工艺条件对硝酸银溶液雾化热分解制备超细银粉的影响

以AgNO₃溶液为原料、柠檬酸为添加剂，在空气气氛下采用溶液雾化热分解法制备超细银粉.采用扫描电镜、激光粒度仪、振实密度测试仪、X射线衍射仪等对银粉进行了表征，系统地研究了反应温度、硝酸银溶液浓度、硝酸银溶液pH值、压缩空气流量、柠檬酸用量等工艺条件对产物银粉形貌、振实密度和平均粒径的影响.结果表明:在反应温度为700 ℃、硝酸银溶液浓度为2.0 mol/L、柠檬酸的添加量为2.5 %（摩尔比）、压缩空气流量为1.0 m3/h、硝酸银溶液pH值为6.0的条件下，可制备得到物相单一、表面光滑、分散性好的球形银粉，银粉的振实密度为4.24 g/cm3，平均粒径为3.16 μm. 

Effect of processing parameters on ultrafine silver particles prepared by spray-pyrolysis of AgNO3 solution

The ultrafine silver powders were prepared by solution spray-pyrolysis with citric acid as additive in air atmosphere using AgNO₃ solution as raw materials. The properties of the ultrafine silver powders were characterized with scanning electron microscope (SEM), laser particle size analyzer, tap density tester and X-ray diffraction (XRD). The effects of reaction temperature, concentration and pH value of AgNO₃ solutions, compressed air flow and amount of citric acid on the morphology, tap density and average particle size of silver powders, were investigated systematically. The optimum conditions are determined as follows: temperature of 700 ℃, solution concentration of 2.0 mol/L, n(C₆H₆O₇)/n(AgNO₃) of 2.5 %, compressed air flow of 1.0 m3/h, solution pH value of 6.0. Under these conditions, the pure and dispersive spherical silver particles with smooth surface, average particle size of 3.16 μm and tap density of 4.24 g/cm3, can be prepared.