Effect of the composition on the immobilization of chromium in slags

E. García-Ramos, A. Romero-Serrano, B. Zeifert, P. Flores-Sánchez, M. Hallen-López, E. G. Palacios

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

Abstract

Chromium containing slags from stainless steelmaking may eventually be leached by acidic environments, therefore they should be treated before being stockpiled or land filled. In this work, synthetic slags were prepared and the effect of CaO/SiO 2, Cr 2O 3, MgO and Al 2O 3 contents on the stability of the mineralogical species formed was analyzed. The morphology and composition of the slags were analyzed by XRD and SEM-EDS, whilst their chemical stability was evaluated by leaching with an aqueous acetic acid solution. It was found that CaCr 2O 4 and CaCrO 4 are present in slags prepared with neither MgO nor Al 2O 3. The Al 2O 3-based slags mainly produced Ca 2Al 2SiO 7 and the Cr(VI)-containing oxide complex Ca 4Al 6CrO 16, whilst MgO-based slags produced MgCr 2O 4 as main mineralogical species. Additionally, Eh-pH diagrams for the Ca-Cr-H 2O and Mg-Cr-H 2O systems at 25 °C were constructed. The lowest Cr concentration levels in the leaching liquors corresponded to MgO-based slags owing to the stable binding of Cr in spinel with MgO. It was also observed in the Al 2O 3-based slags that increasing the slag basicity from 1 to 2 the leachability of the slags are notably increased.

Original languageEnglish
Title of host publicationProceedings of the 2008 Global Symposium on Recycling, Waste Treatment and Clean Technology, REWAS 2008
Pages709-716
Number of pages8
StatePublished - 2008
Externally publishedYes
Event2008 Global Symposium on Recycling, Waste Treatment and Clean Technology, REWAS 2008 - Cancun, Mexico
Duration: 12 Oct 200815 Oct 2008

Publication series

NameProceedings of the 2008 Global Symposium on Recycling, Waste Treatment and Clean Technology, REWAS 2008

Conference

Conference2008 Global Symposium on Recycling, Waste Treatment and Clean Technology, REWAS 2008
Country/TerritoryMexico
CityCancun
Period12/10/0815/10/08

Keywords

  • Chromium oxide
  • Slag
  • Waste management

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