Ural magnetite

Yushkin (1971) proposes for proper interpretation of hardness anisotropy the construction of hardness indicatrices or comparison of hardness formulae, in which the numbers give the hardness in a particular crystallographic direction. For the example of Ural magnetite crystal, such a hardness formula is written as follows ... 

Nonpromoted catalysts rapidly lose their activity, particularly under severe conditions of operation. This is in no way contradicted by reports stating that reduced magnetites are good catalysts without addition of promoters. The author had made a spectrographic analysis of an octahedron crystal of Ural magnetite, and the examination disclosed a content of calcium, not less than 1 %, of titanium between 0.5 and 1 % and smaller contents of magnesium and aluminum, which proves that well-known promoters were present in the magnetite matrix. 

Ural magnetite, although a nice octahedral crystal, was not pure Fe304. 

It may be seen from the figures that the catalyst pattern differs from the pattern of Ural magnetite in three ways. There are some fuzzy extra reflections somewhat removed from the magnetite lines. These reflections may be satellites or may originate from separate phases. There are satellites quite near the (311) reflection, and there is a broadening of the main reflections. In patterns of other catalysts a number of weak satellites are observed nearer to the main reflections. 

Ill northern Sweden are located what may be the largest magnetic-deposits in the world, believed to have been formed by segregation in tile magma. Magnetite is also found in Norway, in the Urals. Italy. 

Figure 49. Permeability of Ural-mountain Magnetite at Various Field Strengths. Variation with Particle Size.

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