Coal Fly Ash: Toxic Waste Product of Burning Coal

Coal_Fly_AshWhen coal is burned, about 10% remains as ash. The heavy ash settles beneath the burner. A light ash, called coal fly ash (CFA), condenses and forms in the hot gases above the burner. Previously, CFA exited smokestacks of coal-burning industries, mainly electricity-producing utilities. But because CFA consists of concentrations of the toxic substances found in coal, such as heavy metals including mercury, arsenic, chromium IV and radioactive elements, regulations in Western nations require CFA to be trapped and sequestered. There is much public concern that the toxins will enter drinking water supplies through dumping, seepage, and spills. Coal fly ash is a major industrial waste product worldwide. CFA forms in micron and submicron size particles, see image at right, courtesy of Wabeggs: CC BY-SA 3.0. The particles form in just the size range needed to spray into the atmosphere for inhibiting rainfall. Because it formed under conditions which are not-natural, water is capable of extracting portions of its toxic substances. These then can be analyzed in post-spraying rainwater and compared to laboratory water-leach experiments on CFA.

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