Application of Hydro-Metallurgy (Wet Etching) To Recovery A Precise Metal (Gold) From A Wasted Printed Circuit Broad (WPCB): Case Study of Ministry of Information Communication and Technology (MICT)
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Date
2017-11
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Addis Ababa University
Abstract
This thesis research is undertaken with the main objective of assessing the existing e-waste management in Ethiopia by taking ministry of information and communication technology as a case study and to propose e-waste recycling approach (hydrometallurgy) to recover gold. To meet the research objectives a blend of qualitative and quantitative methods were used where unstructured key informant interviews, Observation of the e-waste disposal site from the selected govermental organization and computer recycling and refurbishment center (CRTC) at Kality were combined with Case study at laboratory scale hydro-metallurgy to recover gold from waste printed circuit boards (PCB).It is found that E-waste is expected to be a huge problem in the future, given the rise in consumption trend of the target institutions and the general importation trend of the country. There is high accumulation of old ICT equipment in the target institutions of the study. Parallel to that, The current trend of lifecycle management of this electronic waste at CRTC and at Addis Ababa University is out date and the precious metals like that of gold are not properly recycled.in addition by applying hydrometallurgical approach (wet etching), from a sample of 500 gm printed circuit board 1.66 gm of gold was recovered with mineral composition of 99.71% Au, 0.12% Ni,0.16% Cu. this research under takes an experimental procedure where, At the start of the experiment 20 gram of fingers was used for on batch. And added to on an empty beaker. The next step will be dilution of the hydrochloric acid, hydrochloric acid with the concentration of 35% will be diluted by adding 57 ml of water on the biker. Finally we can get hydrochloric acid with the concentration of 15% with a volume of 43 ml. next the addition of hydrogen per oxide which has a concentration of 15% with a volume of 50 ml and the reaction proceeds for 6hr after that The combination of hydrochloric acid and hydrogen per oxide will detached the gold fingers from the silicon chips and a film of gold fingers will float, finally Using kitchen strainer and a large coffee filter the gold foils will be filtered out of the acid peroxide solution. The results were obtained by taking Hydrochloric acid to hydrogen per oxide proportion(1:0.5,1:0.4,1:0.9),retention time( 6hr,12hr,21hr) and hydrochloric acid concentration of ( 5%,10%,15%) as factors and on the basses of the study the optimum conditions to get a maximum amount of gold (0.2455 gm) was HCl: H 2 O 2 proportion of (1:0.5), HCl concentration (10%) and retention tine (12hr) .In conclusion, to draft a solution and act accordingly, the government through its instruments should put a system in place.
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Keywords
printed circuit board, hydrometallurgy, gold