Study Of Sodium Humate On The Property Of Fixing Nitrogen In The Ammonium Phosphate Production

China is a large agriculture country and about 4 to 5 million tons ammonium phosphate is consumed each year. During the course of the Slurry Concentrating Process (SCP) for ammonium phosphate production, when the neutralizing value is above 1.2 the evolution of ammonia can increase sharply with the slurry's neutralizing value rising in the process of concentrating and drying, as a result, the ratio of nitrogen to phosphorus in ammonium phosphate is rather low, the production cost is quite high and it becomes not viable economically, which makes the prodution of (NH4)2HPO4 become quite difficult by slurry process. Although some of the loss of ammonia can be recycled time after time in the production of solid ammonium phosphate, the problem of ammonia loss is still not solved, furthermore the relevant equipments for recycling are required, which result in more investment and operating cost. According to the formation, structure, chemical and physical property of sodium humate, simulating the course of SCP for ammonium phosphate production, by adding sodium humate into the neutralizing slurry the fixing nitrogen property was studied in this paper, so that it could reduce the loss of ammonia in the concentrating and drying process, raise the nitrogen content of ammonium phosphate, decrease the cost of (NH4)2HPO4 production and some benefit can be realized in the practical manufacturing. In order to meet the needs of the practical industry, the property of ammonium phosphate and the effect of sodium humate on the habitude of slurry was investigated firstly by experiments:the relation between neutralization value of the slurry and the pH value, the relation between the boiling point and the density, water content and viscosity of slurry;the influence of sodium humate added into slurry on the relation between the neutralizing value and pH value, and on the density, water content and viscosity of the slurry. The experiments revealed that sodium humate has little effect on the relation between the slurry neutralizing value and the pH value, and the relation between Z (slurry neutralizing value) and pH value is almost a straight line. With the least square method , it could be expressed by an equation : Z = 0.2601P H? 0.0717. The boiling point of the slurry has a close relation to its density, water content and viscosity;the water content of slurry reduces quickly with the boiling point rising, the density and viscosity, however, increase gradually. Sodium humate added into the slurry has little effect on slurry's density and water content, while it has a quite large influence on slurry's viscosity. Then the fixing nitrogen function of sodium humate added into the slurry during the course of ammonium phosphate production was emphatically explored, and the ratio of nitrogen to phosphorus in the slurry with different sodium humate content and in the product of ammonium phosphate was detected and analyzed in detail; moreover the loss of ammonia of neutralizing slurry containing different sodium humate was estimated in the concentrating process, so was the concentrated slurry in the drying process. The relation between the ratio of nitrogen to phosphorus in AP and the ammonia loss was researched respectively with the presence of sodium or not. The experiments showed that the ratio of nitrogen to phosphorus in concentrated slurry and AP product reduced more rapidly as the neutralizing value of the of slurry increased, and the ammonia loss was worse. While the ratio could be enhanced in the slurry and product of AP when sodium humate was added into dilute AP slurry, as a result the loss of ammonia could be decreased. The experiments indicated that the best amount of sodium humate added into the neutralizing slurry was 2% of P2O5 in the slurry. Sodium humate has been greatly researched by a good many scholars at home andabroad, and some important use of sodium humate in lots of fields has been presented. Though many great achievements have been obtained, seldom study had been carried out about the fixing nitrogen property in ammonium phosphate production. A new method of fixing nitrogen has been put forward in this paper, whose experiment design and the results have some reference value of guiding to ammonium phosphate manufacturing and further investigation on sodium humate.