Abstract: In order to employ stripping urea melt to react with NaCl- to produce soda, the phase diagram of the Na+, NH4+/HCO3-, Cl-, (NH2)2CO-H2O system has been studied. In comparison with Na+, NH4+/HCO3-, Cl-, H2O system, the amout of water involved is much less for the urea saturated system. At the NaHCO3-NH4HCO3-NH4Cl saturated point, if there is no urea present, Na-uti-lization coefficient UNa = 83.1%. However, when saturated with urea, UNa= 85.80%. The NaHCO3 mother liquor contains 8.30 moles of water for one mole of NH4C1 in urea free system and contains 5.80 moles of water in urea saturated one. Therefore, 30% of H2O evaporation load would be saved for producing the same quatity of NH4Cl in urea saturated system. As urea wouldset out together with the ammonium chloride, consumption of steam for evaporation would be much less. For the purpose of separating the urea-NH4Cl compound fertilizer from the NaHCO3 mother liquor, it is necessary to investigate the phase diagram of the(NH2)2CO-NaCl-NH4Cl-H2O system at different temperatures.Experiments conducted show that at both 35℃ and 100℃, no double salts are formed, while at 25℃, solid phase of (NH2)2CO. NaCl. H2O is being observed. A NaHCO3-urea-NH4Cl production process is, thereby, being proposed, and a material balance calculation has been made. Theoretically speakly, with this process, for every ton of soda, produced 4.462 tons of urea-NH4Cl compound fertilizers may be produced simultaneously, and the fertilizer thus obtained contains 42.0%N, with 14% in NH4C1 included.

摘要： 自尿素合成塔出来的尿素溶液,含有未转化的NH_3和CO_2,加NaCl和H_2O后碳酸化制碱,再从母液中制取(NH_2)_2CO和NH_4Cl混合肥料,可以简化流程、降低能耗、改善肥料性能.为了探讨这一工艺的可能性及优惠条件,特研究了35℃的Na~+、NH_4~+//HCO_3-Cl~-、(NH_2)_2CO、H_2O体系及35~0、100℃(NH_2)_2CO-NH_4Cl~-NaCl-H_2O体系相图,并在此基础上讨论了工艺流程和进行了物料衡算.