ABSTRACT This study focuses on the recovery of valuable metals, such as gold, silver, and copper, from the printed circuit boards of waste computers, using physical separation followed by leaching methods. Characterization studies revealed that resins and glass fibers were attached as grain together with base and precious metals. A hammer mill was employed as a second stage crusher to disintegrate the different components of the printed circuit board, thus improving the selectivity and recovery of metals. Separation studies using a laboratory-scale shaking table showed that 33% of the feed was removed as a light product and 96.8% of Au, 96.7% of Ag, and 97.7% of Cu were recovered in heavy fraction. Leaching the light fraction using 3 M H2SO4 and 0.33 M HNO3 at 80°C for two h resulted in greater than 90% extraction of Cu. Au and Ag were dissolved at room temperature with a leaching solution of 0.2 M S2O3 2-, 0.02 M CuSO4, and 0.2 M NH3.H2O, which provided a recovery of more than 59% of Au and 98% of Ag within eight h. Direct leaching tests using optimized conditions were also implemented on the crushed sample, and 45% of Au, 87.6% of Ag, and 70.8% of Cu were extracted.

中文翻译：

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重力分离浸出废印刷电路板贵金属回收

摘要 本研究的重点是利用物理分离和浸出方法从废弃计算机的印刷电路板中回收贵金属，如金、银和铜。表征研究表明，树脂和玻璃纤维以颗粒形式与贱金属和贵金属结合在一起。使用锤磨机作为第二级破碎机来分解印刷电路板的不同组件，从而提高金属的选择性和回收率。使用实验室规模的摇床进行的分离研究表明，33% 的进料作为轻质产品被去除，96.8% 的 Au、96.7% 的 Ag 和 97.7% 的 Cu 以重质馏分形式回收。使用 3 M H2SO4 和 0.33 M HNO3 在 80°C 下浸出轻质馏分两小时，铜的提取率超过 90%。Au 和 Ag 在室温下用 0.2 M S2O3 2-、0.02 M CuSO4 和 0.2 M NH3.H2O 的浸出溶液溶解，这在八小时内提供了超过 59% 的 Au 和 98% 的 Ag 的回收率。还对粉碎后的样品进行了优化条件的直接浸出试验，提取了45%的Au、87.6%的Ag和70.8%的Cu。