【摘要】 以聚丙烯酸钠(PAAS)为调控剂,采用化学沉淀法在室温下合成了亚微米级硫酸钡。采用扫描电子显微镜(SEM)、激光粒度分析仪、X射线衍射(XRD)仪对硫酸钡微粒的形貌、粒度分布和结构进行表征。研究了PAAS加入量对硫酸钡颗粒形貌和粒度分布的影响。以硫酸作为沉淀剂时,当PAAS加入量为硫酸钡理论产量的1.0%(质量分数)时,得到平均粒径为0.5μm的球形硫酸钡颗粒,并进一步探讨了PAAS的作用机理。Zeta电位测定结果显示,PAAS吸附到硫酸钡颗粒表面,翻转了颗粒表面的电性,使其带有较强的负电性。提出了硫酸钡颗粒固体-溶液界面的双电层模型。以硫酸铵作为沉淀剂时,副产物氨水(NH3·H2O)电离出的氢氧根(OH-)减缓了表面吸附层变薄的趋势,当PAAS加入量为硫酸钡理论产量的0.4%(质量分数)时,获得平均粒径为0.45μm的硫酸钡颗粒。更多还原

【Abstract】 Submicron BaSO4 particles were synthesized at room temperature by chemical precipitation method with sodium polyacrylate(PAAS) as the regulator.The morphology,size distribution, and structure of BaSO4 particles were characterized by scanning electron microscopy(SEM),laser particle size analyzer(LS-POP),and X-ray diffraction(XRD).The effect of the addition amount of PAAS on the morphology and size distribution of BaSO4 was investigated.When taking sulfuric acid as the precipitator and the mass ratio of PAAS to BaSO4 particles was 1.0%(mass fraction),the as-synthesized BaSO4 particles were spheres with an average particle size of 0.5 μm.And the action mechanism of PAAS was further discussed.Zeta potentials results indicated that the negatively charged groups of PAAS were adsorbed onto the particles surface,enhanced the negative potential and reversed the charge.The double electrical layer model of the solid-solution interface at a particle of BaSO4 was presented.When using(NH4)2SO4as precipitant,the OH-derived from the by-product NH3·H2O slowed down the thinning trend of surface adsorption layer and reduced the addition amount of PAAS;When the mass ratio of PAAS to BaSO4 particles was 0.4%,the average particle size of BaSO4 was 0.45 μm.更多还原