In the manufacture of nitrophosphate according to the method used at Dutch State Mines, calcium nitrate is obtained as a by-product.
Calcium nitrate is a valuable fertiliser which is widely used for top-dressing; it is essential to produce it in an attractive form.
To this end extensive investigations have been made in the laboratories and pilot plants of Staatsmijnen. and these have resulted in a completely new procedure which we intend to discuss here. The leading principles of our process have been laid down in several patents and patent applications (see i.a. the British Patent Specification No: 794855).
The process is based on the crystallization of droplets of calcium nitrate in a mineral oil to which seed crystals have been added. After crystallization the solid prills and the oil are separated by centrifuging.
Mr P J van den Berg and Dr G Hallie, Dutch State Mines, Netherlands
34 pages, 16 figures.