Characterization of non-metal fraction of waste printed circuit boards to promote recycling

Electrical and electronic equipment has become an integral part of modern society. With the current technological advances, the life span of this equipment has been shrinking, leading to waste generation and issues related to end-of-life waste disposal. The circular economy model has been proposed to address the growing volume of e-waste. The model encourages reduction and reuse to decrease waste generation and encourages recycling to promote efficient natural resource usage. One of the challenges with promoting the circular economy model for e-waste is the insufficiency or absence of the recycling process for the non-metal fraction. The low value associated with the non-metal fraction increases its probability of being disposed of in landfills. This research explored the possibility of utilizing low-cost physical separation processes common in the mineral processing industry to recycle the non-metal fraction obtained from waste printed circuit board. The study showed that a density-based separation could theoretically be used to separate organic, inorganic, and residual metal streams from the non-metal fraction, thus increasing its reusability. The float-sink test and derived washability curves and washability indices showed that a conceptual three-product gravity separation process could produce an organic fraction with 47% yield at 86% organic content and a reject stream with a 35% yield at 72% fiberglass content. A gravity separation-based flowsheet was proposed for the recycling of non-metal fraction, and the potential applications of the recycled products were identified. Further test work at the pilot level would be required to estimate the process efficiency, related costs and understand the product characteristics for their proper application. This research also provided a simplified approach for determining the loss on ignition that can be used to estimate the separation efficiency. It also showed the applicability of advanced techniques such as inverse gas chromatography and micro-FTIR for analyzing the surface heterogeneity and polymeric identification of non-metal fraction components. Overall, the research used an interdisciplinary approach to provide a potential solution for the non-metal fraction to the recycling industry using tools and processes used in the coal and mineral processing industry.Applied Science, Faculty ofMining Engineering, Keevil Institute ofGraduat