Study On The Influencing Factors And Mechanism Of Calcium Carbonate Whiskers Prepared From Calcite

Calcium carbonate whisker has very high toughness and strength,and is a new type of needle-like material newly discovered in recent years.It can replace nanocrystalline calcium carbonate and is used in many fields.Calcium carbonate whiskers can not only increase the capacity,but also increase the electrical energy of the material,thereby greatly reducing the cost.Therefore,the research and development and preparation of calcium carbonate whiskers are gradually becoming a new hot spot in the field of whiskers.In this paper,calcite ore is used as the raw material,the prepared heavy magnesium water（Mg（HCO₃）₂）and the intermediate product calcium chloride are used to prepare aragonite-type calcium carbonate whiskers by uniform titration.In the calcination process,the effects of calcination temperature,calcination time,and heating rate on the calcined loss rate were investigated;in the digestion process,the effects of digestion time,digestion temperature,and the mass ratio of CaO and H₂O on the digestibility of CaO were investigated;the differences were explored The influence of reaction temperature and CO₂flow rate on the conversion rate of Mg²⁺;in the titration process,the influence of reaction temperature,reaction time,magnesium calcium concentration ratio,heavy magnesium water concentration and stirring speed on the morphology and aspect ratio of aragonite calcium carbonate whiskers were investigated.The influence of different additives on the morphology of aragonite calcium carbonate whiskers was also investigated.The experimental results show that during the calcination process,the optimal conditions are:the calcination temperature is 850℃,the calcination time is 3h,the heating rate is 15℃/min,and the calcite loss on ignition is 38.8%.In the digestion process,the optimized conditions are:the digestion time is 60 min,the digestion temperature is 40℃,the mass ratio of CaO and H₂O is 4:1,and the CaO digestibility is 96.7%.The optimized conditions for the preparation of heavy magnesium water are the reaction temperature of20℃and the CO₂aeration flow rate of 200m L/min.At this time,the Mg²⁺conversion rate of heavy magnesium water is 84.8%.In the titration process,the optimized conditions are:the reaction temperature is 40℃,the reaction time is 2 h,the ratio of magnesium to calcium is 6:1,the concentration of heavy magnesium water is 0.14 mol/L,and the stirring speed is 150 r/min.The prepared aragonite-type calcium carbonate whiskers have a content of 97.8%,a length of 40-64μm,a diameter of 0.6-1.5μm,and an aspect ratio of25-45;when the contents of H₃BO₃,Na₂CO₃and NH₄Cl are 6.2 g/L,0.25 g/L and 3.0 g/L can optimize the morphology of calcium carbonate whiskers to a certain extent.