Thermodynamic Modeling of Ni-C, Co-C, and Ni-Co-C Liquid Alloys Using the Modified Quasichemical Model
- PDF / 1,113,693 Bytes
- 10 Pages / 593.972 x 792 pts Page_size
- 1 Downloads / 209 Views
NTRODUCTION
NICKEL and cobalt are critical raw materials for high-tech products and emerging industries. They have been utilized for lithium-ion batteries and nickel metal–hydride batteries as well as aerospace structural materials, so-called superalloys.[1–5] For lithium-ion batteries, they contribute to promoting the stable structure and high capacity of cathode materials.[1] The Ni-Co rechargeable battery has been suggested as a potential power source of nickel metal–hydride batteries because of the high energy capacity and long durability.[2] The addition of Co has enhanced the creep rupture lives of Ni-based superalloys.[5] With such increasing
JUNMO JEON, DANIEL LINDBERG, and MIN-KYU PAEK are with the Department of Chemical and Metallurgical Engineering, Aalto University, Espoo, 02150, Finland. Contact e-mail: min.paek@aalto.fi SUN-YONG KWON is with the Department of Mining and Materials Engineering, McGill University, Montreal, QC, H3A 0C5, Canada. Manuscript submitted July 2, 2020 and accepted September 27, 2020.
METALLURGICAL AND MATERIALS TRANSACTIONS B
demand for Ni and Co, their prices have increased, and the supply challenges of the alloys also have risen.[6] Therefore, the recycling of these valuable metals from industrial secondary resources has become an essential substitute for securing critical resources. There have been several attempts to recycle Ni and Co from industrial battery scrap in the Ni slag cleaning process to overcome the conventional hydrometallurgical process, which causes various unattractive byproducts such as toxic gases, acidic wastewater, salt, and organic solvent.[7–9] The discarded batteries and Ni-Co alloy scraps are excellent resources along with dried Ni concentrate for the Ni flash smelting furnace. In the pyrometallurgical extraction process, the carbon can be easily dissolved in the liquid Ni and Co alloy as it is derived from the battery scrap or reducing agents such as cokes and coal. Since C can be dissolved up to 2 to 3 mass pct in the liquid Ni-Co alloy during the high-temperature carbothermic reaction, it influences the recycling efficiency as well as the properties of the final products. To find the optimum condition of the recycling process, it is required to know the basic information such as the distribution behavior of alloying elements and impurities and heat loss by adding the waste materials, and so on. These can be only predicted by accurate thermodynamic data of the activity, an activity coefficient of each element, and enthalpy of mixing of liquid alloy over the wide range of composition and temperature.
The liquid solution properties in Ni-based alloys and Co-based alloys were first compiled by Sigworth et al.[10,11] using Wagner’s formalism, respectively. They reported many thermodynamic data such as the standard Gibbs free energy of solution, activity coefficient of various alloying elements at the infinitely dilute solution, and interaction parameters between alloying elements and impurities in both the Ni and Co alloy melts. However, their interaction param
Data Loading...
