An experimental investigation to recover the nickel from ash of residue of fire power station using ammonium hydroxide was conducted. The experiments were conducted in 0.6 L glass baffled reactor with multi speed mixer. The effect of different rotational velocities studied ( 200, 400, 600, 800 and 1000 rpm ) and different temperatures were ( 50, 60, 70 and 80)ºC and it was found that the recovery of nickel increased with increasing rotational velocity till the 600 rpm while there is no change in nickel recovery with increasing temperature till 70 ºC. Controlling steps were investigation and it was found that the transfer through the film surrounding the particle (interphase) is the controlling step.