Study On Separating Sphalerite From Sulfur Of Zinc Pressure Oxidation Leaching Residue By Flotation

The residues from sulfide zinc pressure oxidation leach processing usually contain a great amount of sulfur and sulfide zinc which is not completely leached into liquid phrase. As in the residues the sulfide zinc is wrapped by sulfur, a pressure acid leach process takes no effect to leach the wrapped sulfide zinc out.In this thesis, with the purpose of processing a large number of residues from a zinc hydrometallurgy factory and recycling the useful composition in the residues, the flotation process was used to separate sphalerite from sulfur. The sulfur preferential flotation was chosen as the best feasible plan to separate sphalerite from sulfur, after having made a series of research from the selection depressants and dosage to the effects of variation in pH. Moreover, the depression mechanisms to sphalerite, using sodium sulfide or thioglycollic acid (TGA) as depressants, were studied in terms of pulp potential and infrared spectroscopic analysis. Finally a closed-circuit experiment using the sulfur preferential flotation plan was made to separate sphalerite from sulfur in residues and the result of experiment was satisfying. The conclusions of this thesis were obtained as follows:(1) The results of flotation test and process mineralogy research on zinc residues manifested that the most possible plan of separation sphalerite from sulfur in zinc pressure oxidation leach residues was the sulfur preferential flotation plan.(2) The sulfur concentration from test of residues flotation contained92.23%of sulfur and2.45%of zinc, and the zinc concentration contained12.97%of zinc with a recovery rate of81.71%, using lime as a regulator and SHMP as a disperser during grinding stage, sodium sulfide and TGA as a combined depresser during flotation stage.(3) In the condition of pH6to7, both sodium sulfide and TGA could be used as depressants in sphalerite flotation, but TGA was higher in efficiency. The main depression mechanism was that TGA could absorb on the surface of sphalerite that made sphalerite hydrophilic, while HS- ions generated from sodium sulfide’hydrolyzation and ionization was not the preferential constituent in pulp.