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The secondary dispersion halos of platinum group elements and rare elements in rocks of the Vysotsky ore occurrence, Svetloborsky massif, Middle Urals
Published in Vladimir Litvinenko, Advances in Raw Material Industries for Sustainable Development Goals, 2020
V.S. Nikiforova, I.V. Talovina, G. Heide
Most of the elements of the iron group are characterized by a relatively uniform distribution. Nickel contents vary from 7 to 150 ppm, cobalt from 2 to 70 ppm, manganese 70-600 ppm, with the exception of several samples with contents of 700-900 ppm, vanadium 18-50 ppm, in single samples - more than 200 ppm. Chromium in samples from Vysotsky ore occurrence is characterized by a less uniform distribution with a change in contents from 30 to 1000 ppm, on average 600 ppm. It should be noted that, unlike the whole array, samples with high chromium content do not always correspond to samples with high platinum content. Cobalt content also varies from 2 to 70 ppm, titanium - from 60 to 1000 ppm. Cobalt content also varies from 2 to 70 ppm, titanium - from 60 to 1000 ppm.
Determination of Metals in Non Saline Sediments
Published in T. R. Crompton, Determination of Metals and Anions in Soils, Sediments and Sludges, 2020
In contrast to the iron group, copper and manganese show a more continuous increase in the amount leached with decreasing pH. At pH 2.3, > 80% of the total cadmium and > 50% of the total manganese are removed from this sample. At higher pH values (4—6), 10–40% of the total cadmium and manganese is removed. Zinc removal follows the gradual increase with decreasing pH found for the manganese group, but with a small percentage of total metal leached at each pH, a characteristic of the iron group.
Feedstock Chemistry in the Refinery
Published in James G. Speight, Refinery Feedstocks, 2020
Hydrotreating catalysts consist of metals impregnated on a porous alumina support. Almost all of the surface area is found in the pores of the alumina (200–300 m2/g) and the metals are dispersed in a thin layer over the entire alumina surface within the pores. This type of catalyst does display a huge catalytic surface for a small weight of catalyst. Cobalt (Co), molybdenum (Mo), and nickel (Ni) are the most commonly used metals for desulfurization catalysts. The catalysts are manufactured with the metals in an oxide state. In the active form, they are in the sulfide state, which is obtained by sulfiding the catalyst either prior to use or with the feed during actual use. Any catalyst that exhibits hydrogenation activity will catalyze hydrodesulfurization to some extent. However, the Group VIB metals (chromium, molybdenum. and tungsten) are particularly active for desulfurization, especially when promoted with metals from the iron group (iron, cobalt, nickel).
Characterisation, hardness and corrosion behaviour of electrodeposited ZnFe and ZnFe/BN composite coatings
Published in Transactions of the IMF, 2022
İsmail Hakki Karahan, Halit Yaylacı
In industry, as a cathodic protector, zinc coatings are widely used for the protection of steel substrates, but highly corrosive and wear environments, highly demanding operating environments combined with temperature mean that the protective and functional properties of Zn coatings need to be further improved. Some studies have shown that these coatings corrode in aggressive environments and at temperatures higher than 384 K. Thus attempts have been made to try to improve the properties of Zn coatings. Firstly, studies were carried out to achieve better properties by alloying zinc with more noble iron group elements such as iron,1,2 nickel,3 cobalt,1,4 and their ternary combinations.5–8 Among the electrodeposited zinc alloys, ZnFe electrodeposits show excellent corrosion resistance due to the inherent inclusion of zinc–iron phases. In addition, the alloy has many excellent properties such as good weldability,9 good electrical resistance,1 good paintability and is considered an alternative to zinc coating.10,11 Zn and Zn alloy composites are obtained by electrochemical co-deposition of nano or micro sized inert metal oxides, nitrides or carbides in a metal or metal alloy matrix. These composites have better wear resistance, hardness, mechanical, corrosion protection, conductivity and photocatalytic properties compared to their constituent metals or alloys.12
International Process Metallurgy Symposium (IPMS) 2021
Published in Transactions of the IMF, 2022
There were three presentations related to electroplating of iron-group metals. Prof. Karen Pantleon, Technical University of Denmark, presented a recently developed process for plating iron-carbon alloy coatings with extreme hardness as a potential environmentally friendly alternative to hard chromium and nickel alloys. Hardness up to 1200 HV can be reached after heat treatment and the coating is thermally stable up to 250 °C. Future focus will be on industrial upscaling and alloying for improving the corrosion resistance. Christine Enowmbi Tambe, University of Strathclyde, United Kingdom, discussed the real role of boric acid based on the fact that the boric acid/borate buffer system has no effect in the pH region relevant for nickel electrodeposition. Experimental results show that boric acid suppresses the rate of hydrogen evolution and decreases the Tafel slope of nickel reduction due to a suggested adsorbed Ni-borate complex. The influence of the many interacting parameters in electroplating was brought to a higher system level by Prof Sudipta Roy, University of Strathclyde, United Kingdom, who discussed the implementation of Industry 4.0 in surface finishing e.g. with significant benefits in electroforming where control of material distribution and internal stress are essential for the quality.
Zn–Ni compositionally modulated multilayered alloy coatings for improved corrosion resistance
Published in Surface Engineering, 2021
Ramesh S. Bhat, P. Nagaraj, Sharada Priyadarshini
Electrodeposition, also known as electroplating or simply plating, is an inexpensive technique for protective and improving the functionality of parts used in a wide range of industries, including home appliances, jewellery, automobile, aircraft/aerospace and electronics, electrical and tools for machinery items [1]. Metal coatings have been widely used in surface protection or for decorative applications. Zinc and its alloy coatings find numerous applications as sacrificial metal coatings [2]. For several years, thick Zn coatings have been used to provide economic protection for metal parts. Slowly zinc alloys replaced the conventional zinc coatings, because of their improved efficiency at elevated temperature [3]. Iron group metals like nickel, cobalt, etc. alloyed with zinc provides better protection efficiency than zinc coating [2–5]. Zinc–Nickel alloy coatings can be obtained by an electroplating process in an acidic or alkaline bath. The Zn–Ni alloy coating, where the wt-%Ni content is 12–16, shows the highest corrosion resistance [6]. For a range of parameters, it has been observed that the process takes place anomalously, since zinc being less noble metal is preferentially deposited. This may be explained by ‘hydroxide suppression mechanism’, where zinc hydroxy compounds inhibit the nickel deposition [7–10]. Vasilache et al. described the mechanism of electrochemical deposition of nickel and zinc–nickel alloy [11,12].