在一些关键的工艺技术问题:还原熔炼过程中铟在水淬渣、含铜生铁中的损失仍然较大,直收率低;冶炼流程中高镉锌无法处理,导致镉的资源流失;精铟产品单一,附加值低等。针对这些问题,本文提出了解决高铁多金属锌精矿铟、镉资源综合利用的新工艺。首先,对高铁闪锌矿还原熔炼过程中元素的行为进行了研究;其次,采用从头算分子动力学模拟对其锌铅混合熔炼的可行性进行了理论研究及试验研究;再次,提出了真空蒸馏处理常压精馏产出的高镉锌的新工艺;最后,进行了铟的提纯实验研究。具体研究内容及进展如下:(1)高铁闪锌矿焙砂高温还原挥发熔炼过程中,锌、铟、镉、铜、铁、银、铅、锡的分布行为研究表明:①锌的直收率为83.86%,铟的直收率为64.45%,锡的直收率为13.55%,银的直收率为32%;②14.87%的铟进入水淬渣和含铜生铁,80.93%的镉富集于高镉锌。③11.62%的铜进入水淬渣,63.85%的铜富集于含铜生铁;60%的铁进入含铜生铁,11%的铁进入水淬渣;83.62%的铅进入粗锌。(2)针对还原熔炼过程中In在含铜生铁及水淬渣中损失较大的问题,研究了锌铅混合熔炼提高铟富集率的方法。首先采用从头算分子动力学模拟(AIMD)研究了还原熔炼过程加铅富集铟的可行性,确定ZnInPb间的相互作用行为。然后进行了锌铅混合熔炼试验研究,探究还原熔炼过程中铅量对铟分布的影响。1)PbnInn、PbnZnn、ZnnInn团簇的模拟结果表明,二元团簇中原子间结合力大小为 Pb-InPb-ZnZn-In;Zn12In6Pb2 团簇(In:Pb=3:1)、Zn14In2Pb4(In:Pb=1:2)团簇、Zn12In2Pb6(In:Pb=1:3)团簇和Zn15InPb4(In:Pb=1:4)团簇模拟结果表明:三元团簇中Zn原子不稳定,动力学模拟,团簇中Zn原子均脱离团簇本体;Zn12In2Pb6(In:Pb=1:3)中In-Pb的结合力最好,Zn15InPb4中In-Pb的结合力最弱;Zn106In11Pb11三元合金的从头算分子动力学模拟表明,In-Pb原子间的作用力较Zn-In、Zn-Pb强。2)利用铅与铟的相互作用,进行了铅锌混合熔炼,改变铅锌比(In:Pb～3:1、1:2、1:3、1:4)研究粗锌中铟的富集率,结果表明入炉铅含量的增加能提高粗锌中铟的富集率,同时减少铟在还原熔炼过程弃渣中的损失,富集还原熔炼铅的含量在0.18～0.2%(In:Pb～1:3)时,铟的富集效果最好。3)In:Pb比为1:3的试验结果表明:①入炉铅的含量的增加可使含铜生铁中铟的含量从573.28g/t降低到100g/t,提高了铟的回收率。②粗锌含铟由1073.7 g/t提高到1442.3g/t,提高了 25.19%,铟回收率提高到95%以上,提高了 18.46%;粗锌中的铁含量降低到0.2%以下。(3)针对火法冶炼过程中产出的高镉锌,提出了高镉锌的真空蒸馏-分级冷凝工艺,研究表明:低温缓蒸有利于锌镉合金的真空蒸馏分离提纯。冷凝盘的级数越高,得到的镉就越纯,分离效果就越好。将锌镉合金在30Pa,673K,30min条件下进行三次真空蒸馏可获得4N的精镉。(4)铟的区域熔炼提纯实验研究表明:铟中的大部分杂质在区域熔炼过程中富集在锭尾;降低区熔熔炼速度、增加区熔熔炼的次数,可以使熔区内的杂质元素得到充分凝聚,从而提高提纯效果。在区熔速度为1mn/min的条件下,经过10道次的区域熔炼提纯,得到纯度为99.9991%的高纯铟。本研究完善了高铟高铁闪锌矿高温还原熔炼流程,通过还原熔炼过程中铟的强化富集、副产物高镉锌的真空处理、区域熔炼提纯金属铟的工艺的研究,实现了铁闪锌矿中铟、镉资源的综合高效回收。
[Abstract]:High iron sphalerite is a unique indium-zinc resource in China, rich in zinc, iron, indium, tin, copper, cadmium, silver and other metals. How to realize its clean and efficient comprehensive utilization is an important problem faced by the indium-zinc metallurgical industry. The combined recovery process realizes the comprehensive recovery of zinc and indium resources, but there are still some key technological problems: the loss of indium in water-quenched slag during reduction smelting is still large, and the direct yield of copper-bearing pig iron is low; the high content of cadmium and zinc in the smelting process can not be treated, resulting in the loss of cadmium resources; the purified indium products are single, and the added value is low. In order to solve these problems, a new process for comprehensive utilization of indium and cadmium resources in high-iron polymetallic zinc concentrate is proposed. Firstly, the behavior of elements in reduction smelting of high-iron sphalerite is studied. Secondly, the feasibility of mixed smelting of zinc and lead is studied theoretically and experimentally by ab initio molecular dynamics simulation. In this paper, a new process of vacuum distillation for the treatment of zinc with high cadmium content produced by atmospheric distillation was studied. Finally, the experimental study on the purification of indium was carried out. The direct yield of 64.45%, tin 13.55% and silver 32%; 2. 14.87% indium enters water-quenched slag and copper-bearing pig iron, 80.93% cadmium enters water-quenched slag, 11.62% copper enters water-quenched slag, 63.85% copper enters copper-bearing pig iron, 60% iron enters copper-bearing pig iron, 11% iron enters water-quenched slag, 83.62% lead enters crude zinc. (2) Aiming at reducing smelting. In the process of reduction smelting, the feasibility of adding lead to enrich indium was studied by ab initio molecular dynamics simulation (AIMD), and the interaction between ZnInPb and ZnInPb was determined. The influence of lead content on indium distribution in reduction smelting process was investigated. 1) The simulation results of PbnInn, PbnZnn, ZnnInn clusters show that the binding force between atoms in binary clusters is Pb-InPb-ZnZn-In, Zn12In6Pb2 clusters (In: Pb = 3:1), Zn14In2Pb4 clusters (In: Pb = 1:2), Zn12In2Pb6 (In: Pb = 1:3) Pb 4 clusters and Zn15InPb4 (In: Pb = 1:4) clusters. Ming: Zn atoms in ternary clusters are unstable, dynamics simulation shows that Zn atoms in the clusters are separated from the clusters; In-Pb binding force is the best in Zn12In2Pb6 (In: Pb = 1:3), and in-Pb binding force is the weakest in Zn15InPb4; Ab initio molecular dynamics simulation of Zn106In11Pb11 ternary alloy shows that the interaction force between in-Pb atoms is stronger than that between Zn-In, Zn-Pb.2) using Pb and Zn. The enrichment rate of indium in crude zinc was studied by changing the ratio of lead to zinc (In: Pb~3:1,1:2,1:3,1:4). The results show that the enrichment rate of indium in crude zinc can be increased with the increase of lead content in furnace, and the loss of indium in slag discarded during reduction smelting can be reduced. The concentration of lead in reduction smelting is 0.18-0.2% (In: Pb~1:3). (3) In: Pb ratio is 1:3. The results show that: (1) The content of indium in copper-bearing pig iron can be reduced from 573.28g/t to 100g/t with the increase of lead content in furnace, and the recovery rate of indium can be increased. (3) A vacuum distillation-fractional condensation process for high cadmium zinc produced in Pyrometallurgical smelting was proposed. The results show that low temperature slow evaporation is beneficial to the vacuum distillation and purification of zinc-cadmium alloy. Refined cadmium of 4N can be obtained by three times vacuum distillation at 30Pa, 673K and 30min. (4) The experimental results of regional smelting purification of indium show that most impurities in indium are concentrated in the tail of ingot during regional smelting, and the impurities in the melting zone can be fully condensed by reducing the zone smelting speed and increasing the number of zone smelting. The purity of indium was 99.9991% after 10 passes of regional smelting and purification under the condition of 1mn/min regional melting speed. The high-temperature reduction smelting process of high-indium high-iron sphalerite was improved in this study. Indium was enriched during reduction smelting, by-product high-cadmium zinc was vacuum treated, and indium was purified by regional smelting. The research of process has realized the comprehensive and efficient recovery of indium and cadmium resources in sphalerite.
【学位授予单位】：昆明理工大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TF803

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