Potassium nitrate is produced from potassium chloride as the potassium source and a nitrate-nitrogen source. In the case of SQM’s production processes in Chile, the nitrate-nitrogen source is sodium nitrate, whereas Haifa uses nitric acid for this purpose. Migao's alternative production process is based on ammonium nitrate as the nitrate-nitrogen source (Figure 1).
Figure 1. Chemical formulae that describe possible production processes of potassium nitrate. (Click on the figure to enlarge, Click here to open and print the figure)