8th International Symposium on High Temperature Metallurgical Processing: Extraction and Recovery of Metals
Sponsored by: TMS Extraction and Processing Division, TMS: Pyrometallurgy Committee
Program Organizers: Jiann-Yang Hwang, Michigan Technological University; Tao Jiang, Central South University; Mark Kennedy, Proval Partners SA; Onuralp Yücel, ITU; P. Chris Pistorius, Carnegie Mellon University; Varadarajan Seshadri, Universidade Federal de Minas Gerais; Baojun Zhao, The University of Queensland; Dean Gregurek, RHI AG; Ender Keskinkilic, Atilim University

Wednesday 8:30 AM
March 1, 2017
Room: 18
Location: San Diego Convention Ctr

Session Chair: P. Chris Pistorius, Carnegie Mellon University; Ender Keskinkilic, Atilim University

8:30 AM Introductory Comments

8:35 AM  
Effect of Carbon Reductant On The Formation of Copper Doped Titanium Oxycarbonitride by Carbothermal Reduction and Nitridation: Yong Jing Hui1; Sheikh Abdul Rezan1; Noor Izah Shoparwe1; Norlia Baharun1; Srimala Sreekantan1; Ahmad Fauzi Mohd Noor1; 1Universiti Sains Malaysia
    In this paper, the effect of carbon reductant on carbothermal reduction and nitridation of Copper doped titanium oxide (Cu-TiO2) was investigated. Reduction was performed under H2-N2 (50 vol.% N2) gas mixtures with a temperature range of 1100°C-1300°C for 1-3 hours respectively. Three different carbon reductant were investigated in the reaction and there were graphite, activated carbon (AC) and carbon nanotubes (CNT). The highest extent of reduction of 99.9% was obtained at 1300°C for 180 min using 1:4 carbon to oxide molar ratio with CNT. Extent of nitridation was 71.7% while extent of carburization was 28.2% for this sample. Elemental analysis indicated an oxycarbonitride phase with a composition of Cu-TiO0.002C0.28N0.717. With CNT and AC as a reductant, the formation of Cu-TiOxCyNz occurred at 1100°C after 180 minutes. Increasing the reduction temperature, time and molar ratio, increased the TiN and TiC content in the synthesized Cu-TiOxCyNz.

8:55 AM  
Cohering Behavior of Scrap Powder in Kiln by a Novel Natural Stacking Method: Xiao-liang Liu1; Yong-bin Yang1; Yan Zhang1; Qian Li1; Bin Xu1; Tao Jiang1; 1Central South University
    The cohering behavior of scrap powder in kiln cannot be reflected entirely through the conventional briquette method, so a novel natural stacking method was proposed in this paper. The results show that the cohering strength of different powders showed the same result in the two methods as following: C>B>A, the cohering briquette strength of natural stacking powders increased with the increase of firing time and temperature, but the compact powders could obtain higher briquette strength in the condition of shorter time and lower temperature. Meanwhile, the microstructure analysis of field ring and cohering briquette in natural stacking method indicate that both of them the connection state of crystallized particles were extremely similar. Therefore, initial cohering information of natural stacking powder could be given by the natural stacking method, improving the methods to study the ringing mechanism and reflecting the actual cohering process of powder in kiln.

9:15 AM  
Direct-to-blister Copper Smelting with the ISASMELT™ Process: Paul Voigt1; Alistair Burrows1; Michael Somerville2; Chunlin Chen2; 1Glencore Technology; 2CSIRO Mineral Resources
    To date, many types of primary concentrate have been smelted using the ISASMELT™ technology, with annual smelting of copper concentrate alone exceeding 7 million tonnes. Most of this material could best be described as chalcopyrite concentrate. The ISASMELT™ technology also stands ready to meet future copper demand through the treatment of new types of concentrates containing relatively low iron and high silica. Two slag systems have been considered for direct-to-blister smelting namely, silica-iron oxide (fay-alite) and lime-silica-iron oxide. These two slag systems were evaluated computationally, using the MPE thermodynamic modelling package, and practically, at pilot scale. The lime-silica-iron oxide slag was found to have the lowest slag make, lower dissolved copper and hence lowest copper loss-es. Based on the outcomes of the modelling and pilot scale testwork a future smelter flowsheet has been defined, comprising a single ISASMELT™ direct-to-blister furnace, an electric slag cleaning furnace, and appropriately designed anode furnaces.

9:35 AM  
Microwave-intensified Reduction of Biochar-containing Briquettes: Zhiwei Peng1; Xiaolong Lin1; Tiancheng Nie1; Zhizhong Li1; Yuanbo Zhang1; Guanghui Li1; Tao Jiang1; 1Central South University
    The coal-based direct reduction process has gradually become the focus of research concerning direct reduced iron production due to its advantages, including high reduction rate, stable chemical composition, and good metallurgical properties. Based on coal-based reduction theory and briquetting technique, this paper reports the use of microwave energy for intensifying the reduction of carbon-containing briquettes mainly consisting of magnetite concentrate and biochar. The heating behaviors of the raw materials show that under the conditions of microwave power of 1250 W, N2 flow rate of 4 L min-1 and briquetting pressure of 400 N, the briquettes present the highest heating rate. The average heating rate reaches 35.16 oC min-1. When the briquettes are irradiated by microwaves at 1050 oC for 45 min, the metallization degree of the reduced briquettes reaches 93.58%.

9:55 AM  
Improving Separation of Cu-Fe from Copper Slag by Mineral Phase Reconstruction: Zhengqi Guo1; Deqing Zhu1; Jian Pan1; Feng Zhang1; 1Central South University
    As iron mainly exists in the magnetite and fayalite, while copper is primarily dispersed in the form of fine matte particle in the copper slags, which are difficult to recover by conventional separation techniques. In this paper, the feasibility of an integrated technological route to improve beneficiation of copper and iron components from copper slag through modification of molten slag was investigated, and the results shows that: the copper grade of rougher copper concentrate was increased from 6.43% to 11.04%, iron recovery of magnetic separation was increased significantly from 32.40% to 63.36%, and other evaluation indexes were changed slightly, in comparison with unmodified copper slag. Meanwhile, the grains of the target minerals in the modified slag grew obviously to the mean size over 50μm after slow cooling. Ultimately, the beneficiation efficiency of copper and iron was improved because of the ease with which the target minerals were liberated.

10:15 AM Break

10:35 AM  
Evaluation of Molybdenum Concentrates: Kagan Benzesik1; Seref Sonmez1; Onuralp Yucel1; 1Istanbul Technical University
    The aim of this study is processing of local molybdenum concentrate to produce quality molybdenum trioxide may be the starting material for the production of various molybdenum products. In order to determine the optimum parameters for the total oxidizing roasting process of molybdenite concentrate to produce MoO3 and purify the MoO3 product by removing the copper content; first, MoS2 was roasted by controlling reaction temperature and duration in a chamber type furnace. The highest Mo concentration rate was obtained as 56.6 wt.% of Mo at 650 °C for the roasting duration of 45 minutes. Secondly, roasted product was leached by H2SO4 to remove copper. Leaching conditions were optimized by investigating the effects of different H2SO4 concentrations and S/L ratios. The minimum copper content was obtained as 0.13 wt.% at leach residue. The raw materials and the products were characterized by using AAS (atomic absorption spectrometry) and XRD (X-Ray Diffraction) techniques.

10:55 AM  
Sensitivity of Contactless Ultrasound Processing to Variations of the Free Surface of the Melt with Induction Heating: Georgi Djambazov1; Valdis Bojarevics1; Dmytro Shevchenko2; David Burnard2; William Griffiths2; Koulis Pericleous1; 1University of Greenwich; 2University of Birmingham
    Contactless ultrasound treatment can be useful for high-temperature alloys where contact with a vibrating probe is undesirable. The necessary sound pressure levels leading to cavitation of the appearing microscopic gas bubbles can be achieved via acoustic resonance. When the melt is heated by induction,the top free surface is not planar and its precise shape may influence the resonance conditions. This is investigated by multi-physics computer modeling. Calculated results for aluminum melts are compared with experimental data. Conclusions are drawn for the sensitivity to process parameters and the reliability of this type of ultrasound metal processing.

11:15 AM  
Extraction of Zinc from Willemite by Sodium Salt Roasting and Ammonia-leaching Process: Xu Dong Liu1; Gang hua Fu1; Yu Feng Guo1; Tao Jiang1; Wei Chen1; Yu jia Tan1; 1Central South University
    Willemite is usually found in high-silicon oxide zinc ore and zinc metallurgical secondary resources but without effective extraction method yet. In this study, zinc was extracted from willemite by sodium salt roasting ammonia-leaching process based on the idea of zinc phase reconstruction. The effect of Na2CO3 dosage, roasting temperature and roasting time on the phase transformation and zinc leaching rate were studied, respectively. The results show that Zn2SiO4 was transformed into ZnO or Na2ZnSiO4during roasting process. After roasting at 800°C for 2.5 hours at ratio of n(Na2CO3) /n(Zn2SiO4)=2.5:1 was thoroughly transformed into ZnO. .After roasting at 800°C for 2.5 hours at the molar ratio of n(Na2CO3)/n(Zn2SiO4)= 2.5:1,the Zn2SiO4 was thoroughly transformed into ZnO. The zinc leaching rate of the roasted sample was 97.62% in NH4Cl-NH3-H2O leaching system, which increased by 91.57 % compared with zinc leaching rate of 6.05% when willemite was directly leached in NH4Cl-NH3-H2O system.

11:35 AM  
Effect of Shrouding Gas on Nozzle Exit Pressure and Temperature of Supersonic Coherent Jet: Fei Zhao1; Lingzhi Yang2; 1University of Science and Technology Beijing; 2Central South University
    Supersonic coherent jet plays a vital role in the steelmaking process, its impact force and stirring ability determine the smelting process. The field characteristics of coherent jet is affected by shrouding gas. The shrouding gas affected the nozzle exit pressure and temperature. It creates a greater incorrect expansion of the supersonic jet at nozzle exit and leads to much kinetic energy loss and is bad for the movement of the supersonic jet. But there is few research about the relationship between the shrouding gas and the nozzle exit parameter of supersonic jet. In this paper, the nozzle exit pressure and temperature of coherent jet under different shrouding gas parameter conditions are studied by numerical simulation and experiment. The relationship between the shrouding gas parameters and the shrouding gas parameter is proposed. It will be of great importance to design parameter of the coherent jet nozzle.