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cement-free concrete and high-grade minerals from waste
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more than 136 million tons of coal ash waste materials are being produced to meet the electricity needs of the us each year. however, more than 55% of these wastes are being dumped in the landfills and ash ponds. many studies indicate the presence of a variety of metal oxides such as iron, aluminum and titanium in these wastes. another application envisioned is to make cement-less concrete using these materials to reduce the portland cement consumption which is responsible for 5-8% of total co2 emissions as a greenhouse gas.
the main objective of this study was to develop a novel flowsheet for extracting valuable metal oxides from coal ash wastes and to develop a suitable process to utilize them as a useful product in the form of a cement-less concrete. we used totally waste materials to produce some useful metals and also cement-less concrete with much less carbon footprint. we not only left nothing behind as waste but also helped the climate and prevented global warming by decreasing carbon dioxide production.