In a significant stride towards sustainable maritime practices, researchers have developed a novel approach to repurpose coal fly ash (CFA), a byproduct of coal combustion, into valuable cementitious materials. The study, led by Shize Cai from the Innovation Institute for Sustainable Maritime Architecture Research and Technology (iSMART) at Qingdao University of Technology, China, offers a promising solution to reduce natural resource consumption and environmental impacts.
CFA, often considered a waste product, can be transformed into a useful resource through a process called flotation. This technique effectively lowers the unburned carbon content in CFA, making it more suitable for recycling. However, the environmental and economic implications of this process have not been thoroughly evaluated until now.
The research, published in the journal ‘Cleaner Environmental Systems’ (translated from Chinese as ‘Cleaner Environmental Systems’), introduces a Calorific-Based Economic Valuation (CBEV) framework. This innovative approach optimizes process parameters by linking market pricing mechanisms with flotation grade-recovery. “We found that the optimal conditions for the flotation process are 1% kerosene and 0.1% turpentine oil per ton of CFA,” explains Cai. “This not only achieves a significant carbon benefit but also ensures economic viability.”
The study reveals that under optimal conditions, the flotation process can achieve a carbon benefit of 94.29 kg CO2-eq, representing a 247.70% improvement. Economically, this translates to a net benefit of 0.986 USD per ton of CFA, a 4.69% return on investment. These findings highlight the potential for maritime sectors to adopt this technology, reducing waste and contributing to a circular economy.
The research also underscores the importance of logistics optimization. A 50% increase in transport distance, for instance, can reduce economic returns by 3.6%, despite only a marginal variation in carbon footprint. This insight is particularly relevant for maritime professionals, who must balance environmental and economic considerations in their operations.
The study’s findings provide a conservative baseline for future industrial applications, offering a dual-perspective framework for assessing the feasibility of CFA flotation. As maritime industries increasingly focus on sustainability, this research offers valuable insights and opportunities for process intensification and resource recovery.
In the words of Shize Cai, “This study establishes a foundation for sustainable process intensification, providing quantitative insights to support the maritime industry’s transition towards a greener future.”