Abstract:
AN IMPROVED PROCESS FOR THE CONTINUOUS PREPARATION OF A NITROPHOSPHATE FERTILIZER WHEREIN PHOSPHATE ROCK IS DECOMPOSED IN AN AQUEOUS SOLUTION CONTAINING SUFFICIENT NITRIC ACID TO DISSOLVE THE PHOSPHATE ROCK, SULPHURIC ACID IS THEN ADDED TO THE SOLUTION IN A SUFFICIENT AMOUNT TO PRECIPITATE GYPSUM WITH THE SIMULTANEOUS REFORMATION OF NITRIC ACID, ADDITIONAL PHOSPHATE ROCK IS THEN ADDED TO THE SOLUTION AND DISSOLVED BY THE REFORMED NITRIC ACID, AMMONIUM SULPHATE IS THEN ADDED TO
THE SOLUTION TO REACT WITH THE DISSOLVED CALCIUM IONS OBTAINED IN DISSOLVING THE ADDITIONAL PHOSPHATE ROCK, THEREBY PRECIPITATING ADDITIONAL GYPSUM, THE PRECIPITATED GYPSUM IS THEN SEPARATED FROM THE SOLUTION, AND THE GYPSUM-FREE SOLUTION IS THEN NEUTRALIZED WITH AMMONIA AND EVAPORATED TO DRYNESS TO FORM A SOLID FERTILIZER COMPOSITION.