China 
Africa 
Explore chapters and articles related to this topic
Open-Circuit Metal Dissolution Processes
Published in Madhav Datta, Electrodissolution Processes, 2020
Selective leaching is the preferential corrosion of one or more constituents of an alloy in a corrosive environment. The preferential dissolution of the more active element in an alloy is caused by the potential difference between the alloying elements. Dezincification of brass is a typical example of selective leaching in which zinc is preferentially leached out of a copper-zinc alloy leaving behind a copper-rich surface layer that is porous and brittle. Graphitic corrosion is also a preferential dissolution process which leads to deterioration of gray cast iron by selective leaching of metallic constituents in the alloy leaving behind graphite. During cast iron graphitic corrosion, the porous graphite network, which makes up 4%–5% of the total mass of the alloy, is impregnated with insoluble corrosion products. As a result, the cast iron retains its appearance and shape but is weaker structurally. Similarly, decarburization is the selective loss of carbon from the surface of a carbon-containing alloy. Decobaltification, denickelification, etc. are other examples of selective leaching.
Mechanical Considerations
Published in Roger Messenger, Homayoon “Amir” Abtahi, Photovoltaic Systems Engineering, 2017
Roger Messenger, Homayoon “Amir” Abtahi
Selective leaching is the preferential removal of one or more of the alloying elements in a metal by the action of an electrolyte. The most common example of this phenomenon is the selective leaching of zinc from brass, leaving a spongy, weak matrix of copper—a process known as dezincification. Aluminum, iron, cobalt, and chromium are also susceptible to leaching. Where and whenever selective leaching occurs, the process leaves the alloy in a weakened, porous condition.
Leaching with Acids
Published in C. K. Gupta, T. K. Mukherjee, Hydrometallurgy in Extraction Processes, 2019
Manganese nodules found at the bottom of the ocean have drawn in recent times a great deal of attention as a source of many metals. Extensive research is being conducted in this area. On the average, the air-dried nodules contain about 30% Mn, 15% Fe, 1% Ni, 1% Cu, 0.2% Co, 10% combined water, and 30% gangue minerals. The manganese is present in the nodules as various forms of manganese oxides, the iron is present as ferric oxides and hydroxides, while Ni, Cu, and Co do not form minerals. There are two schools of thought regarding the mechanism by which minor metals are incorporated into nodules. Bums and Burns46–48 proposed a mechanism for the presence of minor metal elements into manganese nodules as a result of biorganic degradation and recrystallization of manganese oxides, with minor metal elements being incorporated in their lattice during the process. The other school49–50 suggested an adsorption mechanism in which these minor cations were adsorbed as counterions on the surface of the manganese oxides. Murray et al.51 showed the specific adsorption of nickel, copper, and cobalt on hydrous manganese oxides. A typical composition of Pacific Ocean manganese nodules is presented in Table 4. The fact that the nodules when collected contain appreciable amounts of water suggests that their treatment by pyrobased methods would not be practical because of the involvement of the cost of drying. The highly porous nature of the nodules suggests that hydrobased metallurgical processes would be more suitable. The treatment methods investigated so far basically fall into two categories: selective leaching and complete dissolution. In the complete dissolution methods, the purpose is to recover manganese as well as the other nonferrous metals, Cu, Ni, and Co. In the selective leaching methods, the purpose is only to leach Cu, Ni, and Co, leaving behind manganese and iron.
Pulse ultrasonication leaching approach for selective Li leaching from spent LFP cathode material
Published in Canadian Metallurgical Quarterly, 2023
Ahmet Salih Surel, Mehmet Furkan Gul, Emircan Uysal, Duygu Yesiltepe-Ozcelik, Sebahattin Gurmen
A significant and promising method for the efficient recycling of LFP batteries is hydrometallurgical recycling. The process of hydrometallurgical recycling involves extracting metals from waste sources via using water-based solutions, and also high metal recovery rates, high product purity, low energy usage, and little gas emission are a few of the appealing benefits of hydrometallurgical processes [6]. Even, hydrometallurgical recycling is used not only for LFP but also for recycling many lithium-ion batteries such as NMC (Nickel-manganese–cobalt) [7, 8]. These studies have focused on the recovery of lithium and cobalt from batteries with a chemical composition of lithium cobalt oxide (LCO), as well as the recovery of lithium, nickel, cobalt, and manganese metals from batteries with a chemical composition of lithium nickel manganese cobalt oxide (NMC) [9, 10]. During the hydrometallurgical recycling of LFP cathode materials, the olivine structure of LFP cathode materials is destroyed, and the individual Li and Fe are leached [11]. Among the leaching processes, the process based on the dissolution of only the target metal is called selective leaching. Through the use of a selective leaching procedure, lithium is extracted from disseminated LFP batteries while iron and phosphorus are kept as potentially useful by-products. Because it is more energy efficient, produces high-value products, produces less waste, and is ecologically benign, hydrometallurgical recycling stands out as the best technique for recycling lithium-ion batteries, including LFP batteries.
The Synergistic Copper Process concept
Published in Mineral Processing and Extractive Metallurgy, 2018
William Hawker, James Vaughan, Evgueni Jak, Peter C. Hayes
The Synergistic Copper Process involves three basic process steps: Selective leaching of the copper from ores, wastes, or recycled materials.Precipitation of an iron-free copper product (PCP) solid.High-temperature smelting or converting of the copper product in existing sulphide smelting and/or converting technologies.