Making Fertilisers Useful products from the AIR!

Making Fertilisers  Most fertilisers have a high nitrogen content.  Hence they are called nitrogenous fertilisers.  NPK fertilisers contain compounds of nitrogen, phosphorus and potassium

Making Fertilisers  The two most common fertilisers are ammonium nitrate and ammonium sulphate.  Ammonia is NH 3, it is made by the Haber process with nitrogen from the air.

Making Fertilisers  Ammonia is a strong alkali, to turn it into a fertiliser it has to be neutralised with an acid.

Making Fertilisers  Ammonium nitrate is made by neutralising ammonia (a base) with nitric acid.

Making Fertilisers Ammonia + nitric acid ammonium nitrate NH 3(aq) + HNO 3(aq) NH 4 NO 3(aq)

Making Fertilisers  The solution is heated to evaporate the water and the solid ammonium nitrate is formed into pellets.  The nitric acid itself is made from ammonia, this makes ammonia made by the Haber process very important for producing fertilsers.

Making Fertilisers  Ammonium sulphate is made by neutralising ammonia (a base) with sulphuric acid.  This provides plants with sulphur as well as nitrogen.

Making Fertilisers Ammonia + sulphuric acid ammonium nitrate 2NH 3(aq) + H2SO 4(aq) (NH4) 2 SO 4(aq)

Making Fertilisers  The Haber process makes ammonia out of hydrogen and nitrogen.  The Haber process is a very important industrial process