Comparing metal leaching and toxicity from high pH, low pH, and high ammonia fly ash
Previous work with both class F and class C fly ash indicated minimal leaching from most fly ashes tested. However, the addition of NOx removal equipment might result in higher levels of ammonia in the fly ash. We have recently been testing fly ash with a wide range of pH (3.7–12.4) originating from systems with NOx removal equipment. Leaching experiments were done using dilute CaCl2 solutions in batch and columns and a batch nitric acid method. All methods indicated that the leaching of heavy metals was different in the highest ammonia sample tested and the high pH sample. However, toxicity testing with the Microtox* system has indicated little potential toxicity in leachates except for the fly ash at the highest pH (12.4). When the leachate from the high pH fly ash was neutralized, toxicity was eliminated.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 909997
- Report Number(s):
- PNNL-SA-55295; FUELAC; 4298; AA3010000; TRN: US200723%%309
- Journal Information:
- Fuel, 86(10-11):1623-1630, Vol. 86, Issue 10-11; ISSN 0016-2361
- Country of Publication:
- United States
- Language:
- English
Similar Records
Leaching of mixtures of biochar and fly ash
Leaching characteristics of selected South African fly ashes: Effect of pH on the release of major and trace species