Electrolytic Production of Al–Si Alloys: Theory and Technology (Monographs in Electrochemistry)

Description

This monograph presents the theoretical background of the industrial process for the production of Al-Si alloys in standard aluminum electrolyzers. It reviews the physical chemistry and electrochemistry of cryolite melts containing silica and focuses on analyzing the exchange reactions in Na3AlF6–Al2O3–SiO2 melts. It presents the kinetics and mechanism of Si(IV) electroreduction in Na3AlF6–Al2O3–SiO2 melts on Al cathodes while the current yields as well as industrial tests performed are discussed. The modern research trends in the field are also overviewed. Providing readers with information not easily obtained in any other single source, this book is of great interest to researchers, graduates, and professionals working in the fields of electrochemistry and technology of cryolite-based melts. Preface References Acknowledgements Contents About the Authors About the Series Editors 1 Exchange Reactions in Na3AlF6–Al2O3–SiO2 Melts 1.1 Introduction 1.2 Products of Transformations in the Na3AlF6–Al2O3–SiO2 Melts 1.3 Criterion of Thermal Stability of the Na3AlF6–Al2O3–SiO2 Melts 1.4 Ionic Structure of the Na3AlF6–Al2O3–SiO2 Melts 1.5 Conclusions References 2 Kinetics and Mechanism of Si(IV) Electroreduction in Na3AlF6–Al2O3–SiO2 Melts on Al Cathode 2.1 Introduction 2.2 Reduction of Si(IV) by Liquid Al in Na3AlF6–Al2O3–SiO2 Melts 2.3 The Nature of the Passivation Layer on the Interphase Al | Na3AlF6–Al2O3–SiO2 2.4 Electroreduction of Si(IV) on Solid Electrodes 2.5 Electrolytic Reduction of Si(IV) on a Liquid Electrodes 2.6 Mechanism of the Alloy Formation in the Aluminum Electrolyzer 2.7 Conclusions References 3 Current Yield 3.1 Introduction 3.2 Loss of Metal in the Al–Si/Na3AlF6 System 3.3 Studies of Vapor Composition by the Method of Mass Spectroscopy 3.4 System Al/Na3AlF6 3.5 System Al–Si/Na3AlF6 3.6 Solubility of Al–Si Alloy in Cryolite Melt 3.7 Conclusions References 4 Industrial Tests 4.1 Introduction 4.2 Dissolution Rate of SiO2-Containing Minerals in the Cryolite Melts 4.3 Mathematical Model of Al–Si Alloy Production in Aluminum Electrolyzer 4.3.1 Ideal Mixed Reactor Model 4.3.2 Macrokinetics of Silicon Reduction 4.4 Attainable Concentration of Silicon in the Electrolytic Alloy 4.5 Transition Period of Operation 4.6 Analysis of the Early Results of Industrial Tests of the Technology 4.7 Studies and Development of Industrial Technology on Sȍderberg Electrolyzers with 67 kA Current Load 4.7.1 Loading the Sand onto the Crust of the Electrolyte 4.7.2 Continuous Loading of the Sand 4.7.3 Loading of Kaolin–Alumina Mixture 4.8 Physical and Mechanical Characteristics of Electrolytic Alloys 4.9 Conclusions References 5 Modern Research Trends 5.1 Introduction 5.2 Novel Potassium Fluoroaluminate Electrolytes 5.3 Physico-Chemical and Electrochemical Properties of Cryolite–Silica System 5.4 Processing of Spent Pot Lining 5.5 Can a Human Breathe on the Moon? 5.6 Use of Na2SiF6 for the Production of Al–Si Alloys and Cryolite in Aluminum Electrolyzer 5.7 Conclusions References Index