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Adsorptive Recovery of Auro-Dicyanide Anions from Aqueous Solutions using Activated Carbon-Magnesium Oxide (C-MgO) Nanocomposite as Adsorbent

Published online by Cambridge University Press:  26 March 2018

Tatenda C Madzokere ,
Gey T Musarurwa ,
Godcontrols Jere ,
Trymore Chitambwe  and
Haledene Chiririwa
Tatenda C Madzokere*
Affiliation:
Department of Chemical and Process Systems Engineering, School of Engineering and Technology, Harare Institute of Technology, P. O. Box BE 277, Belvedere, Harare, Zimbabwe
Gey T Musarurwa
Affiliation:
Department of Chemical and Process Systems Engineering, School of Engineering and Technology, Harare Institute of Technology, P. O. Box BE 277, Belvedere, Harare, Zimbabwe
Godcontrols Jere
Affiliation:
Department of Chemical and Process Systems Engineering, School of Engineering and Technology, Harare Institute of Technology, P. O. Box BE 277, Belvedere, Harare, Zimbabwe
Trymore Chitambwe
Affiliation:
Department of Chemical and Process Systems Engineering, School of Engineering and Technology, Harare Institute of Technology, P. O. Box BE 277, Belvedere, Harare, Zimbabwe
Haledene Chiririwa
Affiliation:
Centre for Renewable Energy and Water in the Department of Chemical Engineering at the Vaal University of Technology, Private Bag X021, Vander Bijl park, 1911, Andries Potgieter Blvd, South Africa
*
*Corresponding Author: Madzokere T. C, tatendacrispenmadzokere@gmail.com
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Abstract

The reprocessing of tailings or gold mine waste dumps to extract gold has become an attractive proposition for mining houses worldwide because of the availability of gold which was not easily recovered using old technologies. This study seeks to exploit the novel properties of nanostructured materials in enhancing gold extraction from gold mine tailings. The beneficiation of slimes or tailings involved taking samples for mineralogical studies, synthesis of a novel adsorbent medium (nano C-MgO) prepared by using both chemical and mechano-synthesis methods, oxidative pre-treatment of flotation concentrates, cyanidation and final recovery of the precious metal from solution in a Carbon in Column (CIC) system. The nanocomposite adsorbent was studied by powder X-ray Diffraction (XRD) for structural analysis, Field Emission Scanning Electronic Microscopy (FESEM) for surface morphology, Energy-dispersive X-ray spectroscopy (EDX) for elemental analysis and Fourier Transform Infrared (FTIR) spectroscopy for chemical structure analysis. The Brunauer-Emmett-Teller (BET) Surface Area Analysis procedure was employed to determine the total specific surface area of the nano-adsorbent. Representative tailings samples of 100-500 g were obtained for different analytical investigations using a riffle splitter. The tailings grade was analysed using the Atomic Absorption Spectroscopy (AAS) technique and was found to be an average of 0.5 g/tonne. A comparative Pseudo-Equilibrium test showed that the novel C-MgO nano adsorbent had an average of 84% recovery against 70 % for convectional activated carbon. The average crystalline size of 4.5 -11nm for the majority of MgO nanoparticles was obtained using Debye-Scherrer formula. FESEM confirmed that nano MgO was porous in nature and highly agglomerated whilst EDX exhibited the successful synthesis of the nano-composite product. This work also shows that the nano-adsorbent presents a huge potential for application in the conventional processes for gold adsorption.

Keywords

adsorptionnanostructureAuchemical synthesis
Type
Articles
Information
MRS Advances , Volume 3 , Issue 34-35: African Materials Research Society 2017 , 2018 , pp. 1955 - 1967
Copyright
Copyright © Materials Research Society 2018 

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References

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