Description : | Hydrometallurgical treatment of spent hydro-refining catalysts generates residues containing a significant amount of Ni (2-5%), Co (2-5%), and Mo (0.5-1%). These residues are presently dumped or underutilized in construction-related industries. The pyro-metallurgical process developed at CSIR-NML is able to recover more than 90% of these metals as saleable alloys, besides generating calcium aluminate type slag. A process also developed to treat spent HDS catalyst containing 4-18 % Mo, 1-10 % Ni, 1-18 % W, 0.5-5% Co, 30-35% Al and a minor amount of S, P and Si to produce a Co/Ni, Mo-W-Fe alloy with P less than 0.1% and alumina rich slag as a building material. |