Hydrometallurgical treatment of used printed circuit boards after thermal treatment

Abstract

The hydrometallurgical route of copper and tin extraction from printed circuit boards (PCB) of used personal computers after thermal pretreatment is discussed. The PCB fractions crushed and sorted into −8 + 0, −8 + 3 and −3 + 0 mm were used for the experiments. The samples were thermally pretreated at temperatures of 300, 500, 700 and 900 °C during 15, 30 and 60 min with the presence of air (burning) before the leaching process. The leaching solution of 1 M HCl and temperature of 80 °C was used for the leaching. The original as well as thermally pretreated samples were leached under these conditions. The weight losses within the range from 5% to 35% were achieved by burning depending on the burning temperature. The increase of burning temperature causes the copper extraction into solution up to 98%, while copper extraction into solution from non-burned samples was up to 6%. The opposite effect was observed in the case of the tin leaching, where the highest extraction was achieved when the original sample was leached. The increase of the burning temperature caused the lowering of the copper extraction.