废弃线路板中金属的强化重力分选研究

发布时间：2020-08-28 01:13

【摘要】：With the development of the times and the advent of the electronic network era,the world produces a large amount of electronic waste every day,and China has become one of the largest e-waste producers in the world.Among them,the waste circuit boards applied to various electrical appliances and equipment such as televisions,mobile phones,and computers have become e-wastes with high pollution and high recycling value,and are resources of misplaced places.The waste circuit board contains a large amount of metal,of which copper has the largest specific gravity.How to effectively recycle the metal in the waste circuit board and recycle it is a significant issue.At present,the research on efficiently enriching and recovering metals in waste circuit boards is not very mature.The paper takes the abandoned computer motherboard as the research object,studies its physical and chemical properties and fracture characteristics;studies the effects of heat treatment of the circuit board on its own characteristics and fracture characteristics.The waste product of the waste circuit board was sorted by a Falcon centrifugal sorting machine,and the metal recovery rate was used to evaluate the sorting effect.Compare the sorting effect of the heat treated circuit board and the untreated circuit board under the same conditions.The waste circuit board contains metal elements such as Cu,Fe,Ca,Sn,and Al,and the distribution of these elements has a certain regularity.Cu and Sn,which are present in elemental form,are mainly distributed in the coarse-grained grade,and others exist as compounds.The metal elements are more evenly distributed in each particle size.This is the result of selective fracture in the crushing process,and the selective fracture of the heat-treated circuit board is more obvious.The difference between metal and non-metal density is obvious.The density of metal and its continuous body is mainly concentrated in the density level of+2.2g/cm~3,and the yield reaches 56.37%.It is beneficial to the sorting and enrichment of metals in the enhanced gravity field.The degree of dissociation of the heat-treated circuit board in the 1.0-0.5mm grade metal reaches 98%.At this time,the dissociation degree of the untreated circuit board metal is less than 60%.The heat treatment has the effect of improving the dissociation degree of the metal in the circuit board great help.Under the same conditions,the heat-treated circuit board will break when the stress is 142N,and the untreated circuit board will break when it is 215N.It is proved from the side that the circuit board after heat treatment is more easily broken.Single factor test and document test for Falcon sorting of discarded circuit boards,the sorting rules under various factors were obtained.The single factor test results show that the rotational frequency has the most obvious effect on the recovery rate of metal in the waste circuit board.The orthogonal test results show that there is an interaction between the rotational frequency,recoil pressure and feed rate factors.With the help of the software,the metal recovery rate is the highest in the experimental data,and the best sorting conditions are obtained: the rotation frequency is 25 Hz,the backwash water pressure is 0.02 MPa,and the feed rate is 34 ml/s.With Falcon sorting,the metal recovery rate of the heat treated circuit board is higher under the same conditions.The recovery rate of heat treated circuit board metal was 8.37%higher than that of untreated circuit boards.The paper has 31 pictures,18 tables,and 90 references.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2019
【分类号】：TD922;X705
【图文】：

技术路线图,技术路线,线路板

图 1-1 技术路线Figure1-1 Technology route 创新点（Innovation Point）本研究课题的想法来源于当今社会快速发展，电子技术和设备发展日与此同时产生了大量的电子废弃物这一现状，在传统分选方法的基础上，结合本课题组研究的项目，创新性的提出了利用离心重力场电子废弃选这一思路。离心重力场下分选废弃线路板中金属这种方法的提出，使得废弃线路板回收又多出了一种思路与方向。该方法的提出在理论上具有科学性和同时操作上简单，不会对环境造成污染。本课题研究离心重力场下对废中金属的回收，探究最佳操作参数，为废弃线路板中金属的回收工业化贡献，具有很好的创新。

沉降速度,粒度,同密度,沉降过程

硕士学位论文物颗粒在沉降过程中会形成自由沉降速度差，因条件下，即涡流压差产生的阻力条件下，该球形 5.42ON Rd δ ρvρ 以看出，对颗粒沉降速度有着重要影响的是颗粒上式改写为：ON Rv A d Ax 同密度颗粒的沉降速度随粒度的变化关系，从图同密度的颗粒群在沉降过程中实现按密度分层，必的颗粒的粒度比小于等沉颗粒的等沉比。

线路板,破碎机,样品

图 3-1 实验用的废弃线路板Figure 3-1 Spent circuit board used in the experiment实验所用材料是从电子废弃物回收站购买，具有代表性的废弃线路板——弃电脑主板（如图 3-1 所示）8kg。3.3.2 实验方法先将已经拆解的废弃主板放入剪切式破碎机，将废弃线路板初步破碎大小2cm×2cm 左右的小块，然后再把初步破碎的物料放入万能破碎机进行循环破碎万能破碎机筛孔大小为 1mm。对所得样品进行缩分，取中 300g 样品，其中 4用来分析统计废弃线路板的化学组成，60g 样品进行浮沉实验，分析破碎废弃路板样品的密度组成，200g 样品进行筛分，分析破碎样品的粒度组成，筛孔别为 0.5mm、0.25mm、0.125mm、0.074mm 和 0.045mm。对得到的各个粒级样品进行化学成分检测。3.4 结构组成（Structural Component）

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