Extraction and kinetic analysis of Pb and Sr from the leaching residue of zinc oxide ore

NH(4)HCO(3)conversion followed by HCl leaching was performed and proven to be effective in extracting Pb and Sr from zinc extracted residual. The mechanism and operating conditions of NH(4)HCO(3)conversion, including molar ratio of NH(4)HCO(3)to zinc extracted residual, NH(4)HCO(3)concentration, conversion temperature, conversion time, and stirring velocity, were discussed, and operating conditions were optimized by the orthogonal test. Experimental results indicate that NH(4)HCO(3)conversion at temperatures ranging from 25 to 85 degrees C follows the shrinking unreacted core model and is controlled by inner diffusion through the product layer. The extraction ratios of Pb and Sr under optimized conditions reached 85.15% and 87.08%, respectively. Moreover, the apparent activation energies of Pb and Sr were 13.85 and 13.67 kJ center dot mol(-1), respectively.

Automated summary

NH(4)HCO(3) conversion followed by HCl leaching is effective in extracting Pb and Sr from zinc extracted residual, with extraction ratios reaching 85.15% and 87.08% under optimized conditions. The apparent activation energies of Pb and Sr are 13.85 and 13.67 kJ·mol(-1), respectively.