硬脂酸钠对重质碳酸钙的干法改性研究

Study on Dry Modification of Heavy Calcium Carbonate by Sodium Stearate

以咸丰重质碳酸钙为原料,硬脂酸钠为改性剂,采用干法改性制备了改性重质碳酸钙。采用正交试验设计探讨了改性温度、改性剂用量、改性时间和搅拌转速对重质碳酸钙改性效果的影响,利用FT-IR、XRD、SEM、Zeta电位对重质碳酸钙进行表征。结果分析表明,当改性温度为70℃,硬脂酸钠用量为咸丰重质碳酸钙质量的1.5%,改性时间为50 min,转速为700r/min时,硬脂酸钠改性咸丰重质碳酸钙的活化率为85.6%,改性效果较好。经过硬脂酸钠改性重质碳酸钙的红外光谱在2850cm-1和2920cm-1处出现了-CH2-对称伸缩振动和反对称伸缩振动峰,X-射线特征衍射峰向高角度偏移,Zeta电位从14.1mV提高到30.2mV,粒径较小,说明硬脂酸钠已接枝到重质碳酸钙表面,但改性并未改变碳酸钙晶型,改性重质碳酸钙具有良好的分散性。

The modified heavy calcium carbonate was prepared by dry modification with heavy calcium carbonate from Xianfeng as raw material and sodium stearate as modifier.The effects of modification temperature,amount of modifier,modification time and stirring speed on the modification of modified heavy calcium carbonate were investigated by orthogonal test design.The heavy calcium carbonate was characterized by using Fourier transform infrared spectra(FTIR),X-Ray powder diffraction(XRD),scanning electron microscopy(SEM)and Zeta potential.The results showed that when the modification temperature was 70℃,the amount of sodium stearate was 1.5%of the quality of heavy calcium carbonate from Xianfeng,the modification time was 50min,and the speed was 700r/min,the activation rate of modified Xianfeng heavy calcium carbonate by sodium stearate was highest,reaching 85.6%.The results showed that CH2 symmetric and antisymmetric stretching vibration peaks appeared at 2850cm-1 and 2920cm-1 of sodium stearate modified heavy calcium carbonate from FT-IR spectra,the characteristic diffraction peaks of modified heavy calcium carbonate shifted to a high angle from X-Ray powder diffraction and the Zeta potential of the modified heavy calcium carbonate was increased from 14.1mV to 30.2mV,the particle size of the modified heavy calcium carbonate was small,which indicated that the sodium stearate had been grafted onto the surface of heavy calcium carbonate,but the modification did not change the phase of calcium carbonate,the and the modified heavy calcium carbonate had good dispersion.