Electrometallurgy 2020: Hydrometallurgy
Sponsored by: TMS Extraction and Processing Division, TMS: Hydrometallurgy and Electrometallurgy Committee, TMS: Process Technology and Modeling Committee, TMS: Pyrometallurgy Committee
Program Organizers: Antoine Allanore, Massachusetts Institute of Technology; Michael Free, University of Utah; Georges Houlachi, Hydro-Quebec; Hojong Kim, Pennsylvania State University; Takanari Ouchi, University of Tokyo; Shijie Wang, Coeur Mining, Inc
Monday 8:00 AM
February 24, 2020
Room: 14A
Location: San Diego Convention Ctr
Session Chair: Michael Free, University of Utah; Georges Houlachi, Hydro-Quebec
8:00 AM Introductory Comments
8:05 AM Keynote
Future Prospects for Copper Leaching, Solvent Extraction and Electrowinning Technology: David Dreisinger1; 1University of British Columbia
The hydrometallurgical recovery of copper by leach, solvent extraction and electrowinning has been practiced for more than 50 years. The treatment of oxide and secondary sulphide ores is well established. The processing of primary copper sulphide ores using processes such as chloride leaching, the JX Nippon Iodine Process and the Jetti Process have been developing rapidly. The hydrometallurgical treatment of copper flotation concentrates has also been undergoing continuous development with special interest in lower grade or complex materials containing penalty elements such as arsenic. All of these new leaching technologies are expected to provide continued or expanded use of copper electrowinning for metal production.
8:35 AM
Effective Copper Diffusion Coefficients in CuSO4 – H2SO4 Electrowinning Electrolytes: Joseph Bauer1; Michael Moats1; 1Missouri University of Science and Technology
Mass transport is an important factor in the deposit quality of copper electrowinning. Presently, there is limited diffusivity data available at commercially relevant concentrations between 25 and 40 °C. Linear sweep voltammetry at a rotating disk electrode was used to measure effective diffusion coefficients of cupric ion for a wide range of copper concentrations (10-50 g/L), sulfuric acid concentrations (120-240 g/L), and temperatures (25-60 °C). The results were well correlated by the equation: D, m2/s = 2.977×10-10 - 5.462×10-13 [Cu] - 1.212×10-12 [H2SO4] + 1.688×10-11×T, where [Cu] and [H2SO4] are in g/L, and T is °C. Addition of 20 mg/L Cl- slightly increased diffusivity. Other common commercial organic smoothing agents were found to have no effect. The measured diffusivities were used to calculate the maximum permissible current density that can produce smooth dense cathodes as a function of copper concentration and temperature.
8:55 AM
Theories of Electrodeposition, Beings-of-reason, and Reality: Peter Adcock1; Cora Masterlark2; 1PalaTeck Scientific LLC,; South Dakota School of Mines & Technology; 2South Dakota School of Mines & Technology
In any modern science, the interpretation of experimental results often leads to postulation of then unverified entities and these “beings of reason” may become incorporated into scientific theories. Strictly, a being of reason is something with no independent existence outside the human mind. Occasionally, a postulated entity is shown beyond doubt to correspond to a “new” real being. In this paper, examples will be discussed of postulated chemical entities or mechanistic details in modern theories of electrodeposition. Zinc will be considered, then other metals. Several notions of processes / intermediates involved in electrodeposition will be compared, each being scrutinized in terms of chemical reasonableness and agreement with laws and empirical results from studies of external reality. Elimination of some spurious entities or steps may give more acceptable theories of electrodeposition, which would provide firmer ground for meeting current challenges in existing processes, for innovation, and for development of new processes.
9:20 AM Break
9:35 AM
The Electrochemical Conversion of Chalcopyrite to Less Refractory Mineral Phases for Hydrometallurgical Processing: Jonathan Vardner1; Campbell Donnelly1; Zhengyan Zhang1; Minghui Wang1; Angela Ye1; Scott Banta1; Alan West1; 1Columbia University
The high demand for copper is causing a sharp decline in the grade of copper reserves, and as a result, copper scarcities are expected to arise by 2050. In this work, a transformative hydrometallurgical process is being developed to lower the costs of copper production and thereby sustain its use for the coming decades. It has been demonstrated that an electrochemical reactor can convert chalcopyrite into mineral phases that are more susceptible to oxidative treatment. The efficiency of the electrochemical reaction is improved by optimizing the electrode materials, applied current density, and reactor design. The bulk and surface phases of the chalcopyrite mineral during the progression of the electrochemical reaction are monitored using XRD and XPS, respectively. The operating steps for the complete process consist of open-pit mining, concentrating ore, electrochemical conversion, leaching, solvent extraction, and electrowinning. A preliminary analysis suggests that the process can be competitive with industrial standards.
9:55 AM
Modeling Nickel and Zinc Electrowinning Based on Ion Mass Transport and Electrode Reaction Kinetics: Zongliang Zhang1; Michael Free1; 1University of Utah
Nickel and zinc are two metals commonly produced by electrowinning. An advanced electrowinning model has been developed for the simulation of Ni and Zn electrowinning processes by taking into considerations their process-specific characteristics. Gas-liquid two-phase flow, mass transport, and electrochemical reactions are included. For Ni electrowinning, the electrode diaphragms were incorporated into the model with a volume force form of Darcy’s Law developed by the authors. The effects of electrode diaphragms on the fluid flow, concentration, voltage drop, and current distribution were analyzed based on the simulation results. For Zn electrowinning, the current efficiency drop due to the hydrogen evolution on the cathode was studied by involving the hydrogen evolution reaction kinetics into the model. The effects of Zn concentration, H2SO4 concentration, temperature, and current density on the current efficiency were investigated with the model.