Hydrometallurgical and chemical extraction technologies provide a process route for resource recovery of valuable metals from both primary as well as secondary resources. Although the leaching of coal fly ash (CFA) has been a subject of active study in recent years, information is limited regarding the separate leaching of alumina phases in the ash. This book explores factors that influence the process of aluminium extraction from CFA. Data collection and analysis techniques involved experimentation strategies such as statistical design of experiments (DOE), response surface methodology (RSM) and central composite rotatable design (CCRD). Based on the response characteristics of the two alumina phases, a two-step acid leach technique was formulated to extract aluminium from CFA using an inorganic acid. The book makes a technical contribution by providing information which can further be used as a basis for developing viable alternative process technologies for the production of smelter grade alumina from CFA. The book will be useful to the scientific community, graduate and postgraduate students in metallurgical and chemical engineering, and commercial venture SME managers.