Characterization, Processing, and Application of Heavy Fuel Oil Ash, an Industrial Waste Material – A Review

Heavy fuel oil ash (HFOA) is generated as an industrial waste material during the combustion of heavy fuel oil in power/desalination plants. With increasing energy demands, a significant volume of HFOA is generated. It is generally disposed of in landfills, causing environmental pollution, as it contains several toxic elements. Recently, efforts were made towards developing strategies for reusing industrial waste materials and creating value‐added products from the waste materials. Despite significant information available in the literature on the utilization of HFOA, there is still a need for a thorough and systematic review on the characterization and utilization of HFOA in various applications. Consequently, this paper aims to present a critical review of the literature on HFOA generation, its chemical composition, physical properties, morphology, and applications. It is encouraging to note that HFOA has been used in several potential applications, such as the preparation of activated carbon and carbon nanotubes, metal recovery, environmental pollutant removal, polymer composites and construction materials, etc. However, the development of several value‐added materials utilizing HFOA and its applications in other areas such as coatings, cathodic protection systems, and phase change materialswould emerge as a new topic of research. It is expected that this review will act as a precursor for further research on the use of HFOA in industrial applications. Since the use of HFOA will lead to environmental, economic, and technical benefits, research in the utilization of this industrial waste material is highly recommended. This paper provides a comprehensive review on the composition, characterization, and applications of heavy fuel oil ash (HFOA), an industrial waste material generated in power/desalination plants. The utilization of HFOA in various fields, such as metal recovery, activated carbon, carbon nanotubes, nanocomposites, environmental pollutant removal, and construction materials are described. Additionally, areas of future research on the use of HFOA as a value‐added product are recommended.