The mixture is cooled to below 0 °C, where the calcium nitrate crystallizes and can be separated from the phosphoric acid.
The process was an innovation for requiring neither the expensive sulfuric acid nor producing gypsum waste (known in the context of phosphate production as phosphogypsum).
Although Johnson created the process while working for the Odda Smelteverk, his company never employed it.
Instead, it licensed the process to Norsk Hydro, BASF, Hoechst, and DSM.
Today, only a few companies (e.g. Yara (Norsk Hydro), Acron, EuroChem, Borealis Agrolinz Melamine GmbH, Omnia, GNFC) still use the Odda process.