Assessing the Applicability of Gravity Separation for Recycling of Non-Metal Fraction from Waste Printed Circuit Boards

Printed circuit boards (PCB) are one of the most studied electronic waste streams due to the presence of high-value metals. The rejects from waste PCB recycling, also known as a non-metal fraction (NMF), are usually sent to landfill. This work explores the applicability of gravity separation, widely used in the mineral processing industry, to separate organic and inorganic components in the NMF. The float-sink test is conducted to understand the gravity separation performance, and the results show that a 47% yield at 86% organic content with 70% combustible recovery can be obtained using dense media separation. The washability behavior of NMF is assessed using different washability indices standard in the coal industry; and the material is classified as difficult-to-clean. The float-sink products show the concentration of organic stream in -1.8 g cm(-3) range, fiberglass in +2.0-2.5 g cm(-3) range, and metals in +2.5 g cm(-3) range. The recovery of these components will facilitate the concept of the circular economy and promote sustainability.

Automated summary

This study explores the use of gravity separation, commonly used in the mining industry, to separate the non-metal fraction of printed circuit boards. Experimental results show that a yield of 47% with 86% organic content and 70% combustible recovery can be achieved using dense media separation. The washability behavior of the non-metal fraction is assessed and found to be difficult to clean. The float-sink products exhibit concentrations of organic stream, fiberglass, and metals within specific density ranges.