Engineering Research Center of Ministry of Education for Geological Carbon Storage and Low Carbon Utilization of Resources, Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences (Beijing), Beijing 100083, China; Beijing Engineering Research Center of Process Pollution Control, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
Beijing Engineering Research Center of Process Pollution Control, Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.
Waste Manag. 2023 Jul 15;167:55-63. doi: 10.1016/j.wasman.2023.05.018. Epub 2023 May 26.
With the rapid development of the LED industry, gallium (Ga)-bearing waste generated is regarded as one of the most hazardous as it typically contains heavy metals and combustible organics. Traditional technologies are characterized by long processing routes, complex metal separation processes and significant secondary pollution emission. In this study, we proposed an innovative and green strategy to selectively recovery Ga from Ga-bearing waste by using a quantitative phase-controlling transition process. In the phase-controlling transition process, the gallium nitride (GaN) and indium (In) are converted to alkali-soluble gallium (III) oxide (GaO) and alkali-insoluble indium oxides (InO) by oxidation calcination, while nitrogen is converted into diatomic nitrogen gas instead of ammonia/ammonium (NH/NH). By selective leaching with NaOH solution, nearly 92.65% of Ga can be recycled with a leaching selectivity of 99.3%, while little emissions of NH/NH. GaO with a purity of 99.97% was obtained from the leachate which is also economy promising by economic assessment. Therefore, the proposed methodology compared to the conventional acid and alkali leaching methods is potentially greener and more efficient process for extracting valuable metals from nitrogen-bearing solid waste.
随着 LED 产业的快速发展，含镓（Ga）废物被认为是最危险的废物之一，因为它通常含有重金属和可燃有机物。传统技术的特点是处理路线长、金属分离过程复杂且二次污染排放严重。在本研究中，我们提出了一种创新的绿色策略，通过定量相控制转变过程从含 Ga 废物中选择性回收 Ga。在相控制转变过程中，氮化镓（GaN）和铟（In）通过氧化煅烧转化为可溶于碱的 Ga（III）氧化物（GaO）和不可溶于碱的铟氧化物（InO），而氮则转化为双原子氮气而不是氨/铵（NH/NH）。通过用 NaOH 溶液选择性浸出，近 92.65%的 Ga 可以被回收，浸出选择性为 99.3%，而 NH/NH 的排放量很少。浸出液中得到的 GaO 纯度为 99.97%，通过经济评估，该方法从含氮固体废物中提取有价值金属具有潜在的更绿色、更高效的工艺。
