Determinação de metais disponibilizados por lixiviações ácidas em placas de circuito impresso

Abstract

The availability of electrical and electronic equipment grows proportionately with technological advances, making them easily accessible, which has led to an ideology of rapid disposal, producing an increase in the accumulation of waste and generating a major environmental problem, since there is no policy of effective recycling, nor popular collection sites for their correct disposal. In this way, the present work had as objectives the application and study of acid leaching in printed circuit boards from equipment that became obsolete, in order to make available the metals present in its composition, aiming at a future recovery process. Two types of plates were analyzed, one from a notebook (TYPE 1) and another from five cell phones of the same model (TYPE 2), both types were subjected to leaching with hydrochloric acid, nitric acid and aqua regia, during a period of 24 hours. The liquors obtained from the leaching were characterized using the optical emission spectrometric technique with inductively coupled plasma, which proved to be efficient in the identification and quantization of metals, revealing a similar composition between the two types of plates, evidencing that segregation is not necessary. in a large-scale application. Regarding the leaching used, it was concluded that hydrochloric acid is a weak leaching agent and that nitric acid and aqua regia show good performance in the availability of metals such as aluminum, copper, nickel, tin, zinc, among others. Among the analyzed leachates, nitric acid showed an advantage over the others, due to its high efficiency in copper recovery, which among the analyzed metals, is the main metal of interest at the industrial level, of which 22.68% was available ( m/m) on the notebook board and 25.78% (m/m) on the cell phone boards.