The　mechanism　by　which　ice　slurry　crystallizes　under　a　vacuum　was　investigated　in　this　work.　The　crystallization　kinetic　models　for　two　different　aqueous　solutions　(glycerol;　a　combination　of　glycerol　and　nano-SiO2)　were　developed　based　on　the　classic　Avrami　theory.　The　values　of　the　Avrami　exponent　n　under　different　experimental　conditions　were　between　0.58　and　0.84,　indicating　the　one-dimensional　flake　thickening　growth　of　ice　crystals.　Glycerol　inhibited　the　growth　of　ice　crystals　due　to　the　hydroxyl-containing　structure,　and　nano-SiO2,　which　served　as　a　nucleating　agent,　could　enhance　the　crystallization　process　effectively.　The　growth　morphology　of　ice　crystals,　including　the　size　and　shape,　were　also　observed.　Results　showed　that　ice　crystals　produced　by　the　vacuum　method　were　generally　oval　in　shape.　Adding　nano-SiO2　to　the　glycerol　solution　reduced　the　size　of　the　ice　crystals,　suggesting　that　nano-SiO2　is　a　promising　additive　for　ice　slurry　systems.　The　study　of　crystallization　mechanism　of　ice　slurry　can　be　useful　for　future　design　of　vacuum　ice　production　systems.　Copyright　©　2017　The　Society　of　Chemical　Engineers.