Selective Leaching of Hot Filter Cake Residue Produced by Zinc Plant with Sodium Hydroxide

Hot Filter Cake (HFC) is one of the valuable residues in cathodic zinc producer factory inIran that isobtained in cobaltremoval formzincoreleachingstage.HFChas15-25% zinc, 0.5-1.5% Co, 3-8% Mn and some minor other elements. This cake is secondary source of these elements. In this investigation sodium hydroxide was used as selective leaching of zinc from HFC. At high sodium hydroxide concentration zinc ion dissolved as complex.Effective parameters such as sodium hydroxide concentration, temperature, solid liquid ratio, agitation rate and particle size were studied on zinc recovery. Results showed that sodium hydroxide concentration and temperature has significant effect but particle size has minor effect of zinc recovery. Final results maximum zinc recovery obtained 95.66 percent in two stage leaching at temperature 95 0C, sodium hydroxide concentration 8 M, solid liquid ratio 1:10, agitation rate 850 rpm and particle size 38-75 micron.