Tracking of chromium in plasma co-melting of fly ashes and sludges

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Leachable chromium in the incineration fly ash and wastewater sludge has been thermally stabilized by plasma melting at the temperature of 1,773 K. To better understand how chromium is stabilized with the high-temperature treatment, chemical structure of the slags sampled at temperature zones of 1,100- 1,700 K has been studied by synchrotron X-ray absorption spectroscopy. The component-fitted X-ray absorption near edge structure spectra of chromium indicate that the main chromium compounds in the sludge and fly ash are Cr(OH) 3, Cr 2O 3, and CrCl3. A small amount of toxic CrO 3 is also observed in the fly ash. In the plasma melting chamber under the reducing environment, the high-oxidation state chromium is not found. The slags in the plasma melting chamber have much less leachable chromium, which is due to chemical interactions between chromium and SiO 2 in the slags. The existence of the interconnected Cr-O-Si species is observed by refined extended X-ray absorption fine structure spectroscopy. In the Cr 2O 3 phase of the slags, their bond distances, and coordination numbers for the first (Cr-O) and second (Cr-(O)-Cr) shells have insignificant perturbation when experienced with different melting temperatures between 1,300 and 1,700 K. It seems that Cr 2O 3 and chromium encapsulated in the silicate matrix of the slags have relatively much lower leachability. With this concept, to obtain a low chromium leachability slag from the plasma melting process, the residence time of the melting chamber may be decreased, and the slag discharge temperatures may be increased to 1,300 K. This work also exemplifies utilization of moleculescale data obtained from synchrotron X-ray absorption spectroscopy to reveal how chromium is thermally stabilized in a commercial scale plasma melting process.

Original languageEnglish
Pages (from-to)5283-5288
Number of pages6
JournalWater, Air, and Soil Pollution
Volume223
Issue number8
DOIs
Publication statusPublished - 2012 Sep 1

Fingerprint

Coal Ash
Sewage sludge
Chromium
Fly ash
fly ash
chromium
Melting
melting
sludge
Slags
slag
Plasmas
plasma
X ray absorption spectroscopy
Synchrotrons
atomic absorption spectroscopy
X-ray spectroscopy
Chromium Compounds
Chromium compounds
Extended X ray absorption fine structure spectroscopy

All Science Journal Classification (ASJC) codes

  • Environmental Engineering
  • Environmental Chemistry
  • Ecological Modelling
  • Water Science and Technology
  • Pollution

Cite this

@article{1a7ae71f529c4def835b825bf2b4721f,
title = "Tracking of chromium in plasma co-melting of fly ashes and sludges",
abstract = "Leachable chromium in the incineration fly ash and wastewater sludge has been thermally stabilized by plasma melting at the temperature of 1,773 K. To better understand how chromium is stabilized with the high-temperature treatment, chemical structure of the slags sampled at temperature zones of 1,100- 1,700 K has been studied by synchrotron X-ray absorption spectroscopy. The component-fitted X-ray absorption near edge structure spectra of chromium indicate that the main chromium compounds in the sludge and fly ash are Cr(OH) 3, Cr 2O 3, and CrCl3. A small amount of toxic CrO 3 is also observed in the fly ash. In the plasma melting chamber under the reducing environment, the high-oxidation state chromium is not found. The slags in the plasma melting chamber have much less leachable chromium, which is due to chemical interactions between chromium and SiO 2 in the slags. The existence of the interconnected Cr-O-Si species is observed by refined extended X-ray absorption fine structure spectroscopy. In the Cr 2O 3 phase of the slags, their bond distances, and coordination numbers for the first (Cr-O) and second (Cr-(O)-Cr) shells have insignificant perturbation when experienced with different melting temperatures between 1,300 and 1,700 K. It seems that Cr 2O 3 and chromium encapsulated in the silicate matrix of the slags have relatively much lower leachability. With this concept, to obtain a low chromium leachability slag from the plasma melting process, the residence time of the melting chamber may be decreased, and the slag discharge temperatures may be increased to 1,300 K. This work also exemplifies utilization of moleculescale data obtained from synchrotron X-ray absorption spectroscopy to reveal how chromium is thermally stabilized in a commercial scale plasma melting process.",
author = "Tuan, {Yeu Juin} and Hong-Paul Wang and Juu-En Chang",
year = "2012",
month = "9",
day = "1",
doi = "10.1007/s11270-012-1278-2",
language = "English",
volume = "223",
pages = "5283--5288",
journal = "Water, Air, and Soil Pollution",
issn = "0049-6979",
publisher = "Springer Netherlands",
number = "8",

}

Tracking of chromium in plasma co-melting of fly ashes and sludges. / Tuan, Yeu Juin; Wang, Hong-Paul; Chang, Juu-En.

In: Water, Air, and Soil Pollution, Vol. 223, No. 8, 01.09.2012, p. 5283-5288.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Tracking of chromium in plasma co-melting of fly ashes and sludges

AU - Tuan, Yeu Juin

AU - Wang, Hong-Paul

AU - Chang, Juu-En

PY - 2012/9/1

Y1 - 2012/9/1

N2 - Leachable chromium in the incineration fly ash and wastewater sludge has been thermally stabilized by plasma melting at the temperature of 1,773 K. To better understand how chromium is stabilized with the high-temperature treatment, chemical structure of the slags sampled at temperature zones of 1,100- 1,700 K has been studied by synchrotron X-ray absorption spectroscopy. The component-fitted X-ray absorption near edge structure spectra of chromium indicate that the main chromium compounds in the sludge and fly ash are Cr(OH) 3, Cr 2O 3, and CrCl3. A small amount of toxic CrO 3 is also observed in the fly ash. In the plasma melting chamber under the reducing environment, the high-oxidation state chromium is not found. The slags in the plasma melting chamber have much less leachable chromium, which is due to chemical interactions between chromium and SiO 2 in the slags. The existence of the interconnected Cr-O-Si species is observed by refined extended X-ray absorption fine structure spectroscopy. In the Cr 2O 3 phase of the slags, their bond distances, and coordination numbers for the first (Cr-O) and second (Cr-(O)-Cr) shells have insignificant perturbation when experienced with different melting temperatures between 1,300 and 1,700 K. It seems that Cr 2O 3 and chromium encapsulated in the silicate matrix of the slags have relatively much lower leachability. With this concept, to obtain a low chromium leachability slag from the plasma melting process, the residence time of the melting chamber may be decreased, and the slag discharge temperatures may be increased to 1,300 K. This work also exemplifies utilization of moleculescale data obtained from synchrotron X-ray absorption spectroscopy to reveal how chromium is thermally stabilized in a commercial scale plasma melting process.

AB - Leachable chromium in the incineration fly ash and wastewater sludge has been thermally stabilized by plasma melting at the temperature of 1,773 K. To better understand how chromium is stabilized with the high-temperature treatment, chemical structure of the slags sampled at temperature zones of 1,100- 1,700 K has been studied by synchrotron X-ray absorption spectroscopy. The component-fitted X-ray absorption near edge structure spectra of chromium indicate that the main chromium compounds in the sludge and fly ash are Cr(OH) 3, Cr 2O 3, and CrCl3. A small amount of toxic CrO 3 is also observed in the fly ash. In the plasma melting chamber under the reducing environment, the high-oxidation state chromium is not found. The slags in the plasma melting chamber have much less leachable chromium, which is due to chemical interactions between chromium and SiO 2 in the slags. The existence of the interconnected Cr-O-Si species is observed by refined extended X-ray absorption fine structure spectroscopy. In the Cr 2O 3 phase of the slags, their bond distances, and coordination numbers for the first (Cr-O) and second (Cr-(O)-Cr) shells have insignificant perturbation when experienced with different melting temperatures between 1,300 and 1,700 K. It seems that Cr 2O 3 and chromium encapsulated in the silicate matrix of the slags have relatively much lower leachability. With this concept, to obtain a low chromium leachability slag from the plasma melting process, the residence time of the melting chamber may be decreased, and the slag discharge temperatures may be increased to 1,300 K. This work also exemplifies utilization of moleculescale data obtained from synchrotron X-ray absorption spectroscopy to reveal how chromium is thermally stabilized in a commercial scale plasma melting process.

UR - http://www.scopus.com/inward/record.url?scp=84867336108&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84867336108&partnerID=8YFLogxK

U2 - 10.1007/s11270-012-1278-2

DO - 10.1007/s11270-012-1278-2

M3 - Article

VL - 223

SP - 5283

EP - 5288

JO - Water, Air, and Soil Pollution

JF - Water, Air, and Soil Pollution

SN - 0049-6979

IS - 8

ER -