A system for separating contaminants trapping additives from a decomposition catalyst includes one or more fluid connections and contains contaminated decomposition catalysts, contaminated contaminant trapping additives, new contaminant trapping additives and fluidizing gas. It may include a removal container. In the pollutant removal vessel, the spent catalyst may be contacted with a pollutant trapping additive, which may have a larger average particle size and/or density than the cracking catalyst. A separator may be provided for separating the overhead stream from the pollutant removal vessel into a first stream comprising a cracking catalyst and lifting gas and a second stream comprising a pollutant trapping additive. The recirculation line may be used to convey the pollutant trapping additive recovered from the second separator to the pollutant removal vessel by allowing the pollutant trapping additive to accumulate in the pollutant removal vessel. The bottom product line may be provided to recover the contaminant trapping additive from the contaminant removal vessel.