Urea price

Ammonia and urea prices from 1968 to 1986 are shown in Figure 22 (82). The average FOB price of ammonia on the U.S. Gulf Coast in early 1991 was 105/t. 

Fig. 22. Ammonia and urea prices, 1968—1985.---, ammonia prices, F.O.B. (Western Europe) —urea prices, E.O.B. (Western Europe) bagged.

Beginning in 1997, urea prices fell precipitously as China (who used to be a major buyer) began producing urea domestically. Between 1994 and 1997, China opened nine new urea plants and raised domestic production by 50 percent. This shifted world export product toward the US and lowered prices. At the end of 2001, China officially joined the World Trade Organization and re-entered the urea import market. The effect was to pull product away from the United States, which resulted in higher prices230. Historical urea prices are shown in Figure 11.10154. 

Figure 11.10. Urea Prices January, 1996 to October, 2003. (Reproduced by permission of Feitecon)...

Initially, decreased domestic demand in. theSG co.un tries created production surpluses, which were diverted to international markets and depressed fertilizer prices. Between 1991 and 1993, urea prices decreased by about 40%. Prices of other products also decreased significantly. Such depressed prices made fertilizer production unprofitable in Western Europe and North America and forced plant closures. 

Aliphatic Isocyanates. Aflphatic diisocyanates have traditionally commanded a premium price because the aflphatic amine precursors ate mote expensive than aromatic diamines. They ate most commonly used in appHcafions which support the added cost or where the long-term performance of aromatic isocyanates is unacceptable. Monofuncfional aflphatic isocyanates, such as methyl and -butyl isocyanate, ate used as intermediates in the production of carbamate-based and urea-based insecticides and fungicides (see Fungicides, agricultural Insectcontroltechnology). 

Urea peroxohydrate is made commercially by Solvay Deutschland, Degussa (Germany), and Mitsubishi Gas Chemical. It is known commercially as urea hydrogen peroxide, hydrogen peroxide carbamide, Exterol, Hydroperit, Hydroperit, Hyperol, Orti2on, Percarbamid, Percarbamide, Perhydrit, Perhydrol-Urea, Thenardol, and UHP. In 1994 the U.K. price was J7—8/kg ( 10—12/kg). World production in 1993 was several hundred metric t. 

In 1989 quantity costs, which reflect the lowest cost, of urea molding compounds, were approximately 1.41 /kg ( 0.035/in. for black and brown colors, 1.58/kg ( 0.039/in.for white and ivory special colors are somewhat higher in price. The approximate cost of cellulose-filled melamine molding compound is 1.74/kg ( 0.043/in. ). Glass fiber-filled melamine sells for 7.70/kg ( 0.22/in. ). 

Phenolics are consumed at roughly half the volume of PVC, and all other plastics are consumed in low volume quantities, mosdy in single apphcation niches, unlike workhorse resins such as PVC, phenoHc, urea—melamine, and polyurethane. More expensive engineering resins have a very limited role in the building materials sector except where specific value-added properties for a premium are justified. Except for the potential role of recycled engineering plastics in certain appHcations, the competitive nature of this market and the emphasis placed on end use economics indicates that commodity plastics will continue to dominate in consumption. The apphcation content of each resin type is noted in Table 2. Comparative prices can be seen in Table 5. The most dynamic growth among important sector resins has been seen with phenoHc, acryUc, polyurethane, LLDPE/LDPE, PVC, and polystyrene. 

Nickel is required by plants when urea is the source of nitrogen (Price and Morel, 1991). Bicarbonate uptake by cells may be limited by Zn as HCOT transport involves the zinc metal-loenzyme carbonic anhydrase (Morel et al., 1994). Cadmium is not known to be required by organisms but because it can substitute for Zn in some metalloenzymes it can promote the growth of Zn-limited phytoplankton (Price and Morel, 1990). Cobalt can also substitute for Zn but less efficiently than Cd. 

Commercially, formaldehyde is sold as u. IKt aquruus so lulion Good reactivity, low price, and important end-use markets have combined lo give formaldehyde its growth mi pcliiv Formaldehyde is produced by vnpor-pha.se oAidulnm or by dehydration of methanol Its mam muricis are in production ot phenolic and urea resins The price of formaldehyde has historically been coupled closely to the price of methanol... 

In 2001 several major North American ammonia producers unexpectedly curtailed some of their ammonia and urea production. These producers cited over-capacity and low demand that were caused by adverse weather conditions and depressed crop prices. Although many plants take periodic shutdowns, the combination of import competition that depressed prices and very high feedstock costs in many industrialized countries during 2000 resulted in shutdowns of... 

Asia dominates the world import market for urea and ammonium phosphates. China and India are particularly large importers and variations in their import requirements have a major impact on world prices. The agricultural and fertilizer sectors of these two countries could be affected by the World Trade Organization (WTO) agreements with China. The agreements will probably have a beneficial effect globally. However, some individual countries and companies may experience adverse effects36. 

In the United States poor profitability resulted in the closure of five urea plants between 1999 and the end of 2002. These plants had a total capacity of 725 thousand tons per year - about 7 percent of the total US capacity in 1999. During this same period, about one-half of the operating plants were either idled for extended periods or turned down in their output because of natural gas price spikes that drove up the cost of ammonia230. 

FE of urea has been recently shown to be more useful than the FE of sodium in distinguishing between prerenal and renal azotemia in humans (Carvounis et al. 2002) and thus may also be useful in making this distinction in animal models. Changes in the FE of urea also reflect changes in urine flow rates (in general, these values move parallel to each other) and can be used as an estimate of this parameter (Finco 1997). The methods used to detect urea in urine are the same as those used in serum (Newmann and Price 1999). 

Estimation of the glomerular filtration rate (GFR) is considered a sensitive index of functional nephron mass (Newman and Price 1999). Point measurements of the plasma levels of several endogenous small molecules (urea, creatinine, 2-(a-mannopyranosyl)-L-tryptophan) or small (less than 66 kDa) proteins (cystatin C (y-trace), prostaglandin D synthase (15-trace protein), ai-microglobulin, p2-microglobulin, and retinol binding protein) have been used to assess GFR in many species. 

Urea and creatinine elevations in plasma are in general not sensitive enough to detect low-level alterations (less than 75 % loss) in functional nephron mass, due to the contribution of renal secretion and/or reabsorption to their overall excretion, (which can compensate for their decreased filtration), to wide variations in baseline levels of some analytes, and to inherent imprecision in the assays used (Finn and Porter 1998 Price 2002 Starr et al. 2002 Shemesh et al. 1985). In particular, urea will underestimate GFR (due to extensive tubular reabsorption with decreased GFR) (Baum et al. 1975 Kaplan and Kohn 1992 Newman and Price 1999). Creatinine tends to overestimate GFR because it is secreted by the tubule in many species and secretion increases with reduced GFR (Shemesh et al. 1985 Andreev et al. 1999 Newman and Price 1999 Starr et al. 2002). In addition, creatinine synthesis is regulated by feedback inhibition which limits the degree of elevation than can occur in plasma with renal injury (Watson et al. 2002). 

The consumption of ureaform in the United States is approximately 75,000 tons/year, not including that formed in compound fertilizers from solutions. Most of the production goes into compound fertilizer for specialty uses, such as for lawns, flower gardens, and golf courses. The wholesale price of ureaform per unit of nitrogen is about three times that of urea, ammonium nitrate, or ammonium sulfate. 

Formaldehyde condensation products from urea and/or melamine are shown in Fig. 13.2. They are comparable to the corresponding products for permanent press and easy-care finishes (Chapter 5). They have the same advantages and disadvantages and they often improve the perspiration more than the washing fastness. Therefore they are mostly used for lining fabrics, where their price advantage is especially important. 

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