The invention provides a method for preparing
sodium nitrate through
solvent extraction. The method includes the following steps that step1, a
potassium chloride saturated solution with the temperature of 50 DEG C-70 DEG C is prepared,
nitric acid is added to react with the
potassium chloride saturated solution at the temperature of 50 DEG C-70 DEG C, cooling
crystallization and
solid-liquid separation are performed, and an obtained
solid phase is washed with water and dried to obtain a
potassium nitrate product; step2, an extraction agent is added into a
liquid phase obtained in
solid-liquid separation in the step1, and a
raffinate water phase is returned into a reaction vessel in the step1; 3, an organic phase obtained in extraction in the step2 is mixed with water or a second mother solution,
ammonia gas is led into the mixture for reverse extraction, and a reverse extraction organic phase is returned to the step2; 4, condensation
crystallization and solid-liquid separation are performed on a reverse extraction water phase in the step3 to obtain
ammonium chloride and a first mother solution, potassium chloride is added into the first mother solution and reacts with the first mother solution at the temperature of 60 DEG C-80 DEG C, cooling
crystallization and solid-liquid separation are performed to obtain a solid phase and the second mother solution, the obtained solid phase is washed and dried to obtain a
potassium nitrate product, and the second mother solution is returned to the step3.