Silicate production

J. Dacey and W. Pult2, Synthetic Silicate Products for the Rubberindusty, at the CL Meeting of the 147th Rubber Division, Philadelphia, Pa., Mery 2—5, 1995, American Chemical Society, Washington, D.C. 

Silicate minerals, 25 56t Silicate modifications, via silylation, 22 696 Silicate products, prices of, 22 468t Silicates, 26 145-146, 5 640. See also Anthropogenic silicas and silicates commercial soluble, 22 451-452... 

For certain metal alloys, a calcium silicon alloy is required. This alloy also is used as a steel deoxidizer and is favored because it forms a low-melting-point calcium silicate product A representative composition of the alloy is 30-33% Ca, 60-64% Si, 3-5% Fe, 1-2% Al, 0.3-0.6% C, and less than 0.15% S and P. 

Although boron cannot successfully compete with aluminum for sites in the mordenite structure, the more siliceous products contain significant amounts of boron. Figure 2 shows the B2O3 content of the products as a function of the Si02/Al203 ratio in the gel and in the product. It is clear that if enough aluminum is available in the gel to form an... 

For the Amazon shelf, recycling of N and P in the water column is essential for sustaining primary production (providing -60% of the total nutrient uptake). In contrast, silicate supply to the shelf from rivers, upwelling, and surface mixing is sufficient to sustain all of the siliceous productivity on the shelf. 

Cement is made by forming a calcium silicate product from limestone and clay minerals in a kiln which requires very hot temperatures, releasing high levels of CO2 as it bums. Most low carbon cements on the market are based on magnesium silicate, which takes less energy to heat. 

Alkali silicates are used as components, rather than reactants, in many appHcations. In many cases they only contribute partially to overall performance. Utility factors are generally not as easy to identify. Their benefit usually depends on the surface and solution chemical properties of the wide range of highly hydrophilic polymeric silicate ions deHverable from soluble silicate products or their proprietary modifications. In most cases, however, one or two of the many possible influences of these complex anions clearly express themselves in final product performance at a level sufficient to justify their use (102). Estimates of the 1995 U.S. consumption of sodium sihcates are shown in Table 6. 

Aqueous silicate product forms with widely varying properties such as leach rate, hardness, and volume can be produced at various costs by using the three alternative process routes. Typical leach rates for the products in water range from g/cm -day. In general, the volume... 

Silicates and Silicate Products Silicate products are utilized in a multiplicity of applications. They are dealt with under the following product groups ... 

Phase transition of quartz makes firing of silicate products more difficult... 

Mordenite can be synthesized from gels comprised of Na2<), AI2O3, Si02 and H2O (9-13). More siliceous products are formed as the Sit /A C and Si02/Na2<) ratios are increased (13). The range of mordenite compositions which can be prepared as pure phases by this method are represented in Formula 1. 

Figure 1. Sodium silicate production since 1900 as 40° Be 3.3 ratio solution (data smoothed to show trends). CGR since 1925 is 2.6%.

Woddwide silicate production is estimated to be approximately 4 x 106 t/yr. The 1995 prices for typical products are given in Table 4. The price for a Uquid product, normalized to a 100% solids basis, is usually dose to the price of the corresponding bulk glass. International trade of sibcates, especially Uquid products, is limited by the cost of transportation rather than production costs. Production of sibcates has increased in the 1990s (Table 5). This growth is primarily attributed to an increase in the use of sflicate to make derivatives and also to use in peroxide bleaching. 

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