添加剂对高能球磨法制备CaCO_(3)晶型和形貌的影响

Effect of Additives on Polymorphs and Morphologies of CaCO_(3) Powder via High-energy Milling Method

由于球霰石相碳酸钙(CaCO_(3))热力学的不稳定性,其制备需要苛刻的条件。在不添加氯化钠(NaCl)或氯化钾(KCl)稀释剂的前提下,首先研究了机械研磨时间、研磨转速和球料比对高能球磨法制备的CaCO_(3)晶体类型和颗粒形貌的影响。结果表明,反应初期和低转速时会生成无定形CaCO_(3)(ACC),其他条件下产物全部为方解石相;延长球磨时间、提高球磨转速和增加球料比均有利于反应的进行和方解石的结晶。然后研究了十二烷基磺酸钠(SDSN)和六偏磷酸钠(SHMP)对CaCO_(3)晶体类型和颗粒形貌的影响。结果表明,SDSN和SHMP均能促进球状球霰石的生成。SDSN的添加可以得到球霰石相含量为58.2 wt.%的CaCO_(3)粉体,而SHMP的添加可以使球霰石相的含量提高至81.9 wt.%。

Due to its low thermodynamic stability, it is difficult to synthesize vaterite phase of CaCO_(3). The effect of milling time, milling speed and the weight ratio of milling ball to reactant on the polymorphs and the morphologies of CaCO_(3), in absence of NaCl or KCl as diluter, was firstly studied. Amorphous CaCO_(3)(ACC)was formed at the early reaction stage and at low milling speeds, while otherewise calcite is the only phase. Prolonging milling time, enhancing milling speed and increasing the weight ratio of milling ball to reactant are beneficial to the formation and crystallization of calcite. The effect of sodium dodecyl sulfonate(SDSN)and sodium hexametaphosphate(SHMP)on the polymorphs and the morphologies of CaCO_(3)was then evaluated, indicating that both SHMP and SDSN can promote the formation of vaterite. The percentages of vaterite phase are 58.2 wt.% and 81.9 wt.%, when using SDSN and SHMP respectively.