Fertilization processes

Nitric acid acidulation of phosphate rock produces phosphoric acid, together with dissolved calcium nitrate. Separation of the phosphoric acid for use as an intermediate in other fertilizer processes has not been developed commercially. Solvent extraction is less effective in the phosphoric—nitric system than in the phosphoric—hydrochloric system. Instead, the nitric acid acidulate is processed to produce nitrophosphate fertilizers. 

Triple (Concentrated) Superphosphate. The first important use of phosphoric acid in fertilizer processing was in the production of triple superphosphate (TSP), sometimes called concentrated superphosphate. Basically, the production process for this material is the same as that for normal superphosphate, except that the reactants are phosphate rock and phosphoric acid instead of phosphate rock and sulfuric acid. The phosphoric acid, like sulfuric acid, solubilizes the rock and, in addition, contributes its own content of soluble phosphoms. The result is triple superphosphate of 45—47% P2 s content as compared to 16—20% P2 5 normal superphosphate. Although triple superphosphate has been known almost as long as normal superphosphate, it did not reach commercial importance until the late 1940s, when commercial supply of acid became available. 

PH-20, a guinea pig sperm protein of 64 kD, is present on both the plasma membrane and inner acrosomal membrane of sperm. It is essential for adhesion of sperm to the zona peUucida, the initial step in the fertilization process. Active immunization with PH-20 causes infertility in both male and female guinea pigs for a period ranging from 6 to 15 months (120). 

Wakefield Z.T. Distribution of Cadmium and Selected Heavy Metals in Phosphate Fertilizer Processing (Bulletin Y-159), National Fertilizer Development Center, TVA, 1980. 

The destruction of hyaluronic acid by spreading factors in sperms may play an important role in fertilization processes. 0... 

Orifice scrubbers are used in industrial applications including food processing and packaging (cereal, flour, rice, salt, sugar) pharmaceutical processing and packaging and the manufacture of chemicals, rubber and plastics, ceramics, and fertilizer. Processes controlled include dryers, cookers,... 

Profilins are proteins first detected in 1977 and present in eucaryotic cells. They control actin binding in cells or participate in the cell fertilization process. Profilins are present both in plants and in fruits. The profilins from plants and fruits are structurally very similar IgE created against plant allergens may react with fruit allergens. This is an example of a co-sensitization phenomenon. 

The phosphate concentration in the tailings is upgraded to a level adequate for commercial exploitation through removal of the nonphosphate sand particles by flotation [32], in which the silica solids are selectively coated with an amine and floated off following a slurry dewatering and sulfuric acid treatment step. The commercial quality, kiln-dried phosphate rock product is sold directly as fertilizer, processed to normal superphosphate or triple superphosphate, or burned in electric furnaces to produce elemental phosphorus or phosphoric acid, as described in Section 9.2. 

The observations that flavonols are not involved in the fertilization process in certain species, and that this function can be completed using other compounds, suggest that flavonols only affect fertility indirectly. There are various examples of cross-talk between branch pathways of phenylpropanoid metabolism, or the shikimate pathway. The absence of flavonols in maize and Petunia could affect the accumulation of other compounds that are more specifically required for male fertility. Thus, differences between species in terms of flavonoid... 

Hormonal patterns and their regulation are more complex in females than in males due to the female cycle, the fertilization process, gestation and lactation. All functions ofthe female reproductive system are under endocrine control and therefore can be disrupted by effects on the reproductive endocrine system. 

A significant concern in all nitration plants using mixed acid centers on the disposal method or use for the waste acids. They arc sometimes employed for production of superphosphate fertilizers. Processes have also been developed to reconcentrate and recycle the acid. 

Anon., Granulation by layering in new fertilizer process, Brit. Chem. Eng., 10 (1965) 590-592. 

As with inclined discs, the character of the internal surface is important in producing the correct tumbling action in the drum. In iron ore balling, the steel drum is commonly lined with a layer of concrete (approx. 1 in. (2.5 cm) thick) or by expanded metal. Various types of internal scrapers, depicted in Fig. 3.18, are used to limit build-up of material on the inside surface and to provide a uniform layer to promote the correct rolling, tumbling action in the drum. Rubber flaps and liners as well as external knockers are used to limit build-up in fertilizer processing. 

Fig. 3.22. SAI-R granular fertilizer process reaction, granulation and drying in one vessel [38].

Involvement of sperm proteolytic enzymes in fertilization processes has a long history. Perhaps the first definitive observation that sperm proteases affected egg envelopes was that of Yamane in 1935. He demonstrated that an extract of rabbit sperm dispersed the cumulus cells and solubilized the zona pellucida (ZP) or egg envelope of the rabbit egg (1.). The presence of proteases in the sperm extract was presumed by analogy with the dispersing action of the trypsin activity in pancreatin. In 1939, Tyler obtained an extract from sperm of the giant keyhole limpet Meeathura crenulata which dissolved the egg envelope without affecting the egg itself. 

While acrosin has been localized to the acrosome, there are conflicting reports as to exactly where in the acrosomal compartment acrosin is localized before the acrosome reaction and the timing of its release in the fertilization process. From the description of acrosin as a ZP binding lectin, acrosin must be available to bind the ZP, and this would place the molecule on the surface of the intact sperm, or in some species, of the aerosome-reacted sperm. In the mouse, only acrosome intact sperm bind the ZP (66). Once the sperm has undergone the acrosome reaction and the outer membranes (limiting... 

The trend in the fertilizer industry during the past few years has been toward larger and larger fertilizer plants. In terms of plant location, what are the more important factors that should be considered and which factors become even more important as the size of the plant is increased Are these factors of equal importance regardless of the type of fertilizer produced Analyze this situation for ammonia, urea, and phosphate fertilizer process plants. 

While many refractory peridotites were likely produced by melt-rock reactions at nearly constant or increasing melt mass (Kelemen, 1990 Kelemen et al., 1990), some fertile peridotites were conversely refertUized as the result of the solidification of infiltrated melt (a process also referred to as percolative fractional crystallization by Harte et al., 1993). (Re)fertilization processes have been invoked for several types of orogenic, ophiolitic, and oceanic peridotites, such as ... 

Paul, A.C., Pillai, P.M.B., Komalan Nair, S. and Pillai, K.C., Studies on the leaching of Radium and the emanation of Radon from fertilizer process sludge. J. Environ. Radioact. 1 (1984) 51-65. 

Studies on the activity of rabbit sperm acrosomal enzymes have indicated that gossypol at 12-76 pM could significantly inactivate azocoll proteinase, acrosin, neuraminidase, and arylsulfatase. Hyaluronidase, p-glucuronidase, and acid phosphatase were also inhibited at a higher concentration of gossypol (380 pM) (Yuan et al., 1995). Since acrosomal enzymes play important roles in the fertilization process, the inhibition of... 

The method for nitrite determination based on the diazotization-coupling reaction by column preconcentration and on the reduction of nitrate to nitrite using the Cd-Cu reductor column has been proposed for the determination of nitrate and nitrite in water and some fruit samples [6]. On-line monitoring of nitrite in fertilizer process streams, natural and waste water effluents based on the diazotization of nitrite in the sequential injection system with N-(l-naphthyl)etylenediammonium dichloride and the formation of a highly coloured dye has been described [7]. 

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