Recycling metals from -0.5 mm waste printed circuit boards by flotation technology assisted by ionic renewable collector

Abstract

Metals in −0.5 mm waste printed circuit boards (WPCBs) are effectively recycled by flotation technology. Ionic renewable collector was prepared from waste oils and subsequently used in flotation of −0.5 mm WPCBs. Morphology of renewable collector and WPCBs powder was detected by scanning electron microscope (SEM). Laboratory flotation tests were conducted to analyze the flotation performance. The adsorption behavior of the collector was revealed by infrared spectroscopy (FT-IR). SEM results show that the particle size of collector is in the micron scale and the impurity particles in WPCBs are in strip shape. Organic matter is proved to exist on the glass fibers surface, which helps to enhance its hydrophobicity. FT-IR analysis results indicate that both the collector and WPCBs powder contain hydrophobic and hydrophilic groups, which help to increase the attachment point of collector to strengthen the flotation process. Laboratory flotation test results show that the concentrate yield decreases with the increase of collector dosage. When the collector dosage is 2 kg/t, copper and iron grade in concentrate reaches 31.32% and 37.28% with the recovery of 65.75% and 14.55%, respectively. The study has provided an alternative method for the recycling of metals in WPCBs.