Ferric Sulfate Leaching of Pyrrhotite Tailings between 30 to 55 °C

Minerals

Nazanin Samadifard²  Cheryl E. Devine²  Elizabeth Edwards²  Krishna Mahadevan²  Vladimiros G. Papangelakis¹ 

[1] Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON M5S-3E5, Canada

关键词: nickeliferous pyrrhotite;    ferric sulfate leaching;    elemental sulfur;    shrinking core model;   

DOI  :  10.3390/min5040526

来源: mdpi

【 摘 要 】

Mine tailings present major environmental issues in the mining industry. However due to the depletion of high-grade sulfide ores for metal recovery, tailings could also be a potential resource for certain valuable metals. The present study investigates the potential to recover nickel from pyrrhotite tailings. Leaching tests were performed in acidic ferric sulfate media with 0.14 wt % solids to keep the ferric concentration essentially constant. The temperature was varied between 30 and 55 °C, and the ferric concentration was in a range 0.02–0.3 M. The results showed that both temperature and ferric sulfate concentration had significant effects on the nickel extraction kinetics. The shrinking core model (SCM) was applied to the nickel extraction data. The rate controlling step was found to be product layer diffusion. The Arrhenius plot yielded an activation energy of Ea = 62.12 kJ/mol based on apparent reaction rates obtained by the SCM. The reaction order with respect to ferric ion was found to be 1 at the high concentration range. SEM images of partially leached tailings confirmed the presence of elemental sulfur around the pyrrhotite particles, which was responsible for the observed non-linear leaching kinetics (diffusion control).

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.