Abstract: Technology of preparation of calcium carbonate nano-rods using dolomite as raw material，through the processes of calcination，digestion，twice-carbonization，filtrating，washing，and drying was studied.SEM and XRD were employed to characterize the prepared samples.Effects of reaction temperature，mass concentration of calcium hydroxide，amount of crystal controlling agents，and type of added dispersant on product′s particle size in twice-carbonization process were investigated.Experimental results showed that in twice-carbonization process，the calcium carbonate nano-rods whose average particle diameter of about 150 nm， average length of about 1 μm，and average aspect ratio of at 6~8 could be prepared under conditions of carbonization temperature of 20 ℃（mass fraction），mass fraction of calcium hydroxide of 6% by adding 2%（mass fraction） crystal controlling agent and polyvinyl alcohol dispersant.

Key words: dolomite, twice-carbonization, calcium carbonate nano-rods, particle size