Of Topo And ¦Â-diketones, High Resistance, The Ammoniacal Solution Of Zinc Extraction Study

Lack of resources has became a more and more important constraint for the development of non-ferrous metallurgical industry. Therefore, enhancing the effective use of low grade ore and improving resource utilization have became a great need of China's economic. The Lanping area in Yunnan Province of China is one of the largest low grade oxidized zinc reserves over the world with an estimated oxidized zinc reserve which has the characteristics of low zinc content (<8%) and high basic gangue. Conditional acid leaching method can't be applied to the low oxidized zinc ore economically as a result of the high acid consumption. The "ammonia leaching-solvent extraction-electrowinning" process is an ideal means of recovering zinc from low-grade oxidized zinc mine from Lanping area with high basic gangues.The key of this process is the solvent extraction of zinc from ammoniacal leaching solution. In this article, the solvent extraction of zinc from ammoniacal leaching solution in the condition closed to industrial production using mixture of a sterically hindered beta-diketone (HR),1-(4'-dodecyl)-phenyl-3-tertiary butyl-1,3-octadione, and tri-n-octylphosphine oxide (TOPO) in sulphonated kerosene is studied. Then the solvent extraction is applied to the pilot-scale process "ammonia leaching-solvent extraction-electrowinning", which is proposed to deal with the low grade oxidized zinc mine with high basic gangue from Lanping area in Yunnan province of China in the laboratory. Finally, the mechanism of solvent extraction of zinc from ammoniacal ammonium sulfate solution and ammoniacal ammonium actate solution are studied.The result of experiment indicates that TOPO and HR show evident synergistic effects on the solvent extraction of zinc from ammoniacal ammonium sulfate solution. Also, experimental data show that the zinc extraction ratio decreases with the increase of initial pH value and total ammonia concentration of the aqueous phase, the zinc extraction ratio increases with the increase of phase ratio, but the zinc extraction ratio has no relation with the zinc concentration of the aqueous phase. Based on the batch scale equilibriumresult, a continuous extraction of zinc from simulated ammonical solution and real ammonical solution resulting from the process "ammonia leaching-solvent extraction-electrowinning" which is proposed to deal with oxidized zinc ore with high basic gangue from Lanping area is carried out in a mixer-settler unit of the type MSU-0.5 containing two stages solvent extraction and one stripping stage. The two-stage extraction efficiencies of zinc of the used system are 86% and 85% for a simulated ammoniacal leaching solution and real ammoniacal leaching solution, respectively, whereas the stripping efficiency of one stripping is 85% for both processes.The solvent extraction of zinc by the mixture of TOPO and HR from ammoniacal ammonium sulfate solution shows evident synergistic effect and the synergistic enhancement factor is calculated to be 3.98, whereas the solvent extraction of zinc from ammoniacal ammonium actate solution doesn't show evident synergistic effect. At the same time, the extracted complex by the sterically hindered beta-diketone from ammoniacal ammonium sulfate solution and ammoniacal ammonium actate solution are both ZnA2, and the extracted complex by the mixture of a sterically hindered beta-diketone and TOPO in sulphonated kerosene from ammoniacal ammonium sulfate solution is ZnA2B. Compared with the extraction of zinc in ammoniacal ammonium actate solution, the extraction of zinc in ammoniacal ammonium sulfate by the mixture of TOPO and HR is higher.