© Journal Of Chemical Society Of Nigeria (jcsn) . 2011. Vol. 36 No. 1
Publisher: Chemical Society of Nigeria
Dissolution Kinetics and Solvent Extraction of Lead From Anglesite Ore
A. A. Baba, F. A. Adekola, D. P. T. Fapojuwo, F. O. Otokhina
KEYWORDS: Dissolution, solvent, extraction, lead anglesite ore
ABSTRACT:A study of kinetics of the dissolution of a Nigerian anglesite ore by hydrochloric acid has been examined. A detailed investigation on the quantitative leaching of the mineral was also carried out. The effects of some parameters such as acid concentration, contact time, temperature and stirring rate on the dissolution efficiency have been investigated. Experimental results indicate that the dissolution rate is diffusion controlled via hydrogen ion [H+] action. With 2.0M HCl about 87.2% of the ore was dissolved within 120min using particle size 0.05-0.063mm at optimal conditions. The calculated activation energy, reaction order and Arrhenius constant were 18.12kJ/mol, 0.30 and 6.05s-1 for the process respectively. The elemental analysis by inductively coupled plasma-mass spectrometry (ICP-MS) showed that the major elements in the ore are Pb(47.42%), S(14.36%), Si(8.21%), Fe(5.27%), Sn(5.11%), Ca(3.45%), Mn(2.07%). The X-ray diffractometry (XRD) also confirmed the ore to exist in a single phase with anglesite characteristics peaks at 27.20 and 36.00 respectively. Furthermore, an extraction yield of about 89.11% of the total Pb(II) by 0.5M TBP in kerosene was obtained from an initial 543.11 mg/L leach liquor at 25±20C and at optimal stirring time of 30 minutes. The enthalpy and entropy change of -27.13kJ/mol and -14.85J/mol were obtained, respectively for the dissolution reaction.
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