The Pan Granulation Process

Around 1970 Norsk Hydro developed and put into full scale operation a process for the production of a coarse grade (4-11 mm) ammonium nitrate fertiliser for use in forest fertilisation. The process, based on pan granulation of water free melt, has proved very successful. The investment and production costs are low, and the product has excellent physical properties and storage ability.

The new pan granulation technique has since been used for production of NPK, urea and nitrate of lime fertilisers of regular (2-4 mm) and larger sizes in pilot plants, while production of regular size calcium ammonium nitrate and ammonium nitrate fertilisers has been demonstrated in the full size plant. The same good results as to cost and product quality were obtained for all the different fertilisers and size ranges. The process permits production of almost any particle size within narrow size limits. Furthermore, air pollution control is quite simple since the product cooling air is not in contact with the hot melt, thus practically eliminating the haze formation which is so characteristic in prilling of ammonium nitrate and urea.

The new pan granulation process is being patented world wide, and is also being licensed.

Ø Skauli and O H Lie, Norsk Hydro as, Norway.

24 pages, 12 figures, 6 refs.