Calcium plants

McAinsh MR, Webb AAR, Taylor JE, Hetherington AM. Stimulus-induced oscillations in guard cell cytosolic free calcium. Plant Cell 1995 7 1207-1219. 

Liners, F., Letesson, J. J., Didembourg, C., Van Cutsem, P. (1989). Monoclonal antibodies against pectin. Recognition of a conformation induced by calcium. Plant Physiol., 91,1419-1424. 

Sodium, Potassium Calcium, Plants Acid digestion or dry - Flame AAS [94]... 

Sanders, D., Brownlee, C., and Harper, J.F., 1999, Communicating with calcium. Plant Cell 11 691-706. 

Oxalate is found in plants, animals, and in humans. Oxalate content of plants is, compared to that of animals and humans, much higher. The calcium oxalate found in plants can even account for a large amount of their total calcium. Plant oxalate is the main regulator of calcium concentrations in plant tissues, an important factor in plants defense (against herbivores), and in heavy metal tolerance [2]. In contrast to these important roles that have been dedicated to oxalate in plants, in... 

Shinkle, J. R., and Jones, R. L., 1988, Inhibition of stem elongation in Cucumis seedlings by blue light requires-calcium. Plant Physiol. 86 960-966. 

Historically, soda ash was produced by extracting the ashes of certain plants, such as Spanish barilla, and evaporating the resultant Hquor. The first large scale, commercial synthetic plant employed the LeBlanc (Nicolas LeBlanc (1742—1806)) process (5). In this process, salt (NaCl) reacts with sulfuric acid to produce sodium sulfate and hydrochloric acid. The sodium sulfate is then roasted with limestone and coal and the resulting sodium carbonate—calcium sulfide mixture (black ash) is leached with water to extract the sodium carbonate. The LeBlanc process was last used in 1916—1917 it was expensive and caused significant pollution. 

This carbon dioxide-free solution is usually treated in an external, weU-agitated liming tank called a "prelimer." Then the ammonium chloride reacts with milk of lime and the resultant ammonia gas is vented back to the distiller. Hot calcium chloride solution, containing residual ammonia in the form of ammonium hydroxide, flows back to a lower section of the distiller. Low pressure steam sweeps practically all of the ammonia out of the limed solution. The final solution, known as "distiller waste," contains calcium chloride, unreacted sodium chloride, and excess lime. It is diluted by the condensed steam and the water in which the lime was conveyed to the reaction. Distiller waste also contains inert soHds brought in with the lime. In some plants, calcium chloride [10045-52-4], CaCl, is recovered from part of this solution. Close control of the distillation process is requited in order to thoroughly strip carbon dioxide, avoid waste of lime, and achieve nearly complete ammonia recovery. The hot (56°C) mixture of wet ammonia and carbon dioxide leaving the top of the distiller is cooled to remove water vapor before being sent back to the ammonia absorber. 

Calcium Chloride. Distiller waste Hquor from synthetic plants can be evaporated in multiple effect evaporators, precipitating residual sodium chloride. The resulting mother Hquor is then further evaporated to a molar ratio of lCaCl2 2H20 and cooled to produce flakes that are dried in rotary or... 

A broad comparison of the main types of processes, the strength and quaUty of phosphoric acid, and the form and quaUty of by-product calcium sulfate are summarized in Table 7. Because the dihydrate process is the most widely used, the quaUty of its acid and calcium sulfate and its P2O3 recovery are taken as reference for performance comparisons. Illustrative flow diagrams of the principal variations in process types have been pubUshed (39). Numerous other variations in process details ar also used (40—42). The majority of plants use a dihydrate process and some of these have production capacity up to 2100 of P2O3 per day. 

The abatement of fluorine emissions and disposal of by-product calcium sulfate from phosphoric acid plants are environmental concerns. 

Calcium. Soil minerals are a main source of calcium for plants, thus nutrient deficiency of this element in plants is rare. Calcium, in the form of pulverized limestone [1317-65-3] or dolomite [17069-72-6] frequendy is appHed to acidic soils to counteract the acidity and thus improve crop growth. Such liming incidentally ensures an adequate supply of available calcium for plant nutrition. Although pH correction is important for agriculture, and liming agents often are sold by fertilizer distributors, this function is not one of fertilizer manufacture. 

In 1991, U.S. plant capacity for producing acetylene was estimated at 176, 000 t/yr. Of this capacity, 66% was based on natural gas, 19% on calcium carbide, and 15% on ethylene coproduct processing. Plants currendy producing acetylene in the United States are Hsted in Table 13. 

Table 14 Hsts the acetylene-producing plants in Western Europe as of 1991. Of the 782,000 t of aimual capacity, 48% is produced from natural gas, 46% from calcium carbide, 4% from naphtha, and 2% as ethylene coproduct.

Very Htde data are readily available on China s supply and demand situation. It is known, however, that they rely almost entirely on calcium carbidey for acetylene production and that there are numerous low capacity plants, a situation that is probably not too different from that of Japan. 

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... 

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