Carbonates silicate production

The Badische AniKn- und Soda-Fabrik prepared a nitride of undetermined composition by heating a mixture of silica and carbon in an atm. of nitrogen. The reaction proceeds at a relatively low temp, if a hydroxide or salt of a metal be added. The product contains silicon nitride mixed with the nitride of the metal. The Badische Anilin- und Soda-Fabrik also removed many of the impurities—iron, carbon, silicates, carbides, silicides, and phosphides—by treatment with acids or mild oxidizing agents which do not affect the silicon nitride. A. S. Larsen and O. J. Storm prepared the nitride by the action of nitrogen on molten silicides—e.g. ferrosilicon. 

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. 

The nature of surfactant adsorption on solid surfaces depends on the polarity and solubility of the surfactant. Thus, when an aqueous surfactant solution is in contact with non-polar coal particles, adsorption layers are formed which have polar groups oriented towards the aqueous phase. In contrast, surfactant solutions in oils (hydrocarbons, vegetable oil oxidation products etc.) in contact with polar materials or powders (carbonates, silicates) the polar groups are on the solid phase surface. 

Some of fhe chemical processes that influence groundwater chemistry in coal-bearing strata include carbon dioxide production, silicate hydrolysis, pyrite oxidation, carbonate mineral dissolution, cation exchange, sulfate reduction, and the precipitation and dissolution of secondary minerals leading to contamination of the groundwater (Banaszak, 1980 Groenewold et al., 1981 Powell and Larson, 1985). 

Thermogravimetric curves of the studied samples have rather complex character because of overlaying different processes against each other, as the differential thermal analysis (DTA) is poorly informative. The carbon rest of samples approximately on 30% exceed maintenance Si02 in samples. Most likely the thermal thermal-oxidative destruction of the polymers, accompanied also allocation of low-molecular siliceous products mainly proceeds (Table 8). 

Zeolite-citrate-carbonate-silicate system. Certain modem formulas use the four products together, along with polyacrylate polymers. Typical washing liquors contain the following ... 

Goto, S., K. Suenaga, T. Kado and M. Fukuhara (1995). Calcium silicate carbon-ation products ./o r a/ of the American Ceramic Society 78(11) 2867-2872. 

The commercial production of silicon in the form of binary and ternary alloys began early in the twentieth century with the development of electric-arc and blast furnaces and the subsequent rise in iron (qv) and steel (qv) production (1). The most important and most widely used method for making silicon and silicon alloys is by the reduction of oxides or silicates using carbon (qv) in an electric arc furnace. Primary uses of silicon having a purity of greater than 98% ate in the chemical, aluminum, and electronics markets (for higher purity silicon, see Silicon AND SILICON ALLOYS, PURE SILICON). 

Zirconia, ZrOj, is made from the natural hydrated mineral, or from zircon, a silicate. Silicon carbide and silicon nitride are made by reacting silicon with carbon or nitrogen. Although the basic chemistry is very simple, the processes are complicated by the need for careful quality control, and the goal of producing fine (<1 jiva) powders which, almost always, lead to a better final product. 

The alkali metal hydroxides are also readily absorb CO2 and H2S to form carbonates (or hydrogencarbonates) and sulfides (or hydrogen-sulfides), and are extensively used to remove mercaptans from petroleum products. Amphoteric oxides such as those of Al, Zn, Sn and Pb react with MOH to form aluminates, zincates, stannates and plumbates, and even SiC>2 (and silicate glasses) are attacked. 

Elemental phosphorus is prepared by the reduction of calcium phosphate, Ca3(P04)o, with coke in the presence of sand, SiO>. The products are phosphorus, calcium silicate, CaSiOa, and carbon monoxide. 

It was expected that an eggshell thickness of scale would form, but that it would be relatively soft and easily removed (despite normally containing some silicate and sulfate). However, a disadvantage of this method of internal control was that the carbonate degraded to form carbon dioxide, and at higher pressures the rate of breakdown was so great that the necessary carbonate reserve required to prevent sulfate scale often could not be maintained. (Never mind the danger to the steam and condensate lines from the production of carbon dioxide and ultimately carbonic acid.)... 

Alternatives to fossil fuels, such as hydrogen, are explored in Box 6.2 and Section 14.3. Coal, which is mostly carbon, can be converted into fuels with a lower proportion of carbon. Its conversion into methane, CH4, for instance, would reduce C02 emissions per unit of energy. We can also work with nature by accelerating the uptake of carbon by the natural processes of the carbon cycle. For example, one proposed solution is to pump C02 exhaust deep into the ocean, where it would dissolve to form carbonic acid and bicarbonate ions. Carbon dioxide can also be removed from power plant exhaust gases by passing the exhaust through an aqueous slurry of calcium silicate to produce harmless solid products ... 

Silver white, relatively soft metal that is only applied in alloys. Oxygen and water attack pure Ca. The most prominent compound is the oxide (CaO) = burnt calcium, which hardens to calcium carbonate in mortar. Annual production of about 120 million tons. Burnt gypsum (CaS04 0.5 H20) hardens with water. A great step in evolution was the replacement of hard shells of brittle calcium carbonate by an internal skeleton of tough calcium phosphate (hydroxylapatite)-protein composite. Calcium is essential for all life forms. The daily requirement is 0.7-1.0 g. Humans (70 kg) contain 1 kg of calcium. Calcium silicate is the main component of cement. Marble is calcium carbonate in polycrystalline form and the favorite material of sculptors. 

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