Keywords: Potassium nitrate, potassium chloride, solvent extraction, chloride sensitive crops.
Potassium nitrate, containing 57% nutrients (13-0-44) is a new large scale NK fertiliser.
While it has long been recognised that potassium nitrate is an excellent fertiliser, its use has been restricted due to high costs of production. In recent years, however, the situation has changed, and potassium nitrate is offered in the price range of other fertiliser materials, such as potassium sulphate and solid sources of nitrate nitrogen.
In this paper an attempt is made to situate potassium nitrate with respect to other existing and potential chloride-free fertilisers, by reviewing its agronomic properties and describing the technology of its manufacture. Reference is made to the use of potassium nitrate for sensitive crops where high chloride interferes, to its use as a foliar spray, and as an aid to fertiliser granulation.
The manufacturing process described is one based on solvent extraction, a new unit operation in fertiliser manufacture. This technology permits converting solid potassium chloride to solid potassium nitrate at low temperatures. Hydrochloric acid, a by-product of the process, is utilised for co-production of high quality, concentrated phosphoric acid.
Y Araten, A Baniel and R Blumberg, IMI – Institute for Research and Development, Haifa, Israel
38 pages, 2 figures, 5 tables, 34 references.