Exploration of the thiosulphate process for the dissolution of gold from electronic waste and its recovery through ion-exchange
type: CreativeWork
description: Electrical and electronic equipment (EEE) has substantially grown over the past few years due to vast technological advancements and consequently so has electronic waste (e-waste). This growth has shown cause for concern with a generation of 53.6 million metric tonnes of e-waste globally in 2019 alone. Part of this concern may be due to the slow adoption of formal collection and recycling practices in developed countries whilst developing countries bear the brunt of the e-waste produced within the country and the e-waste imported from other countries. Furthermore, the burden of the increasing levels of e-waste has detrimental effects on the environment. In such cases, e-waste landfills have been known to leach metals, such as lead, into soil and groundwater of nearby regions thereby affecting human and animal life in the area. Despite the evident hazardous materials associated with e-waste, there is still value in this waste. The value is attributed to the metals such as gold, silver, copper and palladium found in e-waste. Printed circuit boards (PCBs) are a small but nonetheless crucial fraction of global e-waste making up 6% by mass. The gold content in this small fraction is of much higher concentrations than in typical primary gold ores thus PCBs represent the most economically attractive portion of e-waste. Hydrometallurgical processing has previously been applied for the recovery of gold and copper from primary ores possibly due to it being considered environmentally friendly. Therefore, this thesis investigates a hydrometallurgical process for recovering gold from PCBs. Literature studies show ammonium thiosulphate to be a viable option in comparison to the more widely used cyanide leaching route (Aylmore & Staunton, 2014). Thus, the ammonium-thiosulphate system containing ammonia, ammonium thiosulphate and copper (II) sulphate pentahydrate was incorporated as a hydrometallurgical option for the recovery of gold. This study explores the formulation of synthet…
abstract: Electrical and electronic equipment (EEE) has substantially grown over the past few years due to vast technological advancements and consequently so has electronic waste (e-waste). This growth has shown cause for concern with a generation of 53.6 million metric tonnes of e-waste globally in 2019 alone. Part of this concern may be due to the slow adoption of formal collection and recycling practices in developed countries whilst developing countries bear the brunt of the e-waste produced within the country and the e-waste imported from other countries. Furthermore, the burden of the increasing levels of e-waste has detrimental effects on the environment. In such cases, e-waste landfills have been known to leach metals, such as lead, into soil and groundwater of nearby regions thereby affecting human and animal life in the area. Despite the evident hazardous materials associated with e-waste, there is still value in this waste. The value is attributed to the metals such as gold, silver, copper and palladium found in e-waste. Printed circuit boards (PCBs) are a small but nonetheless crucial fraction of global e-waste making up 6% by mass. The gold content in this small fraction is of much higher concentrations than in typical primary gold ores thus PCBs represent the most economically attractive portion of e-waste. Hydrometallurgical processing has previously been applied for the recovery of gold and copper from primary ores possibly due to it being considered environmentally friendly. Therefore, this thesis investigates a hydrometallurgical process for recovering gold from PCBs. Literature studies show ammonium thiosulphate to be a viable option in comparison to the more widely used cyanide leaching route (Aylmore & Staunton, 2014). Thus, the ammonium-thiosulphate system containing ammonia, ammonium thiosulphate and copper (II) sulphate pentahydrate was incorporated as a hydrometallurgical option for the recovery of gold. This study explores the formulation of synthet…
author: Maharaj, Dasmi
keywords: Chemical Engineering
date published: 2022
date modified: 2026-07-24T01:33:45Z
provider: University of Cape Town
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Department of Chemical Engineering

PropertyValue
property ID: Handle
value: http://hdl.handle.net/11427/37503