The　effect　of　calcium　lignosulfonate　dosage　on　the　recovery　of　fine　serpentine　in　brucite　flotation　was　studied　by　using　an　improved　Hallimond　flotation　tube.　Based　on　the　Plateau　foam　structure　balance　principle　and　Laplace　equation,　combined　with　the　foam　stability　test　results,　the　regulation　mechanism　of　calcium　lignosulfonate　on　the　entrainment　of　fine　serpentine　was　analyzed.　The　results　show　that　the　addition　of　calcium　lignosulfonate　reduces　the　pulp　viscosity　and　increases　the　surface　tension　of　the　liquid,　thus　accelerating　the　drainage　rate　of　the　foam　layer　and　reducing　the　content　of　fine　serpentine　which　is　non-selectively　entrained　into　the　foam　layer.　Eventually,　the　foam　entrainment　rate　of　serpentine　decreases　from　1.15　to　0.41.　©　2022,　Central　South　University　Press.　All　right　reserved.