A PROCESS FOR THE INSTANTANEOUS CONTROL OF PRECIPITATION OF NICKEL AND COBALT PRESENT IN THE LEACH LIQUOR, BY ADJUSTING THE PH OF THE SOLUTION

摘要

Disclosed herein is a process for the control of the precipitation of nickel and cobalt present in a leach liquor, by adjusting the pH of the liquor, comprising the following steps: i) a first pH adjustment of the liquor using lime and/or limestone to provide a first solution; ii) a second pH adjustment of the solution of step (i) by controlling the precipitation of nickel and cobalt using lime and/or limestone and having residual ferrous iron precipitated and separated from the nickel and cobalt solution, the processes being characterized by: iii) a third pH adjustment of the nickel and cobalt solution from step (ii) by adding solid calcined magnesia or a solution of 20% by weight of magnesia as a pulp to the solution from step (ii) to provide a pH of the solution between 7.4 and 7.5 and carrying out the precipitation of nickel and cobalt hydroxides over a period of between 1 to 3 hours and at a temperature of between 40 and 700C.