Ammonium Sulfate: A Nitrogenous Fertilizer Full of Vitality    

By Su Jianying, China National Chemical Information Center  

The proportion of ammonium sulfate output that is produced as byproduct is getting higher and higher owing to its cost advantage. Most ammonium sulfate in China is produced as byproduct in other sectors such as coking, caprolactam, sulfuric acid tail gas desulfurization, power plant desulfurization and acrylonitrile. The coking sector is the major source of ammonium sulfate byproduct. China is the biggest coke producer in the world. Coke output in China has increased rapidly in recent years, yielding 345.02 million tons in 2009 and around 1.47 million tons of ammonium sulfate, accounting for 52% of the national total. Another major source of ammonium sulfate is the caprolactam manufacture sector, accounting for around 30% of the national total. The growth of the total ammonium sulfate output is slow in recent years, the average annual growth being 10%-12%. In 2009 China's total capacity was around 3 million t/a and output was 2.82 million tons.
   China's ammonium sulfate production today is mainly in East China, North China, Central and South China and Northeast China. These four regions account for around 60% of the national capacity. China's five caprolactam makers producing ammonium sulfate as byproduct are all large enterprises such as Sinopec Shijiazhuang Refining & Chemical Company, DSM Nanjing Chemical Co Ltd and Sinopec Baling Petrochemical Co Ltd.
   As the coking sector is faced with the elimination of outdated capacities and the restriction of entry threshold, the capacity of ammonium sulfate from this sector will be limited, possibly reduced. The capacity of ammonium sulfate in caprolactam production and the ammonia-process desulfurization business will continue to grow, becoming major sources for any capacity expansion. Caprolactam is in short supply in China. In spite of a considerable increase in recent years, the domestic output of caprolactam still cannot meet the needs in the development of chemical fibers and plastic products. China's caprolactam capacity will expand substantially in the next few years. With the maturing of the ammonia-process desulfurization technology, its application in power plants will become more popular. Ammonia-process desulfurization can turn sulfur dioxide in flue gas into ammonium sulfate. In this way, environmental protection projects can create byproducts to sell and at the same time get subsidies for desulfurization. Quite a few ammonia-process desulfurization units are being planned or constructed. Substantial capacity growth is likely. Jiangsu Century Jiangnan Environmental Protection (JCJEP) Company alone, a desulfurization technology licenser in China, has constructed and is constructing desulfurization modifications for more than 10 power plants. Each of these plants will now be able to produce 200 000-400 000 tons of ammonium sulfate a year.
   It is expected that China's ammonium sulfate capacity will increase at an annual rate of 12%-15% in the near future, reaching 3.4 million t/a this year and 7 million t/a in 2015.
   Around 30% of the ammonium sulfate made in China is exported and the remaining 70% is consumed domestically. Domestic consumption was 1.94 million tons in 2009. In agriculture, the applications of ammonium sulfate include direct use as chemical fertilizer and use as raw material to make compound fertilizers. In industry, ammonium sulfate is mainly used in producing potassium sulfate and ammonium persulfate, mining rare earth metals, and as raw material for medicines, dyestuffs and leather processing chemicals. Agricultural applications usually account for 80%-85% of the total consumption. (In these applications, ammonium sulfate is mostly used to produce compound fertilizers while the amount used directly as chemical fertilizer is very small.) Industrial uses account for 15%-20% of the total consumption.
   The proportion of China's ammonium sulfate supply that is used in nitrogenous fertilizers is on the low side today - considerably smaller than in advanced countries - indicating an opportunity for expanding the domestic market. For example, 6.4% of all the nitrogenous fertilizer in Western Europe contains ammonium sulfate and 22.2% in ASEAN, but only around 1% in China. With the increased output and the market expansion of ammonium sulfate in China, further development of the market is quite promising. If it is used in 4% of all nitrogenous fertilizers, the demand will potentially reach around 10 million tons in 2015.
   The quality of ammonium sulfate produced in China is still not stable. Ammonium sulfate produced in the coking sector as byproduct, in particular, has a high content of impurities, and most of the product is powdery and has a dark color. Farmers do not like to use it directly as chemical fertilizer. Such product is mainly used by compound fertilizer producers.
   As most ammonium sulfate producers and especially coking enterprises have a small output, they pay little attention to the sales of ammonium sulfate. Larger volumes are sold by agricultural means traders and distributors. Producers themselves put little effort into it. With the future expansion of scale in ammonium sulfate production, however, producers will pay greater attention to agricultural services, put more human and material resources into market development, advertising and post-sale/afore-sale services and make joint sales with strong agricultural means companies.
   Unlike other nitrogenous fertilizer varieties, all ammonium sulfate is basically produced as byproduct in the production of other industrial products. It is a product of cyclic economy and is therefore encouraged by the government. Moreover, in its distribution as chemical fertilizer, ammonium sulfate users can enjoy some favorable policies applicable to the chemical fertilizer sector. Furthermore, the export of ammonium sulfate is not restricted by the policy that restricts the export of chemical fertilizers and concentrates export in slack seasons, and no export tariff is imposed. These factors have already begun to promote the development of the ammonium sulfate sector greatly.

China's production of ammonia sulfate in 2005-2009
Year    Capacity, million t/a    Output, million tons     Utilization rate, %
2005    2.03    1.91    94.0
2006    2.50    2.32    92.8
2007    2.75    2.60    94.5
2008    2.85    2.66    93.0
2009    3.00    2.82    94.0
Source: CNCIC

China's major producers of ammonia sulfate in 2009
Company                                                                               Capacity, thousand t/a      Source
Sinopec Shijiazhuang Refining & Chemical Company
    300     caprolactam production
DSM Nanjing Chemical Co Ltd
     260     caprolactam production
Sinopec Balin