Phosphates phosphorus content

Phosphor-gehalt, m. phosphorus content, -geruch, m. phosphorus odor, -geschoss, n. phosphorus bullet, incendiary bullet, -gruppe, /. phosphorus group, -guano, m. phosphatic guano. 

The analysis of phosphates and phosphonates is a considerably complex task due to the great variety of possible molecular structures. Phosphorus-containing anionics are nearly always available as mixtures dependent on the kind of synthesis carried out. For analytical separation the total amount of phosphorus in the molecule has to be ascertained. Thus, the organic and inorganic phosphorus is transformed to orthophosphoric acid by oxidation. The fusion of the substance is performed by the addition of 2 ml of concentrated sulfuric acid to — 100 mg of the substance. The black residue is then oxidized by a mixture of nitric acid and perchloric acid. The resulting orthophosphate can be determined at 8000 K by atom emission spectroscopy. The thermally excited phosphorus atoms emit a characteristic line at a wavelength of 178.23 nm. The extensity of the radiation is used for quantitative determination of the phosphorus content. 

Total phosphorus content of phosphate rocks is relatively unimportant, since what really matters is its reactivity in the soil, which in turn depends on the soil itself, the rock mineralogy and the level of rock grinding. 

The rat has been used rather widely to study the relation between dietary protein, or acid salt feeding, and calcium loss. Barzel and Jowsey (19) showed that the rat fed a control diet supplemented with ammonium chloride excreted excessive urinary calcium, and experienced a concomitant loss of fat-free bone tissue. Draper, et al. (20) extending this work, reported an inverse relation between dietary phosphate and loss of bone calcium and dry, fat-free tissue. In subsequent studies (21), they reported that this process was accompanied by reduced serum calcium levels the high phosphorus, low calcium diet increased urinary calcium loss. Whereas, increasing the phosphorus content of the diet stopped the excessive urinary calcium loss. To test possible zinc loss that might result from this sort of acid salt feeding, Jacob and her coworkers (22) fed rats a supplement of ammonium chloride and then measured urinary zinc and calcium. The hypercalciuria occurred exclusive of an effect upon urinary zinc loss. 

Phosphorites are hydrogenous precipitates with phosphorus concentrations greater than 5% w/w P2O5. Concentrations as high as 40% have been observed. In comparison the phosphorus content of most sediments is aroimd 0.3%. Phosphorites represent an important economic ore deposit as shown in Table 18.3, supplying phosphorus for fertilizer use. The United States is the leading supplier of processed phosphates in the world, accounting for about 45% of world trade. 

There is a series of arsenatophosphates corresponding with each of the three forms of condensed potassium arsenate and phosphate, the transition points and melting point of which vary systematically with composition (see Fig. 10). A chain structure for the a-form of potassium arsenate and arsenophosphate may be inferred from their isomorphism with (KP03)xB. The 7-forms also contain high-molecular anionic chains for, when they are hydrolyzed, monoarsenate and polyphosphates with chain length up to n = 6 are formed, depending on their phosphorus content. No metaphosphate is produced, however. 

A number of instrumental analytical techniques can be used to measure the total phosphorus content of organophosphorus compounds, regardless of the chemical bonding of phosphorus within the molecules, as opposed to the determination of phosphate in mineralized samples. If the substances are soluble, there is no need for their destruction and for the conversion of phosphorus into phosphate, a considerable advantage over chemical procedures. The most important methods are flame photometry and inductively coupled plasma atomic emission spectrometry the previously described atomic absorption spectrometry is sometimes useful. 

These types of polymers are similar to phosphonates and some actually are phosphonates, despite attempts to confuse the issue by the use of alternative names. They tend to exhibit varying degrees of both deposit-control and corrosion-control properties. Several PCA polymers were introduced in the 1980s and further developed in the 1990s and were termed phosphinocarboxylic acids. Most were, in fact, acrylic acid/organic phosphate polymers, but with a C P C bond (the phosphonates have a C P O bond). In the 1990s some low phosphorus content phosphonocarboxylic acid PCAs have been introduced. Structures for the different chemical PCAs, types 16 and 4, are shown in Figure 5.5. 

This relationship varies slightly because of the vertical fluctuation in the phosphorus content in the sea. For saline water systems, data on the solubility product of a calcium phosphate is difficult to obtain inasmuch as — aside from temperature and hydrostatic pressure — the solubility product is dependent on the type and amount of solutes present. The apparent dissociation constants of H3P04 are defined by the equations129,130 ... 

Phosphorus containing fertilizers Phosphates are the basic substances in these fertilizers. Phosphorus is also essential for plants. Phosphorus compounds are produced by powdering rock phosphate and adding sulfuric acid to it. The resulting products - phosphoric acid and calcium salts (from the rock) are directly applied to the soil to increase its phosphorus content. Potassium fertilizers examples Potassium chloride, Potassium nitrate etc. A complete fertilizer contains nitrogen, phosphorus and potassium in a fixed ratio. This is called NPK fertilizer. 

One embodiment of this general reaction led to a product which was commercially produced for several years by Stauffer as Fyrol 76 (9), a copolycondensation product of dimethyl methyl-phosphonate with bis(2-chloroethyl) vinylphosphonate. The features of Fyrol 76 were high phosphorus content (20%), water solubility, and ability to be polymerized by means of a radical initiator to a crosslinked polymer. A related polycondensation product was developed from tris(2-chloroethyl) phosphate and dimethyl methylphosphonate. By control of the reagents and procedure used for neutralization, these oligomeric products were produced with primary alcohol functional groups (7). 

Phosphorus Content in Starch Phosphates and Degree of Substitution with Phosphoric Acid Moieties22... 

In Anacystis nidulans, the intacellular PolyP level, which was manipulated by growth in the presence of various P concentrations in the medium (0.3-3 mM), increased with the Pi concentration up to 2.1 mM and decreased thereafter (Keyhani et al., 1996). Thus, the PolyP accumulation in cyanobacteria depended on the phosphorus content in the medium, as in other bacteria. The growth rate of cyanobacteria under phosphate starvation has been shown to be a function of the amount of previously accumulated PolyPs in the cells (Rhee, 1973). PolyP storage is a survival strategy under conditions of fluctuating phosphate supply characteristic of the environmental conditions, in which the cyanobacteria live (Falkner et al, 1995). 

Ammonium polyphosphate is one of the most often used phosphoric fertilizers (Corbridge, 1980). It was found to be equally effective when compared with single superphosphate and diammonium phosphate for increasing the yields of wheat and maize and for increasing the available phosphorus content in soil during field experiments (Sharma and Singh, 1998). 

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