Leaching behavior of lignite fly ash

Summarization: The leaching behaviour of an alkaline lignite fly ash was studied by standard tests, such as the USEPA Toxicity Characteristic Leaching Procedure (TCLP), and German DIN 38414 S4 batch and successive leaching tests. The release of both heavy metals and polynuclear aromatic hydrocarbons was investigated. The quantities of toxic substances released were compared to the total amount of these in the fly ash when measured after dissolution in royal water (for heavy metal determination) and ultrasonic extraction in cyclohexane (for the polynuclear aromatic hydrocarbons). In general, only sulphur was released in considerable quantities, reaching a quarter of its total amount in the fly ash. Toxic metal ions were released in extremely low quantities due to the alkaline nature of the fly ash. PAHs were identified at the solid phase in concentrations less than 100 ppb, while no release in the water phase was detected. The EPA standard test gave higher concentrations of metals in the leachate due to the lower pH conditions of the test.Presented on: Journal of Environmental Science and Health, Part