废动力电池破碎产物的风选特性分析及试验

Pneumatic separation characteristic analysis and test on the crushed products of spent power batteries

针对传统废动力电池火、湿回收方法能耗大、环境污染严重等问题,提出分离废动力电池破碎产物中铜和铝的1种新方法,建立了二者在气流场中的运动数学模型,由此推导了风选机的风选效率公式。根据建立的数学模型,采用数值分析法,综合研究气流速度、破碎产物初速度、破碎产物最小粒径、粒径比、密度比、形状系数对风选效果及效率的影响,求解出废动力电池破碎产物粒径在0.20~22.00mm的最优风选参数。基于优化结果,采用FLUENT的RNGk-ε湍流模型和离散相模型(discrete phase model,DPM)模拟了废动力电池破碎产物的风选过程。最后,试验风选了粒径在5.00~22.00mm的铜和铝,分离率达到100%,验证了该数学模型的正确性。研究结果表明:当粒径比大于密度比时无法完成风选;随着形状系数的减小,为达到风选目的就必须减小粒径比及气流速度,并且风选效率也会随之降低;增大破碎产物粒径及形状系数能有效提高风选效率及单台风选机的风选粒径范围。

In view of the problems of large energy consumption and heavy environmental pollution caused by the traditional pyrometallurgical and hydrometallurgical recycling of spent power batteries,a new separation method to separate copper and aluminum from the crushed products of spent power batteries was proposed.The mathematical models of the motion of copper and aluminum in airflow field were established.And the separation efficiency formula of the separator was deduced.According to the established mathematical model,the numerical analysis method was used to study the influences of various factors such as the airflow velocity,the initial velocity and the minimum particle size of crushed products,the particle size ratio,the density ratio and the shape factor on the pneumatic separation effect and efficiency.The optimal pneumatic separation parameters for particle sizes in the range of 0.20 to 22.00 mm of the crushed products of spent power batteries were calculated.The process of pneumatic separation was simulated by using RNGk-εturbulence model and discrete phase model（DPM）in FLUENT based on optimization results.Consequently,the pneumatic separation test successfully separated copper and aluminum particles with the size ranging from 5.00 to 22.00 mm and the separation rate is 100%,indicating the validity of the mathematic model.The results show that it is unable to complete the pneumatic separation when particle size ratio is larger than density ratio;with the decrease of the shape factor,the particle size ratio and airflow velocity must be reduced to achieve the pneumatic separation purpose,and the pneumatic separation efficiency will be reduced as well;the pneumatic separation efficiency and the particle size range of a single separator can be improved effectively by increasing the particle size and the shape factor of the crushed products.