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Doctoral Thesis
DOI
https://doi.org/10.11606/T.3.2022.tde-20122022-084742
Document
Author
Full name
Rafael Piumatti de Oliveira
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2022
Supervisor
Committee
Espinosa, Denise Crocce Romano (President)
Botelho Junior, Amilton Barbosa
Benvenuti, Jaqueline
Bertuol, Daniel Assumpção
Xavier, Lúcia Helena da Silva Maciel
Title in Portuguese
Recuperação de ítrio a partir de resíduo de lâmpadas de LED tubulares por rota hidrometalúrgica.
Keywords in Portuguese
Diodos emissores de luz
Hidrometalurgia
Ítrio
Mineração urbana
Terras raras
Abstract in Portuguese
As lâmpadas de LED atualmente dominam o mercado de iluminação gerando consequentemente um volume crescente de resíduos. A presença de metais críticos e de interesse econômico, como o Y, Ga, Cu, Au e a Ag, tornam o LED uma fonte de material secundário potencial, porém ainda inexplorada comercialmente. Vislumbrando motivar o tratamento do resíduo de lâmpadas de LED e favorecer sua valorização e reciclagem, o presente trabalho teve por objetivo a recuperação de Y a partir de lâmpadas LED por rota hidrometalúrgica. Para tal, foram realizadas a coleta e o desmantelamento; caracterização do resíduo; estudo do pré-processamento, extração e recuperação de metais. As lâmpadas tubulares de LED branco frio foram coletadas e desmanteladas para separação dos dispositivos LED. A caracterização dos dispositivos LED mostrou um teor (%m/m) de 0,5% de Y; 0,02% de Ga; 0,01% de Au; 0,16% Ag; 7% de Pb; 11% de Sn; 0,6% de Bi; 20% de Cu; 28% de Fe e 7% de Zn. O Y foi detectado em partículas de aluminato, encapsuladas em silicone. Portanto, foi adotada a fusão alcalina a 700°C por 3h, relação NaOH/LED 1:1 para o pré-processamento dos dispositivos LED. Por meio da lixiviação em HNO3 2,5 mol/L, por 20 min a 90°C, 91% do Y foi lixiviado. A purificação do licor foi realizada por extração por solventes, com 97% de extração do Y em CYANEX 923, diluído a 10% em querosene, pH 0,5, FA/FO 1:1, 25°C, em único estágio, e reextração de 98% do Y em HCl 4 mol/L, em dois estágios contracorrente, 25°C, FA/FO 1:1. A recuperação do Y foi realizada no licor purificado concentrado 10x por evaporação, através da precipitação como oxalato, obtendo-se o Y2O3 com 99,75% de pureza após calcinação a 800°C por 2h. Por fim, a rota hidrometalúrgica proposta permitiu a recuperação de 86,5% do Y, mostrando ser viável tecnicamente, possibilitando a reinserção do Y no mercado.
Title in English
Yttrium recovery from tubular LED lamps waste by hidrometallurgical route.
Keywords in English
Hydrometallurgy
Light emitting diodes
Rare earths
Urban mining
Yttrium
Abstract in English
LED lamps currently dominate the lighting market and consequently generate an increasing volume of waste. The presence of critical and economically interesting metals, such as Y, Ga, Cu, Au, and Ag, make LED a potential secondary raw material but still unexplored commercially. To motivate the treatment of LED lamp waste and favor its valorization and recycling, the present work aimed to recover Y from LED lamps by the hydrometallurgical route. To this end, the collection and dismantling; characterization of the residue; study of pre-processing, extraction, and recovery of metals were carried out. The cold white LED tubular lamps were collected and dismantled for separation from the LED devices. Characterization of the LED devices showed a content (%m/m) of 0.5% Y; 0.02% Ga; 0.01% Au; 0.16% Ag; 7% Pb; 11% Sn; 0.6% Bi; 20% Cu; 28% Fe and 7% Zn. Y was detected in aluminate particles encapsulated in silicon. Therefore, alkaline melting at 700°C for 3h, NaOH/LED ratio 1:1, was adopted for the pre-processing of the LED devices. By leaching in 2.5 mol/L HNO3 for 20 min at 90°C, 91% of Y was leached out. Purification of the liquor was performed by solvent extraction, with 97% extraction of Y in CYANEX 923, diluted to 10% in kerosene, pH 0.5, FA/FO 1:1, 25°C, single-stage, and re-extraction of 98% of Y in HCl 4 mol/L, two-stage countercurrent, 25°C, FA/FO 1:1. Y recovery was performed in the purified liquor concentrated 10x by evaporation, through precipitation as oxalate, obtaining Y2O3 with 99.75% purity after calcination at 800°C for 2h. Finally, the proposed hydrometallurgical route allows the recovery of 86.5% of Y, showing to be technically feasible, through the reinsertion of the metal into the market.
 
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Publishing Date
2022-12-20
 
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