Recent advances in the electrostatic separation of particulate matter

Abstract

Since the middle of the last century, the electrostatic separation imposed itself as a standard technology in mineral beneficiation. During the last 40 years, it has been more and more widely applied for the recycling of valuable materials (metals, plastics) from industrial wastes. The present paper was aimed to review several recent solutions developed by the authors to surpass several major technical challenges: (i) push the limits of the existing electrostatic separation applications in the recycling industry, in terms of hourly throughput, recovery and purity of the products; (ii) process more complex granular or powdery mixtures, including brominated plastics, and flake-like materials; (iii) recover textile fibers from shredded waste. Described in this short review are: (i) a newly patented modular multi-functional electrostatic separator; (ii) an original procedure for the tribo-electrostatic separation of ternary mixtures of plastics containing brominated flame retardants; (iii) a modified industrial installation for the tribo-electrostatic separation of polyethylene and polystyrene flakes from packaging waste; (iv) a patent-pending equipment for the recovery of PET fibers from end-of-life tires. Research should continue to expand the application of the electrostatic separation in at least the following areas: (i) recycling of composite materials; (ii) recovery of fine powders in food and pharmaceutical industry; (iii) extracting high-value metals from micronized waste electric and electronic equipment.