Abstract
Secondary zinc oxide (SZO), which comes from the zinc industry, is an important secondary resource of zinc and other valuable metals. In this study, the production feasibility and rationality of a cleaner zinc recovery process using SZO and a hydrometallurgical method were described. Zinc extraction is promoted by the addition of ammonium bicarbonate to a NH3–H2O system, and the maximum recovery of zinc could be close to 80% at the optimum leaching conditions of a stirring rate of 400 rpm, an ammonia/ammonium ratio of 7:3, a total ammonia concentration of 4 mol/L, and a liquid/solid ratio of 7 mL/g for 30 min at 35 °C. The kinetics of leaching were modeled using the shrinking core model of constant-size particles, and the rate-controlling step was determined to be the diffusion through the product layer. The apparent activation energy of the reaction was estimated to be 11.04 KJ·mol−1, while the order of reaction with respect to total ammonia concentration was 1.53 and the liquid/solid ratio was 2.26. The analysis results of the initial residue and the leached residue indicated that lead was transferred from PbCl2 to PbCO3 and that ZnFe2O4 was not leached in the NH3-NH4HCO3-H2O system.
Highlights
IntroductionZinc has excellent recycling performance, and the utilization of secondary zinc resources has attracted more and more attention
MeanNH3 –H2 O system (42%) and the NH4 HCO3 –H2 O system (68.38%). It indicated that the adwhile, the extraction of zinc in the NH3–NH4HCO3–H2O system (78.15%) was higher than dition of ammonium bicarbonate promoted the dissolution of zinc
The results indicated that higher total ammonia concentration leads
Summary
Zinc has excellent recycling performance, and the utilization of secondary zinc resources has attracted more and more attention. The advantage of the acid leaching method for leaching secondary zinc oxide is that the zinc extraction efficiency is good, but the leaching selectivity of this method is poor, and impurities such. Crystals of of 15 themanganese, zinc extraction efficiency good, but of thisthe method poor, as aluminum, andisarsenic are the alsoleaching leached,selectivity which increase burdenisof the and impurities such as manganese, aluminum, and arsenic are leached, which inimpurity removal process. Many researchers have extracted zinc from zinc resources with method and analyzed the leaching kinetics, established the secondary kinetic models, and calculated ammonia energy leaching method analyzed leaching established the kinetic the activation [18,19,20]. Shrinking addition, thewhich order accounts of the reaction was estimated a semi-empirical equation for the core model, for chemical reactionusing and product layer diffusion control. The reaction was estimated using a semi-empirical equation for the diffusion-controlled process
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
