Papers by Keyword: Nickel

Abstract: The structure and mechanical properties of gradient transition zones of the copper-nickel system formed by additive electron beam technology have been investigated. Pure copper and nickel alloy Ni80Cr20 were used for printing. The data obtained testify to the complex and heterogeneous nature of structure formation when printing both by single-wire method and using double-wire controlled feeding of material into the melt bath. In the samples, the formation of defects of different scale from local inhomogeneities of the structure to pores and cracks is possible. The mechanical properties of the structural gradient zone are at a sufficiently high level and depend on the ratio of the system components.

Abstract: Pyrolysis of buckwheat straw with or without catalysts was investigated using the TGA-FTIR method to determine the influence of nickel and cobalt ferrites on the distribution of pyrolysis products. According to the obtained results, the overall shape of the thermogravimetric and derivative thermogravimetric curves is unchanged in the presence of nickel and cobalt ferrites but different weight losses were observed. All catalysts contribute to the formation of solid residue from BWS pyrolysis. The presence of cobalt ferrites exhibited the highest bio-oil yields, whereas the highest non-condensable gas yield and the lowest bio-oil yield was obtained with the addition of NiFe₂O₄ (1) catalyst. According to the obtained results, the ability of nickel and cobalt ferrites to catalyze deoxygenation reactions depends on the crystallite size. The nickel or cobalt ferrites with smaller crystallite size (15-22 nm) show a higher ability to catalyzed dehydration reaction than catalysts with larger crystallite size (45-54 nm).

Abstract: The catalytic hydrotreatment of sunflower (SO), linseed (LO), coconut (CO), rapeseed (RO), and its soapstock derived acid oil (RS) over commercial Ni65%/SiO₂-Al₂O₃ catalyst was investigated to evaluate utilization feasibility of various vegetable oil feedstocks with different fatty acid content, composition, and saturation for marketable hydrocarbon production. The active metal loading of catalyst was characterized by XRF and its textural properties by N₂ sorption analysis. The hydrotreatment tests of different vegetable oils were carried out in solvent free medium, under initial H₂ pressure 10 MPa, at operating temperature 340 oC, and residence time 15 min using catalyst amount 5%. GC-FID and GC-MS analysis were used for estimation of dominant n-pentadecane, n-hexadecane, n-heptadecane, n-octadecane, and other hydrocarbon contents in obtained samples. Under studied hydrotreatment conditions complete conversion of different vegetable oils into marketable liquid renewable hydrocarbons without presence of oxygen containing substances was achieved. Highly active Ni65%/SiO₂-Al₂O₃ has remarkable selectivity to hydrocarbons produced by reaction pathways, where elimination of carbonyl groups occurs. The saturation of fatty acids in feedstock determines H₂ consumption, but influence on produced hydrocarbon production is insignificant. Depending on the fatty acid composition different saturated linear hydrocarbons with wide range of carbon chain length C5-C19 and similar calorific value 47.16-47.34 MJ/kg were produced in process. Overall liquid hydrocarbon yields were from 44.6 % to 78.1 %. The highest overall liquid saturated linear hydrocarbon yield was observed for feedstock with high amount of long chain fatty acids – SO, LO, RO and RS. Pure hydrocarbons obtained from vegetable oils depending on hydrocarbon composition can be used in various areas.

Abstract: The possibility of sorption extraction of nickel from leaching solutions of oxidized nickel ores of the Buruktal deposit is considered. Ionite Lewatit TP220 with bis-picolylamine functional groups is effective for nickel recovery against the background of high iron contents. Lewatit TP220 is mechanically strong enough for use in the resin-in-pulp process. Nickel sorption with satisfactory performance occurs both in the variant of sorption leaching and extraction from clarified solutions. At sorption from the pulp, the capacity for nickel was 5.44 mg/g, for iron, 25.17 mg/g. The use of 20% sulfuric acid provides quantitative nickel desorption. To obtain a higher quality nickel-containing product, it is recommended to additionally purify the resulting eluates from iron.

Abstract: Crude petroleum filters were prepared from low-cost materials based on kaolin powder and combustible materials as palm fronds powder which acts as pore creating agent. The samples with different content (10, 20, 30,40) wt% of palm fronds powder (P.F) were fabricated using a dry pressing method and fired at 1100 °C. Crude petroleum filters were characterized by X-ray diffraction (XRD), energy dispersive analysis (EDS) and Scanning electron microscopy (SEM). Physical properties (linear shrinkage, apparent porosity, water absorption, apparent density), mechanical properties (compressive strength and diametrical strength ) and Metallic Content.

Abstract: In this paper, the substantiation of the possibility of additive forming of nitinol billets by simultaneous surfacing of two titanium and nickel wires with an electron beam in vacuum is given. The method of mathematical modeling shows the possibility of forming several molten pools of liquid metal on the bead being deposited immediately behind the main pool for remelting the formed material. The modes of the electron beam for the formation of the main and two additional remelting pools due to the deflection of the beam are determined taking into account the technological capabilities of the installation. The residence time of the metal in the liquid state is calculated for various additive forming modes. Remelting makes it possible to increase the residence time in the liquid state by a multiple of the molten pools number. This significantly improves the conditions for mixing the raw materials and reduces the heterogeneity of the material.

Abstract: Nickel alloying element has been known to play a role in controlling the formation of microstructures in the weld metal (WM). This experiment aims to study the relationship between nickel addition to the microstructure evolution and toughness of shielded metal arc welded SS400 low carbon steel plates. Three welded samples, Ni-01, Ni-03 and Ni-09 were fabricated using electrodes containing different nickel: <0.1% Ni, 0.3% Ni, and 0.95% Ni, respectively. Microstructure of WM was examined using an optical microscope and scanning electron microscopy, and mechanical properties were measured in strength and toughness. The results showed the impact toughness increased when the nickel content of electrodes increased. From the three experimental welded samples, WM of Ni-09 which using electrodes containing 0.95% Ni demonstrated the best result for the impact toughness. It may caused Ni-09 has more AF and finer grains size compared to Ni-01 and Ni-03. It seems with nickel addition in the WM, finer grain size and acicular ferrite (AF) formation were developed.

Abstract: The technology of diffusion saturation of austenitic steels by chromium and nickel in the medium of low-melting liquid metal melts is shown. The saturation temperature was up to 1050°C, and the duration was up to 8 hours. It was found that it is the most effective to apply coatings according to the technological scheme: pre-carburization-diffusion metallization – final carburization. It was found that the coating consists of 4 layers. The surface layer has a thickness of up to 5 mkm and a microtuberance of up to 19500 MPa. The second layer, up to 12 mkm thick, has a microhardness of up to 7500 MPa. The third, up to 50 mkm thick, has a microhardness of 2300 MPa. In the fourth layer, up to 150 mkm thick, the microhardness gradually decreases from 2300 MPa to the microhardness of the base. At the same time, the total thickness of the coatings is up to 200 mkm.

Abstract: The present study considers various technological approaches to the processes of complex utilization of nickel slags with preliminary additional extraction of non-ferrous metals, iron, and ways of utilization of the obtained gangue. The valuable components are often produced from waste using the mineral acids or mixtures; the metals are extracted from acid solutions in a free form or in the form of compounds using electrochemical or chemical methods. Slag dumps have a heterogeneous structure and mineralization; the zone distribution of slag is clearly defined due to different cooling and solidification rates. The slag composition is mostly represented by dense low-porous varieties consisting of dark brown glass. The porous slag fragments are secondary. The third texture diversity in the composition of slag is represented by nodular and kidney-shaped particles. The diversity and size of the ore minerals is directly connected with the distribution of pores in slag. The major ways for utilization of nickel industrial waste are pyro-metallurgical and hydrometallurgical methods. In addition, each of the methods is usually preceded by the stage of mechanical preparation of the raw materials, where the techno-genic waste is crushed.

Abstract: Currently, there are practiced various pyrometallurgical, hydrometallurgical, and com-bined pyro and hydrometallurgical methods for processing of oxidized nickel ores to produce metal-lic nickel, cobalt, and their compounds in non-ferrous metallurgy. The problem is the difficult ore concentration, and consequently the high consumption of reagents or low extraction of valuable components from it. Ural plants previously implemented the technology of reducing-sulphiding smelting of laterite ore to produce fire nickel and transfer of cobalt to matte. The economic ineffi-ciency of this technology predetermined the search for a new method for processing of significant reserves of oxidized nickel ores in the Ural region.