【作者】 杨明；

【导师】 李登新；

【作者基本信息】 东华大学 ， 环境科学与工程， 2013， 博士

【摘要】 近年来,随着电子产业技术发展和电子产品更新换代速度的加快,产生了大量的电子废弃物。日益增长的电子废弃物给地球生态和人类生活环境带来巨大的威胁,如何对电子废弃物进行高效收集并合理、安全的处置已成为社会迫切关注的问题。电路板是各类电子产品最基本且不可或缺的重要组成部分,具有组成复杂、环境危害大、回收价值高等特点,因此对废电路板进行资源化、无害化和减量化处理具有十分重要的意义。本论文以废电路板的资源化回收为目的,将废电路板加热脱焊后,进行人工拆解和分选,将分选出来的不同组分分别用研磨机破碎,然后用ICP-AES、XRD、元素分析仪以及GC-MS进行综合分析,确定其资源特性和可能的环境危害性。测试结果表明废电路板中的组成比例大致为金属：有机物：其它非金属=4:4:2;金属元素中,除了电容和焊锡,铜在各部件中含量均最高；贵金属中,Au在芯片中的分布远远高于其它各部件；废电路板中主要存在的是单质的Cu、Sn、Pb等元素,以及无定形的A12O3、Sb2O3等；热解产物大多是苯酚以及一些含有苯环的有机物。在本课题组前期研究的基础上,以PEG(聚乙二醇)-NOx作为催化氧化剂,在全封闭装置中对废电路板的金属粉末进行催化氧化反应,对其中的基本金属进行浸出,实验了影响催化氧化效果的主要因素,探讨了相关反应机理。实验表明使用PEG-NOx作为催化氧化剂具有良好的催化氧化效果,在最佳条件下以Cu为标志性元素基本金属几乎完全被浸出；以NZ988作萃取剂,对Cu的萃取效率在99%以上,且选择性较好,除了Cu和Sn外,对其它元素几乎不萃取。为避免Sn对后续提Cu工艺的干扰,同时尽量完全的提取废电路板中的Sn,对膨胀石墨吸附Sn前后进行了多种表征,研究了使用膨胀石墨吸附Sn的实验条件、效果以及机理,并研究了使用膨胀石墨去除和富集废电路板反萃液中Sn的可行性。实验结果表明膨胀石墨对Sn具有很好的吸附效果,在最佳条件下对Sn的有效去除率可达到98%以上,同时几乎不吸附溶液中的Cu,受温度等环境因素较小,可安全高效地吸附去除废电路板中的Sn。为进一步提高催化氧化效率,便于试剂的回收和循环使用,研究了使用膨胀石墨以及膨胀石墨协同PEG作用,以提高NOx中氧的转移效率。实验结果表明PEG协同EG对NOx的氧转移效率要明显高于单独用PEG或是EG,说明在NOx氧转移时PEG和EG具有明显的协同作用。在温度0℃,流速0.5L/min,NOX初始浓度0.025mol,吸附剂EG质量0.015g混匀20mL PEG条件下,对NOx的吸附率可达90%以上。为了进一步促进NOx中的NO转化为N02,研究了使用氧化石墨烯(GO)负载C0304做为催化剂,在PMS作为NOx吸附剂的条件下对NOx进行催化氧化,通过XRD、FT-IR、RAMAN、SEM以及TEM等现代分析测试仪器对GO及GO负载C0304进行表征,实验了所制备的催化剂GO负载Co304对于NOx的催化氧化效果,并考察了相关因素对于催化氧化效果的影响。实验表明GO负载C0304做为催化氧化剂,比单独使用PMS做催化氧化剂的氧化效率有显著提高。更多还原

【Abstract】 With the rapid development of information industry while electronic products update more quickly, a large number of electronic waste are produced. The growing electronic waste poses a great threat to the earth’s ecological and human environment. It has become a crucial problem for the society how to effectively collect and reasonably safe disposal of electronic waste.The printed circuit board is a basic and indispensable part of all kinds of electronic products. It will be of great importance for resource, harmless and reduction of waste printed circuit boards due to their complex composition, environmental harmless, high recovery value.The aim of this thesis is to resource recycle of waste printed circuit boards. After heating and unsoldering the waste printed circuit boards, manual dismantling and sorting, the sorting out different components were crushing mill, detecting and comprehensive analysis by ICP-AES, XRD, elemental analyzer and GC-MS so to confirm the resources characteristics and possible environmental hazards. The results show that the components ratio of metals, organics and non-metals in waste printed circuit boards is4:4:2. The content of copper of all metals is the highest in various electric components except capacitance and solder. Gold distribution is much higher than that of other noble metals. The main elementary substances in waste printed circuit boards are Cu, Sn and Pb and so on. amorphous Al2O3and Sb2O3are high levels as well. Most pyrolysis products are phenol and some organic compounds containing benzene ring.At the previous work of this research group, metal powders were catalytic oxidation by PEG(Polyethylene glycol)-NOx in fully enclosed equipment, and the base metals were extracted. Some main factors on catalytic oxidation were optimized, and the reaction mechanisms were discussed. The results show that PEG-NOx as the catalytic oxidizer has good effect, copper as representative base metal elements was almost absolutely extracted.The extraction efficiency of copper was up to99%with NZ988as extractant, which presents good selective for only copper and stannum extracted but other elements not.The removal and preconcentration of Sn in stripping solution by expanded graphite (EG) was investigated to avoid interference of Sn to Cu, and absolutely extraction of Sn from waste printed circuit boards. The adsorptive characteristics of the produced EG were characterized and its experimental conditions of Sn adsorption, effects and mechanisms were studied as well. This study demonstrates that the expanded graphite is an effective and novel adsorbent for the removal of Sn as the removal ratio at optimized conditions reach to98%, but copper was hardly adsorbed. EG is not affected by environmental temperature, and removes Sn in waste board safely and efficiently.The EG and EG-PEG were used to improve the transfer efficiency of oxygen in NOX for improving catalytic oxidation efficiency and recycling of solvents. The experimental results show that the transfer efficiency of oxygen in NOX with EG-PEG is much higher than that of EG or PEG individually, which illustrators that PEG and EG are synergy on the transfer of oxygen in NOX. Adsorption rate of NOX with0.015g adsorbent EG and20mL PEG can reach to90%with0.025mol initial concentration of NOX at the temperature of0℃,0.5L/min flow velocity.To promote NOX transfer to NO, the catalytic oxidation efficiency of NOx with catalyst graphene oxide (GO) load Co3O4was prepared and investigated with PMS as adsorbent to catalytic oxidation NOX, where GO load Co3O4was characterized by morden analytical instruments such as XRD, FT-IR, RAMAN, SEM and TEM. The effect of some relative factors on catalytic oxidation efficiency was studied as well. It shows that the catalytic oxidation efficiency with GO load Co3O4as catalyst has improved significantly than using PMS as catalyst only.更多还原