Materials Processing Fundamentals: Thermodynamic Modeling
Sponsored by: TMS Extraction and Processing Division, TMS: Process Technology and Modeling Committee
Program Organizers: Jonghyun Lee, Iowa State University; Guillaume Lambotte, Boston Metal; Samuel Wagstaff, Oculatus Consulting; Antoine Allanore, Massachusetts Institute of Technology; Fiseha Tesfaye, Metso Metals Oy, Åbo Akademi University
Wednesday 2:00 PM
February 26, 2020
Room: 13
Location: San Diego Convention Ctr
Session Chair: Guillaume Lambotte, Boston Metal; Fiseha Tesfaye, Åbo Akademi University
2:00 PM Invited
Thermodynamic Modeling of as Oxide in the Na2O-CaO-MgO-SiO2 System and its Application to as Oxide Stabilization Process using Glass Formation: Jun-hyung Lee1; Sunyong Kwon1; Pierre Hudon1; In-Ho Jung2; 1McGill University; 2Seoul National University
Copper industry accesses more and more arsenic containing mineral deposits due to the depletion of copper ores. Even in gold industry ore bodies containing significant levels of arsenic are under consideration. In the pyro and hydro process of such minerals, arsenic becomes a major environmental issue to be resolve for the sustainable processing. One of possible industrial routes to minimize the arsenic environmental problem is the stabilization of arsenic oxide into glass phase. In order to understand the fundamental of such stabilization process and design the proper glass composition and operation condition, the thermodynamics of As oxides in the Na2O-CaO-MgO-SiO2 liquid and glass is indispensable. In the present study, the thermodynamic modeling of the As2O5-Na2O-CaO-MgO-SiO2 system and its application to glass composition and operation process design for arsenic stabilization will be presented.
2:40 PM
Structure-thermodynamics Interrelation for the GeO2 and PdO Containing MgO-saturated Ferrous Calcium Silicate (FCS) Slag Relevant to E-waste Processing: Mohammad Hasan1; M. Akbar Rhamdhani1; Mohammad Shuva2; Geoffrey Brooks1; 1Swinburne University of Technology; 2PF Metals
In black copper smelting, the recovery of the valuable metals from the electronic waste depends on the slag and copper’s chemistries. It is therefore important to understand the slag chemistry and its relation to the structure, thermodynamics and how these are affected by processing conditions. This paper explains the recent work from the authors on the study of the structure of MgO saturated Ferrous-Calcium-Silicate (FCS) slags containing Cu2O, GeO2 and PdO investigated using FTIR (Fourier-Transformed Infra-Red) spectroscopy. The effect of slag chemistry on the structure of silicate slag was evaluated. The partition ratio of Ge and Pd in slag and copper was correlated to the structure of the FCS slags. It was found that acidic slags with lower nonbridging oxygen per tetrahedra (NBO/T) are more favourable for Ge-partitioning to copper and for Pd the relation is the opposite.
3:00 PM
Thermodynamic Modeling of Metal Distribution in Electrolytic Extraction: Mary Elizabeth Wagner1; Antoine Allanore1; 1Massachusetts Institute of Technology
Achievement of a high-purity metal product during electrolysis challenges both the primary (e.g. from ore) and secondary (e.g. recycled product) metal extraction industries. Prediction of co-deposition of metallic elements is often limited to standard-state thermodynamics and trial-and-error experimentation. However, in high-temperature processes where both the metal product and the electrolyte can be molten, the thermodynamic behavior of the electrolytic cell as well as the liquid-liquid equilibria thus established will heavily influence which metal, and what purity, is produced from a feed containing multiple metal species. By carefully tailoring the activities of the electrolyte species and cathode products, it is thermodynamically possible to bias the reduction reaction towards one species over another. Therefore, the thermodynamics of both the electrolyte and metal products should be very carefully defined. This talk will discuss the modeling of metal/electrolyte equilibria, and how this approach informs the resulting cathode product compositions.
3:20 PM Break
3:40 PM
Printed Circuit Board Leached Residue as a Substitute Reducing Agent in Pyrometallurgical Processes: Desmond Attah-Kyei1; Guven Akdogan2; Daniel Lindberg1; Christie Dorfling2; 1Aalto University; 2Stellenbosch University
The proliferation of technology has resulted in the rise of electronic waste (e-waste) generated. The main focus of recycling e-waste has been to recover the metallic fractions from printed circuit boards (PCB) due to the inherent high value of metals present such as gold. Hydrometallurgical route, often the most preferred option for recovering the metals, does not address the issue posed by the non-metallic part. In this study, the use of leach residue of PCB as reducing agent in hematite reduction was investigated. Analysis on the leached boards showed that PCB is highly amorphous and has carbon content of 30.10% oxygen content of 20.1%, with ash and volatile matter of 40.1% and 44.8% respectively.Thermodynamic modelling and laboratory-scale experiments that simulate solid-state reduction of hematite were performed using FactSage™ and Single particle reactor. The results revealed that PCB can used to partially replace conventional reducing agents.
4:00 PM Cancelled
The Chemical Stability of MoS2 in Chloride Eutectic Molten Salt: Cheng Lv1; Jianxun Song1; Yusi Che1; Yongchun Shu1; Jilin He1; 1Zhengzhou University
Molten salt electrolysis is used for the preparation of metal with high purity. When dealing with metal sulfides, a modified FFC process shall prevent the emission of sulfur oxides if a protective atmosphere is provided. Instead, sulfur should be the anodic product. In order to investigate chemical stability of MoS2 during electrolysis process, the chemical behaviors of MoS2 in chloride eutectic molten salt system (NaCl-KCl, CaCl2-KCl, CsCl-KCl and LiCl-KCl) was studied separately. In addition, the influence of K2S on chemical stability of MoS2 was also investigated. In this paper, MoS2 pallets were immersed into the molten salt for 8h and the SEM graph of the boundary between the pellet and salt was obtained. XRD was also used to investigate the existence of the intermediate product. In conclusion, MoS2 holds a rather high chemical stability in most common chloride eutectic molten salts, except for CsCl-KCl-K2S system, where some different phenomenon occurred.