- 學位論文
在導電銀漿廢料中回收奈米銀之研究
The study of recovery silver Nano-particles from the scrap with conductive silver paste
摘要
由於貴金屬取得不易，因此回收再利用是取得貴金屬資源的一種方法，本研究以達方電子提供的薄膜式鍵盤中的導電銀漿線路做為回收的原料，利用高溫爐在600℃時將原料熱裂解移除高分子塑料及多餘的水分，得到的銀灰經研磨過篩後用濃硝酸將灰份製成粗硝酸銀溶液並以化學沉澱法將氯化物溶液加入硝酸銀中製成氯化銀沉澱，利用EDS與ICP-AES進行濃度計算及成分分析後，可以得到不含其他雜質的氯化銀且生成率在99%以上。加入氨水將氯化銀分別製成不同濃度的二氨銀錯離子溶液並以此溶液為回收奈米銀的前驅物。本實驗用化學還原法，嘗試製備穩定的高濃度奈米銀膠體溶液，以硼氫化鈉作為反應中的還原劑，配製不同的濃度找出適合的莫耳比，以十六烷基三甲基溴化銨為界面活性劑，改變濃度進行粒徑控制，得到的產物分別以XRD、UV-Vis、SEM、EDS、等進行分析。由UV的結果可以得到在波長400 nm處左右有特性吸收峰、XRD的結果可以得到回收的奈米銀顆粒具有結晶，SEM可以觀察到板狀及球狀的奈米銀顆粒，另外當還原劑與前驅物的莫耳比值為1.5時且CTAB為20 mM時，粒徑最小70 nm，回收率在99%以上。
並列摘要
According to the lack of noble metal resource becomes a serious problem now; recycle is a good way to get noble metal such as gold, silver, platinum and etc. In this study, we recycle silver resource from conductive silver paste which is the main conductor of electricity in the membrane of keyboard. In this research, we want to get silver nanoparticles from this membrane; chemical reduction is a cheap and easy method to get silver Nano-particles. After thermal treatment at 600℃, almost all polymers are removed. Add nitrate into the silver crap then the solution becomes silver nitrate. By using chemical precipitation method, this research can get the silver chloride precipitation from the reactant including silver nitrate and chloride. This study uses different molar concentration of Ag(NH3)2+, NaBH4 and CTAB to find a proper proportion preparing silver nanoparticles. This study analyses the final product by using XRD, SEM, UV-Vis, EDS, and ICP-AES. The XRD result shows that this research can successfully get silver nanoparticles with crystal structure from conductive silver paste. The result of UV-visible spectrometer shows that a characteristic absorbance peak around 400 nm in wavelength can be found. The particle size is around 70nm when the molar ratio of NaBH4 / Ag is 1.5 and the molar concentration of CTAB is 20mM. The conversion rate is above 99%.