Recuperação de prata de células fotovoltaicas por meio de lixiviação ácida, precipitação química e precipitação eletroquímica

• Ano de defesa: 2019
• Autor(a) principal: Oliveira, Larisse Suzy Silva de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Espírito Santo; BR; Mestrado Profissional em Engenharia e Desenvolvimento Sustentável; Centro Tecnológico; UFES; Programa de Pós-Graduação em Engenharia e Desenvolvimento Sustentável
• Palavras-chave em Português: photovoltaic panel; silver; waste electrical and electronic equipment; acid leaching; painel fotovoltaico; prata; resíduo de equipamento eletroeletrônico; lixiviação ácida; Engenharia Sanitária; 628
• Link de acesso: http://repositorio.ufes.br/handle/10/11046

In recent years, due to the technological innovations that have brought about cost reductions, the growth of the photovoltaic sector has stood out among the renewable sources of energy. As a consequence, by the year 2050 it is estimated that 78 million tons of photovoltaic panels will need to be discarded in the world and about 750 thousand tons in Brazil alone. Silicon photovoltaic panels, most used worldwide, are composed of aluminum frame, tempered glass, silicon photovoltaic cell with metal filaments, encapsulating material and backsheet polymer material. The main metals present in the photovoltaic panels are: aluminum, zinc, lead, copper, indium, selenium, tellurium, cadmium and silver. Considering that the recycling should be stimulated from the environmental point of view and at the same time economically advantageous from an economic aspect, this study aimed to verify the technical viability of the silver recovery of photovoltaic cells using acid leaching, followed by the evaluation of the chemical and electrochemical precipitation processes to evaluate their efficiencies. To do so, the gravimetric composition of three photovoltaic panels and the concentration of metals (Ag, Al, Pb, Cu and Fe) in the photovoltaic cells were determined. Subsequently, the concentration factors of HNO3 (1-10M) and temperature (25-60ºC) in the silver leaching process were verified using the Rotational Central Compound Design (DCCR) method for the experimental design. Finally, for the best experimental conditions, it was verified the ideal reaction time and the best way to recover the silver present in the photovoltaic cells tested. After the statistical treatment of the results, it was possible to solubilize 100% of the silver contained in the photovoltaic cells, being the optimized parameters: temperature of 55ºC, concentration of HNO3 of 2,3M and reaction time of 2h. Chemical precipitation by addition of HCl as well as electroprecipitation made it possible to extract more than 99% of silver in solution. Thus, considering all the route used, the recovery of 99.98% of the silver present in the photovoltaic cells was obtained.