Reclamation and Harmless Treatment of Waste Cathode Ray Tube Phosphors: Novel and Sustainable Design

• Published in: ACS sustainable chemistry & engineering Vol. 6; no. 3; pp. 4321 - 4329
• Main Authors: Yin, Xiaofei, Yu, Jiamei, Wu, Yufeng, Tian, Xiangmiao, Wang, Wei, Zhang, Yi-Nan, Zuo, Tieyong
• Format: Journal Article
• Language: English
• Published: American Chemical Society 05.03.2018
• Subjects: Sustainable design; Waste CRT phosphor; Recycling; Zn; Rare earths; SHS
• ISSN: 2168-0485; 2168-0485
• DOI: 10.1021/acssuschemeng.7b04796

In this paper, we propose a novel and sustainable process for recycling rare earths (REs) and zinc (Zn) simultaneously from waste cathode ray tube (CRT) phosphors. First, 95% of the impurities such as glass cullets and aluminum foils are removed by simple screening. Then, a self-propagating, high-temperature synthesis reaction following a water-leaching process is performed to recycle Zn selectively. The REs are recycled by a combined process of oxidative leaching and ionic-liquid-based extraction. They are then regenerated to form a new Y2O3:Eu3+ phosphor. By following this green recycling design, the recovery efficiencies of REs and Zn reach 99.5% and 99%, respectively. The negative bivalent sulfur in ZnS and Y2O3:Eu3+ is converted completely to SO4 2–, which efficiently avoids the secondary pollution. It should also be pointed out that the main recovery processes are all carried out at room temperature, and the “three wastes” emissions are minimized throughout the process. This work is expected to open new avenues for highly efficient, energy-saving, and pollution-reducing recovery processes for waste CRT phosphors.