高压电脉冲对废弃电路板层间剥离效果研究

发布时间：2018-06-15 11:36

本文选题：废线路板 + 高压电脉冲　；参考：《中国矿业大学》2017年硕士论文

【摘要】：随着电子信息产业的迅速发展,废弃线路板已经成为了世界范围内高速增长的固体垃圾。据估计只有15-20%的电子垃圾经历了回收利用,对线路板进行资源化回收具有重大意义。破碎是废弃电路板资源化处理技术的关键环节,有效地破碎解离直接决定着后续分选作业的效率、金属的品位和回收率。本文对废弃线路板进行高压电脉冲放电破碎,验证了高压电对样品的层间剥离效果。提出利用称量颗粒质量的方法表征废弃线路板解离情况,定义了颗粒相对质量ωi和颗粒数比值ηi的概念。根据对高压电脉冲破碎和机械破碎产物颗粒质量的统计,表明颗粒相对质量级为10%-0%时,高压电脉冲破碎颗粒含量为84.84%,机械破碎颗粒含量为8.84%,说明高压电脉冲破碎解离效果优于机械破碎。利用抗弯强度测试验证高压电脉冲对相界面的选择性破碎效果,发现放电后环玻布板—环玻布板界面抗弯强度降低71.52MPa,铜—环玻布板界面抗弯强度降低93.76MPa,说明高压电脉冲对相界面的破碎效果更强。以-13mm产率和-50+13mm铜剥离率为指标,研究电压、脉冲数、频率、间距和入料方式对破碎效果的影响:破碎效果对电压、脉冲数和入料方式的变化响应较大,对间距的响应稍弱,对频率不响应。对破碎仪工作原理进行分析,结合能耗试验数据提出放电能耗方程W=nk1k2CU2。对能耗—破碎效果曲线进行分析,得到能耗与破碎效果呈正相关,超过一定的范围后,增加能量输入对破碎效果的提升开始下降这一结论。根据能耗方程,设计电压、脉冲数显著性试验:同等能量输入下改变电压和脉冲数,产物的铜剥离率均为90%,-13mm产率由24.42%提升至49.37%,说明提高电压比增加脉冲数对破碎效果的提升更显著。对固液环境放电体系进行理论推导,证明脉冲放电在固体样品中进行。利用能带理论解释电击穿过程,分析了雪崩电流的形成机制,解释了高压电脉冲对铜—环玻布板相界面处进行层间剥离的原理。结合SEM和EPMA对产物形貌分析,证明导电通道的形成和扩张是高压电破碎的关键环节,归纳出高压电脉冲对线路板的破碎过程的四个阶段:铜箔提供电子、电子聚集在相界面;电子贯穿势垒、击穿于相界面处率先发生;导电通道沿界面以电树枝形式生长;裂缝相互连接得到破碎颗粒。
[Abstract]:With the rapid development of electronic information industry, the waste circuit board has become a high-speed solid waste in the world. It is estimated that only 15-20% of electronic waste has been recycled, so recycling of circuit boards is of great significance. Crushing is the key link of waste circuit board resource treatment technology. Effective crushing and dissociation directly determine the efficiency of subsequent sorting operation, metal grade and recovery rate. In this paper, the high voltage electric pulse discharge breakage of the waste circuit board is carried out, which verifies the effect of the high voltage on the interlaminar stripping of the sample. The method of weighing particle mass is proposed to characterize the dissociation of waste circuit board, and the concepts of particle relative mass 蠅 I and particle number ratio 畏 I are defined. According to the statistics of the particle quality of the products of high voltage electrical pulse crushing and mechanical crushing, it is shown that when the relative mass level of the particles is 10% to 0%, The particle content of high voltage electric pulse crushing is 84.84 and the content of mechanical broken particle is 8.84, which indicates that the dissociation effect of high voltage electric pulse crushing is better than that of mechanical crushing. The selective crushing effect of high voltage electric pulse on phase interface was verified by bending strength test. It is found that the bending strength of the interface between the ring glass cloth plate and the ring glass cloth plate is reduced by 71.52 MPa after discharge, and the bending strength of the copper ring glass plate interface is decreased by 93.76 MPA, which indicates that the high voltage electric pulse is more effective in breaking the phase interface. Taking the yield of -13mm and the stripping rate of -50 13mm copper as the index, the effect of voltage, pulse number, frequency, spacing and feeding mode on the crushing effect is studied. The effect of crushing effect on the change of voltage, pulse number and feeding mode is larger, but the response to spacing is slightly weaker. No response to frequency. The working principle of the crusher is analyzed, and the equation of discharge energy consumption Wnk1k2CU2 is put forward based on the data of energy consumption test. By analyzing the curve of energy consumption and crushing effect, it is found that the energy consumption is positively correlated with the crushing effect, and when the energy input exceeds a certain range, the increase of energy input begins to decrease the crushing effect. According to energy consumption equation, design voltage, pulse significant test: change voltage and pulse number under the same energy input, The copper peeling rate of the product was increased from 24.42% to 49.37 mm, indicating that increasing the voltage is more significant than increasing the number of pulses to improve the crushing effect. The theoretical derivation of the solid-liquid discharge system shows that the pulse discharge is carried out in the solid sample. The energy band theory is used to explain the electrical breakdown process, the formation mechanism of avalanche current is analyzed, and the principle of interlaminar stripping of the copper-loop glass sheet interface by high voltage electric pulse is explained. SEM and EPMA analysis show that the formation and expansion of conductive channel is the key link of high voltage breakage. Four stages of the breakage process of high voltage electric pulse on circuit board are summarized: copper foil provides electrons, electrons gather at the phase interface; The electron penetrates the barrier and breaks through the phase interface first; the conductive channel grows along the interface in the form of electric tree; the cracks connect to each other to obtain the broken particles.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X705

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