Patent GB-344962-A (GB)
Title: Process for the manufacture of phospho-nitrogenous manures, ammonium phosphate and sodium bicarbonate
IPC: C05B7/00
Filed: 1929-12-21
Abstract: A gaseous mixture containing both phosphorus oxides and carbon dioxide, such as that obtained by the oxidation of the gases liberated from furnaces in which phosphates are reduced at high temperatures, is substituted for the carbon dioxide used in the manufacture of sodium bicarbonate and ammonium chloride from sodium chloride, the quantity of ammonia employed in the manufacture being increased by the amount needed to form ammonium phosphate by combination with the phosphorus oxides.  The composition of the gaseous mixture obtained from the reduction furnaces may be varied by adding thereto carbon dioxide or phosphorus oxides from other sources.  An incomplete combustion of the gaseous mixture from the reduction furnaces may be effected so as to leave part of the carbon monoxide unchanged.  In an example sodium chloride is added to the mother liquors resulting from the process and the resulting solution treated with ammonia and a gaseous mixture containing carbon dioxide and phosphorus oxides.  The precipitated sodium bicarbonate is removed and a fertilizer comprising a mixture of ammonium chloride and phosphate is crystallized from the solution; any excess sodium chloride may be separately crystallized out.  In another example the mother liquor obtained after the separation of the sodium bicarbonate in a previous cycle of operations is treated with sodium chloride and ammonia and a gaseous mixture containing both phosphorus oxides and carbon dioxide, the ammonia being added in sufficient quantity to form in the solution ammonium phosphate and normal ammonium carbonate.  Ammonium phosphate and chloride are then separated out by crystallization, the liquor being cooled if necessary, and the sodium bicarbonate afterwards precipitated from the solution by treating with gas which is rich in carbon dioxide and may be free from phosphorus oxides.  If the mother liquor of the process be treated with the ammonia and the gaseous mixture of carbon dioxide and phosphorus oxides before the addition of the sodium chloride and if the solution is sufficiently concentrated ammonium phosphate is partially precipitated and may be separated. Alternatively before being returned to the process the mother liquors may be enriched with phosphorus oxides by treatment with gas containing both carbon dioxide and phosphorus oxides, in which case only the phosphorus oxides are retained in the solution.ALSO:A fertilizer containing ammonium phosphate and ammonium chloride is produced by substituting a gaseous mixture containing both phosphorus oxides and carbon dioxide, such as that obtained by the oxidation of the gases liberated from furnaces in which phosphates are reduced at high temperatures, for the carbon dioxide used in the manufacture of sodium bicarbonate and ammonium chloride from sodium chloride, the quantity of ammonia employed in the manufacture being increased by the amount needed to form ammonium phosphate by combination with the phosphorus oxides.  The composition of the gaseous mixture obtained from the reduction furnaces may be varied by adding thereto carbon dioxide or phosphorus oxides from other sources.  An incomplete combustion of the gaseous mixture from the reduction furnaces may be effected so as to leave part of the carbon monoxide unchanged.  In an example sodium chloride is added to the mother liquors resulting from the process and the resulting solution treated with ammonia and a gaseous mixture containing carbon dioxide and phosphorus oxides.  The precipitated sodium bicarbonate is removed and a fertilizer comprising a mixture of ammonium chloride and phosphate is crystallized from the solution, any excess sodium chloride being separately crystallized out.  In another example the mother liquor obtained after the separation of the sodium bicarbonate in a previous cycle of operations is treated with sodium chloride and ammonia and a gaseous mixture containing both phosphorus oxides and carbon dioxide, the ammonia being added in sufficient quantity to form in the solution ammonium phosphate and normal ammonium carbonate.  Ammonium phosphate and chloride are then separated out by crystallization, the liquor being cooled if necessary, and the sodium bicarbonate afterwards precipitated from the solution by treating with gas which is rich in carbon dioxide and may be free from phosphorus oxides.  If the mother liquor of the process be treated with the ammonia and the gaseous mixture of carbon dioxide and phosphorus oxides before the addition of the sodium chloride and if the solution is sufficiently concentrated ammonium phosphate is partially precipitated and may be separated.  Alternatively before being returned to the process the mother liquors may be enriched with phosphorus oxides by treatment with gas containing both carbon dioxide and phosphorus oxides, in which case only the phosphorus oxides are retained in the solution.