Spherulitic Growth of Calcium Carbonate
Spherulitic Growth of Calcium Carbonate
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DOI：
10.1021/cg901460g
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发表时间：
2010-07-01
影响因子：
3.8
通讯作者：
Andreassen, Jens-Petter
中科院分区：
文献类型：
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作者：
Beck, Ralf;Andreassen, Jens-Petter
晶体成核的发病进行了研究，在水溶液中，无论是进料速率，种子的大小，或种子的量是不同的种子半批实验。实验结果表明，多晶球文石的成核行为与一般单晶颗粒具有惊人的相似性。在自发沉淀实验过程中的球文石的成核速率的调查已经揭示，它将采取数量级更高的过饱和值，以获得所提出的纳米聚集过程所需的粒子数。多晶球文石的亚基“尺寸”是显着不同的粒子在种子半批实验中，成核发生的颗粒。在相同工艺条件下形成的颗粒的亚单位“尺寸”的差异很难通过前体颗粒的聚集来解释，因为纳米聚集将导致纳米颗粒在所有颗粒中均匀分布。另一方面，晶体生长可以解释这种现象，因为它可能取决于下面的晶体表面和球晶尺寸。这表明球晶生长是潜在的颗粒增大机制。同样可以显示为方解石的球粒，其颗粒生长机制已被发现是依赖于晶体表面结构。目前的研究还建议进一步研究形成多晶颗粒的其他物质，以建立正确的颗粒扩大机制。
The onset of crystal nucleation was studied for seeded semibatch experiments in aqueous solutions in which either the feed rate, the seed size, or seed amount was varied. The results of these experiments show that the nucleation behavior of polycrystalline vaterite features striking similarities with monocrystalline particles in general. Investigations of the nucleation rate of vaterite during spontaneous precipitation experiments have revealed that it would take orders of magnitude higher supersatura lion values to obtain the particle numbers required for a proposed nanoaggregation process. The subunit "size" of polycrystalline vaterite is markedly different from particle to particle in seeded semibatch experiments in which nucleation occurred. Differences in the subunit "size" of particles formed under the same process conditions can hardly be explained by aggregation of precursor particles, as nanoaggregation would lead to a uniform distribution of nanoparticles among all particles. Crystal growth, on the other hand, can explain this phenomenon as it may depend on the underlying crystal surface and on the spherulite size. This points at spherulitic growth as the underlying particle enlargement mechanism. The same could be shown for spherulitcs of calcite for which the particle growth mechanism has been found to be dependent on the crystal surface structure. The current study suggests furthermore the performance of further studies concerning other substances forming polycrystalline particles to establish the correct particle enlargement mechanism.