Properties of Diammonium Phosphate Fertilizer

Abstract

Tennessee Valley Authority, Wilson Dam, Ala. r)iammonium phosphate, produced from anhydrous ammonia and electric-furnace phosphoric acid in a pilot plant using a new, saturator-type process, consisted of aggregates of thin tabular crystals bonded by a film of fine crystals. The product contained 0 to 5% of monoammonium phosphate, but otherwise was substantially free of impurities. Laboratory tests showed the product to be strong enough to withstand ordinary fertilizer handling without excessive degradation, satisfactorily nonhygroscopic, satisfactorily drillable, and suitably stable with r e s p r r t to loss of ammonia by volatilization under normal IllMMONIUM phosphate [(NHJPHPO~; 21.2% nitrogen D and 53.8% phosphorus pentoxide1 has not enjoyed wide usage in this country as a fertilizer; this may be attributed at least in part to the poor behavior of some diammonium phosphate mixtures that have been used in the past and to unfavorable reports on important fertilizer properties of the salt. Most of the diammonium phosphate that has been used in this country wm imported from Germany before World War I1 in the form of granulated nitrogen-phosphorus pentoxide-potassium oxide mixtures (Nitrophoska), prepared by adding a hot concentrated solution of ammonium nitrate to a dry mixture of diammonium phosphate and potassium chloride or sulfate and cooling the mixture in granulating equipment ( 4 , 80). The high initial temperature of the mixture in this procedure was thought to result in some loss of ammonia from diamnionium phosphate (80). ' Most of the Nitrophoslras were characterized by relatively high ammonium nitrate content and nitrogen-phosphorus pentoxide ratio. Therefore, they were hygroscopic and tended to cake and become undrillable unless handled with special care (80). The production of Nitrophoslra from diammonium phosphate was discontinued by the Germans several years ago because of the unsatisfactory physical properties of the product and its tendency to decompose during handling ( I S ) .The properties of diamnioniuin phosphate Chat may affect its use as a fertilizer in this country by itself or in ungranulated mixtures are not well established, although a number of miscellaneous properties of general interest have been reported (5, 6, 9-11, 16, 16, 19, 83'). It is nonpoisonous, nonexplosive, and nonflainmable (it is used as a flame-proofing agent). Several authors have referred qualitatively to the instability of the salt, Collings (8) stated that. it has not been used as extensively as the monosalt "because of its unstable nature and its poor physical condition." Ross, Mehring, and Merz (1'9) observed that it loscs ammonia when moistened with water and concluded that for this reason, and because i t is less convenient t o prepare than t,he monosalt, it would find limited application in this country unlcss mixed with acidic materials. Mehring and Cumings (1.5) reported that it lost ammonia and bcc:tnie paqty when exposed to 1 Present address. Mississippi Chemiual Corporation, Leland, Miss. * Present a...

Thermal Stability, Thermal Decomposition of High-Analysis Fertilizers Based on Ammonium Phosphate

“…The recommended conditions for the manufacture of diammonium phosphate using the vacuum crystallization process were ammoniation of H3P04 to pH 6.5, w'ith a maximum dryer temperature of 80°C. The properties of the diammonium phosphate fertilizers have been investigated by Thompson et al (8). Young, Hicks, and Davis (77) reported ammonia loss from 18-20-0 (18-46-0), during drying, of 2 to 3% at 82°C.…”

Fertilizing benefits of biogenic phosphorous nanonutrients on Solanum lycopersicum in soils with variable pH

“…This was done to understand the comparative efficacy of using nano-formulations over bulk materials and to test if nano-formulations are needed in lower amounts for fertilizer applications. Of these bulk controls, PA forms a soluble phosphorus control studied previously on Lactuca sativa (lettuce) [ 16 ] against P-based NMs, DAP has been conventionally used bulk P fertilizer [ 37 , 38 , 39 ] and RP provides a bulk control for nP and has also been used as a common source for deriving P fertilizers [ 10 ]. Their suspensions were used for irrigation of the plants.…”

Fertilizer Manufacture, Diammonium Phosphate Fertilizer from Wet-Process Phosphoric Acid

“…The authors acknowledge the substantial contributions to the over-all sodium, and phosphate. Several other investigators have studied the flame photometric determination of potassium and observed that various anions affect the intensity of the potassium line (7,2,6,8).…”

“…Monoammonium phosphate fertilizer has been made commercially in Canada since 1931 and in the United States since 1946 from ammonia and wet-process phosphoric acid by a process described by Atwell (7). That process is unattractive for production of diammonium phosphate because of the high vapor pressure of ammonia over diammonium phosphate solutions, which can result in excessive loss of ammonia at the temperatures encountered.…”

“…Schall and Hagelberg (7) adapted the official gravimetric procedure of the Association of Official Agricultural Chemists to flame determination, and reported on the interference of magnesium, phosphate with common fertilizer materials has been discussed in an earlier paper from this laboratory (7). Although the early work indicated that the compatibility with ammonium nitrate was limited to nitrogen-phosphorus pentoxide ratios below 0.75, that point was found to be erroneous.…”