Abstract: Ammonium chloride was employed as removal agent to dispose of magnesium impurity in calcium carbonate whiskers.The influences of different conditions on removal efficiency were investigated.The purified and unpurified samples were analyzed by chemical analysis method and X-ray diffraction，and then the optimum parameters were obtained as follows: the concentration of ammonium chloride was 3 mol/L，the reaction temperature was 100 ℃，and the reaction time was 6 h.Under the optimal conditions，the removal ratio of impurity magnesium calcite achieved to 62.5% and the purity of calcium carbonate whisker was up to 97%.Furthermore，the product was also characterized by field emission scanning electron microscope which showed numerous impurity particles disappeared on the surface of calcium carbonate whiskers.

Key words: calcium carbonate whiskers, magnesium calcite, ammonium chloride, impurity removal