Conventional and recent advances in gravity separation technologies for coal cleaning: A systematic and critical review
Theerayut Phengsaart, Palot Srichonphaisan, Chinawich Kertbundit, Natatsawas Soonthornwiphat, Somthida Sinthugoot, Nutthakarn Phumkokrux, Onchanok Juntarasakul, Kreangkrai Maneeintr, Apisit Numprasanthai, Ilhwan Park, Carlito Baltazar Tabelin, Naoki Hiroyoshi, Mayumi Ito
Abstract
). To reduce the environmental impacts of coal during combustion, coal cleaning-a kind of pre-combustion clean coal technology-is essential. Gravity separation, a technique that separates particles based on their differences in density, is widely used in coal cleaning due to the simplicity of its operation, low cost, and high efficiency. In this paper, recent studies (from 2011 to 2020) related to gravity separation for coal cleaning were systematically reviewed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A total of 1864 articles were screened after removing duplicates, and after a thorough evaluation 189 articles were reviewed and summarized. Among of conventional separation techniques, dense medium separator (DMS), particularly dense medium cyclone (DMC), is the most popular technologies studied, which could be attributed to the growing challenges of cleaning/processing fine coal-bearing materials. In recent years, most of works focused on the development of dry-type gravity technologies for coal cleaning. Finally, gravity separation challenges and future applications to address problems in environmental pollution and mitigation, waste recycling and reprocessing, circular economy, and mineral processing are discussed.