The phosphate rock is initially converted to phosphoric acid (P2O5) by reaction with sulfuric acid. The phosphoric acid is further processed to produce fertilizers, food-grade and feed-grade additives, and detergents. Other marginal applications include metal surface treatment, corrosion inhibition, flame retardants, water treatment, and ceramic production. Despite such widespread use, the latter applications represented only ^3% of the total consumption of various phosphates in the 1990s.
The global consumption of all phosphate fertilizers surpassed 1 MMT Pyr- during the late 1930s. After reaching 14 MMT P yr-1 in 1980, the world consumption of phosphate fertilizers has been relatively stable. It was 14.8 MMT P (34 MMT P2O5) in statistical year 2002-03, and slightly decreased to 13.8 MMT P (31.5 MMT P2O5) in statistical year 2003-04, roughly accounting for 72.8% of the global extraction of phosphate rock. The top three economies, including China, the United States, and India, accounted for one-half of the world consumption. The area of the world current crop land is about 1.4 billion ha, implying that the global fertilizer application intensity averages 10 kg P ha- . The application rate varies significantly among continents, ranging from about 3 kgP ha-1 in Africa to over 25 kgPha-1 in Europe. Among Western Europe countries, application levels range from 8.7 kgPha-1 in Denmark and Sweden to 34kgP ha-1 in Ireland.
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