Nickel silicate spinel

Thus, nickel should be enriched relative to pyroxenes in dense Upper Mande minerals (e.g., silicate spinel and olivine) and their low-temperature alteration products (e.g., gamierite). 

Finger, L. W., Hazen, R. M. Yagi, T. (1979) Crystal structures and electron densities of nickel and iron silicate spinels at elevated temperatures and pressures. Amer. Mineral., 64,1002-9. 

Catalyst deactivation and resistance to coking are two important issues of the methane reforming reaction with CO2 over Ni based catalysts because of their potential industrial application. Chen and Wren (9) and Bhattacharya and Chang (10) have recently proposed that the nickel aluminate spinel produced by interaction between nickel and alumina has a positive effect on the suppression of carbon deposition in CO2 reforming of methane. On the other hand, the formation of various types of nickel silicate species between the nickel and the support, attributed to the strong metal-support interaction, has been reported in Ni-silica catalysts (11,12). From these conclusions, it seems interesting to study the influence of Ni-silica interaction on carbon deposition. 

Fireclay bricks (alumina silica bricks, alumina calcium oxide silica bricks, and other silicate bricks) are not optimal barrier materials for A1 reductirMi cells. As we have mentioned, cryolite-based electrolyte for A1 reduction is a substance that dissolves alumina better than anything else. Certainly, it will dissolve all alumina-based refractory compositions and almost all other oxides similar in chemical structure to alumina. From a chemical point of view, the effective refractory barriers against the penetration of cryolite might be tin oxide, nickel oxide, compounds of nickel oxide, iron oxide, or zinc oxide (such as spinel Fe NiOs). These oxides almost do not react with NaF and aluminium fluoride [175]. Yet the cost of these materials, which is 50-100 times higher than that of firebrick, provides the impetus to find less costly variants of alumina silica materials. 

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