Selective nickel recovery from the spent catalyst

Abstract

Nickel containing catalysts or nickel catalyst are well known in process industries. In Malaysia, there are about 500 metric ton of nickel catalysts being imported every year. They have been used many reactions such as hydrogenation reaction, alkylation reactions, hydroalkylation reactions and cracking reactions. The initial composition of nickel catalyst depends on reaction involved for example catalysts for hydroalkylation reaction containing other metals such as tungsten beside nickel itself. Initially, these catalysts perform at high activity but by time they become less active and reach at a point where they are no more effective to be used in a commercial process. Considerable research has been carried out on developing the process for regenerating the spent catalyst since nickel is expensive to be discarded and more over, the safe disposal of waste nickel requires consideration of environmental hazard. However, the regenerating process of a nickel catalyst from spent catalyst is tedious, time consuming, and careful attention on detailed procedures. Therefore, there is a continuous afford needed to developing methods of recovering nickel from spent catalyst that provides inexpensive recovery of nickel in a usable form. Several methods have been described in literature regarding recovering nickel not only from spent catalyst but also from other solid an liquid wastes such as using electrowinning, fluidized bed an burning processes. In this paper, nickel recovery from spent catalyst using leaching process followed by selective precipitation of nickel using sodium hydroxide will be presented. The initial results show that about 80% of the nickel from spent catalyst was obtained in the form nickel hydroxide.