【作者】 谭之海；

【导师】 何亚群；

【作者基本信息】 中国矿业大学 ， 矿物加工工程， 2011， 博士

【摘要】 电子废弃物的资源化既能实现资源的二次利用,又能防止环境污染,具有重要的理论意义和应用价值。本文采用“湿法破碎——浮选”工艺流程来回收废弃线路板中金属成分,对于浮选方法回收废弃电路板中金属的课题,国外近几年开始研究,但是国内尚属空白。首先研究了湿法破碎各操作因素之间的关系,借助Design-Expert试验设计软件在理论上推导出各操作因素与-0.5mm粒级产率的预测公式。接着对-0.5mm粒级的废弃线路板,进行了自然疏水性浮选试验,借助Design-Expert试验设计软件优化各个试验参数(搅拌速度A、充气量B、温度C、固体浓度D),沉物产率最高为71.6743%;品位最高为28.7950%;回收率90%以上。在理论上推导出沉物产率、品位、回收率和富集比的预测模型。然后在自然疏水性浮选基础之上,进一步研究药剂浮选,选用新型捕收剂9858和9883、丁基黑药和丁基黄药四种捕收剂和甲基异丁基甲醇(MIBC)、起泡剂9862、仲辛醇、2#油四种起泡剂,通过验证得出新型捕收剂9858和起泡剂9862搭配使用时,沉物产率为64.757%,达到最高,金属品位为25.377%,回收率98.438%,富集比1.520,综合评价指标,效果非常显著。结合传统矿物浮选的四个常用浮选动力学模型,研究了废弃线路板自然疏水性浮选和药剂浮选的浮选动力学模型,并通过试验验证了五个不同条件下建立得动力学模型,为废弃线路板浮选工艺参数的优化、浮选流程的简化奠定了理论基础。通过分形对破碎、浮选各环节的产物进行研究,对比研究发现,在浮选过程中粒度分形的变化规律符合多项式方程:D= At~5+Bt~4+Ct~3+Dt~2+Et+1.292;A、B、C、D、E是常数,t是时间,D代表分形维数。应用灰色理论对废弃线路板浮选试验分选结果进行了分析,采用灰色理论中的灰色关联理论对多因素试验分选结果进行了分析,结果表明:对于沉物产率、沉物品位、金属回收率、富集比与各个操作因数的关联度由大至小为:充气量>温度>固体浓度>搅拌速度。即各因素对分选指标的影响程度排序为:充气量、温度、固体浓度、搅拌速度。并最终运用灰色建模理论建立了操作参数与废弃线路板浮选分选效果间的灰色模型。对于废弃线路板的浮选处理,研究结果表明,浮选工艺简单有效、分选效果好,为实现电子废弃物的资源化提供了一条新的处理方法,同时也为浮选拓宽了新的应用领域。论文共包含85幅图,43个表格,192篇参考文献。更多还原

【Abstract】 Study on waste electrical and electronic equipment (WEEE) and the reutilization of waste printed circuit boards (PCBs) have the important significance and application values, which can not only achieve recycling of secondary resources, but also prevent environment pollution. The metals in PCBs are recycled with a flowsheet of wet impact crushing——flotation in the dissertation. In China, the subject of PCBs flotation is novel at present.Firstly, the relationship among the operational factors of the wet impact crushing was studied. With the Design-Expert software, the predicting equation of the operational factors to the yield in -0.5mm fraction was derivated in theory.The natural hydrophobic flotation test on -0.5mm crushed products of the waste PCBs was undertaken, using Design-Expert software to optimize the various experimental parameters (agitation speed, aeration rate, temperature, solid concentration), and the sink yield was up to 71.6743%; the grade was up to 28.7950%; the recovery rate was over 90%. In theory, the predicted models about yield, grade, recovery rate, and enrichment ratio of the sink were deducted. Based on the models, the reagent flotation was studied with selecting four collectors (new type collector 9858, new type collector 9883, butyl dithiophosphate and butyl xanthate) and four frothers (MIBC, new type frother 9862, sec-octyl alcohol, and 2# oil). When the new type collector 9858 and frother 9862 were chosen and mixed to be used in the experiments, the sink yield was up to 64.757%, the metal grade was 25.377%, the recovery rate was 98.438%, and the enrichment ratio was 1.520. Synthesizing the separation indicators, the collector and the frother worked effectivly.Using four usual flotation kinetic models of traditional minerals, the flotation kinetic models for waste PCBs flotation depending on the natural hydrophobicity or reagent were studied. The flotation kinetic models which were achieved in five different conditions were conducted through the experiments. The theoretical foundation was built for optimization of the floation process operation, simpliying the flotation flowsheet.The crushed and flotation products were studied by the fractal. And the results showed that the variation of size fractal in the floation was fitted in with the polynomial equation:D=At~5+Bt~4+Ct~3+Dt~2+Et+1.292 A、B、C、D、E hereby are constants, t is the processing time, D is represent for the dimension of fractal.The sorting results of the flotation of waste PCBs were analyzed by gray theory, and the sorting results of multi-factor test were analyzed by gray relevance theory. The results show that the correlation of sink yield, sink grade, metal recovery and enrichment ratio affected by operation factors from large to small is: aeration rate, temperature, solid concentration, agitation speed. Namely the order of the factors on the influence degree of the sorting index is aeration rate, temperature, solid concentration, agitation speed. A gray model between the operation parameters and the separation effects of the flotation of waste PCBs were established by applying the gray modeling theory.For the flotation of waste PCBs, the results of the study show that the flotation process is simple and effective, and the separation effect is better. It provides a new processing method for electronic waste recycling and also broadens a new application for flotation.The thesis contains 85 figures, 43 tables and 192 references.更多还原