Data analysis and estimation of thermodynamic properties of aqueous monovalent metal-glycinate complexes

M. R. Azadi, A. Karrech, M. Attar, M. Elchalakani

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Recently, an aqueous glycine solution has been proposed as a non-toxic environmentally friendly lixiviant to leach precious metals such as gold. In confined spaces, gold can be leached effectively using cyanide as a lixiviant. However, in unconfined applications, cyanide poses detrimental environmental effects due to its high level of toxicity. In order to investigate the effectiveness of lixiviant systems containing glycine and examine their potential, it is essential to identify the thermodynamic properties and stability domains of metal-glycinate complexes. Numerous studies have been conducted on the thermodynamic equilibrium of divalent metal-glycinate formations but those of monovalent metal-glycinate are scarce in general and inexistent for most precious metals including gold. In this study, we use data analysis to relate the standard partial molal properties of metal-glycinate complexes to the standard partial molal properties of various metals and estimate the equilibrium constants of monovalent metal-glycinate formation at ambient conditions. Finally, the standard partial molal properties of the metal-glycinate complexes and their revised Helgeson-Kirkham-Flowers (HKF) equations of state have been estimated and used to deduce the equilibrium constants of metal-glycine systems at different temperatures. The proposed method has been tested using existing experimental data and showed excellent consistency. (C) 2018 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)25-40
Number of pages16
JournalFluid Phase Equilibria
Volume480
DOIs
Publication statusPublished - 25 Jan 2019

Cite this

@article{a0abd0f0487d448bb685b52d58d43933,
title = "Data analysis and estimation of thermodynamic properties of aqueous monovalent metal-glycinate complexes",
abstract = "Recently, an aqueous glycine solution has been proposed as a non-toxic environmentally friendly lixiviant to leach precious metals such as gold. In confined spaces, gold can be leached effectively using cyanide as a lixiviant. However, in unconfined applications, cyanide poses detrimental environmental effects due to its high level of toxicity. In order to investigate the effectiveness of lixiviant systems containing glycine and examine their potential, it is essential to identify the thermodynamic properties and stability domains of metal-glycinate complexes. Numerous studies have been conducted on the thermodynamic equilibrium of divalent metal-glycinate formations but those of monovalent metal-glycinate are scarce in general and inexistent for most precious metals including gold. In this study, we use data analysis to relate the standard partial molal properties of metal-glycinate complexes to the standard partial molal properties of various metals and estimate the equilibrium constants of monovalent metal-glycinate formation at ambient conditions. Finally, the standard partial molal properties of the metal-glycinate complexes and their revised Helgeson-Kirkham-Flowers (HKF) equations of state have been estimated and used to deduce the equilibrium constants of metal-glycine systems at different temperatures. The proposed method has been tested using existing experimental data and showed excellent consistency. (C) 2018 Elsevier B.V. All rights reserved.",
keywords = "Glycine, Monovalent/divalent metals, Thermodynamics, Equilibrium, Leaching, MIXED-LIGAND COMPLEXES, PARTIAL MOLAL PROPERTIES, N-SALICYLIDENEGLYCINATO COMPLEXES, AMINO-ACID COMPLEXES, STABILITY-CONSTANTS, HIGH-PRESSURES, TERNARY COMPLEXES, TRANSPORT-PROPERTIES, EQUILIBRIUM-CONSTANTS, ION ASSOCIATION",
author = "Azadi, {M. R.} and A. Karrech and M. Attar and M. Elchalakani",
year = "2019",
month = "1",
day = "25",
doi = "10.1016/j.fluid.2018.10.002",
language = "English",
volume = "480",
pages = "25--40",
journal = "Fluid Phase Equilibria",
issn = "0378-3812",
publisher = "Pergamon",

}

Data analysis and estimation of thermodynamic properties of aqueous monovalent metal-glycinate complexes. / Azadi, M. R.; Karrech, A.; Attar, M.; Elchalakani, M.

In: Fluid Phase Equilibria, Vol. 480, 25.01.2019, p. 25-40.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Data analysis and estimation of thermodynamic properties of aqueous monovalent metal-glycinate complexes

AU - Azadi, M. R.

AU - Karrech, A.

AU - Attar, M.

AU - Elchalakani, M.

PY - 2019/1/25

Y1 - 2019/1/25

N2 - Recently, an aqueous glycine solution has been proposed as a non-toxic environmentally friendly lixiviant to leach precious metals such as gold. In confined spaces, gold can be leached effectively using cyanide as a lixiviant. However, in unconfined applications, cyanide poses detrimental environmental effects due to its high level of toxicity. In order to investigate the effectiveness of lixiviant systems containing glycine and examine their potential, it is essential to identify the thermodynamic properties and stability domains of metal-glycinate complexes. Numerous studies have been conducted on the thermodynamic equilibrium of divalent metal-glycinate formations but those of monovalent metal-glycinate are scarce in general and inexistent for most precious metals including gold. In this study, we use data analysis to relate the standard partial molal properties of metal-glycinate complexes to the standard partial molal properties of various metals and estimate the equilibrium constants of monovalent metal-glycinate formation at ambient conditions. Finally, the standard partial molal properties of the metal-glycinate complexes and their revised Helgeson-Kirkham-Flowers (HKF) equations of state have been estimated and used to deduce the equilibrium constants of metal-glycine systems at different temperatures. The proposed method has been tested using existing experimental data and showed excellent consistency. (C) 2018 Elsevier B.V. All rights reserved.

AB - Recently, an aqueous glycine solution has been proposed as a non-toxic environmentally friendly lixiviant to leach precious metals such as gold. In confined spaces, gold can be leached effectively using cyanide as a lixiviant. However, in unconfined applications, cyanide poses detrimental environmental effects due to its high level of toxicity. In order to investigate the effectiveness of lixiviant systems containing glycine and examine their potential, it is essential to identify the thermodynamic properties and stability domains of metal-glycinate complexes. Numerous studies have been conducted on the thermodynamic equilibrium of divalent metal-glycinate formations but those of monovalent metal-glycinate are scarce in general and inexistent for most precious metals including gold. In this study, we use data analysis to relate the standard partial molal properties of metal-glycinate complexes to the standard partial molal properties of various metals and estimate the equilibrium constants of monovalent metal-glycinate formation at ambient conditions. Finally, the standard partial molal properties of the metal-glycinate complexes and their revised Helgeson-Kirkham-Flowers (HKF) equations of state have been estimated and used to deduce the equilibrium constants of metal-glycine systems at different temperatures. The proposed method has been tested using existing experimental data and showed excellent consistency. (C) 2018 Elsevier B.V. All rights reserved.

KW - Glycine

KW - Monovalent/divalent metals

KW - Thermodynamics

KW - Equilibrium

KW - Leaching

KW - MIXED-LIGAND COMPLEXES

KW - PARTIAL MOLAL PROPERTIES

KW - N-SALICYLIDENEGLYCINATO COMPLEXES

KW - AMINO-ACID COMPLEXES

KW - STABILITY-CONSTANTS

KW - HIGH-PRESSURES

KW - TERNARY COMPLEXES

KW - TRANSPORT-PROPERTIES

KW - EQUILIBRIUM-CONSTANTS

KW - ION ASSOCIATION

U2 - 10.1016/j.fluid.2018.10.002

DO - 10.1016/j.fluid.2018.10.002

M3 - Article

VL - 480

SP - 25

EP - 40

JO - Fluid Phase Equilibria

JF - Fluid Phase Equilibria

SN - 0378-3812

ER -