Flotation separation of waste plastics for recycling—A review

• Flotation separation of plastics was reviewed including principles, methods and challenges.
• The specific features of plastics flotation are presented compared to ores flotation.
• Four methods were classified in terms of plastics flotation.
• The problems that hinder the application of plastics flotation are put forward.

The sharp increase of plastic wastes results in great social and environmental pressures, and recycling, as an effective way currently available to reduce the negative impacts of plastic wastes, represents one of the most dynamic areas in the plastics industry today. Froth flotation is a promising method to solve the key problem of recycling process, namely separation of plastic mixtures. This review surveys recent literature on plastics flotation, focusing on specific features compared to ores flotation, strategies, methods and principles, flotation equipments, and current challenges. In terms of separation methods, plastics flotation is divided into gamma flotation, adsorption of reagents, surface modification and physical regulation.