The photo is sourced from gruntovozov.ru
Fly ash is a byproduct of coal-fired thermal power plants (TPPs). Coal is first ground to the finest level of talcum powder, and then burned to heat water and subsequently produce steam energy driving the electric generator. Coal-fired TPPs are usually equipped with an excavation pit, to which the wastewater and the ash produced during coal combustion are directed. As a result, an ash dump forms, the water in which sometimes acquires a beautiful turquoise color due to reaction of trace elements of loamy soil with the process water and dissolved calcium salts and metal oxides.
Every year around 750 million tons of coal ash are produced worldwide, which is partially used for production of building materials, including red bricks. Another option for utilisation of coal combustion waste was proposed by the scientists of the Krasnoyarsk Scientific Centre of the Siberian Branch of the Russian Academy of Sciences who obtained glass-ceramic materials by sintering the dispersed microspheres of fly ash at the temperature of 1,200 degrees Celsius. The experiment did not require energy-intensive milling of raw materials or use of any additives. At the same time, the authors of the study have obtained the material containing a large amount of magnetic phase and characterised by high density and low water absorption.
“Glass-ceramics have such distinctive properties as high mechanical strength, abrasion resistance and corrosion resistance. Our results confirm possibility to successfully produce quality glass-ceramic materials from fly ash by direct sintering, without any additives. This will allow us to ensure large-scale utilisation of fly ash with high efficiency and low energy consumption, minimizing the environmental pollution by the dispersed waste,” the Krasnoyarsk Scientific Centre of Siberian Branch of Russian Academy of Sciences quotes Elena Fomenko, PhD in Chemistry, one of the authors of the study.
