(1. 广东工业大学 环境科学与工程学院,广州 510006;
2. 韶关学院 化学与环境工程学院,韶关 512005)
摘 要: 先采用间歇式固定床真空热解中试装置对废线路板进行真空热解前处理,然后利用剪切破碎和气流分选方法对真空热解渣中的金属铜进行回收,着重分析与讨论真空热解过程中线路板的分层机理,真空热解对破碎过程中铜单质解离度及破碎规律的影响,真空热解对气流分选过程中铜品位及回收率的影响。结果表明:真空热解强化线路板各材料层之间的分层效果显著,增大了粗粒级破碎物料中铜单质的解离度及铜的质量分布率,大幅度提高了分选产品中的铜品位及回收率,铜的回收指标远远优于未经真空热解前处理的线路板。尺寸为40 mm×40 mm的线路板先在升温速率15 ℃/min、反应温度600 ℃、绝对压力20 kPa及恒温时间60 min的条件下进行真空热解前处理,再经剪切破碎,对于粒级为0.45~4.0 mm的破碎产物,铜单质的解离度大于97.06%,铜的质量分布率为98.64%,回收产品中铜品位为99.50%,铜的总回收率为99.86%。
关键字: 废线路板;铜;真空热解;气流分选;回收
of copper from scrap printed circuit boards
(1. Faculty of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China;
2. College of Chemistry and Environmental Engineering, Shaoguan University, Shaoguan 512005, China)
Abstract:The vacuum pyrolysis pretreatment of scrap printed circuit boards (PCB) was carried out by the batch pilot-scale fixed bed reactor. The copper in the vacuum pyrolysis residues was recovered through shearing-crusher and pneumatic separator. The effects of vacuum pyrolysis pretreatment on the delamination mechanism of PCB, the liberation degree of copper and the crushing disciplinarians during the crushing process, the copper grade and recovery during the pneumatic separation process were studied. The results show that the vacuum pyrolysis intensifies the delamination of PCB, greatly improves the liberation degree of copper and the mass distribution rate of copper in the coarse products, and also significantly increases the copper grade and recovery in the pneumatic separation products. The copper recovery of PCB treated by vacuum pyrolysis is superior to that of untreated PCB. The scrap PCB with particle size of 40 mm×40 mm was treated by vacuum pyrolysis under the conditions of heating rate of 15 ℃/min, pyrolysis temperature of 600 ℃, pyrolysis pressure of 20 kPa and constant temperature time of 60 min, and then crushed by shearing-crusher. The liberation degree of copper is higher than 97.06% and the mass distribution rate of copper is 98.64% for coarse products with grain size of 0.45−4.0 mm. The copper grade is 99.50% and the recovery of copper is 99.86% in the pneumatic separation product.
Key words: scrap printed circuit boards; copper; vacuum pyrolysis; pneumatic separation; recovery