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Study on Metals Recovery from –0.074 mm Printed Circuit Boards by Enhanced Gravity Separation 总被引:2,自引:0,他引:2
Nowadays study on discarded printed circuit boards (PCBs) reutilization has great significance for achieving secondary resources recycling and preventing environmental pollution. Physical methods show great potential and advantages on discarded PCBs reutilization, comparing with chemical and biological methods. However for the particles of -0.074 mm PCBs, little work has been done in the past because of lower separation efficiency and recovery. In this paper, the conundrum of -0.074 mm PCBs reutilization was resolved successfully with the help of Falcon concentrator. Separation mechanism for fine particles with different mass densities in a Falcon centrifugal concentrator was analyzed. The main factors such as magnitude of rotation frequency (centrifugal acceleration), anti-charge water pressure and feeding concentration were studied, and interaction of different factors was analyzed using Design-Expert software. The experimental results show that metals grade of -0.074 mm PCBs and integration efficiency were obtained as 76.89% and 80.77% respectively when feeding concentration was 40 g/L with water pressure of 0.01 MPa and rotation frequency of 50 Hz. 相似文献
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关于离散元法计算参数的探讨 总被引:2,自引:0,他引:2
计算时步、接触刚度等计算参数的选取对离散元法解的正确与否至关重要,目前普遍采用的方法是先确定接触刚度并选取保险系数后,按照经验公式求得计算时步,但在保险系数的设定上有关文献却不尽相同.作者提出了一种新的方法——恢复系数检验法来选定计算参数.采用离散元法最常用的弹性-阻尼-滑动接触模型编制了计算程序,以颗粒同静置平面之间的正碰撞考察了不同计算参数下的模拟结果,除模拟得到恢复系数外,还考察了碰撞过程的总接触时间和总接触时步数.统计分析结果表明:计算时步是影响模拟精度最重要的因素;模拟误差还同恢复系数的设定值有关,设定值越大,模拟误差就越小;计算时步的大小虽然对碰撞过程的总接触时间影响不大,但是却决定了碰撞过程的总接触时步数,二者之间存在对数线性相关关系, 相似文献
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计算筛分效率时需要确定筛上物与筛下物的分级粒度界限,即分级粒度。分级粒度不同的划定原则使得与之对应的筛分效率具有不同的意义。在实际筛分作业中应使依照不同原则划定的分级粒度要尽可能地接近直至相等,这样就可以通过对筛机的作业参数进行简单的调而收到显著的经济效益。 相似文献
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