废感光胶片制备超细银粉的研究

Preparation of Superfine Silver Powder from Waste Photosensitive Film

以废感光胶片为原料采用硝酸溶解法浸取并制备高纯度银。再以抗坏血酸为还原剂,大分子(PVP)-表面活性剂(TEA)复合体系为分散剂制备出粒径可控的球形超细银粉。结果表明:在硝酸浓度1.6 mol·L-1,浸取温度50℃,浸取时间10 min,浸取3次条件下,浸取效果好且可得到含量高于99.5%的高纯银。当反应温度为20℃,硝酸银溶液pH值为8,硝酸银浓度为0.02 mol·L-1,m(PVP)/m(AgNO3)>4.5,m(TEA)/m(AgNO3)=1,可得到粒度均匀、形状规则、分散性好、粒径为0.15μm左右的球形超细银粉。

The high purity silver was leaching-out and prepared using a nitric acid dissolution method from waste photosensitive film.The grain size controllable spherical ultrafine silver was prepared with ascorbic acid as reducing agent,macromolecules （PVP） and surfactant （TEA） as dispersant.The results show that the leaching effect is good,and high-purity 99.5％ silver of higher content can be obtained when the concentration of nitric acid is 1.6 mol·L-1,the leaching temperature is 50 ℃,and the leaching is 10 min and 3 times.Superfine silver powder of uniform size 0.15 μm,regular shape and good dispersion can be prepared when the reaction temperature is 20 ℃,pH value of silver nitrate solution is 8,the concentration of silver nitrate is 0.02 mol·L-1,the m（PVP）/m（AgNO3）＞4.5 and m（TEA）/m（AgNO3）=1.