Recovery of Precious Metals from the Spent Catalyst

Catalysts are indispensable in accelerating chemical reactions, and numerous chemical
industries rely on heterogeneous catalysts to efficiently transform raw materials into final
products. The petroleum, petrochemical, and chemical industries employ a range of
heterogeneous catalysts to optimize the conversion of raw materials into products, achieving
this with minimal energy expenditure and reduced processing time. Resource scarcity and
disposal issues with low-activity catalysts pose major global challenges. Fresh catalysts incur
high costs, and the Earth's supply of essential metals is limited. Landfilling of spent catalysts,
which contain valuable and expensive metals, is harmful to human health and the
environment. Recycling catalytic minerals reduces the need for new resources, aiding in
resource conservation.
Conventional recovery methods employed at the commercial level, namely pyrometallurgy
and hydrometallurgy, are effective but exhibit considerable drawbacks, including high energy
demands and notable environmental impacts. Despite the availability of numerous
environmentally friendly techniques for metal recovery, their implementation remains
inconsistent. Organic acids are considered more environmentally friendly and cost-effective
compared to inorganic acids for the extraction of precious metals. Crude spent catalysts
contain trace amounts of valuable metals, such as 0.21 wt.% platinum and 0.25 wt.% rhenium,
and the primary objective is the recovery of these metals using organic acids. A 1M solution
of tartaric acid achieved over 90% platinum extraction from spent catalysts within 24 hours at
80°C. In comparison, organic acid-based hydrometallurgy exhibits significant potential for the
recovery of precious metals from spent catalysts.