Leaching kinetics of low grade zinc oxide ore in NH₃-NH₄Cl-H₂O system

Abstract

The leaching kinetics of low grade zinc oxide ore in NH₃-NH₄Cl-H₂O system was studied. The effects of ore particle size, reaction temperature and the sum concentration of ammonium ion and ammonia on the leaching efficiency of zinc were examined. The leaching kinetics of low-grade zinc oxide ore in NH₃-NY₄Cl-H₂O system follows the kinetic law of shrinking-core model. The results show that diffusion through the inert particle pores is the leaching kinetics rate controlling step. The calculated apparent activation energy of the process is about 7.057 kJ/mol. The leaching efficiency of zinc is 92.1% under the conditions of ore particle size of 69 μm, holding at 80 °C for 60 min, sum ammonia concentration of 7.5 mol/L, the molar ratio of ammonium to ammonia being 2:1, and the ratio (g/mL) of solid to liquid being 1:10.

Keywords

NH₃-NH₄Cl-H₂O system / low-grade zinc oxide ore / leaching / kinetics

References

[1] QinW.-q., LanZ.-y., LiW.-zhong.. Recovery of zinc from low-grade zinc oxide ores by solvent extraction [J]. J Cent South Univ Technol, 2003, 10(2): 98-102

[2] HeJ., TangM.-t., LuJ.-l., LiuZ.-q., YangS.-h., YaoW.-yi.. Concentrating Ge in zinc hydrometallurgical process with hot acid leaching-halotrichite method [J]. J Cent South Univ Technol, 2003, 10(4): 307-312

[3] Abdel-AalE. A.. Kinetics of sulfuric acid leaching of low-grade zinc silicate ore [J]. Hydrometallurgy, 2000, 39(2): 247-254

[4] IginioC., SergioM., UmbertoM.. Kinetic models for the leaching with sulphuric acid of zinc-containing slags [J]. Hydrometallurgy, 1983, 10(1): 61-67

[5] LiuS.-j., OuL.-m., FengQ.-m., ZhangG.-f., LüY.-ping.. Alkaline leaching Zn from zinc oxide ore [J]. Hydrornetallurgy of China, 2005, 24(1): 23-25

[6] LimpoJ. L., FigueiredoJ. M., AmerS., LuisA.. The CENIM-LNETI process: A new process for the hydrometallurgical treatment of complex sulphides in ammonium chloride solutions [J]. Hydrometallurgy, 1992, 28(2): 149-161

[7] YangS.-h., TangM.-t., ChenY.-f., TangC.-b., HeJ.. Anodic reaction kinetics of electro winning zinc in system of Zn(II)-NH₃-NH₄Cl-H₂O [J]. Trans Nonferrous Met Soc China, 2004, 14(3): 626-630

[8] YangS.-h., TangM.-tang.. Thermodynamics of Zn(II)-NH₃-NH₄Cl-H₂O system [J]. Trans Nonferrous Met Soc China, 2000, 10(6): 830-833

[9] LimpoJ. L., LuisA.. Solubility of zinc chloride in ammoniacal ammonium chloride solutions [J]. Hydrometallurgy, 1993, 32(2): 247-260

[10] ZhuY., HuH., SuY.-s., YangB.-min.. Kinetics of leaching poorly-floated zinc-oxide-ore with ammonia [J]. The Chinese Journal of Process Engineering, 2002, 2(1): 81-85

[11] JuS.-h., TangM.-t., YangS.-h., LiY.-nian.. Dissolution kinetics of smithsonite ore in ammonium chloride solution [J]. Hydrometallurgy, 2005, 80(1): 67-74

[12] XuinG. H., YuD. Y., SuY. F.. Leaching of Scheelite by hydrochloric acid in the presence of phosphate [J]. Hydrometallurgy, 1986, 16(1): 27-40

[13] EkmekyaparA., OyaR.. Dissolution kinetics of an oxidized copper ore in ammonium chloride solution [J]. Chemical and Biochemical Engineering Quarterly, 2003, 17(4): 261-266

[14] MulakW., MiazgaB., SzymlzychaA.. Kinetics of nickel leaching from spent catalyst in sulphuric acid solution [J]. Internation Journal of Mineral Processing, 2005, 77(4): 231-235

[15] KunkulA., MuhtarK. M., YapiciM., DemirbaA.. Leaching kinetics of malachite in ammonia solutions [J]. Mineral Processing, 1994, 41(3): 167-182