Banca de DEFESA: RAFFAEL ANDRADE COSTA DE MELO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : RAFFAEL ANDRADE COSTA DE MELO
DATA : 30/03/2017
HORA: 08:00
LOCAL: AUDITÓRIO DO NUPEG
TÍTULO:

"Study of leaching of printed circuit boards of obsolete desktops computers from the UFRN"

PALAVRAS-CHAVES:

Printed circuit boards, recycling, leaching.

 

PÁGINAS: 73
GRANDE ÁREA: Engenharias
ÁREA: Engenharia Química
RESUMO:

The reduction of mineral reserves and the growing concern of society with the environment and sustainability brings exciting prospects in the areas of recycling of waste electrical and electronic equipment (WEEE). Therefore, this paper aims to develop a route to recycle metals present on the printed circuit boards (PCB) of obsolete desktops computers. For this, leaching tests were performed using different acids (nitric, regal water, hydrochloric and sulfuric), varying the parameters of temperature and molar concentration of the acid following a complete factorial experimental design of the type 2² with repetitions at the central point to evaluate the efficiency of the process through the percentage of leached mass obtained by gravimetric analysis. Furthermore, the samples before and after the leaching tests were analyzed by FRX, MEV and EDS to identify and quantify the main chemical elements as well as the morphology of the PCB samples used. The best results obtained in percentage terms of leached mass were obtained for nitric acid and royal water. The worst results were obtained for hydrochloric acid and sulfuric acid. The statistical study of nitric acid showed that the molar concentration of the acid was the only factor that had a significant effect on the response variable, there was no lack of fit and the estimated coefficient of correlation (R²) was close to unity for a first order model for the range of the factors tested. However, for the royal water the acid molar concentration and the temperature/concentration interaction were the two factors that had a significant effect on the response variable and the best model was the second order. Finally, the FRX reviews demonstrated which elements were or were not leached by each acid. Regal water has shown ease in dissolving practically all metals. The nitric acid dissolved copper, lead and calcium. Already the hydrochloric and sulfuric acid did not leach copper well, but were efficient in the dissolution of tin, iron and nickel.  In general, each acid was selective for different chemical elements present in the composition of the PCB and for this reason a viable recycling route based on this study is possible.

 

 

 

MEMBROS DA BANCA:
Presidente - 349801 - CARLSON PEREIRA DE SOUZA
Interno - 2929066 - ANDRE LUIS LOPES MORIYAMA
Externo à Instituição - GILSON GARCIA DA SILVA - IFRN