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Contact Materials
Published in Milenko Braunovic, Valery V. Konchits, Nikolai K. Myshkin, Electrical Contacts, 2017
Milenko Braunovic, Valery V. Konchits, Nikolai K. Myshkin
Layer-Structured Contacts. The layer-structured contacts are widely used to replace the allmetal materials and to avoid the use of precious materials. Such contacts can be made by deposition of noble metals on the substrate base metals by using processes such as galvanic plating, ion-plasma deposition, and electric-spark alloying. The thickness of the working layer is usually less than 50% and in some cases it is 2–50% of the total contact thickness. Typical layered-structure contact materials are Ag–Ni, Ag–C, Ag–CdO, Ag–CuO, Ag–Ni–C, Ag–W(Mo), Cu–Ag–W, etc. The base metal can be copper, copper-based alloys, nickel, and steel. The following deposition methods are commonly used to fabricate the layer-structured materials: rolling; drawing; pressing; but, cold and diffusion welding; friction welding; sputtering; facing; and electroplating. Electroerosion coating deposition is an alternative method.
Filtration in the Mineral Industry
Published in Michael J. Matteson, Clyde Orr, Filtration, 2017
Some minerals may be processed by both hydrometallurgy and beneficiation. Base metals such as copper, lead, and zinc are good examples. Also, many hydrometallurgy plants may have a preceding beneficiation process due to the economic advantage of processing a smaller tonnage at a higher mineral concentration.
Overview
Published in Sehliselo Ndlovu, Geoffrey S. Simate, Elias Matinde, Waste Production and Utilization in the Metal Extraction Industry, 2017
Sehliselo Ndlovu, Geoffrey S. Simate, Elias Matinde
Base metals have irreplaceable industrial and commercial applications, and their consumption is directly correlated with global economic growth (IMF, 2015). Basically, base metals broadly refer to a category of non-ferrous metal commodities typically consisting of copper, nickel, cobalt, lead, zinc and mercury (Craig and Vaughan, 1990; Jones, 1999; Cole and Ferron, 2002; Crundwell et al., 2011; Schlesinger et al., 2011). In general, the primary pyrometallurgical production of base metals involves the following steps (Jones, 1999; Cole and Ferron, 2002; Crundwell et al., 2011; Schlesinger et al., 2011): (1) smelting of base metal concentrates in flash or electric furnaces to produce base metal–rich matte, (2) matte converting under hydrodynamic oxidizing conditions to produce base metal–enriched matte (significantly higher than the smelter furnace matte) and (3) the refining and purification process to produce high-purity metals.
Toward the Implementation of Circular Economy Strategies: An Overview of the Current Situation in Mineral Processing
Published in Mineral Processing and Extractive Metallurgy Review, 2022
Luis A. Cisternas, Javier I. Ordóñez, Ricardo I. Jeldres, Rodrigo Serna-Guerrero
Base metals, such as aluminum, copper, zinc, and tin, are non-ferrous metals that have a wide range of industrial applications, such as components for alloys as brass, steel, and bronze and as the basis for the generation of structural constructions, among others. For the extraction of the base species from the ore, depending on the physical, chemical, and mineral characteristics of the deposits, two processing routes can be carried out: hydrometallurgy and pyrometallurgy (Botelho Junior, Dreisinger and Espinosa 2019) (Figure 2). Other resources as cobalt, PGMs (platinum group metals) and ferrous metals (nickel and iron) may be treated by pyrometallurgy after a concentrating stage.
Characterization of a Doped MnO2Al2O3 Catalyst and its Application Inmicrobubble Ozonation for Quinoline Degradation
Published in Ozone: Science & Engineering, 2021
Xinwang Liu, Shutao Wang, Hao Yang, Zhisheng Liu, Ying Wang, Fucheng Meng, Jun Ma, Oksana S. Izosimova
It is known that many types of metal catalysts have been developed in the past, which are considered as useful catalysts. Most highly functionalized catalysts are prepared by using noble metals including Pd, Pt, and Au. However, due to the shortage of noble metals, the development of substitution catalysts using base metal such as Mn, Fe, and Ni are strongly desired. Base metals have advantages of lower costs and easier availability over noble metals, making them more competitive in practical applications. Among various base metals, Mn is an inexpensive, abundant element and it also has a significant potential to oxidation activity. Therefore, it is an ideal substitute for a noble metal. Manganese oxide has attracted much attention for catalytic oxidation of refractory pollutants (Najafpour et al. 2014; Nakamura et al. 2019). Some modified Mn catalysts (Du et al. 2020; Najafpour et al. 2016; Tang et al. 2016) and novel metal catalysts supported on active carbon have been developed for catalytic oxidation of pollutants (Hu et al. 2016; Li et al. 2016). In this study, manganese dioxide (MnO2) was used as the active catalyst component. Commonly, the active component, for example, platinum oxide (PtO2), palladium oxide (PdO), and manganese oxide (MnO), is loaded (or supported) on the surface of porous supports, such as granular activated carbon or aluminum oxide (Al2O3). However, in the practical applications including wastewater treatment, the loaded or supported components tend to fall off the support, an effect attributed to abrasion and hydraulic shear during the application, which reduce the catalytic performance and subsequently, the service life. In this study, a doping method was used to fabricate the catalyst. In other words, nano-sized MnO2 was prepared and then doped into a porous Al2O3 support to make a granular doped-MnO2/Al2O3 catalyst. The granular catalyst was utilized in the catalytic ozonation for quinoline degradation.