TITLE:
Kinetic Analysis of Isothermal Leaching of Zinc from Zinc Plant Residue
AUTHORS:
Ali Reza Eivazi Hollagh, Eskandar Keshavarz Alamdari, Davooud Moradkhani, Ali Akbar Salardini
KEYWORDS:
Zinc; Hydrometallurgy; Kinetic Model; Zinc Plant Residue; Model-Free Method
JOURNAL NAME:
International Journal of Nonferrous Metallurgy,
Vol.2 No.1,
January
25,
2013
ABSTRACT: The sulfuric acid leaching of zinc plant
residues was studied in an attempt to find a suitable hydrometallurgical method
for zinc recovery. The parameters evaluated consist of reaction time,
Solid-to-liquid-ratio, reaction temperature, agitation rate and pH. The
results of kinetic analysis of the leaching data under various experimental
conditions indicated that there is a reaction controlled by the solution
transport of protons through the porous product layer with activation energy of
about 1 kJ/mol for different constant solid to liquid ratios. Based on the
shrinking core model (SCM), the following semiempirical rate equation was
established:1-3(1-a)2/3+2(1-a)=0.001187×[H+]0.016×[(S/L)]-1.34×exp(-1/RT)
×t. On the other hand, activation
energy was obtained from a model-free method using isothermal measurements.
Values for activation energy were calculated as a result of the conversion
function with an average of 2.9 kJ/mol. This value is close to that determined
previously, using shrinking core model (SCM).