RECOVERY OF VALUED METAL FROM WASTE NI CATALYST

摘要

PROBLEM TO BE SOLVED: To enable Ni, Co, Mo and V to be recovered at a high yield from a waste Ni catalyst by using a method such as wet crushing, water leaching or sulfuric acid spraying by flame. SOLUTION: Waste Ni catalyst is mixed with water and the mixture is crushed using a ball mill. The waste Ni catalyst completely undergoing this wet crushing process is subjected to a water leaching process 2 and consequently, a decoction consisting mainly of the MO and V components and a decoction residue containing Ni, Co, Mo and V are obtained. Ni and Co contained in the water decoction residue are dissolved by heating the water decoction residue at a high temperature using a mixture of sulfuric acid and water (cooking 3). After adjusting the pH value of the obtained solution (4), a sulfiding agent such as sodium sulfide or sodium hydrogen sulfide is added to Ni, Co and Mo contained in the filtrate. Thus it is possible to recover Ni, Co and Mo as a mixed sulfide at an yield of 98%. On the other hand, Mo and V are contained as main components in the liquid after the water leaching step 2, and are separated and recovered using a routine process.