Pan American Materials Congress: Minerals Extraction and Processing: Poster Session
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

Tuesday 5:30 PM
February 28, 2017
Room: Poster Area
Location: Marriott Marquis Hotel

PAN-42: Biotechnologies for Water Recycling in the Mineral Industry: Natalia Barboza1; Sueli Bertolino2; Renata Guerra-Sá1; Versiane Leao1; 1Universidade Federal de Ouro Preto; 2Universidade Federeal de Uberlandia
    Biotechnological processes are important alternatives for water recycling in hydrometallury and mineral processing and thus this paper is focused on two biotechnologies: (i) sulfate reduction and (ii) manganese bioremediation. While high sulfate concentrations are related to hydrometallurgical operations, manganese is one of the most difficult metals to remove from wastewaters. It is demonstrated herein that a bacterial consortium enriched from a mine water removed 99.7% Mn(II) from 50mg/L Mn solution. Molecular studies revealed Stenotrophomonas, Bacillus and Lysinibacillus genera in the sample. Cell metabolism resulted in a pH increase which catalyzed chemical Mn(II). Subsequently, sulfate reduction with sulfate reducing bacteria (SRB) was addressed. A fluidized bed reactor (FBR), containing immobilized biomass enabled a high bacterial population (> 10E9 cells/mL) in the bioreactor and thus a large sulfate reduction efficiency (97%) for a specific sulfate reducing rate (4.8 gSO4-2.gVSS-1.d-1). Vale and the funding agencies FINEP, CAPES, CNPQ, FAPEMIG are acknowledged.

PAN-43: Effect of Ethylenediamine on Smithsonite Flotation: Chao Lv1; Shuming Wen2; Shaojun Bai2; Kun Yang2; 1 Kunming University of Science and Technology,; 2Kunming University of Science and Technology,
    As a typical zinc oxide mineral, smithsonite has been developed as alternative sources of zinc metal to satisfy future demands with the gradual depletion of nature zinc sulfide ores. Restricted to inferior ability of floating, Zinc oxide is one well-known refractory zinc resource mineral with poor selectivity and high regent consumption.In this paper, ethylenediamine(NH2CH2CH2NH2) was selected to active flotation of smithsonite. The relationship of dosage of ethylenediamine and flotation efficiency was conducted, the results showed that the optimum dosage of ethylenediamine was 6×10-3 mol/L and flotation recovery could be reached to 95% when using dodecylamine-hydrochloride (5×10-4mol/L) as collector.this finding may have promote the recovery of refractory zinc oxide mineral resource.

PAN-44: Electrochemical Preparation of Ti5Si3/TiC Composite from Titanium-rich Slag in Molten CaCl2: Shangshu Li1; Xingli Zou1; Xionggang Lu1; Kai Zheng1; Xin Li1; Yinshuai Wang1; 1Shanghai University
    Ti5Si3/TiC composite has been successfully prepared from the titanium-rich slag/SiO2/C mixtures precursors by an electrochemical process. The electrochemical production process was carried out in molten CaCl2 salt at 1000 °C and 3.8 V. A pressed cylindrical pellet of titanium-rich slag/SiO2/C mixtures served as a cathode, and a solid oxide oxygen-ion-conducting membrane (SOM) tube filled with carbon-saturated liquid tin acted as an anode. The phase transformation of the cathode pellets during electrolysis process was investigated, the microstructure of the obtained products was characterized. It is found that the reaction pathways can be divided into three main stages during the electro-reduction process. The first stage is the generation of calcium compound, the second stage is the electrochemical reduction, and the third stage is the formation of Ti5Si3/TiC composite. The prepared Ti5Si3/TiC composite exhibits homogenous and nodular particle morphology.

PAN-45: Kinetic Study on the Leaching of Vanadium-bearing Converter Slag with Dilute Sulfuric Acid: Junyi Xiang1; Qingyun Huang2; Xuewei Lv1; Chenguang Bai1; 1School of Materials Science and Engineering, Chongqing University; 2School of Materials and Metallurgical Engineering, Chongqing University of Science and Technology
    Calcification roasting-sulfuric acid leaching process was used to the extraction vanadium from converter slag. The kinetics of the extraction process based on both unmilled and ball milled slags in dilute sulfuric acid solution (pH=2.5±0.2) were investigated. The results showed that the extraction of vanadium was a rapid process with particularly a considerable proportion of vanadium rapidly dissolved in the first 10 minutes. The kinetics analysis showed that the diffusion through product layer was rate–determining step in the course of the dissolution of vanadium. The linear relationship between the rate constant and the inverse square of the particle diameter also illustrated this phenomenon. Mechanical activation can significantly accelerate the vanadium leaching efficiency, and decrease the corresponding apparent activation energy from 9.94 kJ/mol to 7.63 kJ/mol.

PAN-46: Leaching of Celestite Concentrate in Hcl Media with BACl2-NACl Addition: Emre Yilmaz1; Aysegul Bilen1; Rasit Sezer1; Selim Erturk1; Ibrahim Hizli2; Cuneyt Arslan1; 1Istanbul Technical University; 2Istanbul University
    In this study, solubility of celestite concentrate in HCl-BaCl2-NaCl media is investigated. Experimental study is carried out to determine the basic parameters such as BaCl2 concentration (up to 1.1 times of stoichiometrically required), solid/liquid ratio (1/50, 1/100, 1/150, 1/200, and 1/250 w/v), effects of dissolving time (up to 240 min). Initial experiments are conducted at constant temperature (60 °C), stirring speed (500 rpm), HCl (0.5 M)-NaCl (1.0 M) concentrations, and grain size of celestite (-54 μm). Effect of stirring speed, HCl-NaCl concentrations and temperature are investigated separately to specify the optimum conditions. All the experiments are carried out in a three-necked glass reactor with a 500 ml capacity. AAS results of leach liquors show that increasing BaCl2 concentration and dissolving time causes dissolution efficiency to increase. On the other hand, increasing solid /liquid ratio decreases the leaching efficiency.

PAN-47: Mechanical Activation Strengthen the Leaching of Oxide-sulphide Zinc Ore: Kun Yang1; Shiwei Li1; Chao1; Libo Zhang1; Jinhui Peng1; 1Kunming University of Science and Technology
    In this paper, mechanical activation is adopt to strengthen the leaching of oxide-sulphide zinc ore. By means of chemical analysis, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscope and X-ray photoelectron spectroscopy et al. analysis technologies, effect of mechanical activation on the leaching of oxide-sulphide zinc ore is investigated. The results show that mechanical activation can truly improve leaching rate, and within one hour, zinc leaching rate is 85%, under conditions of total concentrate of ammonia being 7.5 mol/L, molar ratio of NH3 and NH4Cl being 1:1, the ratio of solid and liquid being 10: 1, and activation time being 2h, while in a magnetic stirring leaching, the leaching rate just can reaches 78%. The activation mechanism is also discussed in this paper.

PAN-48: Production of Strontianite from Celestite Ore in Carbonate Media: Ibrahim Hizli1; Aysegul Bilen2; Rasit Sezer3; Selim Erturk2; Cuneyt Arslan2; 1Istanbul University; 2Istanbul Technical University- ATUM; 3Karadeniz Technical University
    Celestite ore (SrSO4) is used as raw material for the production of strontium compounds utilized in industry. The aim of this study is to develop a new and highly efficient strontianite production method. Thus, the effect of particle size, time, and ammonia concentration on the conversion of celestite was investigated. Strontianite (SrCO3) was obtained from domestic celestite concentrate with direct conversion method in which celestite reacts with CO32- and NH4+ containing solution. (NH4)2CO3 solution was used as carbonate agent. Because the solution is decomposed at 58°C, experiments were performed low temperatures. Celestite ore was converted to strontianite between 3 to 6 hours depending on ammonia concentration and celestite mass. Characterization of celestite ore, products and reaction residues were carried out by DSC, TG, XRD, and AAS analytical techniques.

PAN-49: Recovery of Zinc from Oxide–sulfide Zinc Ore through Oxidation and Chelation: Kun Yang1; Libo Zhang1; Chao Lv; Shiwei Li1; Jinhui Peng1; 1Kunming University of Science and Technology
    In this paper, three different processes are designed for leaching of oxide–sulfide zinc ore. Through calculating and comparing redox potentials, suitable oxidations are determined for each process. Meanwhile, effects of different added amount of various oxidants such as Na2O2,NaClO, and H2O2 et al., on zinc leaching are investigated. Results show that in a process of simultaneously oxidizing and chelating, zinc leaching degree can reach 83.72% with Na2O2 adding 0.3 mol/L, in the process of oxidizing first followed by chelating, optimum leaching rate of oxide–sulfide zinc ore is 92.40% with Na2O2 adding 0.5 mol/L, and in the process of acidification-oxidizing in the beginning, and followed by chelating, leaching degree of zinc reaches 93.02% (84.50%) under condition of NaClO (H2O2) added amount being 0.1 mol/L. Though the optimum leaching rate of zinc is slightly different, all three processes show their values.

PAN-50: The Direct Leaching of Micro-disseminated Gold Concentrate by Bromide Process and the Characterization of Leaching Products: Chao Li1; Hongxu Li1; Qiankun Jing1; 1University of Science and Technology Beijing
    Gold is an important industry and strategic reserves of metal, but cyanide leaching process have adverse to the environment. In this paper, an absolutely non-cyanide bromide gold-leaching system was puts forward to leaching a kind of micro-disseminated gold concentrate from China.The influence of different reagent concentration and temperature on the bromide leaching process were tested in this research, and various testing methods as X-ray diffraction (XRD), scanning electron microscopy, infrared spectroscopy, and laser particle size analysis were carried to characterize the leaching residue.Results show that the leaching rate of Au is increasing as the concentration of leaching agent and oxidant rising; temperature rise will accelerate the leaching reaction rate, gold-leaching efficiency after 8h can reach 97.93%; XRD and infrared spectroscopy testing indicate that the mineral structure is destroyed completely, the desulfurization rate of S element can reach 96%.