Recovery of Ni and Co Elements from Superalloy Leaching Solution by Sodium Roasting and Water Leaching

Ni and Co elements in superalloy scraps are scarce metal resources in China, and recycling these metal elements has great environmental and economic significance. This present study proposes a novel and efficient recycling process for the recovery of nickel and cobalt elements from superalloy leaching solution. The superalloy leaching solution reacted with NaOH solution to obtain precipitates. Then, the precipitates were mixed with Na2CO3 and roasted at high temperature. After sodium roasting, Al and Cr elements were removed by water leaching to obtain pure NiO and CoO as raw materials for preparing ternary precursors. As the nuclear part of this process, the impacts of sodium roasting on the water leaching behaviors of Al and Cr elements from Ni and Co sediments was investigated. Under suitable conditions of sodium roasting, the leaching efficiencies of Al and Cr elements are 99.11% and 99.39%. Moreover, the promoting mechanism of sodium roasting on leaching of Al and Cr elements was discussed from the view of phase composition.