%0 Generic %A Silva, Walner Costa %A Corrêa, Roger de Souza %A Gismonti, Pedro Rosário %A Afonso, Júlio Carlos %A Silva, Rubens Souza da %A Vianna, Cláudio Augusto %A Mantovano, José Luiz %D 2018 %T RECOVERY OF LEAD AND NOBLE METALS AFTER PROCESSING PRINTED CIRCUIT BOARDS FROM CELL PHONES BY LEACHING WITH MIXTURES CONTAINING HYDROGEN FLUORIDE %U https://scielo.figshare.com/articles/dataset/RECOVERY_OF_LEAD_AND_NOBLE_METALS_AFTER_PROCESSING_PRINTED_CIRCUIT_BOARDS_FROM_CELL_PHONES_BY_LEACHING_WITH_MIXTURES_CONTAINING_HYDROGEN_FLUORIDE/7243730 %R 10.6084/m9.figshare.7243730.v1 %2 https://scielo.figshare.com/ndownloader/files/13334942 %2 https://scielo.figshare.com/ndownloader/files/13334948 %2 https://scielo.figshare.com/ndownloader/files/13334954 %2 https://scielo.figshare.com/ndownloader/files/13334960 %2 https://scielo.figshare.com/ndownloader/files/13334966 %2 https://scielo.figshare.com/ndownloader/files/13334975 %2 https://scielo.figshare.com/ndownloader/files/13334984 %2 https://scielo.figshare.com/ndownloader/files/13334990 %2 https://scielo.figshare.com/ndownloader/files/13334999 %2 https://scielo.figshare.com/ndownloader/files/13335005 %2 https://scielo.figshare.com/ndownloader/files/13335011 %2 https://scielo.figshare.com/ndownloader/files/13335014 %2 https://scielo.figshare.com/ndownloader/files/13335017 %2 https://scielo.figshare.com/ndownloader/files/13335020 %K PCB %K metals recovery %K acidic leaching %K gold %K silver %K hydrofluoric acid %X

This work examines the leaching of printed circuit boards (PCBs) from cell phones in aqueous solutions containing HF + H2O2 or HF + NaClO under mild experimental conditions. The PCBs were not ground but were previously treated with 6 mol L-1 NaOH at 50 ºC for 1 h to remove their soldering mask. The HF + H2O2 mixtures leached copper and base metals (except lead) at 35-40 ºC, leaving a solid residue containing lead and noble metals. Leaching was fastest (1 h) when HF and H2O2 concentrations were at least 5 mol L-1 and 3 mol L-1, respectively. The processing of the solid residue is also described in detail. It was leached with water at ~90 ºC followed by HNO3aq. at 25 ºC. Lead, palladium and silver were recovered in this order, leaving gold as final solid. After 1 h at 35-40 ºC, 5 mol L-1 HF + 0.3 mol L-1 NaClO mixtures leached the base metals, copper, gold and palladium. Gold was recovered by liquid-liquid extraction with methyl isobutyl ketone. Silver precipitated as chloride. This salt was isolated by leaching with NH3aq. Loss of fluoride ions (as HF) was below 0.5 wt.% after leaching and handling the solid residue.

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