Patent GB-347729-A (GB)
Title: Process for the manufacture of phospho-nitro-potassium fertilizer
IPC: C05B7/00
Filed: 1930-01-02
Abstract: Ammonium phosphate; sodium bicarbonate; magnesium ammonium carbonate and phosphate.--In the treatment of a mixture of sodium and potassium chlorides by the ammonia soda process, instead of carbon dioxide, a gas mixture containing also phosphorus oxides, such as is obtained by oxidation of the gases produced by the high temperature reduction of phosphates, is used, and the quantity of ammonia increased to fix the phosphorus oxides as ammonium phosphate.  Mother liquor after separation of sodium bicarbonate is treated with ammonia, a mixture of carbon dioxide and phosphorus oxides, and the mineral containing sodium and potassium chlorides in any order provided that the addition of the gas mixture does not precede that of the ammonia and so cause the formation of sodium bicarbonate.  A mixture of potassium and ammonium chlorides and ammonium phosphate, for use as a fertilizer, crystallizes on cooling, and the mother liquor is treated with ammonia and the mixture of carbon and phosphorus oxides to precipitate sodium bicarbonate, the mother liquor of which is treated as above.  Phosphorus oxides may be present in the gas used in one stage only of the carbonation.  If the mineral used contains magnesium salts such as the chloride, the treatment of the sodium bicarbonate mother liquor results in the precipitation of magnesium compounds of phosphoric acid and also, unless an excess of phosphorus oxides is present, of magnesium ammonium carbonate.  These, if left in the liquor, are obtained mixed with the potassium and ammonium chlorides and ammonium phosphate which separate.  The solid mixture may be treated with gases containing phosphoric oxides to convert all the magnesium into phosphates.ALSO:In the treatment of a mixture of sodium and potassium chlorides by the ammonia soda process, instead of carbon dioxide, a gas mixture containing also phosphorus oxides, such as is obtained by oxidation of the gases produced by the high temperature reduction of phosphates, is used, and the quantity of ammonia increased to fix the phosphorus oxides as ammonium phosphate. Mother liquor after separation of sodium bicarbonate is treated with ammonia, a mixture of carbon dioxide and phosphorus oxides, and the mineral containing sodium and potassium chlorides in any order provided that the addition of the gas mixture does not precede that of the ammonia and so cause the formation of sodium bicarbonate.  A mixture of potassium and ammonium chlorides and ammonium phosphate, for use as a fertilizer, crystallizes on cooling, and the mother liquor is treated with ammonia and the mixture of carbon and phosphorus oxides to precipitate sodium bicarbonate, the mother liquor of which is treated as above.  Phosphorus oxides may be present in the gas used in one stage only of the carbonation.  If the mineral used contains magnesium salts such as the chloride, the treatment of the sodium bicarbonate mother liquor results in the precipitation of magnesium compounds of phosphoric acid and also, unless an excess of phosphorus oxides is present, of magnesium ammonium carbonate.  These, if left in the liquor, are obtained mixed with the potassium and ammonium chlorides and ammonium phosphate which separate.  The solid mixture may be treated with gases containing phosphorus oxides to convert all the magnesium into phosphates.