14:45 〜 15:00
[1217] ヨウ素―ヨウ化物浸出と活性炭吸着による廃電子基板からの金の回収
司会: 所 千晴 (早大)
キーワード：金, ヨウ素－ヨウ化物, 吸着, 廃電子基板
In this article, a viable extraction method for recovery of gold from printed circuit board waste (PCBW) using iodine-iodide leaching followed by activated carbon adsorption is presented.
Preliminary tests revealed that the higher concentration of base metals (Cu, Al, Fe, Zn) in PCBW showed a negative effect on gold dissolution, hence a high pressure acid leaching was carried out using an toclave in order to remove base metals and upgrade gold in the PCBW. Dissolution of Cu, Al, Fe and Zn were 99.3 %, 82.3 %,61.2 % and 96.4 % respectively under the selected condition which were 1M of H2SO4,100 g/L of pulp density, 2 MPa of inner pressure at 120 °C for 30 min.
Dissolution behavior of gold from the solid residues of the pressure leaching into iodine-iodide solution was studied using various parameters such as iodine/iodide concentration, pulp density, leaching time and leaching temperature. Results from this study indicate that more than 99 % of gold was dissolved in the
solution from the residue under the optimized leaching condition which were established to be 2 g/L for iodine, 12 g/L for iodide, 500 rpm for stirring at 40 °C for 120 min.
Adsorption tests were conducted on pregnant solutions resulting from the iodine-iodide leaching using
activated carbon. Different adsorption parameters like iodine/iodide concentration, particle size of the carbon, carbon dosage, pH, shaking speed and temperature were investigated. The optimal condition on the adsorption was achieved using activated carbon with 75 µm size, 1 g/L carbon dosage, pH 3.2,
shaking speed of 140 rpm at 20 °C during 30 min. Under the condition the vast majority (more than 98 %) of gold was adsorbed onto the activated carbon from the pregnant solution.
Preliminary tests revealed that the higher concentration of base metals (Cu, Al, Fe, Zn) in PCBW showed a negative effect on gold dissolution, hence a high pressure acid leaching was carried out using an toclave in order to remove base metals and upgrade gold in the PCBW. Dissolution of Cu, Al, Fe and Zn were 99.3 %, 82.3 %,61.2 % and 96.4 % respectively under the selected condition which were 1M of H2SO4,100 g/L of pulp density, 2 MPa of inner pressure at 120 °C for 30 min.
Dissolution behavior of gold from the solid residues of the pressure leaching into iodine-iodide solution was studied using various parameters such as iodine/iodide concentration, pulp density, leaching time and leaching temperature. Results from this study indicate that more than 99 % of gold was dissolved in the
solution from the residue under the optimized leaching condition which were established to be 2 g/L for iodine, 12 g/L for iodide, 500 rpm for stirring at 40 °C for 120 min.
Adsorption tests were conducted on pregnant solutions resulting from the iodine-iodide leaching using
activated carbon. Different adsorption parameters like iodine/iodide concentration, particle size of the carbon, carbon dosage, pH, shaking speed and temperature were investigated. The optimal condition on the adsorption was achieved using activated carbon with 75 µm size, 1 g/L carbon dosage, pH 3.2,
shaking speed of 140 rpm at 20 °C during 30 min. Under the condition the vast majority (more than 98 %) of gold was adsorbed onto the activated carbon from the pregnant solution.
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