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

  • PDF / 1,326,802 Bytes
  • 13 Pages / 432 x 648 pts Page_size
  • 22 Downloads / 206 Views

DOWNLOAD

REPORT


MRS Advances © 2018 Materials Research Society DOI: 10.1557/adv.2018.314

Adsorptive Recovery of Auro-Dicyanide Anions from Aqueous Solutions using Activated CarbonMagnesium Oxide (C-MgO) Nanocomposite as Adsorbent Madzokere Tatenda C1, Musarurwa Gey T1, Jere Godcontrols1, Chitambwe Trymore1, Chiririwa Haledene2 1

Department of Chemical and Process Systems Engineering, School of Engineering and Technology, Harare Institute of Technology, P. O. Box BE 277, Belvedere, Harare, Zimbabwe

2 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

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 Xray 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 nanoadsorbent. Representative tailings samples of 100-500 g were

Downloaded from https://www.cambridge.org/core. University of Warwick, on 21 May 2018 at 00:19:46, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1557/adv.2018.314

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.

Corresponding Author: Madzokere T. C, [email protected]

I.

INTRODUCTION

Gold predominantly exist