摘要
以硝酸银为原料,氨水为络合剂,抗坏血酸为还原剂,采用液相还原法及连续加料方式制备了球形超细银粉。采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、紫外-可见光谱仪(UV-Vis)等对银粉进行表征,考察了分散剂种类、抗坏血酸溶液初始p H值、温度以及加料速度对于银粉形貌、粒径、分散性和振实密度的影响,并讨论了阿拉伯树胶的分散机制。结果表明:阿拉伯树胶相比于其他分散剂具有更优的分散性能;抗坏血酸溶液初始p H值对银粉的粒径及其分布有较大的影响,p H≤4.0时,银粉粒径为0.6μm左右且粒径分布较窄,p H>4.0时,银粉粒径为0.7μm左右且粒径分布较宽;加料速度对银粉粒径和振实密度影响较大,随着加料速度的增加,银粉粒径减小,振实密度先增大后减小;在抗坏血酸溶液初始p H值为2.45,反应温度30℃,加料速度133.3 ml·min-1的条件下,制备出了分散性好,平均粒径为0.73μm,振实密度为4.3 g·cm-3的球形超细银粉。
Spherical uhrafine silver powders were prepared by liquid-phase reduction method with continuous feeding mode using sil- ver nitrate as raw silver source, aqueous ammonia as complexing agent, ascorbic acid as reducing agent. The properties of the uhrafine silver powders were characterized by scanning electron microscope （SEM） , X-ray diffraction （XRD） and ultraviolet-visible （UV-Vis） absorption spectrum analyzer. The effects of different dispersants, initial pH value of ascorbic acid solution, reaction temperature and feeding speed on the morphology, mean particle size, dispersity and tap density of uhrafine silver powders were investigated. The results showed that the gum arabic had better dispersity than other dispersants, and the mechanism of dispersion was discussed. The initial pH value of aseorbie acid solution had a great influence on particle size and distribution of silver powders, the particle size was about 0.6 μm and the distribution was narrow with pHi〈4.0, while the particle size was about 0.7 μm and the distribution was wide with pH 〉 4.0. The feeding speed had a great influence on the particle size and tap density, the particle size of silver powder decreased and the tap density of silver powder increased at first then decreased with the feeding speed increasing. Spherical silver powder with good dispersibility, particle size of 0.73 μm and tap density of 4.3 g·cm-3 could be obtained under conditions with the pH of 2.45, the temperature of 30 ℃ and the feeding speed of 133.3 ml·min-1.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2015年第9期818-825,共8页
Chinese Journal of Rare Metals
基金
国家国际科技合作专项项目(2014DFA90520)
广东省产学研项目(2013A100003)
湖北大冶有色科技计划项目(2014DY048)资助
关键词
超细银粉
液相还原
阿拉伯树胶
振实密度
uhrafine silver powder
liquid-phase reduction
gum arabic
tap density
