What are the NPK Fertilisers?

Let’s talk a little about the NPK fertilizers.

By the end of this article, you should be able to state the elements in NPK fertilizers. 

You should then be able to describe how the compounds and NPK fertilizers are produced. Finally, you should be able to compare the industrial production of fertilizers with their production in a lab, and all of this is for triple chemistry students only.

Let’s start:

Now fertilizers are critical for modern farming and not because they replace the elements which have been taken up by plants. 

A really important group of fertilizers is called NPK.

Fertilizers NPK fertilizers contain compounds of nitrogen phosphorus, and potassium compounds containing these elements improve agricultural productivity. 

In other words, they helped plans to go larger and also more rapidly.

Now NPK fertilizers are produced in large industrial facilities such as this one, here a variety of different raw materials are processed together to produce the exact fertilizer required. 

NPK fertilizers of formulations of different salts, these salts contain the required elements and the percentages needed by the plants. 

So in this blog post, we’re going to look at how the difference. Compounds in NPK fertilizers are produced, and we’re going to start by looking at it. 

compounds of nitrogen:


The main compound of nitrogen and NPK fertilizers is ammonium nitrate, and that has a formula NH for no.3. 

To make this, we use ammonia, which is produced by the harbor process.  

We can use ammonia to produce nitric acid. We then react the nitric acid with more ammonia to make ammonium nitrate. 

The potassium in NPK fertilizers comes from the salt potassium chloride or potassium sulfate, and both of these compounds are mined from the ground. They can be used directly without any further processing. 

Okay, I’m showing you here phosphate rock is mined from the ground. 

Phosphate rock has to be chemically processed before being used in fertilizers. We’re going to look at how phosphate rock is treated with nitric acid, sulfuric acid, and unbirth phosphoric acid. This does contain a lot of detail, and you do need to learn it. 

Treating phosphate rock with nitric acid produces phosphoric acid and calcium nitrate. 

Phosphoric acid contains phosphorus, but we cannot add this directly to plants. 

So we neutralize it with ammonia. 

This produces ammonium phosphate, and that can be used in NPK fertilizer. 

If we treat phosphate rock with sulfuric acid, then we make a mixture of calcium phosphate and calcium sulfate this mixture is called single super phosphate and again we can use this in NPK fertilizers and finally if we treat phosphate rock with phosphoric acid then we make triple super phosphate and once again this can be found in NPK fertilizers. 

Okay, now in your exam you could be asked to compare the production of fertilizers in the industry with their production in a lab such as in a school, so we’re going to finish by looking at that wagon look at the production of ammonium nitrate, and this is produced by reacting ammonia with nitric acid, and that’s a neutralization reaction in the school lab we would use dilute solutions of ammonia on nitric acid that’s to make them safe to work within the industry the ammonia would be used as a gas, and the nitric acid will be concentrated. 

Now, this is much more dangerous as the reactions very exothermic. This means that the heat produced has to be safely removed. This heat is then used. 

In later stages, in the lab, we produce crystals using a water bath and a Bunsen burner. 

This requires a lot of heat energy; however, in the industry, some of the energy for of operation is provided by the exothermic reaction we saw earlier. 

Finally, in the lab, we can only produce a small amount of ammonium nitrate. This is called a batch process in the industry the chemicals produced by a continuous process, which means that thousands of kilograms can be produced easily.

Thanks for reading!