Removal of Nickel

Selective removal of nickel from copper alloys is common. However, denickelification does not commonly cause the affected component to fail. Rather, the liberated nickel may deposit downstream and/or be released into the environment. 

Mogollon, L. Rodriguez, R. Larrota, W., et al., Biocatalytic removal of nickel and vanadium from petroporphyrins and asphaltenes. Appl Biochem Biotechnol, 1998. 70-72 pp. 765-777. 

Data obtained in scrubbing tests can be presented graphically, such as by plotting the concentration of metals in the organic phase against A/O ratio, salt concentration in the scrub solution, temperature, etc. Typical plots for the removal of nickel from cobalt in a DEHPA-containing solvent are shown in Figs. 7.3 and 7.4 [3]. 

Fig. 7.3 Effect of scrub solution composition on the removal of nickel from cobalt in a DEHPA-kerosene solvent.

In human serum, nickel binds to albumin, L-histidine, and 2 i croglobulin (Sarkar 1984). The principal binding locus of nickel to serum albumin is the histidine residue at the third position from the amino terminus (Hendel and Sunderman 1972). A proposed transport model involves the removal of nickel from albumin to histidine via a ternary complex composed of albumin, nickel, and L-histidine. 

The results of the study are summarized in part in Table 2 and demonstrate two useful consequences. The first result was an effective removal of nuisance transition metal ions 98% removal of zinc ion, 93% removal of nickel(II), 73% removal of copper(II) species. The second result, as a consequence, was the ability to reduce the fresh water intake by recycling reducing water usage by 67%. 

This article is focused on HDN, the removal of nitrogen from compounds in oil fractions. Hydrodemetallization, the removal of nickel and vanadium, is not discussed, and HDS is discussed only as it is relevant to HDN. Section II is a discussion of HDN on sulfidic catalysts the emphasis is on the mechanisms of HDN and how nitrogen can be removed from specific molecules with the aid of sulfidic catalysts. Before the discussion of these mechanisms, Section II.A provides a brief description of the synthesis of the catalyst from the oxidic to the sulfidic form, followed by current ideas about the structure of the final, sulfidic catalyst and the catalytic sites. All this information is presented with the aim of improving our understanding of the catalytic mechanisms. Section II.B includes a discussion of HDN mechanisms on sulfidic catalysts to explain the reactions that take place in today s industrial HDN processes. Section II.C is a review of the role of phosphate and fluorine additives and current thinking about how they improve catalytic activity. Section II.D presents other possibilities for increasing the activity of the catalyst, such as by means of other transition-metal sulfides and the use of supports other than alumina. 

For the recovery of Ni2+ from the waste liquors (WL) of the nickel plant located in Nicaro, Cuba, the following methodology was proposed [5,37,60] (see Figure 7.14) carbonate-ammonium liquors (fresh liquors [FL]) are used for the exchange of the natural zeolite to the ammonium form (first cycle), and for the activation of the exhausted natural zeolite after the removal of nickel from the WL previously passed through the zeolite column. The exchanged nickel is recovered and the obtained NH4-zeolite is heated to get H-zeolite, thereby recovering the ammonium. The process is thus repeated cyclically. 

Hammack, R. W. and H. M. Edenbom. 1991. The removal of nickel from mine waters using bacteria sulfate reduction. In W. Oaks and J. Bowden, Eds. Proceedings of the 1991 National Meeting of the American Society of Surface Mining and Reclamation Vol. 1. Princeton, WV, pp. 97-107. 

Preparation of Nickel Salts free from Cobalt.—As has already been mentioned, nickel closely resembles cobalt in many of its properties, and for many purposes it is quite unnecessary to effect a complete separation of the metals. When, however, pure salts of either metal are required, several convenient methods are to hand for effecting the removal of the unwanted element. In order to remove small quantities of cobalt from nickel salts any of the methods suggested for the removal of nickel from cobalt salts may be utilised. Of these, Fischer s nitrite process is specially convenient. 

The metal ions sequentially removed from the acid/alkali solutions were silver, copper, chromium(III), and cadmium/nickel. The cadmium and nickel were later separated from each other. The first separation performed with the chrome solution involved the selective separation of Cr(VI) as C1O4 from the feed solution. Chromium(III) remained in the solution in small amounts after Cr(VI) was removed. Neither the Cr(VI) nor the Cr(III) SuperLig material is capable of removing the other chromium species. The second separation from the chrome solution involved copper removal. The third separation was the removal of the remaining chromium as Ciflll). The final separation was the removal of nickel. 

Removal of nickel by deposition as amine-sulfate double salt or by solvent extraction. 

It is also clear that the removal of vanadium and sulphur is much easier than the removal of nickel and nitrogen. Deposition profiles across catalyst pellets show that most vanadium is deposited near the pellet exterior, while the maximum for nickel lies some distance inside the pellet [19, 20]. 

If this is the case, then nickel deposition, will also be affected by pore blocking by vanadium. As a result, subsequent removal of nickel should occur near the deposit exterior, as has been observed towards the end of the bed [35]. The resulting improvement in the catalytic activity of the deposit (as compared to the activity of vanadium sulphides) would be significant in view of possible interactions between nickel and molybdenum sulphides, and the role of nickel sulphide in facilitating the distribution of molybdenum sulphide across the surface [44]. 

The CNFs were refluxed for 1 hour in a 1 M KOH solution in order to remove the silica support. For the activation of the CNFs and the removal of nickel, the CNFs were refluxed in concentrated nitric acid for 2 hours and washed with demi-water. 

Selective leaching applies to the situation where one element of an alloy is removed preferentially to another metallic constituent. The most common example of this phenomenon is the so-called dezincification of brass (see Section 10.2.1), but it may also occur through the selective removal of nickel from cupro nickel alloys and aluminium from aluminium bronze. 

Khodadoust R, Reddy KR, Maturi K. (2004). Removal of nickel and phenanthrene from kaolin soil using different extractants. Environmental Engineering Science 21(6) 691-704. 

Steel made from scrap will have at least traces of nickel because scrap invariably contains a small quantity of austenitic stainless steel, which contains nickel. Removal of nickel from steel is very difiicult, so it is left in the steel. 

TABLE 7.31. Removal of Nickel and Iron from Brine at 60°C... 

The removal of nickel from nickel-containing alloys is an important factor determining the corrosion rate of these materials in several liquid metals. If a high nickel source is placed upstream in an isothermal zone, the nickel removal rate from an alloy sample downstream could be reduced, If several alloys with different nickel contents are included in the same test it would seem appropriate to arrange them in... 

Vijaya Y, Popuri SR, Boddu VM, Kiishnaiah A (2008) Modified chitosan and ceilcium eilginate biopolymer sorbents for removal of nickel (II) through adsorption. Carbohydr Polym... 

Borba, C. E., GuirardeUo, R., Silva, E. A. Removal of nickel (II) ions from aqueous solution by biosorption in a fixed bed column, experimental and theoretical breakthrough. Biochem Eng J. 2006, 30,184-191. 

Apart from HDS, another important reaction during hydrotreating of heavy crude oils is hydrodemetallization, particularly the removal of nickel (HDNi) and vanadium (HDV). 

The profiles of nickel and vanadium concentrations on catalyst surface and liquid bulk as functions of reactor length and 1/LHSV at 400°C are depicted in Figures 9.11 and 9.12, respectively. Similar to HDS reaction, the simulated removal of nickel and vanadium is in good agreement with the experimental values. 

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