Minerals phosphorus-rich

Table 14.28. Phosphorus-rich industrial minerals and synthetic chemicals used in fertilizers (ordered by decreasing phosphorus content) ...

The cycling of phosphorus in marine sediments is quite different from that of nitrogen in that its remineralized form, HPO , is readily sequestered in several mineral phases, namely carbonate fluoroapatite (CFA) and iron-rich clays and oxyhydroxides. 

Most commercial phosphorus is produced in electric furnaces where the phosphate-rich minerals are heated to drive off the phosphorus as a gas, which is then condensed under water. Another process uses sulfuric acid to remove the phosphorus. 

In clay samples Zr-Th-rich coffinite was found around remnants of zircon. It is likely that it is the result of solid solution with zircon, ZrSi04 and thorite, ThSi04, which are isostruc-tural with coffinite (Finch Murakami 1999 Jensen Ewing 2001). The presence of phosphorus and sulphur in coffinite suggests that both elements substituted for Si in the coffinite structure. A previous study at the Bangombe site in Gabon has clearly shown that coffinites are most important secondary minerals for the retention of fissiogenic lanthanides and actinides (Stille et al. 2003). 

A rich source of minerals, including iron, phosphorus, and calcium... 

Around 23 million tormes of cottonseeds and their derivatives are fed to animals every year. This comprises 6.8 million tonnes of whole cottonseeds, and 16.4 million tonnes of cottonseed hulls and meal by-products of the extraction of cottonseed oil. These materials are rich in energy protein, fibre, and minerals such as potassium, sodium, magnesium and phosphorus, and can represent as much as 25% of a dairy herds total nutritive ration. ... 

The initial assumption might be that a photobiological H2 process would not require any raw materials. However, any biological process requires water and an adequate supply of macronutrients (i.e., nitrogen and phosphorus) and possibly some supplemental micronutrients, depending upon what nutrients and minerals are already present in the water supply to the process. One method to reduce raw material costs would be to utilize the waste stream from another process. For example, effluent streams from wastewater treatment anaerobic digesters are nitrogen rich, and blowdown streams from power plants are relatively pure. 

QS are also rich in micronutrients such as minerals and vitamins. Table 1.8 shows the mineral content of QS and quinoa flour. The main minerals are potassium, phosphorus, and magnesium (Table 1.8). According to the National Academy of Sciences (2004) the magnesium, manganese, copper, and iron present in 100 g of QS cover the daily needs of... 

The raised solubility of phosphate in some types of soils at both low and high pH has led to the observation that phosphorus solubility is lowest near neutral pH, contrary to the model of solubility based on simultaneous A1 hydroxide, A1 phosphate, and Ca phosphate precipitation. The latter model predicts phosphorus to be most soluble between pH 6 and 7, although there is little evidence from soils to confirm this prediction. While precipitation in very acid and in Ca-rich mineral soils is undoubtedly a key process in determining the solubility of phosphate, oversimplified precipitation models for this and other ions can lead to misleading generalizations about solubility in a material as complex as soil. 

Calcium and phosphorus are major minerals that are needed for the development of healthy bones and teeth. These two minerals are found in a crystalline calcium phosphate mineral known as hydroxyapatite, [Cajo(P04) (OH)2l, that makes up the mineral matrix of bone and teeth. In addition, calcium is required for normal blood clotting and muscle function. The RDA for calcium is 1200 mg/day for adults between nineteen and twenty-four years of age and 800 mg/day for adults over age twenty-five. Milk, cheese, canned salmon, and dark green leafy vegetables are all rich sources of dietary calcium. 

Phosphates are fixed by Fe-hydroxides and together with these by clay minerals. In tropical soils, phosphorus fixing on Fe-com-pounds is widespread. Phosphate fixation is appreciable in soils rich in allophane, derived from volcanic rocks. 

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