Recuperação hidrometalúrgica do cobre a partir de placas de circuito impresso de computadores descartados

Abstract

Discard, residue, reject, rubble, detritus, remainder, leftover, excrement. Whatever the name, garbage has always been a human problem since early days. With the sedentism of prehistoric man and, later, the set of factors called industrial revolution, chain production and increased consumption, waste production grown up to alarming levels. Among them, electronic waste stands out, which is a type of waste composed of electrical circuits or components with a battery or electrical connection. In this class of waste, it is usual to find what is called a printed circuit board (PCB), which is the basis of any electronics. PCBs have metallic circuits in their structure where the main component is copper. Thus, given the need to reintroduce electronic waste into society's production chain, the hydrometallurgical recovery of copper from discarded computer PCBs was studied. Serial leachings were performed, one acid followed by another acid with oxidizing agent, with final volumes of 150 mL and 250 mL. The leach liquors were analyzed by an inductively coupled plasma - optical emission spectrometer (ICP-OES) and also by an energy dispersive x-ray fluorescence (EDXRF) equipment, which showed the presence of the following metals: Ag, Al, As, B, Ca, Cd, Cl, Cr, Cu, Fe, Hg, Gd, K, Li, Ni, Pb, Rb, Si, Sn, Ti, Tl and Zn. The PCB in natura and the leach pulps were analyzed by EDXRF and the following metals were found: Ag, Al, As, Ba, Br, Ca, Cl, Cr, Cu, Fe, Hg, Ni, Pb, Rb, Si. Sn, St, Ti and Tl. The copper extraction in g of element per kg of PCI was calculated and the values of 42.875 g/kg and 82.398 g/kg were found for the respective final volumes of 150 mL and 250 mL. Furthermore, in the pricing of metals present in the leach liquor, copper was the metal that most contributed to the added value of the liquor.