11th International Symposium on High Temperature Metallurgical Processing: High-Temperature Processing
Sponsored by: TMS Extraction and Processing Division, TMS: Pyrometallurgy Committee
Program Organizers: Zhiwei Peng, Central South University; Jiann-Yang Hwang, Michigan Technological University; Jerome Downey, Montana Technological University; Dean Gregurek, RHI Magnesita; Baojun Zhao, Jiangxi University of Science and Technology; Onuralp Yucel, Istanbul Technical University; Ender Keskinkilic, Atilim University; Tao Jiang, Central South University; Jesse White, Kanthal AB; Morsi Mahmoud, King Fahd University Of Petroleum And Minerals

Tuesday 2:00 PM
February 25, 2020
Room: 12
Location: San Diego Convention Ctr

Session Chair: Tao Jiang, Central South University; Ender Keskinkilic, Atilim University


2:00 PM Introductory Comments

2:15 PM  
Control of the Distribution of Vacuum Arcs within Vacuum Arc Remelting with Externally Applied Magnetic Fields: Paul King1; Matthew Cibula1; Joshua Motley1; 1Ampere Scientific
    Ampere Scientific has previously developed and provided industrial validation of the VARmetricTM measurement system to measure the location of electric arcs during vacuum arc remelting (VAR) of high temperature specialty alloys. With the advent of VARmetricTM, it is now possible to continuously monitor and control arc distributions in order to tailor the heat flux that drives solidification during the VAR process. Laboratory experiments have applied transverse magnetic fields to generate specified Lorentz forces as a control mechanism across the arc gap in order to drive arc locations to predetermined distributions. This type of control makes it possible to react to undesirable arc conditions during VAR operations or to provide a continuous control to specify a thermal profile for heat input to the melt pool necessary for ensuring defect free ingots.

2:35 PM  
High Temperature Processing of Tungsten Slag: Xu Wang1; Xiaodong Ma2; Chunfa Liao1; Baojun Zhao2; 1Jiangxi University of Science and Technology; 2University of Queensland
    Tungsten is extraordinary important for a broad range of industrial processes. It has the highest melting point of all metals (3410 oC) and a high density of 19.3 g/cm3. Tungsten carbide is known as one of the hardest materials. Tungsten is economically extractable from the two minerals wolframite ((Fe,Mn)WO4) and scheelite (CaWO4) through the intermediate ammonium paratungstate (APT). Tungsten concentrates are usually digested either by concentrated NaOH solution or by soda to form sodium tungstate solution which is further converted to APT. The leaching residue (tungsten slag) separated from the sodium tungstate solution consists of significant valuable metals such as W, Mo, Cu, Sn, Mn and Fe. These metals can be efficiently recovered by high temperature process with optimum conditions. Experimental work and thermodynamic calculations confirmed that most of the valuable metals can be concentrated to a low-melting point alloy and the clean slag can be used for cement additives.

2:55 PM  
Upgrading Pilot-scale Facility at MINTEK to Evaluate the Effect of Pre-heating on Smelter Operations: Joalet Steenkamp1; Glen Denton1; Tertius Pieters2; 1MINTEK; 2Allied Furnace Consultants
     MINTEK in South Africa is investigating the effect of pre-heating on smelter operations mainly to reduce the electrical energy requirement for smelters. A pilot-scale facility is being developed which includes a one t/h rotary kiln coupled to an electric arc furnace (EAF) optionally served by either an alternating current (AC) or direct current (DC) power supply. The facility also includes integrated materials handling, product handling, and water-cooling systems. It allows for the evaluation of cold vs. hot feed (up to 900°C) on smelter operations over periods of 2–3 weeks continuous operation. The first application will study the effect of pre-heating onthe smelting of titaniferous magnetite (15% TiO2) using a DC-furnace as part of the TiMag project. The second application will evaluate the effect of pre-heating on the production of high carbon ferromanganese (targeting 78%Mn) using an AC-furnace as part of the PreMa project. The paper presents the results of the basic engineering of the project.

3:15 PM  
Influence of Atmosphere on Melting Behaviour of Synthetic Slags from Ta Recycling: Dominik Hofer1; Stefan Luidold1; 1Montanuniversitaet Leoben
    Tantalum joined the list of 43 critical raw materials (CRM) concerning the latest report of the European Comission, published in 2017. Global Ta and Nb ore production, publicly known as Coltan, is dominated by D.R. Congo and Rwanda accounting for a combined share of at least 60 %. Recycling constitutes an evolving chance for European countries to lower the complete reliance on importation. Consequently, tin slags as well as process residues like dusts or sludges are processed by pyrometallurgical treatment and hence offer great economic potential due to the content of valuable Ta2O5. Flowability tests with various atmospheres are performed to evaluate the similarity of industrial and synthetic slags. These experiments, thermodynamic FactSage simulations plus slag viscosity calculations provide a solid foundation for follow up high temperature furnace rheometer trials, to deepen fundamental knowledge about such melts and improve existing process steps.

3:35 PM Break

3:50 PM  Cancelled
Non-isothermal Kinetics of Carbothermic Reduction of Fayalite: Zhi Li1; Guojun Ma1; Xiang Zhang1; Wei Zhang1; 1State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology
    Fayalite is one of the major components in many metallurgical slags, such as copper slag and nickel slag, which contains higher iron grade than that in minable iron ores. It is believed that carbothermal reduction process at high temperature is an effective way to reutilize fayalite-bearing slags. In this paper, the non-isothermal reduction kinetics of fayalite were conducted using thermogravimetric differential thermal analyzer heated to 1400℃ with different contents of carbon and heating rates. The methods of Flynn-Wall-Ozawa and Coats-Redfern were adapted to handle the kinetic data. The results show that the activation energy increases until the conversion rate is 50% due to the deterioration of kinetic conditions, and then decrease. By method of Coats-Redfern, the model reaction is the interfacial reaction, and the activation energy is 514.20 kJ/mol.

4:10 PM  
Preparation of Expanded Slag Ball with Blast Furnace Slag by Rotary Cup: Feifei Pan1; Xuewei Lv1; Wenchao He1; Guishang Pei1; 1ChongQing University
    Molten blast furnace (BF) slag is a kind of high temperature liquid resource with abundant waste heat has not been recycled in iron and steel making industry. At present, the treatment of blast furnace slag is usually water quenching and air cooling accumulation. But, there are some disadvantages in this way to treatment of blast furnace slag, such as serious air pollution and high water consumption. This paper described the preparation of expanded slag ball with blast furnace slag by rotary cup. The effects of rotating speed, diameter of rotary cup and water content on particle size distribution, vitreous content and grindability of slag ball were studied. The blast furnace slag ball produced by this method can realize self-drying because of its own heat. It does not need follow-up dehydration, drying and other processes to save energy.

4:30 PM  Cancelled
Study of the Influence of the Angle Between the Bottom Blowing Elements on the Dynamic Conditions of the 300t Converter: Liujie Yao1; Rong Zhu1; Huixiang Yu1; Kai Dong1; Qiang Feng1; Yixing Tang1; 1University of Science and Technology Beijing
    In this paper, numerical simulation and hydraulic model experiments were carried out to study the influence of the angle between the bottom blowing elements and gas flow rate on the flow characteristics of the molten pool in a 300t converter. The results showed that the mixing time and velocity field distribution of the molten bath changed with the angle between the bottom-blowing nozzles, and increasing the bottom-blowing gas flow rate was beneficial to improve the dynamics condition of the bath, thereby accelerating mass transfer process and reducing the volume fraction of the dead zone. Two arrangements with angle of 90° and 105° were applied to two furnace campaigns, respectively. The industrial experiments showed that when the angle between the nozzles was large, it was favorable for accelerating the decarburization and dephosphorization, reducing the endpoint carbon-oxygen equilibrium of molten steel and reducing the contents of FeO and TFe in endpoint slag.