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.