纳米CaCO_3的室温固相合成及三聚磷酸钠的控制机理

Synthesis and Characterization of CaCO_3 Nano-powders by Solid State Reaction at Room Temperature and Controlling Mechanism of Na_5P_3O_(10)

以Ca(NO3)2.4H2O和Na2CO3.10H2O为原料,采用室温固相反应合成出粒径为19nm的CaCO3,BET比表面积为36.3m2.g-1。反应中Na5P3O10能有效地抑制CaCO3晶体的生长和团聚。其作用在于Na5P3O10电离产生的离子可进入CaCO3晶格位置或选择性地吸附在CaCO3的晶面上,从而降低了CaCO3的表面能。当CaCO3的活性部位被完全包覆时,继续增加Na5P3O10用量,将不再抑制CaCO3的生长。

CaCO_(3) nano-powders were first prepared by the solid state reaction of Ca(NO_(3))_(2)4H_(2)O with (Na_2CO_3)10H_2O and additive Na_(5)P_(3)O_(10) at room temperature. The results showed that the nano-powders had average particle size of 19 nm and BET specific surface area of 36.3 m^(2)g^(-1). In this reaction, (Na_5P_3O_(10)) could effectively prohibit CaCO_(3) crystal growth and aggregate. The ions produced due to the electroionization of the (Na_5P_3O_(10)) could occupy the CaCO_(3) lattice-sites, or be Absorbed on CaCO_(3) crystal faces, therefore change the CaCO_(3) crystal surface energy. When the additive or cleaning amount was large enough to cover active sites on crystal faces, the increasing of additive or cleaning concentration could not further inhabit crystal growth.