Sustainable recovery of metals from intermediate products

Fast industrialization and modern life have increased the demand for critical metals such as titanium and rare earth elements. On the other hand, high-grade ore natural reserves are just mosly used and their quantity is decreased. Therefore, alternative sources of valuabled metals such as intermediate products need to be considered and investigated. Massive amounts of industrial wastes are being generated annually in production of aluminium oxide and titanium oxides. The majority is sent to landfills, which eventually poses environmental challenges such as ecological contamination and health hazards to living beings. Such industrial wastes contain various major elements (Fe, Na, Ca, Si, Al, and Ti), whose improper disposal leads to adverse effects to human being and the environment. As a result, hydrometallurgical and pyrometallurgical operations such as leaching, filtration, precipitation, solvent extraction, crystallization and metal winning have received much attention due to the fact that they improve cost effectiveness over time and enable the metal recovery businesses to thrive profitably. This paper provides a state of art review on the current technologies existing for the recovery of titanium from industrial wastes streams to analyse the sustainability. Among the wastes, red mud, electric furnace dust and fly ash are some of the largest metallurgical generated wastes. Various metal recovery processes involve wastes from aluminium and titanium industry aiming separation and extraction of target metals. The current challenges of hydrogen reduction in pyrometallurgy, sustainable hydrometallurgy other advanced technologies such as ultrasonic spray pyrolysis are partially metnioned in this paper. The hydrometallurgical method, which involves dissolving and leaching, is aproven and successful process for recovering metals from ores and concentrates. The limitations placed on waste disposal and stringent environmental legislation require environmental-friendly metal recovery technologies. This review paper provides critical information that enables researchers to identify a proper research strategy for metal recovery from different industrial intermediate products.