Noble metals dissolved without aqua regia

A photo of part of a car exhaust system

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Decades-old study inspires acidic salt solutions for recovering gold and platinum group metals from catalytic waste

Scientists in Belgium have developed a simple and environmentally-benign method for recovering precious metals from metal wires and spent automotive catalysts. Using highly-concentrated aluminium nitrate and aluminium chloride solutions, they were able to dissolve both gold and platinum group metals, and then precipitate out the pure metals, allowing them to potentially be recycled and reused.