ISSN: 1003-6326
CN: 43-1239/TG
CODEN: TNMCEW

Vol. 27    No. 5    May 2017

Leaching kinetics of pyrolusite ores using coking wastewater as reductant
FENG Ya-li1, KANG Jin-xing1, LI Hao-ran2, DENG Xiang-yi1, SUN Ming1
(1. School of Civil and Resource Engineering, University of Science and Technology, Beijing 100083, China;
2. National Key State Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
)
Abstract: Using the coking wastewater as reducing agent to pressure leaching the pyolusite, the shrinking core model was used to investigate the kinetics of the manganese reductive leaching process in the sulfuric acid solution. The effects of stirring speed, reaction temperature, the particle size of the pyrolusite and the concentrations of H2SO4 and coking wastewater on the leaching rate were investigated. The results show that the leaching of manganese increases with the increase of the temperature, the concentrations of H2SO4 and coking wastewater, whereas decreases with the increase of particle size. The kinetic equation for the manganese pressure reduction is presented at the temperature ranging from 393 K to 423 K, with the apparent activation energy of the leaching process is obtained to be 15.2 kJ/mol and the reaction orders for the concentration of H2SO4 and coking wastewater are 1.21 and 0.98, respectively. It suggests that the reduction of manganese from pyrolusite is controlled by the diffusion through the ash-inert layer. The mechanism analysis shows that pyrolusite is reduced by the multikey macromolecules of coking wastewater through providing the oxygen atom for the macromolecular organic compounds decomposition, or is reduced directly by small organic molecules. The thin-walled with holes superficial layer constituted by residual of Fe, Si, Al affects the Mn leaching.
Key words: coking wastewater; pyrolusite ore; reductive leaching; kinetics
Superintended by The China Association for Science and Technology (CAST)
Sponsored by The Nonferrous Metals Society of China (NFSOC)
Managed by Central South University (CSU)