The Chemistry of Fertilizer (cont.2)

Extracting Phosphorus To extract phosphorus, which is not found in its elemental form, it must be taken out of phosphate rock. Phosphate rock is simply a generic term for a general class of rocks; it is not a single type. It is used to describe any rock that contains amounts of phosphorus in it. The main element that these ores possess is called fluorapatite. The equation of this element is given below: 3Ca3(PO2) + CaF2 This fluorapatite can be used to make phosphoric acid, which is the chief source of phosphorus in order to make up the N-P-K equation. Reacting the fluorapatite with an acid, such as hydrochloric, nitric, or sulfuric acid, makes the phosphoric acid. The equation for such a reaction is: {3Ca3(PO2) + CaF2} + 10H2SO4 + 20H2 --> 6H3PO4 + {10CaSO4 + 2H2O} + 2HF The resulting phosphoric acid (6H3PO4) is then filtered, and is taken in the form of P2O5. Within this filtration process, approximately 30% of the total amount of phosphoric acid is made. Figure 3: Factory for Fertilizer Production

Extracting Potassium In order to extract potassium to finish off the last element of the central N-P-K formula, formation of crystalline chloride salts, with a 60% K20 content. Alternatively, potassium sulfate, with a 50% K20. Figure 4: Fetilizer is used promote the growth of various crops. VI. Examples of Fertilizers Ammonium nitrate is the most commonly used commercial fertilizer, with a 35% nitrogen makeup. It is a soluble salt, which explains why ammonium nitrate is usually used as an aqueous solution. It is produced by reacting nitric acid with ammonia, which also results in heat being released as a byproduct. This heat is generally then taken to evaporate away the water and ammonia in order to leave remaing the desired salt solution. NH4 (aq) + NH3^+ (aq) --> NH4NO3 (aq) + H2O (l) + NH3 (aq) Sodium nitrate is a popular fertilizer that is especially suited for growing cotton plants. This type of fertilizer could prove useful to the colonists on the planet, who would need the cotton in order to produce warm clothing. It is made up of 16% nitrogen content BACK - HOME - NEXT