【作者】 王超；

【导师】 杨保俊；

【作者基本信息】 合肥工业大学 ， 化学工程（专业学位）， 2018， 硕士

【摘要】 论文针对纳米CaCO3合成过程易发生团聚、粒径过大、粒度不均匀,以及未改性的纳米CaCO3亲水疏油等主要不足,在大量文献调研和实验室前期研究工作的基础上,采用CO2碳化法,以大宗工业固废电石渣为原料,着重开展较高Ca2+浓度、Ca2+-H2O-CO32-反应体系条件下纳米CaCO3的制备和改性过程的优化工艺条件研究,并对添加剂的作用机制进行了初步探讨。所开展的主要工作及所得主要结论如下:(1)筛选并确定STP+PEG为较适宜的复合添加剂,较适宜的纳米CaCO3制备工艺条件为:添加剂加量3%STP+1.5%PEG、反应温度25℃、CO2流率400mL·min-1、Ca2+初始浓度1mol·L-1、搅拌速率600rpm、陈化时间0min。此条件下所制得的碳酸钙粒径约45nm,粒度分布较均匀、分散性较好。(2)添加剂的作用机制分析认为:STP与PEG可能存在某种协同效应,降低了碳酸钙粒子的表面能,从而限制碳酸钙颗粒的生长,抑制碳酸钙粒子的团聚,降低碳酸钙样品平均晶粒尺寸。(3)筛选并确定油酸钠为较适宜的改性剂,确定纳米CaCO3改性较适宜的工艺条件:油酸钠用量2.5%、固液比8.5:100、改性时间120min、改性温度45℃,搅拌速率300rpm。改性后纳米碳酸钙各项指标为:碳酸钙质量分数96.2%、镁质量分数0.3%、水分0.3%、pH8.5、白度95%、比表面积19.1,符合国家标准GB/T 19590-2011中橡胶塑料用纳米碳酸钙要求。更多还原

【Abstract】 In this dissertation,in the view of the main deficiencies in the production of nano CaCO3,such as agglomeration,larger particle size,worse size distribution and the hydrophily and hydrophobicity of unmodified nano CaCO3,based on a large amount of literature and the previous research results,nano CaCO3 was prepared via carbonization method using CO2 and carbide slag as raw materials.The work focused on the optimization of the preparation and modification conditions of nano CaCO3 from Ca2+ solution with higher concentration under Ca2+-H2O-CO32-reaction system and the action mechanism of the additives was preliminarily studied.The main work and obtained results include:(1)STP and PEG was selected as the more appropriate compound additive.The preparation conditions of nano CaCO3 were investigated and optimized as follows:addition of additive 3%STP and 1.5%PEG,reaction temperature 25℃,CO2 flow rate 400mL·min-1,initial concentration of Ca2+ lmol·L-1,stirring rate 600rpm and aging time Omin.The nano CaCO3 obtained performed preferable dispersity with a diameter of about 45nm.(2)From the analysis,the action mechanism of the additives might be:a certain kind of synergistic effect between STP and PEG reduces the surface energy of CaCO3 particles,restraining the growth of CaCO3 particles,inhibiting its aggregation,and thus reducing the average grain size of CaCO3 samples.(3)Sodium oleate was selected as the more suitable modifier of CaCO3 and the modification conditions of nano CaCO3 were optimized as follows:addition of sodium oleate 2.5%,the mass ratio of solid to liquid 8.5:100,modification time 120 min,modification temperature 45℃ and stirring rate 300rpm.The main technical indexes of the modified nano CaCO3 was as follows:the content of CaCO3 96.2%,Mg content 0.3%,water content 0.3%,pH 8.5,whiteness 95%and BET specific surface area 19.1,which could meet the national standard requirements of nano CaCO3 for the use in rubber and plastics(GB/T 19590-2011).更多还原