【作者】 赵永；

【导师】 蒋开喜； 涂赣峰；

【作者基本信息】 东北大学 ， 有色金属冶金， 2009， 博士

【摘要】 火法炼锌的锌精矿在高温氧化焙烧过程中,会产出占加入总量20%的焙烧烟尘,该烟尘成分复杂,回收处理困难。目前应用于工业上的二次焙烧方法,存在着污染严重、流程长、成本高、综合回收率低等无法解决的问题。以焙烧烟尘为研究对象,提出了热酸浸出处理焙烧烟尘的新工艺,并在回收主金属锌的同时,综合回收其它有价金属,从而实现了焙烧烟尘的全湿法清洁生产工艺。同时,本论文还对新工艺的反应机理、动力学和工艺条件进行了系统研究。首先对焙烧烟尘分别采用了浮选法、生物浸出法和热酸浸出法进行了探索性的实验,实验结果表明,浮选法处理过程中各产物中的有价金属更为分散,无法继续分离回收；生物浸出法存在着时间长,浸出率低,溶解的镉对细菌生长有影响等缺点。因此,前两种方法均不适合处理焙烧烟尘。系统研究了中性浸出焙烧烟尘的工艺条件、反应机理及其动力学。最终确定的最优工艺条件为：反应温度65℃,始酸浓度90g/l,液固比5:1,反应时间60min,在此条件下,锌的浸出率为71.29%,渣率54.84%,渣中含锌23.12%。动力学研究表明,该过程表观活化能为E=11.92kJ/mol,处于扩散控制步骤。深入研究了热酸浸出中性浸出渣的工艺条件、反应机理及其动力学。最终确定的最优工艺条件为：始酸浓度200g/1,反应温度95℃,液固比5:1,反应时间180min,二氧化锰加入量为理论量的0.6倍,在此条件下,锌浸出率为93.37%,渣含锌8.38%。动力学研究表明,该过程可用收缩核模型表示,反应的表观活化能为48.09kJ/mo1,说明反应处于化学控制步骤,[H+]及[Fe3+]对反应的影响级数分别为0.4、0.2,反应的宏观动力学方程为：1-(1-α)1/3=4.90[H+]0.4[Fe3+]0.2d0-exp(-48090/RT)t+A研究了针铁矿法对热酸浸出液进行除铁的工艺,并优化了工艺条件：pH=3.0,温度60℃,反应时间80min,空气流量为20L/min,在此条件下,浸出液除铁率99.5%以上,除铁液含铁小于0.1g/1。分别研究了焙烧烟尘综合回收铟、镉、铅及银等工艺。铟回收工艺包括预中和富集、铟渣酸浸、萃取及反萃取、置换等工序,并获得了品位为97.75%的海绵铟,铟的总回收率为92.66%。镉回收工艺包括浸出液净化除铜、铜镉渣的酸浸、酸浸液置换除铜、酸浸液置换除镉及粗镉熔铸等工序,可获得品位为98.45%的粗镉,镉总回收率为90.73%。铅及银回收采用浮选脱硫及碱熔工艺,可获得含铅98.29%,含银0.169%的粗铅,铅及银的总回收率分别为90.09%和94.14%。基于实验的结果,在葫芦岛锌厂进行了热酸浸出焙烧烟尘的扩大试验,并验证了实验结果,锌总浸出率为97.45%。以葫芦岛锌厂每年所产的焙烧烟尘量6.3万吨为基础,分析了焙烧烟尘中各主要成分的全流程走向,每年回收进入中浸液中的锌量为2.63万吨,总锌回收率为93.93%;回收粗镉394.9吨；粗铅2330吨(其中含铅2290吨、银3.86吨)；海绵铟2.56吨。焙烧烟尘中主要有价金属损失有：锌进入浸出渣1.50%,进入除铁渣4.49%,其它0.08%；铅进入除铁渣3.90%,进入熔炼渣3.61%,其它2.40%；镉进入浸出渣0.11%,进入除铁渣中的2.89%,进入其它铜镉渣及镉渣0.53%；铟进入浸出渣0.89%,进入除铁渣4.17%,其它渣2.28%银进入熔炼渣1.74%,进入熔炼烟尘2.63%,其它1.49%。综上所述,本论文针对火法炼锌焙烧烟尘的特点,提出了热酸浸出的新工艺,通过实验系统地研究了该工艺的反应机理、动力学和最优化工艺条件,并通过扩大试验对该工艺进行了验证。该工艺有着流程短、成本低、综合回收率高的优点,它不仅减少了环境污染,还实现了资源的综合利用和清洁生产。与其它火法炼锌处理焙烧烟尘回收工艺相比,具有一定的推广前景和重要的意义。更多还原

【Abstract】 During the high-temperature oxide roasting of zinc concentrate in zinc pyrometallurgy, a large quantity of roasting dust will be produced, which account for 20% of the total input. Because of its complex components, it is difficult to be recycled. At present, the recovery method in industrial, such as roasting kiln, causes serious environmental pollution, and it is also complicated and cost high. Therefore, in my thesis, I focus on "Study on the recovery of Zinc and other valuable metals from roasting dust of Zinc pyrometallurgy". A new process for deal with roasting dust with hot acid leaching is put forward, which can recycle zinc and other valuable metals. The process realizes the clean production with completely hydrometallurgy, the conditions and reaction mechanism of the process is investigated systematically.Pre-Experiments of roasting dust with method of flotation, bio-leaching and hot acid leaching showed that:the flotation process made the valuable metal more deconcentration and can not be recycled; bio-leaching has the shortcomings with a long time and low leaching ratio, and dissolved cadmium has bad effects on the growth of bacteria. As a result, the pre-experiments illustrate that both flotation and bio-leaching methods are not suitable to deal with roasting dust.The operation condition, reaction mechanism and kinetics of neutral leaching roasting dust are investigated. The optimal operating conditions are determined as follows:reaction temperature 65℃, acid concentration 90g/L, solid-liquid ratio 5:1 and reaction time 60min, in accordance with these conditions, zinc leaching ratio is 71.29%, slag ratio is 54.84%, and the content of zinc in slag is 23.12%. The kinetics show that the apparent activation energy for the process is E=11.92kJ/mol, the process is under the control of diffusion.The operation condition, reaction mechanism and kinetics of hot acid leaching slag are studied. The optimal operating conditions for the process are obtained as follows:reaction temperature 95℃acid concentration only 200g/L, solid-liquid ratio 5:1, reaction time 180min. The MnO2 addition is 0.6 times of the theoretical capacity. In accordance with these operation conditions, zinc leaching ratio is 93.37%, slag ratio 8.38%. The kinetics shown that the process can be expressed with shrinking core model. The apparent activation energy for the process is 48.09kJ/mol, it is under the control of chemical reaction, the reaction order of [H+] and [Fe3+] is 0.4,0.2 respectively, the reaction kinetics equation is: 1-(1-α)1/3=4.90 [H+]0.4 [Fe3+]0.2d0-exp(-48090/RT)t+AThe process of removing iron from hot-acid leaching solution with the method of goethite is researched, and the operation condition is optimized as follows:the end of pH=3.0, temperature 60℃, reaction time 80min, air flow velocity 20L/min, the results shows that the ratio of removing iron is over 99.5% and iron in liquid is less than 0.1g/L.The processes for recycling indium, cadmium, lead, and silver form roasting dust are studied respectively. Indium recovery process includes:indium enrichment from hot acid leaching solution, acid leaching indium slag, extraction and anti-extraction, and extracting sponge indium with the replacement of aluminum plate. After that, sponge indium can be obtained at the purity of 97.75%, and its recovery ratio is 92.66%. Cadmium recovery process includes:the cleaning of neutron leaching solution, the acid leaching of copper and cadmium slag, the copper removal of acid leaching solution, the extraction of sponge cadmium with the replacement of zinc powder, and the casting of sponge cadmium etc. The pig cadmium can be obtained at the purity of 98.45%, and its recovery ratio is 90.73%. The lead and silver can be recycled by the folation process of sulphur and the alkali smelting technology, and pig lead can be obtained in which contain lead 98.29% and silver 0.169%. The recovery ratio are 90.09% for lead and 94.14% for sliver.Based on the experimental results, the expanding test is done in Liaoning Huludao Zinc Smelter. The experiment result, total zinc leaching ratio 97.45%, is verified at the expanding test in factory.According to the amount of 63,000 tons roasting dust per year produced by Liaoning Huludao Zinc Smelter, the whole industry process for dealing with roasting dust is designed. According this process, it is known that 26,300ton zinc per year will be recycled from neutron leaching solution, which occupies 93.93% of total zinc amount in roasting dust. Cadmium can be recycled 394.9 tons, pig lead 2330 tons (in which lead 2290t, sliver 3.86t), and sponge indium 2.56 t. The loss of metal in roasting dust as follows:zinc loss 1.50% since its residue in leaching slag, loss 4.49% in the slag of removing ferrous, and 0.08% in other slag. Lead loss 3.90% in ferrous slag, loss 3.61% in smelting slag,2.40%in other. Cadmium loss 0.11% in leaching slag,2.89% in ferrous slag, and 0.53% in other slag like cupper cadmium and cadmium slag. Indium loss 0.89% in leaching slag,4.17% in ferrous slag, and 2.28% in other slag. Sliver loss 1.74% in smelting slag,2.63% in dust of smelting,1.49% in other. To sum up, base on the characteristic of zinc roasting dust, a new process of treating roasting dust with hot acid is put forward, the operation condition, reaction mechanism, and kinetic of the process are studied systematically, and the process is verified with expanding test in industry. It is very important to dealing with zinc roasting dust, and recycle all metals, this not only can meet the industrial production, but also protect environmental, and make the resource to be utilized in the comprehensive way.更多还原