Phosphorus-based ammonium phosphate

Phosphorus-based fertilizers usually are produced from wet-process phosphoric acid or directly from phosphate rock. Normal superphosphate, triple or concentrated superphospate, and ammonium phosphate are the three common types used. Normal or ordinary superphosphate is mostly monocalcium phosphate and calcium sulfate. It is made from phosphate rock and sulfuric acid and is equated to a 20% phosphorus pentoxide (P205) content. The production of normal superphosphate is similar to that for the manufacture of wet-process phosphoric acid except that there is only partial neutralization. 

Ammonia in Multinutrient Fertilizers. All the ammonia-based fertilizers discussed thus far contain only one of the three major plant nutrients, namely nitrogen. Referring again to Fig. 24.8, one may see that ammonia is the source of fertilizer nitrogen also, either directly or via nitrogen solids or solutions, in multinutrient fertilizers. These are fertilizers that contain two or three of the major plant nutrients—nitrogen, phosphorus, and potassium. Ammonium phosphates, both mono- and di-,... 

AMMONIUM PHOSPHATE or sec-AMMONIUM PHOSPHATE or AMMONIUM PHOSPHATE, DIBASIC or AMMONIUM PHOSPHATE, MONOBASIC (7783-28-0, dibasic 7722-76-1,monobasic) HgN04P (monobasic) H9N2O4P (dibasic) Noncombustible solid. Contact with air slowly forms anhydrous ammonia. Contact with caustics forms anhydrous ammonia gas. Violent reaction with strong oxidizers, potassium chlorate sodium hypochlorite strong bases. Reacts with antimony(V) pentafluoride lead diacetate magnesium, silver nitrate zinc acetate. Heat of decomposition produces toxic fiimes of ammonia and phosphorus oxides. 

In general purpose applications competitively priced thermosets are used for the printed circuit board base material which is usually FR4 (Flame Retardant) . One of the main flame retardants used in America is to have tetrabromobisphenol-A reacted into the epoxy resin. Non-halogen systems include additives such as alumina trihydrate, alumina trihydrate/red phosphorus and aromatic phosphates. Flame retardant epoxy coatings are reported to use ammonium polyphosphate with char-forming additives. 

Phosphorus-based flame retardants such as ammonium polyphosphate or phosphate esters are thought to form phosphoric acid in the flame and the acid is thought to promote char forming crosslinking reactions. They are often used... 

The use of urea is well documented in the literature [74, 75], as well as the effect of phosphorus-based FRs is strongly affected by the presence of metals [47,49-51,53-56, 62,74-76]. As an example, Gao et al. [76] have recently investigated complexes of cellu-lose-THPC-urea-ammonium dihydrogen phosphate (ADP) with transition metal ion Co and lanthanide metal ions such as La , Ce , Nd and Sm . The experimental data from TG, DTA, DTG and cone calorimetry tests have shown that for the complexes of cellulose-THPC-urea-ADP with the metal ions, the activation energies and thermal decomposition temperatures are higher than those of cellulose-THPC-urea-ADP this finding demonstrates that these metal ions can increase the thermal stability of cellulose-THPC-urea-ADP. Furthermore, these lanthanide metal ions can further increase the thermal stability of samples, unlike the transition metal ion Co . 

The simple colorimetric method is based on that originally published by Murphy and Riley (1962). Phosphates are colorless or pale in solution, so the phosphorus in the test solution is quantitatively converted to a colored compound, firstly using an acidic molybdate solution (ammonium molybdate in nitric acid) ... 

Another test for phosphorus (as phosphate) is based on the fact that the phosphomolybdates (and phosphotungstates) form deeply coloured insoluble lakes with triphenylmethane dyes such as methyl violet or malachite green (Chapter 12.8). The procedure is as follows a drop of test solution is placed on a filter paper which is then sprayed with a 1% solution of methyl violet. After about half a minute the paper is then sprayed with a solution of acidified ammonium molybdate and a blue spot develops. This method is sensitive to 1 part in 500,000. 

Other flame retardant materials in use include ammonium polyphosphate, organophosphates (112), bromoaromatic phosphates, red phosphorus, aluminum oxide trihydrate, antimony oxide, melamine, and synergistic combinations of two or more of these (110,111). Currently, people are focusing more on phosphorous containing compounds relative to halogens (113-115). The percentage of each of these materials in use today, based on dollar value, is given in Table 14.9. 

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