Sisa elektrikal dan elektronik (e-sisa) yang semakin banyak dalam negara and antarabangsa mendesak keperluan untuk kitar semula. Permintaan emas semakin meningkat. Sumber bekalanya semakin kurang. Pemulihan logam berbaloi ini dari e-sisa melalui larut lesap thiourea dan elektropengenapan berpotensi menjadi alternatif untuk mengganti larut lesap sianida. Larut lesap sianida menghasilkan larutan akueus yang bertoksik tetapi masih digunakan secara meluas dalam industri pemulihan logam. Kajian hanya tertumpu kepada larut lesap tetapi kurang dalam aspek pemulihan terutamanya pengenapan. E-sisa diimbaskan bawah X-ray Pendarfluor (XRF) dan tembaga adalah spesies yang paling banyak di dalamnya. Voltammetri Berkitar (CV) kajian tembaga diperlukan dalam sistem thiourea yang berasid untuk menentukan potensi pengurangan. Potensi perlu ditetapkan bagi mengelakkan pengurangan tembaga dan meningkatkan pemendapan emas pada katod. Elektropengenapan dilakukan dengan menggunakan sistem dua elektrod yang diperbuat daripada keluli tahan karat 316 dalam sistem thiourea berasid mengandungi jalur emas dengan perubahan parameter yang berbeza iaitu tempoh proses, voltan dan suhu. Deposit pada katod dicirikan melalui Tenaga serakan X-ray Spektroskopi (EDX) dan larutan akueus itu dihantar untuk analisis Pasangan Plasma Induktif (ICP) selepas eksperimen. Elektropengenapan berlaku secara optimum pada 2.0V dan 80˚C apabila proses itu berlaku selama 45 minit. Larut lesap dan elektropengenapan yang menggunakan sampel e-waste sebenar dilakukan dengan parameter optimum. Kaedah pertama dijalankan melalui larut lesap sampel diikuti oleh elektropengenapan. Kaedah kedua adalah larut lesap langsung dan pengenapan secara serentak. Jumlah emas dipulihkan melalui kaedah kedua adalah 0.0003g, lebih kurang sepuluh kali lebih tinggi dengan kaedah pertama.
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E-waste is heaping domestically and globally urging a need for recycling it. Accompanying increasing demand and diminishing supply of precious elements especially gold, recovery from e-waste via TU leaching and electrodeposition is seen as a promising alternative to cyanide leaching. The latter is known for being toxic but still used extensively in metal recovery industries. Studies have always been focused on leaching instead of recovery particularly electrodeposition. E-waste was put under X-ray Fluorescence (XRF) scanning and copper was the most abundant species in it contributing 38.8% among the metals present, leading to Cyclic Voltammetry (CV) studies of copper in acidic-thiourea system to determine its reduction potential. The applied potential was set to avoid copper reduction but promoted gold deposition on cathode. Electrodeposition was done using a two-electrode system made of stainless steel 316 in acidic thiourea system containing a gold strip with variation of different parameter i.e. duration of process, applied potential and temperature. Deposits on cathode were characterised through Energy Dispersive X-ray Spectroscopy (EDX) and the solution was sent for Inductively Coupled Plasma (ICP) analysis after the experiment. Electrodeposition was found to be optimum at 2.0V and 80˚C when the process was allowed to occur for 45 minutes. The amount of gold obtained was the highest i.e. 0.0181g when the experiment was carried out at ambient temperature and 3.0V for 60 minutes. E-waste samples were then used in two different methods of recovering gold. The first method was carried out by leaching the sample followed by electrodeposition with the second one being direct leaching and electrodeposition. The amount of gold recovered via the second method was 0.0003g which was about ten times higher compared the one obtained through the first method.
Electrodeposition study of thiourea based leaching solution for gold recovery in e-waste / Chow Lily