本论文针对我国电镀行业厂点多，规模小及电镀污染治理水平低等特点，试图寻求一种灵活简便、成本低、适合于处理中小型电镀厂废水的工艺。本论文设计了内循环式流化床，利用廉价易得的FeS来处理含铬，铜，锌和镉的混合电镀废水，论文的研究内容主要有：FeS投加量、水力停留时间、FeS的粒度以及曝气量等工艺参数对重金属离子处理效率的影响研究、一定反应条件下对电镀废水中重金属离子的去除效果研究、不同重金属离子的去除机理研究。论文通过大量试验得出了流化床工艺的最佳操作参数：FeS投加量200g，水力停留时间3h，曝气量120m3/h，FeS粒度240目以下。在最佳工艺参数条件下，利用内循环式硫化床处理1#模拟混合电镀废水时，Cr（Ⅵ）的平均去除率为99.91%，Cd2+的平均去除率为99.76%，Cu2+的平均去除率为99.89%，Zn2+的平均去除率为99.82%。处理2#含铬混合电镀废水时，Cr（Ⅵ）的平均去除率为99.69%，Cd2+的平均去除率为97.88%，Cu2+的平均去除率为99.89%，Zn2+的平均去除率为97.42%。处理3#混合电镀废水时，Cr（Ⅵ）的平均去除率为99.91%，Cd2+的平均去除率为98.21%，Cu2+的平均去除率为99.89%，Zn2+的平均去除率为98.24%。 通过XRD、XRF及XPS测试，结合前人的研究成果，本论文认为电镀废水中重金属离子的主要去除机理为：氧化还原反应、化学沉淀反应、吸附共沉淀、混凝、絮凝多种因素的共同作用。在酸性条件下，Cd2+、Cu2+、Zn2+的去除起主要作用的是生成难溶金属硫化物，Cr（Ⅵ）的去除先被还原为Cr（Ⅲ），然后以氢氧化物沉淀以及共沉淀的形式被去除，Fe2+和S2-都是有效的还原剂。

Aiming at the characteristic of our country electroplating industry’s lot’s of factories, small scale, the low level of electroplating pollution’s control and so on, this paper attempts an agile and low cost treatment process that pertains to treat middle and small electroplating factory’s wastewater. This paper designs the intetnal recyling fluid bed and treat mixed electroplating wastewater with chromium, copper, cadmium and zinc. The FeS amount, water power resident time, FeS granularity and aerations’ effection of the removal rates, the removal effection under a certain reaction conditions and different heavy metal ion’s removal mechnics are studied in this paper. The best fluid bed’s process parameters that FeS amount is 200g,water power resident time 3h, aeration 120m3/h and FeS granularity under 240 holes are got by lots of experiments. Under the best process parameters, when the first simulant mixed electroplating wastewater is treated by the internal recyling fluid bed, the Cr（Ⅵ） average removal rates is 99.83%, the Cd2+ 99.81%, the Cu2+ 99.89%, the Zn2+ 99.98%. When the sencod mixed electroplating wastewater with chromium is treated, the Cr（Ⅵ） average removal rates is 98.21%, the Cd2+ 97.94%, the Cu2+ 99.89%, the Zn2+ 98.16%. When the third mixed electroplating wastewater is treated, the Cr（Ⅵ） average removal rates is 99.83%, the Cd2+ 98.21%, the Cu2+ 99.89%, the Zn2+ 98.24%. By XRD, XRF and XPS detection, combined with the fore research achievement, this paper thinks that the removal mechanism of electroplating wastewater’s heavy metal ion with FeS is oxidation-reduction reaction, chemical deposition reaction, adsorption coprecipitation, oagulation and flocculations’ combined action. Under the acidity condition, the removal of Cd2+, Cu2+ and Zn2+ mainly dues to hardly dissolved metal sulfide’s generation. The removal of Cr（Ⅵ） is that Cr（Ⅵ） is reduced firstly, and then removed in the hydroxide and coprecipitation form. Fe2+ and S2- are all powerful reducing agent.