Critical analysis of metallic and non-metallic fractions in the flotation of waste printed circuit boards

Abstract

The processing of e-waste is gaining importance worldwide as it contains a large number of valuable metals. In the present investigation, an attempt has been made to analyze the influence of surfactants on the flotation of printed circuit boards. Flotation kinetic studies have been carried out by varying different surfactant combinations such as C0F0 (without surfactants), C0F1 (only frother), C1F0 (only collector), and C1F1 (collector and frother). A first-order kinetic model has been proposed to explain the recovery of metallic and non-metallic particles. The hydrophobic plastic particles could be recovered to the froth products without surfactants. The addition of collector and frother imparts movement of few metallic particles to the froth products causing a decrease in the recovery of metals to the non-froth products (Cu recovery decreased from 92% to 72% and Sn recovery decreased from 90.1% to 65%). However, the frother is essential to impart stability to the froth and facilitate transportation of particles to the froth products. Frother alone can satisfactorily separate metallic and non-metallic particles.