Premium
Immobilizing chromium in stainless steel slags with MnO addition
Author(s) -
Wang Zhanjun,
Sohn Il
Publication year - 2021
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.17473
Subject(s) - spinel , leaching (pedology) , materials science , chromium , metallurgy , amorphous solid , phase (matter) , scanning electron microscope , chromite , chemical stability , analytical chemistry (journal) , mineralogy , chemistry , crystallography , composite material , geology , organic chemistry , chromatography , soil science , soil water
This work investigates the stabilizing impact of MnO on the leaching behavior of hazardous Cr‐containing CaO‐SiO 2 ‐Al 2 O 3 ‐Cr 2 O 3 ‐MnO stainless steel slags after equilibrating at various elevated temperatures and evaluates the potential immobilization of Cr into a MnCr 2 O 4 spinel phase from the existing Cr 2 O 3 phase. The MnCr 2 O 4 spinel phase was found to be an excellent Cr‐stabilizer in stainless steel slags, where the leaching tendency of potentially hazardous Cr‐related ions decreased with higher MnO content and lower equilibration temperatures within the range of 0 to 15 mass pct. and 1500 to 1300°C, respectively. Thermodynamic calculations by conducting the phase stability diagram also showed that the MnCr 2 O 4 spinel phase was relatively stable and the Ca 3 Si 2 O 7 (Ca 3‐x Mn x Si 2 O 7 ) phase was relatively unstable compared with other crystal phases in acid extractant with pH value of 3.2. Combined with the scanning electron microscopy and X‐ray powder diffraction results along with the thermodynamic calculations, the leached Cr‐related ions was predominantly originating from the unstable amorphous glass phase.