【作者】 魏莉莉；

【导师】 张于峰；

【作者基本信息】 天津大学 ， 供热、供燃气、通风及空调工程， 2008， 硕士

【摘要】 随着电子工业的迅速发展,在人类享受巨大效益的同时,大量的印刷线路板被淘汰。这些废弃的印刷线路板如果随着一般的生产生活垃圾被填埋或焚烧,过程中产生的废气和残渣等会对环境造成严重的污染,甚至危害人类的身体健康甚至生命安全。目前,处理废弃印刷线路板的方法主要有(1)机械/物理法(2)高温火法冶金(3)湿法冶金(4)生物技术(5)电化学法(6)热解处理法等。其中,各种方法都存在难以克服的缺点。而热解处理法是较新的处理技术,目前还不太成熟,需要进一步的研究。在这种环境下,本文研究了FR4型废弃印刷线路板在N2环境下的热失重情况,并自行设计订制了小型固定床热解装置来对未经过破碎的废弃印刷线路板的热解进行进一步的研究,以便为进一步的工业处理提供依据。同时对实验过程中收集的液体、气体产物以及分离出来的金属进行了元素分析以判断其成分,并探讨其对环境的作用。对FR4型废弃印刷线路板的热失重分析表明,热解过程约在300℃时开始,在320~370℃之间出现热解峰,在330~430℃之间,反应基本完成。由于热传递等原因,随着升温速率的提高,热解开始的温度逐渐延后,反应时间缩短,剧烈程度增强。通过对热解残余物的分析知,FR4型线路板热解得到18.91%的气体产物,8.33%的液体产物,以及72.76%的固体产物。Kissinger法计算得到的热解反应的指前因子为386972.8min-1,活化能为102.65kJ/mol;Coats-Redfern法得到的热解反应的指前因子为8827.428min-1,活化能为130.4572 kJ/mol。经分析知,升温速率为10℃/min时热解的气体产物主要成分为一氧化碳、二氧化碳、丙烯、溴乙烷、二氯甲烷;此外还有一些含有3~11个碳原子的小分子有机物。液体产物分离出来的轻质馏分的分子量在50~240之间,主要成分是含有3~17个碳原子的丙酮、苯酚以及一些芳香族化合物。此外常压蒸馏中还有一些稠油和蜡质出现。固体残渣主要是由炭和金属构成。制作过程中镀金的金属片热解后含有铜、镍、铁、金以及附着在上面未清除干净的碳;而未镀金的金属片仅有铜和附着的碳。本研究为废弃印刷线路板的处理和资源化提出了一个新途径。经研究发现,FR4型废弃印刷线路板的处理条件为:升温速率随着要求而定,加热终温为500℃。升温速率为10℃/min时,可回收金属约为总质量的8%-8.8%,得到的气体产物占18.91%,液体产物占8.33%,固体产物占72.76%。更多还原

【Abstract】 As the development of electronic industry, people enjoy the huge benefit. At the same time, lots of printed circuit boards fall into disuse. If these waste PCBs are filled into the dumping site or combustion furnace, the products will be very harmful and will do lots of damage on the environment and the health of the human beings.Until now, waste PCBs treatment approaches can be roughly divided into several categories: (1) mechanical means; (2) fire metallurgy under high temperature; (3) wet-process metallurgy; (4) biological method; (5) electrochemical process; (6) pyrolysis method and so on. The first three of them are traditional ones and are more widely used. But there are also some faults that are difficult to overcome. At the same time, pyrolysis is a new way and is not fully developed so far. Under this circumstance, this article does some research on the weight loss of PCBs under medium temperature when the whole device is filled with nitrogen. Also, a new miniature stationary bed are designed and made to study the chemical reaction. The result of the research will provide some gist for the industry. During the process, some gas and liquid are gathered and some metal are obtained from the solid residue. There are also some experiments to check what chemical materials are produced in the chemical reaction and their effect on the environment.The analyses of the curve of DTA show that, the chemical reaction starts at around 300 Celsius degree, and reaches the highest reaction rate at 320~370℃. When the temperature reaches 330~430 Celsius degree, the reaction finished. Caused by the heat transfer, the starting temperature becomes high as the temperature rising rate rises, the whole reaction process takes less time, and the reaction becomes more acute. After the reaction, the result shows that the weight of gas takes 18.91% of the products, liquid takes 8.33%, and solid 72.76%. The activation energy of the pyrolysis reaction is 102.65kJ/mol, and the pre-exponential factor is 386972.8min-1 according to the Kissinger and they are 8827.428min-1 and 130.4572 kJ/mol according to Coats-Redfern .The result of the chemical analysis shows that: the main component of the gas mainly is carbon monoxide、carbon dioxide、propene、ethyl bromide、methylene chloride, and some other micro-molecule organic substance which contains 3~11 carbon atoms; The light fraction separated from the oil is acetone, phenol and some other aromatic compound. The molecular weight of them is between 50~240 and the number of carbon is between 3~17. Other than these, there are also some thick oil and some waxy bitumen. The solid residue consists of brittle coke and metal. The copper sheet which is in the outer layer contains copper、nickel、iron、gold and some carbon attaching on the sheet which is difficult for scavenging. The internal sheet contains carbon and copper only.In this paper, a new method, pyrolysis at medium-level temperature is used in the treatment and reclamation of the waste PCBs. The result of the research shows that the nest condition is: the final temperature is 500 Celsius degree. The heating-up rate can be decided according to the experiment. Finally, the metal we get from the experiment is about 8% to 8.8%; gaseous product account for 18.91%, the oil takes 8.33% and the other solid products take 72.76%.更多还原