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

doi:10.1016/j.heliyon.2023.e13083

Conventional and recent advances in gravity separation technologies for coal cleaning: A systematic and critical review

Heliyon. 2023 Jan 21;9(2):e13083. doi: 10.1016/j.heliyon.2023.e13083. eCollection 2023 Feb.

Authors

Affiliations

¹ Department of Mining and Petroleum Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand.
² Division of Sustainable Resources Engineering, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan.
³ Department of Groundwater Resources, Ministry of Natural Resources and Environment, Bangkok 10900, Thailand.
⁴ Department of Geography, Faculty of Education, Ramkhamhaeng University, Bangkok 10240, Thailand.
⁵ Department of Earth Sciences, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand.
⁶ Department of Materials and Resources Engineering Technology, College of Engineering and Technology, Mindanao State University-Iligan Institute of Technology, Iligan City 9200, Philippines.

Abstract

"Affordable and clean energy" is enshrined in the UN Sustainable Development Goals (SDGs; #7) because of its importance in supporting the sustainable development of society. As an energy source, coal is widely used because it is abundant and its utilization for electricity and heat generation do not require complex infrastructures and technologies, which makes it ideal for the energy needs of low-income and developing countries. Coal is also essential in steel making (as coke) and cement production and will continue to be on high demand for the foreseeable future. However, coal is naturally found with impurities or gangue minerals like pyrite and quartz that could create by-products (e.g., ash) and various pollutants (e.g., CO₂, NO_X, SO_X). 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.

Keywords: Coal; Coal cleaning; Gravity separation; Separation technology.

Publication types

Review