The industrial production of fertilisers

1. Importance of Fertilisers

• Fertilisers replenish essential nutrients in the soil to promote plant growth.
• Industrial processes produce fertilisers containing nitrogen $(N)$**, phosphorus $(P),$ **and potassium $(K).$

2. Common Industrial Fertilisers

Fertiliser	Chemical Formula	Nutrient Supplied
Ammonium Sulphate	$(NH_4)_2SO_4$	Nitrogen $(N)$ & Sulphur $(S)$
Ammonium Nitrate	$NH_4NO_3$	Nitrogen $(N)$
Monoammonium Phosphate (MAP)	$NH_4H_2PO_4$	Nitrogen $(N)$ & Phosphorus $(P)$
Diammonium Phosphate (DAP)	$(NH_4)_2HPO_4$	Nitrogen $(N)$ & Phosphorus $(P)$
Superphosphate	$Ca(H_2PO_4)_2·H_2O$	Phosphorus $(P)$
Urea	$(NH_2)_2CO$	Nitrogen $(N)$

3. Industrial Processes for Fertiliser Production

(a) Ammonium-Based Fertilisers ($N-$Fertilisers)

• Produced from ammonia $(NH₃)$ via the Haber Process.

• Ammonium nitrate $(NH₄NO₃)$ is formed from: $NH_3 + HNO_3 \rightarrow NH_4NO_3$

• Ammonium sulphate $(NH_4)_2SO_4$ is made using sulphuric acid: $2NH_3 + H_2SO_4 \rightarrow (NH_4)_2SO_4$

(b) Phosphate-Based Fertilisers (P-Fertilisers)

• Made from phosphate rock treated with sulphuric acid $(H₂SO₄)$ or phosphoric acid $(H₃PO₄).$
• Example: $Ca_3(PO_4)_2 + H_2SO_4 \rightarrow Ca(H_2PO_4)_2 + CaSO_4$

(c) Urea (Organic N-Fertiliser)

• Produced by reacting ammonia $(NH₃)$ with carbon dioxide $(CO₂):$ $2NH_3 + CO_2 \rightarrow (NH_2)_2CO + H_2O$

4. Properties of Industrial Fertilisers

• Highly soluble → Absorbed quickly by plant roots.
• Provide essential nutrients $(N, P,$ or $K).$
• Used worldwide to improve crop yield.

5. Key Takeaways

• The Haber Process produces ammonia for $N-based$ $fertilisers.$
• Superphosphates are made by treating phosphate rock with acids.
• Urea is an organic fertiliser that releases nitrogen into the soil.
• Fertilisers improve soil fertility and increase food production.