微波-电化学协同处理废印刷电路板回收有价金属基础研究

With the rapid development of electronic industry, the waste electronic and electrical products have been increasing, and its harmless and resource-based treatment has become a hot research issue. Traditional methods have low resource efficiency and environmental pollution. But microwave and electrochemical treatments show relatively high efficiency, environmental friendliness and low energy consumption. This project aims to recovery of copper, gold and silver form waste printed circuit boards in "urban mines" resources by microwave-electrochemistry co-processing. However, the responding characteristics between microwave and waste printed circuit board, electrode, and electrolytic solution and mechanism of microwave-electrochemistry co-processing are not clear, which llimit its application. Therefore, this project studies on interaction mechanism and the responding characteristics between microwave and waste printed circuit board, electrode and electrolytic solution. The law of dissolution, transport and electro-deposition of copper, gold and silver from waste printed circuit boards under microwave-electrochemistry co-processing are investigated in detail. The correlation between microwave absorbability and related reactions is determined. The kinetic model of dissolution, migration and electro-deposition is established. Coupling effect of microwave-electrochemistry and coupling mechanism are discussed. These works will provide theoretical basis for microwave-electrochemistry co-processing in recovery of rare metals from waste printed circuit boards, and extend new recycling way.

随着电子工业的迅猛发展，废旧电子、电器产品不断增加，其无害资源化处理成为研究热点。传统方法资源化效率低，环境污染较大，而微波和电化学处理方法表现出相对高效、环境友好、低能耗的特性。本项目针对“城市矿产”资源废印刷电路板中有价金属如铜、金、银的高效回收利用问题，拟采用微波和电化学协同处理。然而，目前废印刷电路板、电极、电解溶液与微波的响应特性及其对微波-电化学协同作用机制的影响尚不明确，限制其应用。因此，本项目系统研究废印刷电路板、电极、电解溶液与微波的响应特性及机制，研究微波-电化学协同作用下废印刷电路板中铜、金、银的溶出、迁移、电沉积规律，明确吸波特性与相关反应的相关性，建立微波-电化学过程中铜、金、银溶出、迁移、电沉积的动力学模型，查明微波-电化学协同处理过程的耦合作用机制，为最终开发出微波-电化学协同处理废印刷电路板回收有价金属新技术新方法奠定理论基础及开辟新的途径。

基于二次资源循环利用角度及国家资源环境可持续发展需求，本项目针对重要“城市矿产”资源废印刷电路板(PCBs)中有价金属高效回收利用问题，采用微波和电化学协同处理技术，研究废印刷电路板、电解溶液与微波的响应特性及机制，研究了废印刷电路板中金属溶出、迁移、电沉积规律，开发出微波-电化学协同处理废印刷电路板回收有价金属新技术新方法，为废弃印刷电路板中有价金属的高效回收利用开辟新的途径。.常规电解浸出，铜的浸出率随着盐酸浓度增加显著，当浸出槽HCl浓度为3 mol/L，电解槽盐酸浓度为5mol/L，电解电流4A，浸出槽温度为30℃，250min时铜的浸出率达88%，锌、锡、铝、铅的浸出率为92%以上。串联浸出槽有利于提高Cl2有效利用，提升处理量；双电源电解双进气管有效提高金属的的浸出效率和浸出率，失重率显著增大，浸出时间为250min后失重率增加20%。250min后铜的浸出率显著提升10%。.微波-电化学协同电解浸出结果显示，虽然水吸收微波能力强，但金属粉末也竞争吸附微波，金属粉末比热容小所以温度高于水温，为微波强化浸出金属提供有利条件，微波场下失重率提高20%左右，各种金属离子显示Cu、Ni、Zn、Au、Ag、Fe、Al、Sn、Pb等金属浸出率高达95%以上，其结果比与常规电解浸出时间为250min时的效果好，微波具有强化废弃印刷电路板金属浸出的特性。.PCBs中的主要金属为铜、铅、锡、锌、铝，这些金属和电解溶液同时在微波场中时均能吸收一定的微波能量，PCBs中的金属吸收微波能量后其温度明显高于溶液温度，金属表面具有高能高温容易与溶解中的浸出剂和Cl2反应溶出，金属表面短暂高温与溶液形成明显的温度差，对溶液形成热扰动，促进溶液中浸出试剂迁移，同时金属表面溶出的金属快速迁移出去，促进反应的进行。沉积的铜金属也具有一定吸收微波能力，沉积金属吸收微波后温度短暂时间下高于溶液，形成显著温差，形成较大温差促进对流搅动溶液，提高铜离子的迁移，加快沉积的进行。