Gold Metallurgy and the Environment

Description

"This book gives an overview of all the gold extraction processes along with their mechanistic study and environmental impact. Different approaches in gold extraction are discussed including traditional pyrometallurgy, amalgamation, leaching by cyanide or non-cyanide lixiviants and emerging bioleaching using micro-organisms, in detail."--Provided by publisher. Abstract: "This book gives an overview of all the gold extraction processes along with their mechanistic study and environmental impact. Different approaches in gold extraction are discussed including traditional pyrometallurgy, amalgamation, leaching by cyanide or non-cyanide lixiviants and emerging bioleaching using micro-organisms, in detail."--Provided by publisher Content: Cover Half Title Title Page Copyright Page Dedication Contents Acknowledgement Preface Editors 1. Gold Ore Processing and Environmental Impacts: An Introduction 1.1 Overview 1.2 A Historical Perspective 1.2.1 Mining 1.2.2 Gold and Alchemy 1.3 Occurrence of Gold 1.4 Gold Mineralogy 1.4.1 Mineral Processing of Gold-Bearing Ores 1.4.1.1 Gravity Concentration 1.4.1.2 Froth Floatation 1.5 Classification of Gold-Bearing Ores 1.5.1 Free Milling 1.5.2 Complex Ores 1.5.2.1 Cyanide Consuming Complex Ore 1.5.2.2 Oxygen Consuming Complex Ore 1.5.2.3 Preg-Robbing Ore. 1.5.3 Refractory Ores and Pretreatments1.5.3.1 Roasting 1.5.3.2 Biological Pretreatment 1.5.3.3 Pressure Oxidation Pretreatment 1.6 Extraction Techniques of Gold Ores 1.6.1 Amalgamation 1.6.2 Chlorination 1.6.3 Cyanidation 1.7 Gold Metallurgy and Environmental Impact References 2. Artisanal Gold Mining and Amalgamation 2.1 Introduction 2.2 Process of Gold Extraction by ASGM 2.3 Gold Amalgamation 2.3.1 Whole Ore Amalgamation Process 2.3.2 Amalgamation of a Concentrate 2.3.3 Decomposition of Amalgams 2.3.4 Cyanidation of Amalgam Tailings. 2.4 Processing Centres of ASGM in Various Countries2.5 Environmental Impact by ASGM Activities and Associated Hazards 2.5.1 Associated Hazards of ASGM 2.5.1.1 Chemical Hazards 2.5.1.2 Biological Hazards 2.5.1.3 Physical Hazards 2.5.1.4 Psychosocial Hazards 2.6 Trends in Sustainable Development of ASGM 2.6.1 Technical Aspects 2.6.2 Policy and Legal Framework References 3. Cyanidation of Gold-Bearing Ores 3.1 Development History of Gold Cyanidation 3.2 Cyanide Leaching of Gold 3.2.1 Various Theories of Gold-Cyanidation 3.2.2 Factors Affecting the Cyanidation Process. 3.2.2.1 Effect of Cyanide Concentration3.2.2.2 Effects of the Eh-pH 3.2.2.3 Effect of Alkali Addition 3.2.2.4 Effect of Oxygen Concentration 3.2.2.5 Effect of Particle Size 3.2.2.6 Effect of Temperature 3.2.2.7 Effect of Agitation Speed 3.2.2.8 Effect of Foreign Metal Impurities 3.2.2.9 Effect of Film Formation onto Gold Surface 3.2.2.10 Effect of Flotation Reagents on Cyanidation 3.2.3 Intensive Cyanidation 3.2.3.1 Gravity Concentration Technique 3.2.3.2 Froth-Flotation Technique 3.2.4 Gold Recovery from Cyanide Pregnant/Leach Liquor 3.2.4.1 Zinc Cementation. 3.2.4.2 Carbon Adsorption3.2.4.3 Resin Ion-Exchange 3.2.4.4 Electrowinning of Gold from Cyanide Solutions 3.2.5 Toxicity of Cyanide 3.2.5.1 Toxicity Standards for Cyanide Disposal 3.2.6 Methods of Cyanide Destruction/Removal 3.2.6.1 Ion Exchange 3.2.6.2 Electrowinning 3.2.6.3 Hydrolysis Distillation 3.2.6.4 Membrane Treatment 3.2.6.5 Electro Dialysis 3.2.6.6 Complexation Methods 3.2.6.7 Alkali Chlorination 3.2.6.8 Hypochlorite Oxidation of Cyanides 3.2.6.9 Hydrogen Peroxide Process 3.2.6.10 Ozone Treatment of Cyanides 3.2.6.11 INCO Process 3.2.6.12 Photolytic Degradation.