ZHU Tianxiao1,XU Linchong1,ZHU Yong2,BAI Lijuan1,YUAN Aiqun1,HUANG Zengwei1
(1.School of Chemistry and Chemical Engineering,Guangxi University for Nationalities,Nanning 530006,China；2.Guangxi Huana New Material Technology Co.,Ltd.,Nanning 530103,China)
Abstract:Core-shell structure CaCO3@SiO2 was prepared by parallel flow method using heavy calcium carbonate(CaCO3)as core and sodium silicate as shell silicon source.The single factor method was used to study the influence of process parameters such as reaction temperature,reaction time,pH,calcium carbonate initial mass concentration,silica mass fraction,aging time,stirring rate,etc.on the acid resistance of the core-shell structure.The process parameters were optimized to reduce the acid solubility of the product and improve the acid resistance of calcium carbonate.CaCO3@SiO2products were characterized by SEM,TEM,XRD,XPS,FT-IR.The kinetic analysis of shell silica growth under different pH conditions was explored.The results show that when the reaction temperature is 90 ℃,the reaction time is 120 min,the pH is from 9.5 to 10,the initial mass concentration of calcium carbonate is 100 g/L,the mass fraction of silica is 6%,the aging time is 36 h and the stirring rate is 250 r/min,the acid solubility of prepared CaCO3@SiO2 can reach the lowest value of 17.92%.The surface of calcium carbonate particles is a kind of amorphous silica nanoshell and is bonded to the surface with Ca—O—Si.The pH has a great influence on the growth of silica on the surface of calcium carbonate.When the pH is 10,the growth rate of the shell layer is about twice that when the pH is 7.
Keywords:calcium carbonate coated withsilica；core-shell structure；calcium carbonate；growth dynamics
中图分类号： TQ623 文献标志码：A
文章编号：1008-5548(2022)04-0043-11
DOI:10.13732/j.issn.1008-5548.2022.04.005
收稿日期： 2021-06-28， 修回日期：2021-12-23，在线出版时间：2022-06-22。
基金项目：国家自然科学基金项目，编号：21666006。
第一作者简介：朱天孝(1997—)，女，硕士研究生，研究方向为材料化学。E-mail：781805634@qq.com。
通信作者简介：黄增尉(1971—)，男，高级实验师，硕士，硕士生导师，研究方向为材料化学。E-mail：87526612@qq.com。
