Lu Xin, Miki Takahiro, Takeda Osamu, Zhu Hongmin, Nagasaka Tetsuya
Graduate School of Engineering, Tohoku University, Miyagi, Japan.
Sci Technol Adv Mater. 2019 Jul 10;20(1):813-825. doi: 10.1080/14686996.2019.1641429. eCollection 2019.
The collected end-of-life (EoL) silicon wafers from the discharged photovoltaic (PV) panels are easily contaminated by impurities such as doping elements and attached materials. In this study, the thermodynamic criteria for EoL silicon wafers refining using three most typical metallurgical refining processes: oxidation refining, evaporation refining, and solvent refining were systemically and quantitatively evaluated. A total of 42 elements (Ag, Al, Au, B, Be, Bi, C, Ca, Ce, Co, Cr, Cu, Fe, Ga, Gd, Ge, Hf, In, La, Mg, Mn, Mo, Na, Nb, Ni, Os, P, Pb, Pd, Pt, Re, Ru, Sb, Sn, Ta, Ti, U, V, W, Y, Zn, Zr) that are likely to be contained in the collected EoL silicon-based PV panels were considered. The principal findings are that the removal of aluminum, beryllium, boron, calcium, gadolinium, hafnium, uranium, yttrium, and zirconium into the slag, and removal of antimony, bismuth, carbon, lead, magnesium, phosphorus, silver, sodium, and zinc into vapor phase is possible. Further, solvent refining process using aluminum, copper, and zinc as the solvent metals, among the considered 14 potential ones, was found to be efficient for the EoL silicon wafers refining. Particularly, purification of the phosphorus doped -type PV panels using solvent metal zinc and purification of the boron doped -type PV panels using solvent metal aluminum are preferable. The efficiency of metallurgical processes for separating most of the impurity elements was demonstrated, and to promote the recycling efficiency, a comprehensive management and recycling system considering the metallurgical criteria of EoL silicon wafers refining is critical.
从退役光伏（PV）面板收集的报废（EoL）硅片很容易被诸如掺杂元素和附着材料等杂质污染。在本研究中，系统地、定量地评估了使用三种最典型的冶金精炼工艺（氧化精炼、蒸发精炼和溶剂精炼）对报废硅片进行精炼的热力学标准。总共考虑了42种可能包含在收集的基于硅的报废光伏面板中的元素（银、铝、金、硼、铍、铋、碳、钙、铈、钴、铬、铜、铁、镓、钆、锗、铪、铟、镧、镁、锰、钼、钠、铌、镍、锇、磷、铅、钯、铂、铼、钌、锑、锡、钽、钛、铀、钒、钨、钇、锌、锆）。主要研究结果是，铝、铍、硼、钙、钆、铪、铀、钇和锆可以进入炉渣中去除，锑、铋、碳、铅、镁、磷、银、钠和锌可以进入气相中去除。此外，在所考虑的14种潜在溶剂金属中，使用铝、铜和锌作为溶剂金属的溶剂精炼工艺被发现对报废硅片精炼是有效的。特别是，使用溶剂金属锌对磷掺杂型光伏面板进行提纯，以及使用溶剂金属铝对硼掺杂型光伏面板进行提纯是优选的。证明了冶金工艺分离大多数杂质元素的效率，为提高回收效率，考虑报废硅片精炼冶金标准的综合管理和回收系统至关重要。
