Use of solid hematite to fix arsenic contained in a gas phase

A. González, E. Balladares, R. Parra, M. Sanchez

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

3 Citations (Scopus)

Abstract

Arsenic is one of the main contaminants present in Chilean copper concentrates and its abatement represents a challenge for the process metallurgy, particularly under the strong environmental requirements in the global community. The possibility to form ferric arsenate directly from a gas phase by means of a heterogeneous reaction between an arsenic gas bearing and iron oxide was studied at laboratory scale. A thermodynamical analysis for the system Fe-As-O-S has been initially made, in order to obtain the stability conditions for the ferric arsenate or other FexAsyOz type compounds. Experiments were made using an hematite sample suspended in a thermogravimetric device. As4O6 that was passed through the iron oxide sample and its instantaneous weight change was recorded directly. A kinetic study for the As4O6 volatilization was made to control the gas composition. A chemical control between 300 and 600°C with an apparent activation energy of around 14 Kcal/mol As2O3 was determined. The samples after the reactions were chemically and XRD analysed. Arsenates detected corresponds to complex compounds. Results shows a dependence on temperature and oxygen content in the gas phase. The kinetics for iron arsenates formation is slow, reaching an arsenic capture of 6% after 80 minutes of reaction when an oxygen content of 50% is fed continuously at 800°C and 3,56% As in the gas. Experiences made at the same temperature but under higher oxygen content in a closed reactor, allowed arsenic capture close to 60%. For higher temperatures the capture is considerably lower.

Original languageEnglish
Title of host publicationYazawa International Symposium
Subtitle of host publicationMetallurgical and Materials Processing: Principles and Techologies; High-Temperature Metal Production
EditorsF. Kongoli, K. Itagaki, C. Yamauchi, H.Y. Sohn, F. Kongoli, K. Itagaki, C. Yamauchi, H.Y. Sohn
Pages625-642
Number of pages18
Publication statusPublished - 2003
Externally publishedYes
EventYazawa International Symposium: Metallurgical and Materials Processing: Principles and Technologies; High-Temperature Metal Production - San Diego, CA, United States
Duration: 2 Mar 20036 Mar 2003

Publication series

NameYazawa International Symposium: Metallurgical and Materials Processing: Principles and Techologies; High-Temperature Metal Production
Volume2

Conference

ConferenceYazawa International Symposium: Metallurgical and Materials Processing: Principles and Technologies; High-Temperature Metal Production
Country/TerritoryUnited States
CitySan Diego, CA
Period2/03/036/03/03

ASJC Scopus subject areas

  • Engineering(all)

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