用废弃大理石粉末和商业石灰石制备纳米CaCO_3填料及其改性用于造纸湿部

Preparation and modifi cation of nano calcium carbonate filer from waste marble dust and commercial limestone for papermaking wet end application

本研究的目的是制备低成本的纳米CaCO_3填料以应用在造纸湿部。通过湿碳化技术,纳米CaCO_3填料已经成功从商业石灰石和白色废弃大理石粉末中制备。阴离子(油酸钠)和阳离子表面活性剂(CTAB)用来改性制备的CaCO_3填料的尺寸、形态以及表面性能。制备的CaCO_3填料将应用在纸张中并且它们对纸张性能的影响也将被系统地研究。XRD和FTIR的结果揭示制备的CaCO_3填料是典型的方解石。TEM结果显示,填料制备过程中表面活性剂的存在很大程度上削弱了填料颗粒的尺寸并且将偏三角面形的填料表面形态改变到菱形的填料表面形态。研究发现,表面活性剂改性能够改善填料的留着以及提高所有的光学性能。与GCC相比,尽管填料留着比较高,但是纸张强度性能几乎没有改变,这显示了改性使填料颗粒和纤维间结合关系得到改善。油酸钠改性CaCO_3填料对其留着、加填纸张的表观密度、不透明度以及机械性能的影响比CTAB改性的大。纸张的SEM证实了这些结果,并且显示改性的纳米CaCO_3填料更容易截留以及与纤维的结合更加有效。除此以外,SEM图还表明纳米CaCO_3填料在纸张表面分布均匀。

The aim of this study was to prepare low cost CaCO3 nano-fillers for application on wet end papermaking. CaCO3 nano fillers have been successfully prepared from commercial limestone and white waste marble dust by wet carbonation technique. Anionic （sodium oleate） and cationic surfactants （CTAB） were used to modify the size, morphology and surface property of prepared CaCO3. The prepared CaCO3 fillers were used in paper hand-sheets and their impact on the quality of paper was systematically explored. The results obtained from XRD and FTIR indicated that the prepared CaCO3 particles were typically calcite. The addition of surfactant during the preparation greatly decreased the particle size and changed the morphology from scalenohedral to rhombohedral as illustrated from TEM results. The surfactant modification of filler improved the retention and consequently all the optical properties of paper significantly increased. However, despite the high retention values obtained compared with GCC, the strength properties were practically unchanged, indicating improved affinity between filler particles and fibres. CaCO3 modified with oleate showed higher effect on retention, apparent density, opacity, and mechanical properties than the CaCO3 modified with CTAB. The SEM images of paper hand-sheets confirmed the results and revealed that the modified nano CaCO3 are highly retained and more effectively adhered and bonded to pulp fibre, in addition to their uniform distribution on paper surface.