Fluorine detoxification mechanisms of spent potlining incineration in
response to calcium compounds
In this study, the detoxification and distribution mechanisms of
fluorine during the spent potlining (SPL) incineration were
characterized. CaSiO3, CaO, Ca(OH)2, and CaCO3-assissted SPL
incineration detoxified NaF in the bottom ash yielding a conversion
range of 54.24 to 99.45% relative to the individual SPL incineration.
The fluorine leaching content of the bottom ash was estimated at 13.71
mgL-1 after the SPL co-incineration with CaSiO3 (Ca:F=1.2:1). The two
main mechanisms of the fluorine transformation were the substantial
formations of CaF2, and Ca4Si2O7F2. The fluorine transformation
efficiency was greater with CaSiO3 than CaO, Ca(OH)2, and CaCO3.
Fluorine during the SPL co-incineration with CaSiO3 (Ca:F=1.2:1) at 850
°C for 60 min was partitioned into 83.37, 13.90 and 2.72% in the bottom
ash, fly ash, and flue gas, respectively. The transformation and
detoxification mechanisms of fluorine provide new insights into controls
over fluorine emission from the SPL incineration.