Aplicação de planejamentos experimentais multivariados à lixiviação de cobre presente em placas de circuito impresso
Applying multivariate experimental design to copper leaching from printed circuit boards
Rodrigo Ferreira Gomes, Matheus Mello Pereira, Versiane Albis Leão
Resumo
O volume de Resíduos de Equipamentos Elétricos e Eletrônicos (REEE) gerados no mundo em 2018 foi de 50 milhões de toneladas. Cerca de 2% desses resíduos são Placas de Circuito Impresso (PCI) que possuem em sua composição metais nobres e base, sendo o cobre presente em teores de 10-20%. Além disso, também estão presentes metais tóxicos, tais como chumbo, cádmio e mercúrio, os quais podem acarretar grandes malefícios a natureza e a saúde humana. Portanto, a reciclagem de PCI é uma iniciativa importante, não só devido a questões ambientais, mas também a aspectos econômicos. Diante do exposto, o presente trabalho visou otimizar as variáveis (i) densidade de polpa, (ii) concentração de cloreto férrico hexahidratado, (iii) concentração de ácido clorídrico e (iv) tempo durante a lixiviação do cobre contido em PCI de computadores utilizando planejamentos experimentais multivariados. Os ensaios de lixiviação foram realizados em bateladas em um shaker, sob agitação de 150min-1 e temperatura de 25±1°C. As condições ótimas para a lixiviação de cobre foram densidade de polpa de 120g.L-1, concentrações de cloreto férrico hexahidratado e de ácido clorídrico de 1mol.L-1 e tempo de 40 minutos. Para a condição otimizada, a percentagem de lixiviação de cobre foi de 96,22±1,20%.
Palavras-chave
Abstract
The volume of Waste Electrical and Electronic Equipment (WEEE) produced worldwide in 2018 was 50 million tons. Around 2% of this waste is Printed Circuit Boards (PCB), which contain noble and base metals, with copper being the most abundant element (10-20%). Additionally, toxic metals as lead, cadmium and mercury are present, which can cause harmful effects to the environment and human health. Therefore, PCB recycling is an important initiative, not only due to environmental issues but also considering the economic aspects. This research aimed to optimize the variables (i) pulp density, (ii) concentration of ferric chloride hexahydrate, (iii) concentration of hydrochloric acid and (iv) time that influence the copper leaching process contained in PCB of computers through a multivariate experimental design. The leaching assays were carried out in batches, in a shaker, under stirring of 150min-1 and temperature of 25±1°C. The optimum conditions for copper leaching were pulp density of 120g.L-1, concentration of ferric chloride hexahydrate and hydrochloric acid of 1mol.L-1, and time of 40 minutes. For the optimized condition, the percentage of copper leaching was 96.22±1.20%.
Keywords
Referências
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Submetido em:
30/01/2019
Aceito em:
18/03/2020
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