Pan American Materials Congress: Minerals Extraction and Processing: Waste Treatment and Processing
Sponsored by: Third Pan American Materials Congress Organizing Committee
Program Organizers: Mery Gómez Marroquín, Asociacion Peruana de Metalurgia Materiales y Minerales-APMMM; Mark Schlesinger, Missouri University of Science and Technology; Alejandro Valdivieso, U.A. of San Luis Potosi; Carlos Sampaio, UFRGS

Wednesday 3:40 PM
March 1, 2017
Room: Marina E
Location: Marriott Marquis Hotel

3:40 PM  
Comparative Study of Gas Reduction of Pure Zinc Ferrite and Zinc Ferrite Contained into Electric Arc Furnace Dusts: Mery Gómez-Marroquín1; Jose Carlos D´Abreu2; 1Universidad Nacional de Ingenieria; 2Pontificia Universidade Catolica do Rio de Janeiro
    The present work deals about the zinc ferrite-ZF synthesis, occurred through a solid-solid reaction in a selected range of temperatures, using as reactant an equimolar mixture of pure iron oxide and pure zinc oxide. After that, took place the reduction of equimolar synthetic ZF and Electric Arc Furnace Dusts-EAFD by gas mixtures CO - CO2, from 50% and 100% of CO and from 1073 to 1373 K. Both materials were supported by physical, chemical, structural and microscopic characterizations. The maximum reductions of ZF indexes obtained in these experiments were 85%, for 100% CO at 1373K in 105 min and 52%, for 50% CO at 1373K, elapsed 105 min and 100%, for 100% CO at 1273K, in 80.75 min, and 60%, for 50% CO at 1373K during 105 min in the case of EAFD reduction.

4:00 PM  
Biotechnological Recycling of Precious Metals Sourced from Post-consumer Products: Norizo Saito1; Toshiyuki Nomura1; Yasuhiro Konishi1; 1Osaka Prefecture University
    We have developed new recycling technologies, based upon an eco-friendly biotechnology, in order to extract precious metals sourced from post-consumer products. Recently we have been focusing on metal ion-reducing microorganisms, Shewanella bacteria that are able to separate and concentrate platinum group metals and gold from solution into microbial cells. In a process, Shewanella bacteria can then be processed to generate metallic nanoparticles at room temperature, within 60 min. When processing the aqua regia leachate of printed circuit boards, Shewanella bacteria were able to rapidly and selectively collect gold ions from acidic solution. This microbial ability demonstrates the potential for commercialization of this bio-recovery process. The biotechnological procedure also has the potential to allow the recovery of platinum group metals from the leachates of spent automotive catalysts. Our proposed biological method enables the rapid and highly efficient recovery of precious metals by using microbial reactions at room temperature.

4:20 PM  
Extraction of Gold from Sands and Slimes Tailings Dump from Mazowe Mine, Zimbabwe: Alain Bantshi1; 1Baldmin Projects
     The Mazowe Gold Mine is managed by Metallon Gold (Zimbabwe) and is situated in the west-central part of the Harare greenstone belt. Orebodies here generally comprise shear zones which are in-filled with gold-bearing sulphides and quartz. The mineralised zones are up to 1 m in width, have average grades of 4 to 5 g/t. Mazowe Mine is one of the oldest mines in Zimbabwe, and exploration and development in this region dates back to 1890, with over 1.4 million ounces of gold produced to date. Ore is processed in a single plant which consists of conventional crushing and milling and carbon-in-leach facility. Baldmin Projects was awarded the contract for the design, construction and commissioning of the 60,000 tonnes per month plant at Mazowe mine in 2014 for the processing of sand and slimes tailings from previous operations at Mazowe mine. The average grades of the tailings is 1.1 g/t.

4:40 PM  
Reduction Kinetics and Characterization Study of Synthetic Magnetite Micro Fines: Saikat Kuila1; Ritayan Chatterjee1; Dinabandhu Ghosh1; 1Jadavpur University
    The present work deals with the characterization of pure magnetite microfines (<5μm) and its hydrogen reduction. The structural and morphological properties of magnetite powder were analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption analysis by five points isotherm BET method, and scanning electron microscopy along with energy dispersive X-ray spectroscopy (SEM-EDS). The hydrogen reduction of the magnetite powder was carried out in a thermogravimetric analyzer (TGA) under a steady flow of hydrogen or hydrogen-argon mixture (to produce different partial pressures of hydrogen). The variables studied were reduction temperature (973-1273 K), hydrogen partial pressure (0.25-1 atm) and sample bed height (0.184-0.68 cm). The apparent activation energy was obtained as 22 kJ mol-1. The rate equations developed for the reaction system under study were applied to determine the rate controlling step. The reduction was found to be rate controlled by diffusion through the stagnant gas film enclosed above the sample inside the crucible. The true activation energy was calculated to be 9 kJ mol-1.

5:00 PM  
Novel Adsorbent from Iron Ore Concentration Tailings for Toxic Cationic Dye Removal from Water: Yongmei Wang1; Alejandro Lopez-Valdivieso2; Teng Zhang3; Teza Mwamulima3; Changsheng Peng3; 1College of Environmental Science and Engineering, Ocean University of China; Instituto de Metalurgia, Universidad Autónoma de San Luis Potosí; 2Instituto de Metalurgia, Universidad Autonoma de San Luis Potosi; 3College of Environmental Science and Engineering, Ocean University of China
    A novel adsorbent (FB-mZVI) was prepared, using tailings from iron ore concentration plants, fly ash and bentonite, to remove toxic crystal violet (CV) and methylene blue (MB) from water. The adsorbent was prepared as cylindrical-shape pellets to easily separate it from the water after the adsorption process. SEM Characterization revealed that the adsorbent was highly porous and constituted by Feo particles finely dispersed on an aluminosilicate matrix. The FB-mZVI adsorbent showed to have a superior adsorption capacity for CV and MB when compared to conventional adsorbents. Optimal synthesis parameters for the adsorbent synthesis are presented. In addition, adsorption mechanisms are proposed for the removal of CV and MB by the adsorbent.

5:20 PM  
Removal of Heavy Metals from Water with Nano-Sheet Molybdenite as Adsorbent: Feifei Jia1; Shaoxian Song1; 1Wuhan University of Technology
    Nano-sheet molybdenite is a novel two-dimensional material with single or several layers of MoS2 sheets. The common method for preparing nano-sheet molybdenite is to exfoliate bulk molybdenite through chemical method based on ion intercalation. After the exfoliation process, large quantities of oxidant functional groups are present on the nano-sheet molybdenite surfaces, increasing the active sites and surface energy. In addition, the surface is composed of two layers of S atoms, which was might be utilized as a adsorption sites for many kinds of heavy metals. In this work, the efficiency of nano-sheet molybdenite was firstly explored in the removal of heavy metals (Hg and Pb) from contaminated water. The adsorption isotherms and kinetics were presented, as well as SEM, AFM and XPS results for the adsorption mechanisms. The results have demonstrated that nano-sheet molybdenite could be a very effective adsorbent for removing the heavy metals from water.