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Evaluation of foamed bitumen efficiency in warm asphalt mixtures recycling
Published in Cândida Vilarinho, Fernando Castro, Mário Russo, Wastes: Solutions, Treatments and Opportunities, 2015
Cândida Vilarinho, Fernando Castro, Mário Russo
The final rule of Environmental Protection Agency (EPA), EPA “Hazardous and Solid Waste Management System; Disposal of Coal Combustion Residuals from Electric Utilities.” address serious human health and environmental risks from unsafe coal ash disposal (EPA, 2015). Table 3 shows two case studies of incorporation of wastes (coal fly ash and rubber tires) into concrete (both for Portland cement and/or asphalt concrete) and shows the heavy metals associated to each waste. In accordance with research (Torgal et al., 2012; Yao et al., 2015; EPA, 2015), the coal fly ashes contain: chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), zinc (Zi), arsenic (As), mercury (Hg), cadmium (Cd), tin (Sn) and selenium (Se). A study on the properties of recycled tire rubber (Cao, 2007) shows that its chemical composition is acetone extract (15.5%), ash content (6.0%), carbon black (29.5%) and rubber hydrocarbon (49.0%).
Microstructural behaviour of quarry fines stabilised with fly ash-based binder
Published in Road Materials and Pavement Design, 2023
Yinning Zhang, Amandine Miksic, Daniel Castillo, Leena Korkiala-Tanttu
The Ecolan stabiliser is a commercial product composed of coal ash, wood biomass, lime and cement. The fly ash stabiliser is 100% coal combustion residuals with a major component of fly ash, obtained from Hanasaari power plants in Helsinki. It is well-established that fly ash can be self-cementitious depending on the type of coal used and the nature of the combustion process. However, the behaviour of fly ash can vary significantly from plant to plant. Therefore, it is vital to identify the chemical compositions of the studied fly ash, so that the binding properties of the material could be better understood and utilised. Table 2 lists the basic index properties, as well as the chemical compositions of the fly ash used in this study.
Landfill Solar: Trash To Treasure*
Published in Energy Engineering, 2018
Bryan A. Jacob, Michael R. Ayers
There are approximately 2000 active municipal solid waste (MSW) landfills with typical surface area from 5 to 80 acres.[14] In 2013, the U.S. Environmental Protection Agency (EPA) pre-screened over 1,600 of the country's landfills for renewable energy potential and issued “Best Practices for Siting Solar Photovoltaics on Municipal Solid Waste Landfills”.[15] In addition, the U.S.A has more than 1000 landfills and surface impoundments for coal combustion residuals (CCR). The CCR landfills average 120 acres and the CCR impoundments average 50 acres.[16] In total, more than 100,000 acres of surface area could become available for solar PV as these landfills/impoundments are properly closed.
Development of a novel biocollector for flotation of low grade graphite ore
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Vasumathi Nallusamy, Chennakesavulu Kattela, Cassandra Austen Immanuel, Ajita Kumari, Jayasankar Kalidoss, Sreejakumari Sukumaran Suseelamma, Vijayakumar Tadiparthi Venkata, Gopalkrishna Sirigeri Jois
In graphite ore beneficiation by flotation, the ore is often subjected to a suitable hydrocarbon oil treatment to enhance its hydrophobicity, increase recovery, and/or improve selectivity (Patil et al. 2000). In recent years, significant advances were made in the area of chemical reagents utilized in froth flotation process. Mainly in commercial scale plants, the control of reagent addition becomes the most important part of the flotation strategy (Chehreh Chelgani et al. 2016). Hence, more studies by researchers focused on flotation reagents to improve the flotation efficiency leading to better economic benefits. Effective processing of low-grade ores by flotation requires more selective and specific flotation reagents. Amidst the presence of conventional petroleum-based flotation reagents, a renewable collector made by transesterification of waste fried oil was studied for removal of unburned carbon present in coal combustion residuals providing a cost-effective solution (Gan Cheng 2022; Vasumathi et al. 2014). Hydrocarbon oils like kerosene, fuel oil, paraffin, and diesel oil are mostly used as collectors for graphite flotation while kerosene was found to be more suitable collector than the rest (Chehreh Chelgani et al. 2016). The hydrocarbon oil, diesel, a nonpolar collector with pine oil as frother was used in flotation of Indonesian graphite ore (Florena et al. 2016). Also, emulsified kerosene improved the selectivity index in flotation of graphite with decrease in average droplet size of kerosene emulsions (700 nm) (Zhou et al. 2020). In fine flake graphite flotation, emulsified kerosene as graphite collector outdid pristine kerosene, resulting in an increased graphite recovery by 3% and also reduced the consumption of kerosene by 26%−34% (Sun et al. 2022). Development of graphite collector emulsification of β-cyclodextrin/kerosene Pickering emulsion was found to improve the recovery of graphite by 6% (Gao 2022). Co-emulsified diesel-hexyl alcohol and diesel-octanol systems were used as co-emulsified collector for higher recovery of graphite than common diesel (Shi et al. 2015). A single reagent, Sokem705C was also found to be effective than dual diesel-frother system for graphite flotation (Vasumathi 2013). Also, bio-surfactants synthesized from micro-organisms were found to have comparable effects similar to that of chemically synthesized surfactants and vegetable oils-based glycolipids derivatives were also found to be alternatives for petroleum-based collectors (Kyzas and Matis 2019). Due to stern environmental regulations in the recent years, the development and design of new, environmental friendly and natural product-based flotation reagents remain one of the highly focused research areas as most of the hydrocarbon oil-based reagents are non-eco-friendly.