Millions of tonnes of substances (raw materials and products) are transported in bulk by sea across continents for the fertilizer industry. Some of the materials are classified as dangerous for transport. This article considers their nature, potential hazards and classification. It describes various precautions to take to minimise safety and environmental risks.
The fertilizer industry is a global and large tonnage industry, requiring shipments of large quantities of raw materials and finished products across continents. This is because fertilizers are essential for crop production and agriculture, and the source materials for the three main plant nutrients viz. nitrogen, phosphate and potassium are not available naturally in all regions.
In modern manufacturing processes nitrogen is obtained from air to produce ammonia, the process requiring natural gas or other similar hydrocarbons as the main raw material. Ammonia is then used to produce ammonium nitrate (AN) and urea, which are widely used main nitrogen fertilizers. The main source of phosphate (commonly expressed as P2O5) is rock phosphate mineral, which is processed to produce phosphoric acid. Ammoniation of phosphoric acid enables production of mono-ammonium phosphate (MAP) and di-ammonium phosphate (DAP); whereas acidification of the rock can give single super-phosphate (SSP) and triple superphosphate (TSP). These materials are the common sources of P2O5. Lastly, potassium (expressed as K2O) is mainly sourced from potassium chloride, described in the industry as potash, which is mined. Other source materials are also used for the above nutrients, for example, ammonium sulphate (AS), potassium nitrate, potassium sulphate, calcium nitrate and sodium nitrate.
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