【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.
【學(xué)位授予單位】：中國礦業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2019
【分類號(hào)】：TD922;X705
【圖文】：

圖 1-1 技術(shù)路線Figure1-1 Technology route 創(chuàng)新點(diǎn)（Innovation Point）本研究課題的想法來源于當(dāng)今社會(huì)快速發(fā)展，電子技術(shù)和設(shè)備發(fā)展日與此同時(shí)產(chǎn)生了大量的電子廢棄物這一現(xiàn)狀，在傳統(tǒng)分選方法的基礎(chǔ)上，結(jié)合本課題組研究的項(xiàng)目，創(chuàng)新性的提出了利用離心重力場(chǎng)電子廢棄選這一思路。離心重力場(chǎng)下分選廢棄線路板中金屬這種方法的提出，使得廢棄線路板回收又多出了一種思路與方向。該方法的提出在理論上具有科學(xué)性和同時(shí)操作上簡單，不會(huì)對(duì)環(huán)境造成污染。本課題研究離心重力場(chǎng)下對(duì)廢中金屬的回收，探究最佳操作參數(shù)，為廢棄線路板中金屬的回收工業(yè)化貢獻(xiàn)，具有很好的創(chuàng)新。

碩士學(xué)位論文物顆粒在沉降過程中會(huì)形成自由沉降速度差，因條件下，即渦流壓差產(chǎn)生的阻力條件下，該球形 5.42ON Rd δ ρvρ 以看出，對(duì)顆粒沉降速度有著重要影響的是顆粒上式改寫為：ON Rv A d Ax 同密度顆粒的沉降速度隨粒度的變化關(guān)系，從圖同密度的顆粒群在沉降過程中實(shí)現(xiàn)按密度分層，必的顆粒的粒度比小于等沉顆粒的等沉比。

圖 3-1 實(shí)驗(yàn)用的廢棄線路板Figure 3-1 Spent circuit board used in the experiment實(shí)驗(yàn)所用材料是從電子廢棄物回收站購買，具有代表性的廢棄線路板——棄電腦主板（如圖 3-1 所示）8kg。3.3.2 實(shí)驗(yàn)方法先將已經(jīng)拆解的廢棄主板放入剪切式破碎機(jī)，將廢棄線路板初步破碎大小2cm×2cm 左右的小塊，然后再把初步破碎的物料放入萬能破碎機(jī)進(jìn)行循環(huán)破碎萬能破碎機(jī)篩孔大小為 1mm。對(duì)所得樣品進(jìn)行縮分，取中 300g 樣品，其中 4用來分析統(tǒng)計(jì)廢棄線路板的化學(xué)組成，60g 樣品進(jìn)行浮沉實(shí)驗(yàn)，分析破碎廢棄路板樣品的密度組成，200g 樣品進(jìn)行篩分，分析破碎樣品的粒度組成，篩孔別為 0.5mm、0.25mm、0.125mm、0.074mm 和 0.045mm。對(duì)得到的各個(gè)粒級(jí)樣品進(jìn)行化學(xué)成分檢測(cè)。3.4 結(jié)構(gòu)組成（Structural Component）

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