The　inefficient　disposal　of　gold　tailings　with　high　dependence　on　carbon-intensive　cementitious　materials　poses　substantial　environmental　and　safety　risks.　This　study　develops　an　eco-friendly　cementation　technique　combining　steel　slag　(SS)　with　enzyme-induced　carbonate　precipitation　(EICP)　for　low-carbon　ultrafine　tailings　backfilling.　Systematic　investigation　of　SS　content　(SC),　binder　content　(BC),　and　EICP　content　(EC)　revealed　the　evolution　of　slurry　fluidity　and　mechanical　strength.　At　complete　cement　replacement　(SC　=　100　%)　with　BC　=　20　%　and　EC　=　75　%,　the　fresh　slurry　demonstrated　242.3　mm　spread　diameter,　and　1.45　MPa　28-day　unconfined　compressive　strength,　fulfilling　backfill　specifications.　Dynamic　leaching　test　verified　over　90　%　heavy　metals　stabilization　efficiency　with　leaching　levels　below　the　groundwater　tertiary　threshold.　The　established　multi-factor　coupling　model　accurately　predicts　engineering　performance.　Microstructural　analyses　(XRD,　FTIR　and　SEM-EDS)　indicated　EICP　facilitates　silicate　network　depolymerization,　hydration　enhancement,　and　free-phase　carbonation　stabilization　in　SS,　forming　a　dense　multiphase　cementitious　system.　Mechanistic　analysis　based　on　the　shrinkage　core　model　shows　that　EICP　achieves　synergistic　enhancement　by　accelerating　dissolution　and　nucleation　in　the　dominant　stage　of　the　chemical　reaction,　and　pathway　optimization　in　the　dominant　stage　of　the　diffusion　with　a　positive　feedback　cycle　of　ions.　At　the　same　time,　damage　problems　caused　by　excessive　pursuit　of　the　reaction　rate　while　neglecting　the　mass　transfer　limitations　and　the　structural　stability　of　the　product　layer　should　be　avoided.　This　technology　achieves　10–15　%　cost　reduction　and　61　%　carbon　emission　mitigation,　offering　an　innovative　approach　for　tailings　utilization　and　carbon　neutrality　goals.　©　2025　Elsevier　B.V.