nitrogen

Nitrogen for industrial use is produced largely by the fractional distillation of liquid air. It is used in the manufacture of stainless steel and as a coolant for the immersion freezing of food products, for the transportation of foods, for the preservation of bodies and reproductive cells (sperm and eggs), and for the storage of biological samples. However, the chief importance of the element lies in its compounds, among them ammonia, nitric acid, and cyanide. China's nitrogen industry has had to develop from small beginnings--in 1949, fertilizer production in China was less than 6,000 t/a nutrient. However, imported Soviet technology led to the development of domestic urea and SSP plants, with production rising to 80,000 t/a nutrient by 1955. Domestic technology led to the development of ammonium bicarbonate capacity in 1958, and over subsequent years this became the dominant method of nitrogen production, achieving more than half of N capacity. China imported 120,000 tons of nitrogen, phosphorus and potassium valued at 30.796 million US dollars in November 2006. The import in January-November reached 1,720,000 tons valued at 416.598 million US dollars, down 18.3 percent and 14.4 percent respectively year on year.