Executive Summary : | Rare earth elements (REEs) are a set of elements with unique chemical and physical characteristics, including yttrium, scandium, and other 15 lanthanide elements. They have gained attention due to their significant roles in defense applications, renewable energy production, high technology applications, electronic industries, fiber optics, semiconductor, and aerospace industries. The United States and the European Union have classified REEs as critical metals due to their high demand and supply risk. Coal and coal by-products are potential sources of REEs, with 100 to 1000 ppm reported in coal ash. However, more data and studies are needed to understand their distribution and identify the "sweet spots" of rare earths. Millions of tons of coal ash have been produced due to coal burning over decades, and if high concentrations of REEs could be identified, these underutilized materials could become valuable resources. To recover REEs from coal and coal waste, hydrometallurgical processes, selective leaching, strong acid and strong base, and mechanical methods can be explored. However, the study of REEs in coal and coal by-products is in its infancy, and limited studies have been conducted on the identification and development of recovery processes in India. This research will help understand the potential of coal and coal waste as secondary resources of rare earths and explore the feasibility of recovering valuable rare earth compounds in converting "Waste to Wealth." |