A combined kinetic and thermodynamic approach for interpreting the complex interactions during chloride volatilization of heavy metals in municipal solid waste fly ash

Kenta Kurashima, Kaho Matsuda, Shogo Kumagai, Tomohito Kameda, Yuko Saito, Toshiaki Yoshioka

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

This study elucidated complex interactions during the chloride volatilization of heavy metals (Pb, Cu, Zn, Mn, and Cr) from municipal solid waste fly ash by combining thermodynamic and kinetic approaches. Chloride volatilization tests under HCl flow at 900 °C and subsequent rinsing with water achieved almost complete removal of Pb, Zn, and Mn. In contrast, almost 100 % of Cr and ∼40 % of Cu were not removed by either volatilization or rinsing processes. Kinetics indicated that the chlorination of Pb, Zn, and Mn followed a pseudo second order reaction and their apparent activation energies were 96.3, 89.2, and 43.5 kJ/mol, respectively. Further thermodynamic calculation revealed that the components contained in fly ash greatly influenced the chlorination of each heavy metal. Unburned carbon facilitated the chlorination of Pb, Zn, and Mn, while it inhibited Cu chlorination. MgO immobilized Cr and inhibited chlorination. KCl and NaCl promoted Zn and Mn chlorination, respectively. The revealed chloride volatilization behavior and effects of co-existing elements could be useful in the design of high-efficiency recovery process of heavy metals from fly ash and the utilization of residues as raw materials for cement. Furthermore, these findings could guide the realization of a recycling-oriented society in terms of reducing waste disposal.

Original languageEnglish
Pages (from-to)204-217
Number of pages14
JournalWaste Management
Volume87
DOIs
Publication statusPublished - 2019 Mar 15

Keywords

  • Chloride volatilization
  • Fly ash
  • Heavy metal
  • Kinetics
  • Thermodynamic calculation

ASJC Scopus subject areas

  • Waste Management and Disposal

Fingerprint Dive into the research topics of 'A combined kinetic and thermodynamic approach for interpreting the complex interactions during chloride volatilization of heavy metals in municipal solid waste fly ash'. Together they form a unique fingerprint.

Cite this