Nickel chemical analysis

Analysis of Trace or Minor Components. Minor or trace components may have a significant impact on quaHty of fats and oils (94). Metals, for example, can cataly2e the oxidative degradation of unsaturated oils which results in off-flavors, odors, and polymeri2ation. A large number of techniques such as wet chemical analysis, atomic absorption, atomic emission, and polarography are available for analysis of metals. Heavy metals, iron, copper, nickel, and chromium are elements that have received the most attention. Phosphoms may also be detectable and is a measure of phosphoHpids and phosphoms-containing acids or salts. 

Selective removal of the less noble constituent has been demonstrated by chemical analysis in the case of nickel-rich alloys in fused caustic soda or fused fluorides ", and by etching effects and X-ray microanalysis for Fe-18Cr-8Ni steels in fused alkali chlorides. This type of excessive damage can occur with quite small total amounts of corrosion, and in this sense its effect on the mechanical properties of the alloy is comparable with the notorious effect of intercrystalline disintegration in the stainless steels. 

Much of the early work with certified reference materials was linked to the derivation of reference methods and there was a period in which primary or definitive (i.e. very accurate but usually very complex) and secondary (or usable) methods were reported e.g. steroid hormones (Siekmann 1979), creatinine (Siekmann 1985), urea (Welch et al. 1984) and nickel (Brown et al. 1981). Although there are some application areas, such as checking the concentrations of preparations listed in a pharmacopoeia, where a prescribed, defined method has to be used, in practice such work is limited. However, this approach to chemical analysis is no longer widely used and will not be further discussed. The emphasis now is placed on using RMs to demonstrate that a method in use meets analytical criteria or targets deemed to be appropriate for the application and to develop figures of merit (Delves 1984). 

Dr. William Brownrigg describes platinum. Cronstedt isolates nickel. H. T. Scheffer fuses platinum with the aid of arsenic. Claude-Frangois Geoffrey s research on The Chemical Analysis of Bismuth is published. 

Relatively few reports of the catalysed reactions of n-butenes with hydrogen were extant up to the early 1960 s. Those studies which had been performed were mainly concerned with nickel as catalyst. The major problem was the difficulty of chemical analysis of the reaction products. However, with the advent of gas chromatography as a general analytical technique, the analysis of reaction products has become a relatively simple task and, accordingly, over the last 15 years the hydrogenation of higher olefins has received considerable attention. 

NiO(200) presents a small excess of oxygen, whereas NiO(250) contains metallic nickel (Table I). Magnetic measurements (15) have confirmed the chemical analysis (19). However, both oxides are p-type semiconductors, as shown by the Seebeck effect measurements. In the case of NiO(250), this result means that, although there is a total excess of nickel, the oxide phase still contains a small excess of oxygen (13). The electrical properties of both oxides are identical. 

The modern investigations of trace elements in coals were pioneered by Goldschmidt, who developed the technique of quantitative chemical analysis by optical emission spectroscopy and applied it to coal ash. In these earliest works, Goldschmidt (31) was concerned with the chemical combinations of the trace elements in coals. In addition to identifying trace elements in inorganic combinations with the minerals in coal, he postulated the presence of metal organic complexes and attributed the observed concentrations of vanadium, molybdenum, and nickel to the presence of such complexes in coal. 

The nickel and aluminium contents of the catalysts were determined by atomic absorption spectroscopy [AAS). Tin and chlorine contents of the modified catalysts given in Table 2 were determined by AAS and chemical analysis, respectively. 

For preparation of alloys nickel by cleanliness of 99.99 %, magnesium by cleanliness of 99.95 %, lanthanum by cleanliness of 99.79 %, and mishmetall (industrial mixture of rare-earth metals (REM) Ce - 50, La - 27, Nd - 16, Pr - 5, others REM - 2wt. %) were used. The melting of metal charge was carried out in the vacuum-induction furnace under fluxing agent from eutectic melt LiCl-KCl. The composition of alloys was supervised by the chemical analysis and the X-ray testing. 

The nickel concentration on this particle is extremely low with traces of the nickel impurity at the external surface. This low nickel concentration means that the particle in Figure 2 was in the refinery unit only a short time, otherwise more nickel would be present for the average particle (by bulk chemical analysis) contains 900ppm Ni and 4700 ppm V. The particle in this image contains a disproportionate amount of vanadium relative to nickel. If the nickel on the external skin of the catalyst accumulates by nickel porphyrin cracking at the first surface contacted, then vanadium must arrive not only by cracking vanadyl porphyrins but also by some other means like transfer from older catalyst particles in the FCC unit. The high vanadium concentration relative to nickel on new catalyst particles provides evidence that vanadium has interparticle mobility as well as intraparticle mobility. 

Chemical analysis (Reheis et al, 2002) of the <50 p.m fraction of the dusts that originate from the dry Owens Lake bed indicate that they contain quite high levels of a variety of metals or metalloids including iron (several percent) zinc (tens of thousands of ppm), manganese and lead (hundreds of ppm) arsenic, chromium, nickel, and lithium (tens of ppm), and uranium (several ppm). Given the oxidized conditions of the playa lake surface, it is likely that arsenic, chromium, and... 

The stoichiometric compositions of pure and doped nickel oxides were determined by chemical analysis (30). As presented in Section II, the difference 2[Ni3+] — [Ni ) is evaluated and results are expressed in at.% Oexc if the difference is positive or in at.% Niexc if the difference is negative. Chemical analyses (30) and magnetic measurements (33) have shown that pure nickel oxide prepared under vacuum at 250° contains a small excess of metallic nickel (Table X). The surprising result is that oxides containing up to 4 at.% Li (total) or 1.5 at.% Li (actually dissolved) present a stoichiometric composition which is similar to that of pure NiO(250°) (Table X). Nickel oxide containing 9.5 at.% Li (total) presents an excess of oxygen (0.052 at.% Oexc) which is small, however, compared to the amount of lithium ions actually incorporated in the lattice (1.95 at.% Li) (Table X). 

Chemical analysis of the solutions after anodic dissolution have shown that the oxidation state of chromium in the dissolution products depends on the alloy composition and, correspondingly, on the potential of alloy dissolution. At potentials less positive than the potential of the onset of pure-chromium passivity breakdown, chromium dissolves from the nickel-based alloys as Cr(III). The alloys with chromium contents of not more than 15% dissolve in this manner in NaCl solution. At higher Ea, chromium from the alloy dissolves, for the most part (about 90%), in the form of Cr(VI). This is true for all alloys in Na2SC>4 (or NaNC>3) solution and for the alloys containing more than 25% chromium in NaCl solution. 

Chukhlantsev and Tomashevsky [57CHU/TOM] prepared nickel selenite by mixing 0.1 M solutions of nickel sulphate and sodium selenite in stoichiometric amounts. The precipitate was aged for 24 hours in the mother liquor. Chemical analysis confirmed the 1 1 ratio between Ni(ll) and Se(lV). No X-ray diffraction measurements were performed. The solubility of the specimen, which is assumed by the review to have the composition NiSe03-2H20, in dilute solution of nitric or sulphuric acid was measured at 293 K. The experiments were performed and the data recalculated as described in Appendix A, [56CHU]. The result for... 

Nickel selenite was prepared by mixing 0.1 M solutions of sodium selenite and nickel nitrate in stoichiometric proportions at room temperature. The amorphous precipitate crystallised on boiling the reaction mixture for 2 hours. X-ray diffraction showed that the preparation was crystalline and chemical analysis agreed with the formula NiSe03-2H20. 

All the XRD analysis of nickel-molybdenum catalysts with 0chemical analysis and the specific surface areas (BET) are also given. 

The content of nickel in catalyst samples was determined by a standard chemical analysis, using dimethylglyoxime. 

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