Sulphide nickel

Alternatively, add 1 or 2 drops of 5 per cent, nickel nitrate solution to 2-3 ml. of the fusion solution, filter off the nickel cyanide and/or nickel sulphide, acidify the filtrate with 2N nitric acid, and test for hahdes as above. 

The tlrermodynamic activity of nickel in the nickel oxide layer varies from unity in contact with tire metal phase, to 10 in contact with the gaseous atmosphere at 950 K. The sulphur partial pressure as S2(g) is of the order of 10 ° in the gas phase, and about 10 in nickel sulphide in contact with nickel. It therefore appears that the process involves tire uphill pumping of sulphur across this potential gradient. This cannot occur by the counter-migration of oxygen and sulphur since the mobile species in tire oxide is the nickel ion, and the diffusion coefficient aird solubility of sulphur in the oxide are both vety low. 

Dinickel trioxide Nickel dioxide Nickel monoxide Nickel subsulphide Nickel sulphide Potassium chromate Potassium dichromate... 

Continued exposure of the nickel-chromium alloy to more severely sulphurising and reducing atmospheres results in local depletion of chromium to such an extent that nickel sulphide and the eutectic are formed internally. The latter constituents are not often observed in service failures, but the relative instability of nickel sulphide in the presence of chromium sulphide can result in its reduction to nickel during slow cooling on shut down. That nickel sulphide is formed is suggested by the frequent occurrence of blisters, associated with the formation of molten eutectic on the surface of sulphur-attacked specimens . 

Copper-Nickel and Nickel Sulphide Deposits with PGM as a By-Product... 

COPPER-NICKEL AND NICKEL SULPHIDE DEPOSITS WITH PGM... 

The catalyst used is colloidal nickel sulphide. The sulphur is run off from the surface, and after filtering and washing is obtained as a paste containing 55 per cent, of water. After drying, a product is obtained which is more toxic than most other forms of sulphur and is very effective in agricultural work as a fungicide the particles are almost of colloidal size, most being less than 15 p..1... 

Hydrogen may be oxidised by sulphur dioxide under suitable conditions thus when a mixture of the gases is passed over finely divided nickel or over nickel sulphide at a dull red heat, water, hydrogen sulphide and sulphur are produced.3 If the gases are passed sufficiently slowly the whole of the sulphur dioxide is decomposed. Cobalt sulphide and, with less efficiency, ferrous sulphide, may also be used as catalysts in this hydrogenation.4 A similar reaction occurs at a slightly higher temperature in the absence of a catalyst, but in this ease the sulphur is obtained mainly in the free condition the presence of a little water vapour facilitates the reaction.5... 

S. Yali, G. Xiyun, D. Andao, Determination of platinum group elements by inductively coupled plasma-mass spectrometry combined with nickel sulphide E>re assay and tellurium coprecipitation, Spectrochim. Acta, 53B (1998), 1463D1467. 

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