Urea-ammonium phosphates

Mixed with additives, urea is used in soHd fertilizers of various formulations, eg, urea—ammonium phosphate (UAP), urea—ammonium sulfate (UAS), and urea—phosphate (urea + phosphoric acid). Concentrated solutions of urea and ammonium nitrate (UAN) solutions (80—85 wt%) have a high nitrogen content but low crystallization point, suitable for easy transportation, pipeline distribution, and direct spray appHcation. 

Country / Reaion Ammonia Urea Ammonium Phosphates... 

TVA developed a process for producing granular ammonium polyphosphate, and in late 1973 the process was put into operation in a demonstration-scale plant with a capacity of 13-17 tph. The plant produced straight ammonium polyphosphate and urea-ammonium phosphate alternately. A flow diagram is shown in Figure 12.16. The process uses the heat of reaction of phosphoric acid (54% P2O5) with gaseous ammonia to evaporate water and dehydrate the ammonium phosphate,... 

A later paper gave a detailed description of a granulation plant that produces urea-ammonium phosphate OJAP) grades, such as 28-28-0, 22-22-11, 18-18-18, etc. [40]. The main raw materials are crushed urea prills, spray-dried ammonium phosphate (12-50-0), and potash salts. One unusual feature of the plant is a methylene-urea reactor, which is used for production of some NPK... 

In the presence of urea, ammonium phosphates will polymerise to metaphosphates below the temperature required for their decomposition to ammonia and phosphoric acid (Section 5.4) (Figure 5.4a,b). 

Effective additives include urea, ammonium phosphate, magnesium carbonate, antimony oxide, alumina hydrate, silicates, and borates. Though brominated and chlorinated organic compounds are fire retardants, they decompose at high temperatures to produce HBr and HCl which, as corrosive gases, can often do more harm than good. 

Production of nitric phosphates is not expected to expand rapidly ia the near future because the primary phosphate exporters, especially ia North Africa and the United States, have moved to ship upgraded materials, wet-process acid, and ammonium phosphates, ia preference to phosphate rock. The abundant supply of these materials should keep suppHers ia a strong competitive position for at least the short-range future. Moreover, the developiag countries, where nitric phosphates would seem to be appealing for most crops except rice, have already strongly committed to production of urea, a material that blends compatibly with sulfur-based phosphates but not with nitrates. 

Insoluble Ammonium Polyphosphate. When ammonium phosphates are heated ia the presence of urea (qv), or by themselves under ammonia pressure, relatively water-iasoluble ammonium polyphosphate [68333-79-9] is produced (49). There are several crystal forms and the commercial products, avaUable from Monsanto, Albright WUson, or Hoechst-Celanese, differ ia molecular weight, particle size, solubUity, and surface coating. Insoluble ammonium polyphosphate consists of long chains of repeating 0P(0)(0NH units. 

Urea—Phosphate Type. Phosphoric acid imparts flame resistance to ceUulose (16,17), but acid degradation accompanies this process. This degradation can be minimized by iacorporation of urea [57-13-6]. Ph osph oryl a ting agents for ceUulose iaclude ammonium phosphate [7783-28-0] urea—phosphoric acid, phosphoms trichloride [7719-12-2] and oxychloride [10025-87-3] monophenyl phosphate [701-64-4] phosphoms pentoxide [1314-56-3] and the chlorides of partiaUy esterified phosphoric acids (see Cellulose esters, inorganic). 

Markets. Industrial use of ammonia varies according to region. Eor example, industrial usage represents 20% of the ammonia production in the United States and Western Europe, 10% in the USSR, 1—10% in Asia, and 5% in Latin America and North Africa (79). Fertiliser ammonia consumed domestically in most countries is converted to straight or compound fertilisers such as urea, ammonium nitrate, diammonium phosphate, and various grades of mixed fertilisers. However, almost 29% of ammonia nitrogen in the United States is consumed as direct appHcation material. The use of nitrogen solution such as urea and ammonium nitrate (UAN) has also become popular in the United States and the USSR. 

Nitrogen solutions consist of fertilizer product combinations, eg, ammonium nitrate —ammonia, urea—ammonium nitrate—ammonia, urea—ammonium nitrate, and urea—ammonia solutions. Mixed fertilizers cover a broad range and can be loosely defined as fertilizers which contain chemically mixed nitrogen, phosphoms, and potassium (N—P—K). Examples are ammonium phosphate—potash mixtures and ammonium phosphate nitrates. 

Sodium nitrate is used as a fertiliser and in a number of industrial processes. In the period from 1880—1910 it accounted for 60% of the world fertiliser nitrogen production. In the 1990s sodium nitrate accounts for 0.1% of the world fertiliser nitrogen production, and is used for some specific crops and soil conditions. This decline has resulted from an enormous growth in fertiliser manufacture and an increased use of less expensive nitrogen fertilisers (qv) produced from synthetic ammonia (qv), such as urea (qv), ammonium nitrate, ammonium phosphates, ammonium sulfate, and ammonia itself (see Ammonium compounds). The commercial production of synthetic ammonia began in 1921, soon after the end of World War I. The main industrial market for sodium nitrate was at first the manufacture of nitric acid (qv) and explosives (see Explosives and propellants). As of the mid-1990s sodium nitrate was used in the production of some explosives and in a number of industrial areas. 

Chisso-Asahi Fertilizer Company, Ltd. This company utilizes thermoplastic resins, such as polyolefins, poly(vinyhdene chloride), and copolymers, as their coating materials. The coatings are dissolved in fast-drying chlorinated hydrocarbon solvents and are appHed to a variety of substrates including urea, diammonium phosphate [7783-28-0] potassium sulfate [7778-80-3], potassium chloride [7447-40-7], and ammonium nitrate/potassium sulfate-based N—P—K fertilizers. 

A number of products are being marketed under the trade name POLYON. These include coated basic fertilizer materials, ie, urea, potassium nitrate, potassium sulfate, potassium chloride, ammonium sulfate, ammonium phosphate, and iron sulfate, in various particle sizes. Coatings weights on urea vary from 1.5 to 15%, depending on the release duration desired. Table 6 Hsts typical products. 

In cases of still higher levels of BOD an additional supply of biomass may become essential, and this can be easily obtained from cowdung or municipal waste. To supplement biomass growth, nutrients such as urea and di-ammonium phosphate may be added. 

Nitrogen sources include proteins, such as casein, zein, lactalbumin protein hydrolyzates such proteoses, peptones, peptides, and commercially available materials, such as N-Z Amine which is understood to be a casein hydrolyzate also corn steep liquor, soybean meal, gluten, cottonseed meal, fish meal, meat extracts, stick liquor, liver cake, yeast extracts and distillers solubles amino acids, urea, ammonium and nitrate salts. Such inorganic elements as sodium, potassium, calcium and magnesium and chlorides, sulfates, phosphates and combinations of these anions and cations in the form of mineral salts may be advantageously used in the fermentation. 

The major end use of ammonia is the fertilizer field for the production of urea, ammonium nitrate and ammonium phosphate, and sulfate. Anhydrous ammonia could be directly applied to the soil as a fertilizer. Urea is gaining wide acceptance as a slow-acting fertilizer. 

An enormous quantity of ammonium nitrate is produced annually primarily for use a fertilizer and also as an explosive. Ammonium sulfate, ammonium phosphate, and urea are also used as nitrogen-containing fertilizers. They are produced by the reactions... 

Table 4.1 gives the use profile for ammonia. It can be applied directly for fertilizer or made into other nitrogen-containing compounds used for fertilizer such as urea, ammonium nitrate, ammonium phosphate, ammonium sulfate, and nitric acid. Overall approximately 80% of ammonia has an end use as fertilizer. Explosives, a second important end use, made from ammonia are ammonium nitrate and, via nitric acid, the nitroglycerin used in dynamite. Chemical intermediates include acrylonitrile and caprolactam, which eventually go into fibers. 

Crystalline polyammonium catena-polyphosphate, (NH4) H2P 03 + 1, has been prepared by heating urea and monoammonium orthophosphate under ammonia vapor for 16 hours,1 by ammoniation of superphosphoric acid,2 by thermal condensation of urea phosphate,3 and by heating various ammonium phosphates in a current of ammonia.4,5 The procedure given below, in which crude ammonium tetrametaphosphate is reorganized and condensed to a long-chain polymer in a stream of ammonia, is straightforward and permits the use of common laboratory equipment and supplies. 

Certain antiseptic and therapeutic agents (such as sodium fluoride, stannous fluoride, strontium chloride, urea, dibasic ammonium phosphate, are used in dentrifrices for their anticarcinogenic, bacteriostatic and bactericidal actions. 

Ammonium ions—To reduce the incidence of dental caries, ammonium ions are applied locally in the oral cavity. Certain dentifrices which contain ammonia or ammonium compounds e.g. dibasic ammonium phosphate and urea carbamide which liberates ammonia in the mouth are used. They decrease the number of acid producing pathogen, decrease the acidity of the oral cavity and dissolve the dental plaques. 

In the fourth type of fire retardants, a chemical bond between the molecules of the fire retardant and cellulose should produce a finish that strongly resists the effects of laundering and weathering. Among such retardants may be cited cellulose-ammonium phosphate, cellulose-urea phosphate, cellulose-titanium complexes cellulose-titanium-antimony finishes... 

Derived from Ammonium Phosphate, Potassium Phosphate, Potassium Nitrate, Urea, Iron EDTA, Manganese EDTA and Zinc EDTA. 

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