title: Innovative Application of Mechanical Activation for Rare Earth Elements Recovering: Process Optimization and Mechanism Exploration.
abstract: With the rapidly expanding use of fluorescent lamps (FLs) and increasing interest in conservation and sustainable utilization of critical metals such as rare earth elements (REEs), the recovering of REEs from phosphors in waste FLs is becoming a critical environmental and economic issue. To effectively recycle REEs with metallurgical methods, mechanical activation by ball milling was introduced to pretreat the waste phosphors. This current study put the emphasis on the mechanical activation and leaching processes for REEs, and explored the feasibility of the method from both theoretical and practical standpoints. Results showed physicochemical changes of structural destruction and particle size reduction after mechanical activation, leading to the easy dissolution of REEs in the activated samples. Under optimal conditions, dissolution yields of 89.4%, 93.1% and 94.6% for Tb, Eu and Y, respectively, were achieved from activated waste phosphors using hydrochloric acid as the dissolution agent. The shrinking core model proved to be the most applicable for the leaching procedure, with an apparent activation energy of 10.96 ± 2.79 kJ/mol. This novel process indicates that mechanical activation is an efficient method for recovering REEs from waste phosphors, and it has promising potential for REE recovery with low cost and high efficiency.
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China.
authors.forename: Quanyin
authors.initials: Q
authors.lastname: Tan
authors.affiliation: Basel Convention Regional Centre for Training and Technology Transfer for Asia and the Pacific, Beijing 100084, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Deng
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China.
authors.forename: Jinhui
authors.initials: J
authors.lastname: Li
references.citation: Environ Sci Process Impacts. 2015 Sep;17(9):1522-30
references.pmid: 26283597
references.citation: Waste Manag. 2014 Jul;34(7):1237-50
references.pmid: 24613592
references.citation: Nature. 2014 Jan 2;505(7481):19-20
references.pmid: 24380940
references.citation: J Air Waste Manag Assoc. 2013 Jan;63(1):2-10
references.pmid: 23447859
references.citation: J AOAC Int. 2014 Jan-Feb;97(1):3-11
references.pmid: 24672854
references.citation: J Hazard Mater. 2005 Aug 31;123(1-3):112-9
references.pmid: 15993295
references.citation: Waste Manag. 2011 Dec;31(12):2559-68
references.pmid: 21840197
references.citation: Environ Sci Technol. 2012 Jun 5;46(11):6020-7
references.pmid: 22550973
references.citation: Waste Manag. 2003;23(10):879-86
references.pmid: 14614922
references.citation: J Hazard Mater. 2013 Jun 15;254-255:79-88
references.pmid: 23587931
references.citation: Waste Manag. 2013 Nov;33(11):2390-6
references.pmid: 23831004
references.citation: J Hazard Mater. 2014 May 15;272:96-101
references.pmid: 24681591
references.citation: Environ Sci Technol. 2015 May 19;49(10):5849-61
references.pmid: 25884338
references.citation: Environ Sci Technol. 2012 Apr 3;46(7):4109-14
references.pmid: 22385285
references.citation: Science. 2012 Aug 10;337(6095):690-5
references.pmid: 22879508
references.citation: Anal Methods. 2013 Mar 28;5(8):1901-1903
references.pmid: 33985300
references.citation: Waste Manag. 2008;28(2):318-25
references.pmid: 17566725
references.citation: Chem Soc Rev. 2014 Apr 21;43(8):2451-75
references.pmid: 24464346