Nonmetal silicates

Figure 4 shows the results of propylene conversion on the H-Fe-silicate (first stage) and Pt(l 0)/nonmetal silicate (second stage), at a GHSV of 1000 h with the addition of the same... 

Figure 4. Comparison of the product distributions on the Pt(1.0)/nonmetal silicate catalyst with 0.5 wt% Pt/H-ZSM-5 (Si/Al=100) catalyst in the second stage.

The iron formed in a blast furnace, called pig iron, contains impurities that make the metal brittle. These include phosphorus and silicon from silicate and phosphate minerals that contaminated the original ore, as well as carbon and sulfur from the coke. This iron is refined in a converter furnace. Here, a stream of O2 gas blows through molten impure iron. Oxygen reacts with the nonmetal impurities, converting them to oxides. As in the blast furnace, CaO is added to convert Si02 into liquid calcium silicate, in which the other oxides dissolve. The molten iron is analyzed at intervals until its impurities have been reduced to satisfactory levels. Then the liquid metal, now in the form called steel, is poured from the converter and allowed to solidify. 

I ILICON-CONTAINING CERAMICS include the oxide materials, silica and silicates the binary compounds of silicon with nonmetals, principally silicon carbide and silicon nitride silicon oxynitride and the sialons main group and transition metal silicides and, finally, elemental silicon itself. Throughout the world, research activity on the preparation of all of these classes of solid silicon compounds by newer preparative techniques is vigorous. 

Silicon is a shiny, blue-gray, high-melting, brittle metalloid. It looks like a metal, but it is chemically more like a nonmetal. It is second only to oxygen in abundance in the earth s crust, about 87% of which is composed of silica (Si02) and its derivatives, the silicate minerals. The crust is 26% Si, compared with 49.5% O. Silicon does not occur free in nature. Pure silicon crystallizes with a diamond-type structure, but the Si atoms are less closely packed than C atoms. Its density is 2.4 g/cm compared with 3.51 g/cm for diamond. 

However, it turns out that native copper is extraordinaiily variable in composition even within single sources. Native copper nonnally contains a vaiiable amount of other, nonmetallic minerals including copper sulfides, oxides, and silicates. These other minerals are not ductile but break upon cold-working the copper, which decreases the amounts of these minerals in varying amounts and thus alters the composition. Other elements that are soluble in an alloy solution with copper increase in abundance simply because the ratio of metal to nonmetal changes. 

Rules for some other reactions make use of information from a database. For example, sodium sulfite will react with silicon dioxide at high temperatures to form sodium silicate and sulfur dioxide. This example follows the general rule nonmetal oxide displacement if... 

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