This to prepare of potassium nitrate on the basis of potassium chloride and of nitric acid.

摘要

The present invention relates to a process for the manufacture of potassium nitrate from potassium chloride and nitric acid. According to the invention, potassium chloride and nitric acid are reacted in an aqueous medium at a temperature in the range of between -25 DEG C. to +10 DEG C. From the brine solution obtained after the separation of the resulting potassium nitrate, nitric acid is extracted by an organic solvent solution containing at least one compound selected from the group consisting of ketones having five to ten carbon atoms, straight or cyclic polyethers having molecular weight in the range of 100 to 1000, polyalkylene glycols slightly miscible in water and having molecular weight in the range of 1000 to 3000, and organic esters of phosphoric acid, phosphonic acid and phosphinic acid, or mixtures thereof, in an organic diluent which does not substantially extract hydrochloric acid. The remaining aqueous solution consists of a substantially nitrate-free brine containing hydrochloric acid. The NO3--loaded solvent is washed, the nitric acid as well as the organic solvent being respectively recycled in the process. The process saves appreciable amounts of nitric acid. Optionally, pure hydrochloric acid could be obtained from the nitrate-free brine, by distillation or by solvent extraction using butanols or pentanols as extractants.