以20 kg纳米碳酸钙熟浆、硅酸钠和硫酸为原料,在温度为90±10℃、转速为1 500 r/min下,进行中试放大试验生产CaCO₃@SiO₂纳米颗粒,对产品进行表征和性能测试;再以20 t纳米碳酸钙熟浆为原料进行5万t/a的产业化生产。所生产的产品为核壳结构的CaCO₃@SiO₂纳米颗粒,壳层是一厚度为5 nm左右的二氧化硅。与CaCO₃相比,CaCO₃@SiO₂纳米颗粒在空气中稳定性更好,在软PVC中应用,加工流动性、色差指标更优;在硅酮胶中应用,拉伸强度和模量指标有所提高,可以解决纳米碳酸钙应用中存在的黄变、分散、流动、机械强度等问题。

CaCO₃@SiO₂ nanoparticles are produced through pilot amplification test by using 20 kg of nano calcium carbonate pulp,sodium silicate and sulfuric acid solution as raw materials under 90±10℃ and 1,500 r·min^-1.The product is characterized and its performance is tested.Taking 20 tons of nano calcium carbonate pulp as raw material,50 000 t/a industrial production is performed.It is verified that the product is CaCO₃@SiO₂ nanoparticles with core-shell structure,and the shell of the particle is a layer of silica with a thickness of about 5 nm.Compared with nano CaCO₃,CaCO₃@SiO₂ has a better stability in the air,shows better processing fluidity and color difference indexes as it is used in soft PVC,and exhibits improved tensile strength and modulus indexes as it is applied in silicone adhesive.Some problems in the application of nano calcium carbonate,such as yellowing,dispersion,flow and mechanical strength,can be solved by using CaCO₃@SiO₂.