Nickel oxide, deposition

The preparation of nickel oxide deposits with high surface area on steel, nickel, copper, graphite or titanium electrodes partly for anodic oxidation of organic compounds and the preparation of pressed nickel oxide powder electrodes mainly for application in storage batteries is described. The performance of nickel oxide anodes for batteries is improved by addition of cobaltflljhydroxide... 

Nickel Oxide Deposition at the Cathode at High Pressure... 

Comparing data in Table 1, it is obvious that increasing the number of impregnation steps raises the Ni-loading in the catalyst samples, reduces the pore volume and increases the BET surface area. Compared with the MgO support, an increase in the BET-surface area and a decrease in the pore volume of the obtained catalyst samples can be explained by the porosity of nickel oxide deposit within the support. 

Early catalysts for acrolein synthesis were based on cuprous oxide and other heavy metal oxides deposited on inert siHca or alumina supports (39). Later, catalysts more selective for the oxidation of propylene to acrolein and acrolein to acryHc acid were prepared from bismuth, cobalt, kon, nickel, tin salts, and molybdic, molybdic phosphoric, and molybdic siHcic acids. Preferred second-stage catalysts generally are complex oxides containing molybdenum and vanadium. Other components, such as tungsten, copper, tellurium, and arsenic oxides, have been incorporated to increase low temperature activity and productivity (39,45,46). 

HydrometallurgicalProcesses. HydrometaHurgical refining also is used to extract nickel from sulfide ores. Sulfide concentrates can be leached with ammonia (qv) to dissolve the nickel, copper, and cobalt sulfides as amines. The solution is heated to precipitate copper, and the nickel and cobalt solution is oxidized to sulfate and reduced, using hydrogen at a high temperature and pressure to precipitate the nickel and cobalt. The nickel is deposited as a 99 wt % pure powder. 

Nickel Sulfamate. Nickel sulfamate [13770-89-3] Ni(S02NH2)2 4H2O, commonly is used as an electrolyte ia nickel electroforming systems, where low stress deposits are required. As a crystalline entity for commercial purposes, nickel sulfamate never is isolated from its reaction mixture. It is prepared by the reaction of fine nickel powder or black nickel oxide with sulfamic acid ia hot water solution. Care must be exercised ia its preparation, and the reaction should be completed rapidly because sulfamic acid hydrolyzes readily to form sulfuric acid (57). 

Bunsenite (NiO), a nickel oxide, is often found in deposits (albeit only in low concentrations) with zinc and copper oxides as a result of the corrosion of brasses and cupronickels. 

Nickel is sometimes found in boiler deposits as nickel oxide, either in the gray-black nickel (-ous, -ic) oxide Ni304 form, or the black nickel sequioxide Ni203. Where present in the boiler, it usually originates from corrosion of condenser or preheater tubes. 

With nickel/alumina catalysts (cf. 4 ) preparation by coprecipitation or by the decomposition of a high dispersion of nickel hydroxide on fresh alumina hydrogel, yields nickel aluminate exclusively. On the other hand, when, as in impregnation, larger particles of nickel compound are deposited, the calcination product is a mixture of nickel oxide and nickel aluminate. The proportion of nickel oxide increases when occlusion of the impregnation solution leads to a very nonuniform distribution (49). 

More than 90% of the world s nickel is obtained from pentlandite ((FeNi)9S8), a nickel-sulfitic mineral, mined underground in Canada and the former Soviet Union (Sevin 1980 IARC 1976 WHO 1991). One of the largest sulfitic nickel deposits is in Sudbury, Ontario (USPHS 1993). Nickeliferous sulfide deposits are also found in Manitoba, South Africa, the former Soviet Union, Finland, western Australia, and Minnesota (Norseth and Piscator 1979 USPHS 1993). Most of the rest of the nickel obtained is from nickel minerals such as laterite, a nickel oxide ore mined by open pit techniques in Australia, Cuba, Indonesia, New Caledonia, and the former Soviet Union (Sevin 1980). Lateritic ores are less well defined than sulfitic ores, although the nickel content (1 to 3%) of both ores is similar (USPHS 1993). Important deposits of laterite are located in New Caledonia, Indonesia, Guatemala, the Dominican Republic, the Philippines, Brazil, and especially Cuba, which holds 35% of the known reserves (USPHS 1993). Nickel-rich nodules are found on the ocean floor, and nickel is also present in fossil fuels (Sevin 1980). 

Hybinette A process for extracting nickel from sulfide ores. The nickel ore that occurs in Canada is a mixture of the sulfides of nickel, copper, and iron. Several methods have been used to separate these metals. In the Hybinette process, the ore is first smelted in a blast furnace, yielding a nickel-copper matte (i.e., a mixture of their lower sulfides). This is roasted to remove sulfur and leached with dilute sulfuric acid to remove copper. The resulting crude nickel oxide is used as the anode of an electrochemical cell. The nickel deposits on the cathode, which is contained in a cloth bag. Precious metals collect in the anode slime. The process was invented by N. V Hybinette in 1904 and operated at the Kristiansand refinery, Norway, from 1910. 

I-M Chan, T-Y Hsu, and FC Hong, Enhanced hole injections in organic light emitting devices by depositing nickel oxide on indium tin oxide anode, Appl. Phys. Lett., 81 1899-1901, 2002. 

At least 75% of intratracheally deposited nickel chloride had been absorbed 72 h after the operation in rats [265]. Nickel chloride was cleared from the lungs of rats more rapidly after intratracheal instillation compared with nickel oxide [266], the slower clearance being attributed to an increased solubility of nickel chloride compared with the oxide. 

Nickel is a silver-white, lustrous, hard, malleable, ductile, ferromagnetic metal that is relatively resistant to corrosion and is a fair conductor of heat and electricity. Nickel is a ubiquitous trace metal that occurs in soil, water, air, and in the biosphere. The average content in the earth s crust is about 0.008%. Nickel ore deposits are accumulations of nickel sulfide minerals (mostly pentlandite) and laterites. Nickel exists in five major forms elemental nickel and its alloys inorganic, water-soluble compounds (e.g., nickel chloride, nickel sulfate, and nickel nitrate) inorganic, water-insoluble compounds (e.g., nickel carbonate, nickel sulfide, and nickel oxide) organic, water-insoluble compounds and nickel carbonyl Ni(CO). ... 

Electrochemically generated nickei(lll) oxide, deposited onto a nickel plate, is generally useful for the oxidation of alcohols in aqueous alkali [49]. The immersion of nickel in aqueous alkali results in the formation of a surface layer of nickel(ll) oxide which undergoes reversible electrochemical oxidation to form nickel(lll) oxide with a current maximum in cyclic voltammetry at 1.13 V vj. see, observed before the evolution of oxygen occurs [50]. This electrochemical step is fast and oxidation at a prepared oxide film, of an alcohol in solution, is governed by the rate of the chemical reaction between nickel oxide and the substrate [51]. When the film thickness is increased to about 0.1 pm, the oxidation rate of organic species increases to a rate that is fairly indifferent to further increases in the film thickness. This is probably due to an initial increase in the surface area of the electrode [52], In laboratory scale experiments, the nickel oxide electrode layer is prepared by prior electrolysis of nickel sulphate at a nickel anode [53]. It is used in an undivided cell with a stainless steel cathode and an alkaline electrolyte. 

Following inhalation exposure, about 20-35% of nickel deposited in the lungs of humans is absorbed into the bloodstream. Absorption from the respiratory tract is dependent on the solubility of the nickel compound, with higher urinary nickel observed in workers exposed to soluble nickel compounds (nickel chloride, nicke sulfate) than in those exposed to less-soluble nickel compounds (nickel oxide, nickel subsulfrde). Following oral exposure, about 27% of the nickel given to humans in drinking water was... 

Following a single 70-minute inhalation exposure of rats to green nickel oxide ( NiO 9.9 mg nickel/rrf AMAD 1.3 pm), the fraction of the inhaled material deposited in the total respiratory tract was 0.13, with 0.08 deposited in the upper respiratory tract and 0.05 deposited in the lower respiratory tract (Benson et al. 1994). During the 180 days postexposure, nickel was not detected in extrarespiratory tract tissues. Following a single 120-minute inhalation exposure of rats to nickel subsulfide ( Ni3S2 ... 

Kodama Y, Ishimatsu S, Matsuno K, et al. 1985a. Pulmonary deposition and clearance of a nickel oxide aerosol by inhalation. Biol Trace Elem Res 7 1-8. 

---