PROCESS FOR OBTAINING OF ORDINARY OR ENRICHED SUPERPHOSPHATE

The method is used for production of mineral fertilisers. Through the method, the concentrated sulphuric acid is used directly without preliminary dilution and cooling of the solution. This medium helps to attain a high rate of decomposition for the natural phosphate and maintain low content of free phosphoric acid in the product. The method runs in two stages. The first stage includes simultaneous mixing of phosphate (up to 70 per cent in weight) and concentrated sulphuric acid or a mixture of concentrated sulphuric acid and phosphoric acid and water (30 per cent of its total quantity). In the second stage, after the pulp is ready, the remaining quantity of the phosphate and the water are added. The prepared unthickening pulp is neutralised and, if necessary, is hydrolysed at 80 - 120 degrees C for 10 to 40 minutes.