Status of Recovery of Strategic Metals from Spent Secondary Products

Abstract

The need to drive towards sustainable metal resource recovery from end-of-cycle products cannot be overstated. This review attempts to investigate progress in the development of recycling strategies for the recovery of strategic metals, such as precious metals and base metals, from catalytic converters, e-waste, and batteries. Several methods for the recovery of metal resources have been explored for these waste streams, such as pyrometallurgy, hydrometallurgy, and biohydrometallurgy. The results are discussed, and the efficiency of the processes and the chemistry involved are detailed. The conversion of metal waste to high-value nanomaterials is also presented. Process flow diagrams are also presented, where possible, to represent simplified process steps. Despite concerns about environmental effects from processing the metal waste streams, the gains for driving towards a circular economy of these waste streams are enormous. Therefore, the development of greener processes is recommended. In addition, countries need to manage their metal waste streams appropriately and ensure that this becomes part of the formal economic activity and, therefore, becomes regulated.

Synthesis of a Highly Selective Scavenger of Precious Metals from a Printed Circuit Board Based on Cellulose Filter Paper Functionalized with a Grafted Polymer Chain Bearing N-Methyl-2-hydroxyethylcarbamothioate Moieties

“…Consequently, waste electrical and electronic equipment is an essential resource for recovering valuable metals. 5 , 6 Printed circuit boards are the key components of electrical and electronic equipment, where large amounts of valuable metals are used, and hence, these are considered as a greater source of precious metals than natural high-grade ores. 7 − 10 Further, the amounts of these treasured metals are diminishing and in many mines are already exhausted.…”

“…The recent technological advancements of electrical and electronic equipment are rapidly changing our lifestyles, resulting in a discharge of a substantial amount of waste electrical and electronic equipment at a quick pace. − The quick production is accelerating the consumption of valuable metals such as gold, silver, and palladium. Consequently, waste electrical and electronic equipment is an essential resource for recovering valuable metals. , Printed circuit boards are the key components of electrical and electronic equipment, where large amounts of valuable metals are used, and hence, these are considered as a greater source of precious metals than natural high-grade ores. − Further, the amounts of these treasured metals are diminishing and in many mines are already exhausted. As a result, viable recuperation of these valuable metals from secondary assets such as waste printed circuit boards (WPCBs) is quite crucial from economic and environmental points of view. , The precious metals in circuit boards coexist with other base metals, and their ratios and the coexisting metals are widely different.…”

Leaching of Gold and Copper From Printed Circuit Boards Under the Alternating Current Action in Hydrochloric Acid Electrolytes

“…There are three leading technologies for recycling electronic waste -pyrometallurgy, hydrometallurgy, and bio-metallurgy [4]. Pyrometallurgy requires significant capital investments and is characterized by high energy consumption compared to the hydrometallurgical process and is used mainly for recycling large volumes of primary (ore) and secondary raw materials [5].…”

Towards Understanding the Cathode Process Mechanism and Kinetics in Molten LiF–AlF3 during the Treatment of Spent Pt/Al2O3 Catalysts

“…The lifespan of catalysts varies between 3 to 5 years after which either the precious metals can be extracted from the spent catalysts or they can be regenerated [4]. Hydrometallurgical [5][6][7][8] and pyrometallurgical methods are extensively used at laboratory and industrial scales for the recovery of PGMs from the spent catalysts, while electrochemical techniques are infrequently used [9][10][11][12]. New methods and materials are reported annually.…”