Ammonium orthophosphates

Orthophosphate Hquid mixtures are ineffective as micronuttient carriers because of the formation of metal ammonium phosphates such as ZnNH PO. However, micronutrients are much more soluble in ammonium phosphate solutions in which a substantial proportion of the phosphoms is polyphosphate. The greater solubiHty results from the sequestering action of the polyphosphate. The amounts of Zn, Mn, Cu, and Fe soluble in base solution with 70% of its P as polyphosphate are 10 to 60 times their solubiHties in ammonium orthophosphate solution. When a mixture of several micronutrients is added to the same solution, the solubiHty of the individual metals is lowered significantly. In such mixtures the total micronuttient content should not exceed 3% and the storage time before precipitates appear may be much shorter than when only one micronuttient is present. 

Evolution of ammonia from a boiling dilute solution of diammonium phosphate gradually reduces the pH. This process is used commercially to control the precipitation of alkaH-soluble—acid-insoluble coUoidal dyes on wool. Other ammonium orthophosphate salts of interest are ammonium hemiphosphate [28537-48-6] NH4H2PO4 H3PO4, and its hydrate [28037-74-3], as well as the trihydrate [78436-07-4] of DAP. 

In most analytical procedures for determining the total phosphoms content (normally expressed in terms of P20 ), the phosphates are converted to the orthophosphate form. Typically, condensed phosphates are hydrolyzed to orthophosphate by boiling in dilute mineral acid (0.1 N). The orthophosphate is then deterrnined by gravimetric or spectrophotometric methods. For gravimetric deterrnination, insoluble phosphomolybdates (or magnesium ammonium orthophosphate) is formed. 

UREA-AMMONIUM ORTHOPHOSPHATE. A fertilizer developed especially for food-deficient regions, particularly rice-dependent areas. Several grades contain all three primary plant nutrients (nitrogen, phosphorus, and potassium). Contains up to 60% nitrogen, phosphoric anhydride and potassium oxide. 

There are three possible ammonium orthophosphates, only two of which are manufactured on any scale. 

Ammonium orthophosphates.—Evaporation of a solution of phosphoric acid neutralized with excess of ammonia yields the trihydrate of tjae normal phosphate, (NH4)3P04,8HS0, in the form of transparent prisms.5 A pentahydrate has also been described.6 When the ammoniaeal solution is heated with aluminium, the phosphate of this metal is formed zinc liberates hydrogen.7... 

Ammonium orthophosphates are highly concentrated sources of plant food containing as much as 18% N and 48% P2OS. Ammonium phosphates are generally made by reacting phosphoric acid and anhydrous ammonia. Potash salts may be added if desired and the final product is granular and free flowing. 

Ammonium Orthophosphate S 23 365 9 0.1 102 DuPont Delrin 127x12.7x3.2 mm bars... 

Copper pyrophosphate (electrolytical) Determination of ammonium, orthophosphate, and nitrate... 

Phosphate. Because of interference by uranium in the usual magnesium ammonium orthophosphate procedure,5 uranium is first removed by a cation-exchange procedure. A column (2.5 by 36 cm.) of 50 to 75 cc. of Dowex-50 resin is washed with 200 ml. of Z N hydrochloric acid and then 200 ml. of water at flow rates of 2 to 3 ml./min. An acidic solution of the product, containing 100 to 150 mg. of orthophosphate, is passed through the column at a rate of 1 ml./min. The column is washed with water until the washings are neutral to litmus, and phosphate is determined in the combined eluate and washings by the usual gravimetric procedure.6 Uranium can be eluted from the... 

A13-25349 Akoustan A Ammonium hydrogen phosphate solution Ammonium monohydrogen orthophosphate Ammonium orthophosphate dibasic Ammonium phosphate Ammonium... 

Synonyms magnesium ammonium orthophosphate Magnesium Carbonate... 

Magnesium Aluminum Silicate BC 1(H)] Magnesium Aluminum Silicate BC 101] Magnesium Aluminum Silicate BC 102] Magnesium Aluminum Silicate BC 103. See Magnesium aluminum silicate Magnesium ammonium orthophosphate. See Magnesium ammonium phosphate, hexahydrate... 

Urea - ammonium nitrate - ammonium orthophosphate -potash - water... 

Although alkali metal and ammonium orthophosphates are water soluble, most orthophosphates of other metals are insoluble or nearly so (Table 5.12). Melting points are often in excess of 1000°C (Table 5.13), although many of these salts under normal atmospheric conditions tend to lose P2O5 before their melting point is reached. 

Ammonium orthophosphates are very important. Known salts include... 

The mono-, p = 1.803 g/cc, and di-, p = 1.619 g/cc, ammonium orthophosphates find huge application as fertilisers where they function as sources of both nitrogen and phosphorus (Chapter 12.2). The tri-ammonium salt (NH4)3P04 -3H20 slowly loses ammonia on standing in the atmosphere. 

FIGURE 5.4 Water solubility of (a) sodium and (b) ammonium orthophosphates. 

Insoluble pyrophosphates of several divalent metals (e.g. Be, Mg, Zn, Ni) can be prepared by heating the appropriate metal ammonium orthophosphate. Decomposition of these ammonium salts occurs in stages. 

Ammonium orthophosphate was first suggested as a fireproofing agent for theatre curtains by Gay Lussac [38] in 1821. The relatively cheap ammonium orthophosphates (mono, di or a mixture) (Section 12.2) were the first compounds to be used and they are still widely employed as fire retardants in paper, fibre boards, wood and fabrics where water solubility and susceptibility to leaching during washing is not important. 

Sodium, potassium or ammonium orthophosphate, acetate, perchlorate or citrate salts are commonly used for buffering the eluent and should be of the highest... 

The effect of etch time (30 sec vs. 180 sec) on the composition of a Ti-6-4 surface etched in hydrofluoric acid/ammonium orthophosphate solution was followed by two SIMS spectra shown in Figure 29.(33) The aluminum signal decreases with increasing etch time while the vanadium signal increases. Preferential etching of the aluminum-rich a phase relative to the vanadium-rich p phase by the etch leads to the decreased aluminum signal. 

FIGURE 29. SIMS spectra of titanium-6-4 etched in hydrofluoric acid/ammonium orthophosphate for 30 sec (b) and titanium-6-4 etched in the same acid mixture for 180 sec (a). Reprinted with permission from Reference 33. Copyright 1981 Gordon and Breach Science Publishers. 

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