Silicates plant

Siliceous plant fibers from Phalaris canariensis L. (canary grass) (and others of the same family) have been implicated in the etiology of esophageal cancer in certain regions of the world (11). These fibers are considered to act in the same way as asbestos fibers in causing cells to... 

Methods involving triphenylmethane dyes were applied in determination of antimony in air [74], water [44], silicates, plants, sewage and waste waters [25], copper-zinc and copper-nickel alloys [48], steel [50], lead [12], silver and gold [42], palladium [45], and tellurium [27]. Antimony was determined in duralumin alloys and steel with the use of Rhodamine 6G... 

The main merchant producers of soluble silicates in the United States are The PQ Corporation, OxyChem, Crosfields Chemicals, Power Silicates, and Chemical Products. Several companies including PPG Industries, W. R. Grace, J. M. Huber, DuPont, and Albemade Corporation produce silicates for captive use. There were more than 30 soluble silicate plants in the United States in 1996 and production capabilities were more than adequate for demands. A key producer woddwide is The PQ Corporation, which has plants in both North and South America, Europe, Asia, and AustraUa. In Japan, Toso Sangyo, Fuji Chemical, and Nippon Chemical are the largest producers. Henkel, Rhcjme-Poulenc, Foret, and Crosfield Chemicals are principal producers in Europe (90). 

Silicates. In 1990, a continuous hydrothermal production plant was started up in Sulitjehna, Norway for manufacture of 9000 m /yr of calcium sihcate [10101-39-0] having average density of 0.255 g/cm. The calcium siUcate is of the xonodite [12141 -77-4] form, Ca Sig02y(0H)2, which can easily be... 

At the end of a brief life, the diatom settles to the bottom of the body of water where the organic matter decomposes, leaving the siliceous skeleton. These fossil skeletons, or fmstules, are in the shape of the original diatom plant and have designs as varied and intricate as snowflakes. Examples are shown in Figure 1. 

Hydrogen fluoride Catalyst in some petroleum refining, etching glass, silicate extraction by-product in electrolytic production of aluminum Petroleum, primary metals, aluminum Strong irritant and corrosive action on all body tissue damage to citrus plants, effect on teeth and bones of cattle from eating plants... 

A soft, gritty amorphous silica composed of minute siliceous skeletons of small aquatic plants. Used in filtration and decoloration of liquids, insulation, filler in dynamite, wax, textiles, plastics, paint, and rubber. Calcined and flux-calcined diatomaceous earth contains appreciable amounts of cristobalite, and dust levels should be the same as for cristobalite. 

Corrective Action Application In Massachusetts, a municipal wastewater treatment plant receives a number of wastestreams containing heavy metals from local industries. When tested, the dewatered sludge failed the EP toxicity test. In order to permit landfill disposal of the sludge, solidification processes were examined. A soluble, silicate-based system, developed by Chemfix, was ultimately selected which produced a product whose leachate passed the EP toxicity test (Sullivan, 1984). 

The separation capacity of a TLC method can be easily improved by use of a two-dimensional high performance TLC technique (2D HPTLC). Various plant essential oils (menthae, thymi, anisi, lavandulae, etc.) have been analysed by 2D TLC with florisil (magnesium silicate) as the adsorbent, using dichloromethane/ -heptane (4 6) in the first direction and ethyl acetate/n-heptane (1 9) in the second direction (69). 

The poor efficiencies of coal-fired power plants in 1896 (2.6 percent on average compared with over forty percent one hundred years later) prompted W. W. Jacques to invent the high temperature (500°C to 600°C [900°F to 1100°F]) fuel cell, and then build a lOO-cell battery to produce electricity from coal combustion. The battery operated intermittently for six months, but with diminishing performance, the carbon dioxide generated and present in the air reacted with and consumed its molten potassium hydroxide electrolyte. In 1910, E. Bauer substituted molten salts (e.g., carbonates, silicates, and borates) and used molten silver as the oxygen electrode. Numerous molten salt batteiy systems have since evolved to handle peak loads in electric power plants, and for electric vehicle propulsion. Of particular note is the sodium and nickel chloride couple in a molten chloroalumi-nate salt electrolyte for electric vehicle propulsion. One special feature is the use of a semi-permeable aluminum oxide ceramic separator to prevent lithium ions from diffusing to the sodium electrode, but still allow the opposing flow of sodium ions. 

Typically, high-pressure WT boiler plants (say, over 650-900 psig) require some degree of MU water silica removal. Most commercial and general industrial facilities however, operate boiler plants at pressures below 300 psig, and irrespective of whether FT or WT boilers are employed, a silicate removal process usually is nor provided or deemed necessary. 

Where MU water sources contain relatively high natural silica levels (i.e., above 30-40 ppm Si02) or a high ratio of silica to TDS (say, > 25-30% of TDS present as Si02), this reasoning is often invalid. And in those boiler plants that use high-silica waters but operate without benefit of external silica removal equipment, extremely careful control of BW chemistry with very tight control parameters is vital to avoid risks of serious silicate deposition. 

As a result of the volatility of silica and its ensuing risks, such as the deposition of hard, amorphous, or glassy silicates in superheaters and on turbine blades, various actions are commonly taken in higher pressure boiler plants to limit silica vapor in steam. The maximum permissible silica concentration in steam is generally accepted as 0.02 ppm... 

Self-Test L.2B Carbon dioxide can be removed from power plant exhaust gases by combining it with an aqueous slurry of calcium silicate 2 C02(g) + H,0(l) + CaSiOds) — Si02(s) + Ca(HC03)2(aq). What mass of CaSiO, (having molar mass 116.17 g-mol ) is needed to react completely with 0.300 kg of carbon dioxide ... 

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 ... 

A summary is given in Table III of the results of the elucidation of the sources of the elements in remote atmospheric dusts. Four main sources are identified silicate o dust, marine spray, high temperature natural emissions (e.g. volcanic, plant and rock... 

Silicate dust Marine High temperature processes volcanic, rock and plant emissions, forest fires Anthropogenic... 

As part of a study of the secondary chemistry of members of Cistus (the rock-rose) in France, Robles and Garzino (1998) examined the essential oil of C albidus L. Plants were sampled from two areas in Provence characterized by different soil types, calcareous sites west of Marseille, and siliceous sites near Pierrefeu-du-Var and Bormes les Mimosas (PF and BM, respectively, in Fig. 2.23), which lie about 60 km and 80 km to the east, respectively, in the Massif les Maures. Regardless of the soil type, a-zingiberene [88] (Fig. 2.24) was the dominant component. Concentrations of other major components of the plants varied between the two soil types, as summarized in Table 2.6. Many other compounds were present in lesser amounts, but varied little between the two areas. A more recent paper by the same workers (Robles and Garzino, 2000) described an analysis of C. monspeliensis L. leaf oils, the results of which are summarized in Table 2.7. 

Silicon w is first isolated and described as an element in 1824 by Jdns Jacob Berzelius, a Swedish chemist. Silicon does not occur uncombined in nature, i.e.- as an element. It is found in practically aU rocks as well as in sand, clays, and soils, combined either with oxygen as silica (Si02= silicon dioxide) or with oxygen plus other elements (e.g., aliuninum, mcignesium, calcium, sodium, potassium, or iron) as silicates. Its compounds also occur in all natural waters, in the atmosphere (as siliceous dust), in many plants, and in the skeletons, tissues, and body fluids of some animals. 

The glass polyalkenoate cement was originally intended as a substitute for dental silicate cements for the aesthetic restoration of front (anterior) teeth (Wilson Kent, 1972 Knibbs, Plant Pearson, 1986a Osborne Berry, 1986 Wilson McLean, 1988). It is suitable for restoring anterior cavities in low-stress situations, that is when the restoration is completely supported by surrounding tooth material. These cavities occur on the adjacent surfaces of neighbouring teeth (class III cavities) and at the gum line (class V cavities). 

Figure 11.1a [1] shows a schematic representation of a micropreparative thin-layer chromatogram obtained on a 0.5-mm Florisil (magnesium silicate) layer prewetted with benzene of a crude extract, i.e., containing coextracted plant oil obtained from Heracleum moelendorfi fruit. The initial band of extract was washed with benzene and then separated by continuous development with ethyl acetate in benzene [1]. As seen from the fraction analysis presented in Figure 11.1b, small quantities of pure bergapten and xanthotoxin can be isolated in this maimer. 

BOF steel-making byproducts include BOF slag, air pollution control (APC) dust, and water treatment plant (WTP) sludge. BOF slag is composed of calcium silicates and ferrites combined with... 

Copper smelting Copper concentrate, siliceous flux Sulfur dioxide, particulate matter containing arsenic, antimony, cadmium, lead, mercury, and zinc Acid plant blowdown slurry/sludge, slag containing iron sulfides, silica... 

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