What are the main raw materials used in the industrial production of NPK fertilisers?

The main raw materials used in the industrial production of NPK fertilisers include nitrogen from the Haber process, phosphorus from phosphate rock, and potassium from potassium chloride or potassium sulfate.

A strong answer should directly address the approved learning objective to explain that industrial production of NPK fertilisers can use several raw materials and integrated processes. (Chemistry only). This question belongs to Production and uses of NPK fertilisers within The Haber process and the use of NPK fertilisers, so the response should use that exact curriculum context rather than a generic statement. The answer is correct when it names the key idea, explains the link to chemistry only, and keeps the wording specific to AQA GCSE revision.