C10__Resources

Definition

Fertilisers are important as they replace elements that have been taken up by plants. NPK fertilisers contain compounds of nitrogen, phosphorus and potassium which improves agricultural activity. NPK fertilizers are produced in large industrial facilities. NPK fertilisers are formulations of different salts which contain the required elements needed by plants.

Nitrogen

The main compound of nitrogen in NPK fertilisers is ammonium nitrate . To make this you use ammonia made by the Haber Process which can be used to produce nitric acid which is then reacted with more ammonia to make ammonium nitrate.

Potassium

The potassium in NPK fertilisers comes from potassium chloride or potassium sulfate which both come from mining without processing.

Phosphorous

Phosphate rock has to be chemically processed before being used in fertilisers. Treating Phosphorus Rock

  1. Treating phosphate rock with nitric acid produces phosphoric acid and calcium nitrate. Phosphoric acid contains phosphorus but this cant be directly added to plants so it must be neutralised with ammonia. This produces ammonium phosphate which can be used.
  2. Treating phosphate rock with sulfuric acid produces a mixture of calcium phosphate and calcium sulfate. This mixture is called single superphosphate which can be used.
  3. Treating phosphate rock with phosphoric acid produces triple superphosphate.