To　study　the　effects　of　ion　type　and　dosage　of　alkali　activators　on　the　carbonation　of　one-part　alkali-activated　nickel　slag　(OAANS)　mortar,　NaOH,　Na2SiO3,　NaOH+Na2SiO3,　KOH,　and　KOH+Na2CO3　were　used　as　activators.　The　carbonation　depth,　compressive　strength,　and　microstructure　(via　MIP,　XRD,　and　FTIR)　were　analyzed.　Results　show　that　OAANS　mortar　with　K+　as　the　cation　has　significantly　lower　carbonation　resistance　than　those　with　Na+.　Compressive　strength　with　K+　decreases　initially　after　carbonation,　then　increases,　while　strength　with　Na+　grows　rapidly　early　and　slows　later.　With　the　same　cation,　mortars　with　OH−　exhibit　higher　strength　than　those　with　(Formula　presented.)　after　28　days　of　carbonation.　Increasing　alkali　dosage　promotes　hydration,　reduces　porosity,　and　enhances　carbonation　resistance,　with　effects　depending　on　the　alkali　activator　type.　©　2025　Informa　UK　Limited,　trading　as　Taylor　&　Francis　Group.