废印刷线路板的常温粉碎特性研究

废弃线路板的粉碎和所含金属组分的高效解离是后续分选回收的前提条件。本文借助万能试验机、空气动力枪及颗粒高速动态分析系统分析了FR-4型线路板的力学性质;比较了锤式粉碎机、振动磨和微粉碎机在常温条件下粉碎线路板时,金属解离度、粒级分布、金属分布率以及颗粒形状的差别,探讨了线路板的解离机理。研究结果表明:FR-4型线路板为韧性较强的材料,在高速冲击粉碎下,其解离机理以脱离解离为主、分散解离为辅;采用剪切、摩擦粉碎时,以分散解离为主、脱离解离为辅。选择性粉碎有利于金属组分在粗级别富集。线路板在锤式粉碎机作用下,金属组分在0.6mm实现解离,过粉碎现象较轻,85.1%的金属集中在-0.9+0.074mm粒级中,为后续的静电分选回收金属富集体创造了良好的条件。

STUDY ON COMMINUTION PERFORMANCE OF WASTE PRINTED WIRING BOARDS AT AMBIENT TEMPERATURE

Comminution of waste Printed Wiring Boards(PWBs) and high effective liberation of the metal composition from nonmetals is the prerequisite of the following sequence separation for better recovery of waste Printed Wiring Boards.In this paper,the mechanics properties of FR-4 PWBs were tested with the help of omnipotent tester,air gun impact device and high speed dynamic analysis system.The metal liberation degree,particle size distribution,metal distribution and particle shape were compared and analyzed under three conventional crushers,viz hammer mill,vibrating mill and shredder.The liberation mechanics of PWBs were discussed based on liberation degree of metal composition.Experimental results showed that FR-4 presented strong ductility under ambient condition.The metal liberation mechanics of PWBs under high speed impaction was on disengaging liberation combined with dispersing liberation,and that under shredding or attrition action was on dispersion liberation accompanied with disengaging liberation.Selectivity comminution of waste PWBs was propitious for metals to enrich in coarse particle fractions.Under the action of hammer mill,the ideal size of metal liberated was around 0.6mm,and the overgrinding was relatively slight.85.1% of the metal was distributed in-0.9+0.074mm feed,favorable to the following electrostatic separation process.