“…Notably, impurities such as Fe 2 O 3 , TiO 2 and K 2 O do not influence the synthesis of FAU zeolite, and do not need to be removed in the synthesis. The mineral phases present in CFA were identified by XRD as quartz (SiO 2 ) and mullite (3Al 2 O 3 •2SiO 2 ), together with some amorphous silica, as shown in Fig.S1, † in good agreement with the literature 34,[39][40][41]. Fig.…”