废旧印刷线路板细菌浸出液中铜的电沉积回收研究

发布时间：2018-03-26 19:20

  本文选题：废旧印刷线路板　切入点：细菌浸出液　出处：《西南科技大学》2016年硕士论文

【摘要】：利用细菌浸出的生物湿法冶金技术,实现了将废旧印刷线路板(Waste Printed Circuit Boards)变成富含各种金属离子的生物浸出液,对生物浸出液中的金属进行回收,同时实现含重金属废水的处理与回用,成为了近年来WPCBs金属资源化利用研究的热点。本文以人工配制的硫酸铜溶液、废旧印刷线路板的化学酸浸液和生物浸出液为研究对象,利用电沉积的方法回收生物浸出液中的金属铜,探讨了影响铜沉积的主要因素,获取并优化了金属铜高回收率的关键技术参数,得到结果如下:(1)通过对化学酸浸液和配制硫酸铜溶液的电沉积试验对比,系统考察电沉积过程中电流密度、电解液pH值和溶液中其它金属离子对电沉积效果的影响。当初始铜离子浓度为4.00 g·L-1、6.00 g·L-1时,阴极电流效率仅仅在前30 min达到90%,继续电沉积,阴极电流效率下降明显,120 min时阴极电流效率不足20%,电解槽阴极析氢现象明显;在pH值2.0-4.0范围内,提高初始pH值能显著降低Fe3+的浓度,有利于铜的沉积,但过高的pH可能导致Cu2+的沉淀和吸附反应;优化沉积条件(铜离子浓度9.75 g·L-1、pH=3.00、电流密度200 A·m-2)对化学酸浸液和配制硫酸铜溶液电沉积180 min后,铜回收率分别达到92.24%、89.41%,阴极电流效率分别为71.01%、62.84%。结果表明:用电沉积的方法能够对铜进行有效回收,增加初始铜离子浓度会显著提升阴极电流效率;铜回收率随电流密度的增大而逐渐上升,但阴极电流效率会有所下降;酸浸液中杂质金属离子对铜回收有明显抑制作用,主要表现在Fe3+对Cu2+的竞争还原。(2)探讨影响WPCBs细菌浸出液中铜回收的因素及电沉积条件优化。对WPCBs细菌浸出液去除部分有机物后,电沉积120 min后,铜回收率、阴极回收效率分别达到90.41%、92.14%。对比发现,当电沉积过程中当铜回收率达到90%左右时,经过臭氧氧化处理的细菌电解液阴极电流效率达到92.14%,明显高于未经处理的细菌浸出液(68.23%)。在电流密度200 A·m-2,pH=3.00,常温条件下沉积180 min,在电沉积前期90 min时,铜回收率达到77.04%,高于酸浸液(67.66%),阴极电流效率基本保持90%以上且阴极沉积铜纯度较高。结果表明:有机物含量对铜回收率、阴极电流效率有较为明显的影响,去除有机物后铜回收率、阴极回收效率明显提升;优化电沉积条件,细菌浸出液的沉积效果较酸浸液好。
[Abstract]:The waste Printed Circuit boards were transformed into bioleaching solution rich in various metal ions, and the metals in the bioleaching solution were recovered by the biological hydrometallurgy technology of bacteria leaching, the waste printed circuit board (PCB) waste Printed Circuit Boardswere transformed into bioleaching solution rich in all kinds of metal ions, and the metal in the bioleaching solution was recovered. At the same time, the treatment and reuse of wastewater containing heavy metals has become a hot spot in the research of metal resource utilization of WPCBs in recent years. In this paper, the artificial copper sulfate solution, the chemical acid leaching solution of waste printed circuit board and the biological leachate are taken as the research objects. Using electrodeposition to recover metal copper from bioleaching solution, the main factors affecting copper deposition were discussed, and the key technical parameters of high recovery rate of metal copper were obtained and optimized. The results are as follows: (1) by comparing the electrodeposition test of chemical acid leaching solution with that of copper sulfate solution, the electric current density during electrodeposition is systematically investigated. The effect of pH value of electrolyte and other metal ions in solution on the electrodeposition effect. When the initial concentration of copper ion is 4.00 g / L ~ (-1) and 6.00 g ~ (-1) g 路L ~ (-1), the cathodic current efficiency is only 90 g 路L ~ (-1) at the first 30 min. The cathodic current efficiency is less than 20 when the cathodic current efficiency is decreased significantly (120 min), and the phenomenon of cathode hydrogen evolution is obvious in the electrolytic cell. In the range of pH 2.0-4.0, increasing initial pH value can significantly reduce the concentration of Fe3, which is beneficial to copper deposition. However, too high pH may lead to the precipitation and adsorption reaction of Cu2, and the optimum deposition conditions (copper ion concentration 9.75g / L ~ (-1) pH ~ (3.00), current density 200A ~ (-2)) were optimized for 180 min after electrodeposition of chemical acid leaching solution and preparation of copper sulfate solution. The recovery rate of copper is 92.240.89.41, and the cathodic current efficiency is 71.01and 62.84.The results show that the electrodeposition method can effectively recover copper and increase the initial concentration of copper ions can significantly improve the cathodic current efficiency. The recovery rate of copper increases gradually with the increase of current density, but the cathodic current efficiency decreases, and the impurity metal ions in the acid leachate can obviously inhibit the recovery of copper. The factors affecting the recovery of copper from WPCBs bacterial leachate and the optimization of electrodeposition conditions were discussed. After removing some organic matter from WPCBs bacterial leachate, copper recovery rate was obtained after electrodeposition for 120 min. The cathodic recovery efficiency reached 90.41% and 92.14% respectively. The results showed that when copper recovery reached 90% during electrodeposition, The cathodic current efficiency of bacterial electrolyte treated by ozone oxidation was 92.14%, which was significantly higher than that of untreated bacterial leachate (68.23%). At the current density of 200A m ~ (-2) and pH ~ (3. 00) at room temperature, the cathode current efficiency of bacterial electrolyte deposited at room temperature was 180 mins and 90 min during the early stage of electrodeposition. The recovery rate of copper is 77.04, which is higher than that of acid leaching solution 67.66%, the cathodic current efficiency is above 90% and the purity of cathode deposited copper is high. The results show that the organic content has obvious influence on the recovery rate and cathodic current efficiency of copper. After removing organic matter, the recovery rate of copper and the efficiency of cathodic recovery were improved obviously, and the deposition effect of bacterial leachate was better than that of acid leaching solution by optimizing the electrodeposition conditions.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TF811;X705
，

本文编号：1669250