Graduate Institute of Environmental Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei, 10617, Taiwan, ROC.
Graduate Institute of Environmental Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei, 10617, Taiwan, ROC; Water Innovation, Low Carbon and Environmental Sustainability Research Center, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei, 10617, Taiwan, ROC.
Chemosphere. 2021 Oct;280:130905. doi: 10.1016/j.chemosphere.2021.130905. Epub 2021 May 17.
Indium recovery from spent liquid crystal displays (LCDs) of monitors was studied by using microwave pyrolysis as a pretreatment step prior to hydrometallurgical processes including acid leaching, solvent extraction, and stripping. After microwave pyrolysis at 150 W for a processing time of 50 min, the hydrometallurgical processes were carried out to sequentially solubilize and increase the purity of indium ions in the product solution. The leaching efficiency of indium was approximately 98% when using 0.5 M of sulfuric acid at a solid-to-liquid ratio (S/L) of 0.1 g/mL. Afterwards, the indium ions in the leachate were extracted by using 20% di(2-ethylhexyl)phosphoric acid (D2EHPA) in kerosene. The purity of indium ions in the organic phase was approximately 87% at an oil-to-aqueous ratio (O/A) of 1/10. Finally, the indium ions in the extract were stripped by using 6 M of hydrochloric acid at an O/A ratio of 10/1. The purity of indium ions in the aqueous phase was as high as 99.98%. The final recovery rate of indium from spent LCDs was approximately 75%, substantially higher than those that were obtained by using shredding or grinding pretreatment. The maximum processing capacity of microwave pyrolysis of spent LCDs could be approximately 500 g, which means that it would only need 0.5 kWh of electricity for the microwave pyrolysis of 1 kg of spent LCDs. According to the experimental results and advantages, it can be concluded that microwave pyrolysis is an effective technique for the pretreatment of spent LCDs.
采用微波热解作为预处理步骤，对显示器废液晶显示器（LCD）中的铟进行了回收研究，然后进行湿法冶金工艺，包括酸浸、溶剂萃取和反萃。在 150 W 微波功率下处理 50 min 后，进行湿法冶金工艺，以顺序溶解并提高产品溶液中铟离子的纯度。当使用 0.5 M 硫酸，固液比（S/L）为 0.1 g/mL 时，铟的浸出率约为 98%。然后，使用 20%的二（2-乙基己基）磷酸（D2EHPA）在煤油中萃取浸出液中的铟离子。当油相与水相（O/A）比为 1/10 时，有机相中铟离子的纯度约为 87%。最后，使用 6 M 的盐酸在 O/A 比为 10/1 的条件下从萃取相中反萃铟离子。水相中铟离子的纯度高达 99.98%。从废 LCD 中回收铟的最终回收率约为 75%，远高于使用粉碎或研磨预处理的回收率。废 LCD 微波热解的最大处理能力约为 500 g，这意味着每公斤废 LCD 的微波热解仅需 0.5 kWh 的电力。根据实验结果和优势，可以得出结论，微波热解是处理废 LCD 的有效技术。
