Production of High Nitrogen NPK Granular Fertilisers

Introduction.

This paper deals with recent developments in processes and plant for manufacturing granular, high analysis, high nitrogen, NP and NPK fertilisers formulated with ammonium phosphate, potash and ammonium nitrate or urea. These are essentially analogous to nitrophosphate products. However, the commonly accepted definition of a nitrophosphate process is one wherein all or part of the phosphate rock is reacted with nitric acid rather than with sulphuric acid. In the processes under consideration the nitric acid, when used, is neutralised with ammonia and the high nitrogen materials including urea are added in solid or solution form.

This paper may also be considered a progress report on the paper which was presented by one of the authors and M. Giorgini to the Technical Conference of the International Superphosphate Manufacturers’ Association at Stockholm in l959. At that time ammonium nitrate or urea had not been used in the granulation process which was described but it was predicted that it could be done when a demand developed for higher analysis, high nitrogen products. This has now been done.

Wm. C. Weber and I. S. Mangat, International Product Services Division, Dorr-Oliver Company, London, UK.

45 pages, 4 figures, 8 refs.