Zinc recovery and waste sludge minimization from chromium passivation baths

► Selective zinc and iron separation from trivalent chromium passivation baths is performed. ► Zinc is recovered from spent passivation bath. ► Metallic zinc, 98.5% is obtained by electrodeposition. ► Waste sludge generation is avoided. ► Loss of 13 kg of zinc and 10 kg of chromium per cubic meter of spent bath is avoided.