Abstract
The physico-chemical characterization and dissolution kinetics study of a Nigerian galena ore in nitric acid has been undertaken. The effects of acid concentration, temperature, particle size, stirring speed and solid/liquid ratio on the leaching of galena were investigated. The X-ray fluorescence data showed that the galena ore used in the study exists mainly as PbS. Lead (Pb) was detected as the major metal for galena with metals such as Na, Ca, Fe, Zn, Al and Mg occurring as minor elements. The XRD analysis also confirmed the originality of the galena ore as it revealed that galena exists mainly as lead sulphide (PbS). The Fourier transform infrared (FTIR) analysis also supported the XRF and XRD analysis by revealing the presence of sulphur in the ore. The scanning electron micrograph (SEM) analysis revealed a high level of crystallinity of the ore. Results of the leaching studies showed that galena dissolution in nitric acid (HNO3) increases with increasing concentration of nitric acid, temperature and stirring rate, and decreases with increasing particle diameter and solid/liquid ratio. In 10 M HNO3 at a temperature of 90°C using 75 μm particle diameter with solid/liquid ratio of 20 g/L and stirring speed of 540 rpm, about 84.5% of galena was dissolved in 150 minutes. The values of activation energy, order of reaction and Arrhenius constant calculated at the conditions above for galena were 27.01 KJ/mol, 0.93, 26.71 s-1 respectively. The mechanism of dissolution of galena was established to follow the shrinking core model for the diffusion controlled mechanism, with surface chemical reaction as the rate controlling step for the leaching process. Finally, the XRD analysis of the post-leaching residue revealed the presence of gahnite and anglesite.
Highlights
IntroductionCalled lead glance, is the natural mineral form of lead (II) sulphide
Galena, called lead glance, is the natural mineral form of lead (II) sulphide
The XRD analysis confirmed the originality of the galena ore as it revealed that galena exists mainly as lead sulphide (PbS)
Summary
Called lead glance, is the natural mineral form of lead (II) sulphide. It is the most important ore of lead and an important source of silver. It is one of the most abundant and widely distributed sulphide minerals. It crystallizes in the cubic crystal system often showing octahedral forms. It is often associated with the minerals sphalerite, calcite and fluorite [1]. It is estimated that there are at least 30 lodes within an aggregate length of about 600 m as detailed [2] [3]
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Journal of Minerals and Materials Characterization and Engineering
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.