An introductory electrochemical approach to studying hydrometallurgical reactions

Robertson, Sherryl; Jeffrey, Matthew I; Zhang, Hongguang; Ho, Elizabeth

doi:10.1007/s11663-005-0061-9

Cited by 15 publications

(6 citation statements)

References 27 publications

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“…As with other corrosion reactions, they can be understood in terms of mixed potential theory, and the overall rate of displacement may be strongly influenced by mass transport, kinetics, or surface passivation. 52,53 The occurrence of a displacement reaction in the Cu-Ni citrate system can be rationalised by considering the partial and total current for copper and nickel as a function of potential (Fig. 5).…”

Section: Analysis Of Corrosion Typesmentioning

confidence: 99%

Review—Influence of Corrosion Reactions on the Pulse Electrodeposition of Metals and Alloys

Green,

Roy

2023

J. Electrochem. Soc.

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In the electrodeposition of metal and alloys by pulse plating, the importance of the pulse off-time is often neglected. Traditionally it is considered an electrochemically inactive period, allowing, for example, the relaxation of concentration gradients, desorption of additives, recrystallisation and discharge of the double layer capacitance. However, more recent studies have shown that it is possible to have corrosion processes occurring in the off-time which can significantly influence the deposit properties and current efficiency. This has been observed in both aqueous and non-aqueous systems, and appears a very general phenomenon. Typically, in these systems, corrosion is caused by dissolved oxygen or via comproportionation reactions. Similarly, during the pulse electrodeposition of binary and ternary alloys from aqueous and non-aqueous solutions, displacement (corrosion) reactions have been observed in the off-time that can alter the alloy composition and microstructure. The main aim of this paper is to review these various types of corrosion, establish the conditions under which they occur, and quantify their effects related to deposit characteristics, current efficiency and alloy composition.

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Section: Analysis Of Corrosion Typesmentioning

confidence: 99%

Review—Influence of Corrosion Reactions on the Pulse Electrodeposition of Metals and Alloys

Green,

Roy

2023

J. Electrochem. Soc.

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“…The E-pH diagrams developed by Pourbaix became widely known in 1949 [18]. The graphical methods to show the dependence of electrochemical reactions known as the Evans diagrams for 70 years [13 -15] were renamed to Ritchie diagrams in 2003 when they are applied in hydrometallurgy instead of corrosion science [19]. Fig.…”

Section: Factors Governing Leachingmentioning

confidence: 99%

The Use of Hydrometallurgy in Treatment of Secondary Raw Materials and Low – Grade Ores

Forsén¹,

Aromaa

2013

Acta Metall. Slovaca

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The available raw material types for metals production are primary high-grade ores, primary low -grade ores and secondary raw materials. Treatment of primary raw materials is often easier than treatment of secondary materials as the latter ones can have metals in combinations never found in nature. The basic phenomena in treating primary and secondary materials are the same. Thermodynamics and reaction kinetics are the same when applied to pure metals or compounds. The differences are in the complexity of the raw material that has strong influence on selectivity. Leaching of complex low -grade materials and secondary materials can result in higher chemical and energy consumption. The solution purification after leaching complex low -grade and secondary materials can also be technically more difficult than when operating with primary high -grade materials. This is due to higher number of metals in the solution. The origin of raw materials has no influence on production of metals from purified solutions.

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“…To demonstrate the occurrence of a chemical reaction in a system, the temperature of the system should be varied. An increased reaction rate with increasing temperature is a strong proof for chemical reaction [39]. However, increased contaminant removal with increasing temperature is not necessarily coupled to contaminant reduction by Fe 0 as water is also an oxidizing agent and resulting corrosion products are contaminant scavengers.…”

Section: Aqueous Contaminant Removal By Metallic Ironmentioning

confidence: 99%

“…(1)) is precipitated from solution and replaced by a metal higher in the electromotive series (M m+ 1 -Eq. (2)) [39][40][41][42][43][44][45]. Cementation, also known as contact reduction or metal displacement, is necessarily a spontaneous heterogeneous reaction ( G 0 < 0) that takes place through the galvanic cell M 0 1 /M m+ 1 /M n+ /M (Eq.…”

Section: Cementation and Its Use In The Hydrometallurgymentioning

confidence: 99%

Elemental metals for environmental remediation: Learning from cementation process

Noubactep¹

2010

Journal of Hazardous Materials

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The further development of Fe(0)-based remediation technology depends on the profound understanding of the mechanisms involved in the process of aqueous contaminant removal. The view that adsorption and co-precipitation are the fundamental contaminant removal mechanisms is currently facing a harsh scepticism. Results from electrochemical cementation are used to bring new insights in the process of contaminant removal in Fe(0)/H(2)O systems. The common feature of hydrometallurgical cementation and metal-based remediation is the heterogeneous nature of the processes which inevitably occurs in the presence of a surface scale. The major difference between both processes is that the surface of remediation metals is covered by layers of own oxide(s) while the surface of the reducing metal in covered by porous layers of the cemented metal. The porous cemented metal is necessarily electronic conductive and favours further dissolution of the reducing metal. For the remediation metal, neither a porous layer nor a conductive layer could be warrant. Therefore, the continuation of the remediation process depends on the long-term porosity of oxide scales on the metal surfaces. These considerations rationalized the superiority of Fe(0) as remediation agent compared to thermodynamically more favourable Al(0) and Zn(0). The validity of the adsorption/co-precipitation concept is corroborated.

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An introductory electrochemical approach to studying hydrometallurgical reactions

Cited by 15 publications

References 27 publications

Review—Influence of Corrosion Reactions on the Pulse Electrodeposition of Metals and Alloys

Review—Influence of Corrosion Reactions on the Pulse Electrodeposition of Metals and Alloys

The Use of Hydrometallurgy in Treatment of Secondary Raw Materials and Low – Grade Ores

Elemental metals for environmental remediation: Learning from cementation process

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