Abstract: The phase equilibrium of sodium salts in the NaOH-NaNO3-Na3VO4-Na2CrO4-H2O systems was determined. Based on the solubility data, sodium vanadate can be separated by cooling from the solution. By examination of NaOH concentration, NaNO3 concentration, crystallization end temperature, cooling rate, stirring speed, and seeds on the crystallization of sodium vanadate from multi-component alkaline solutions, the optimal experimental conditions for separation of sodium vanadate were obtained as follows: NaOH concentration 200~250 g/L, NaNO3 concentration 200 g/L, stirring speed 200 r/min, temperature from 80℃ to 40℃ with natural cooling, and seed addition 1%(w). Under the optimal conditions, the sodium vanadate yield of 61% was obtained, and the purity of the crystal was about 95%. The obtained crystal particles with large size (147 mm) exhibited excellent sedimentation and separation property (sedimentation speed 10 min).

Key words: NaOH, NaNO3, sodium vanadate, crystallization separation, vanadium slag

摘要： 测定了NaOH-NaNO3-Na3VO4-Na2CrO4-H2O五元体系各盐在碱中的相平衡浓度，根据所得数据对该体系中的Na3VO4进行了冷却结晶分离. 通过研究NaOH浓度、NaNO3浓度、结晶终点温度、降温速度、搅拌速度、晶种对钒酸钠结晶分离的影响，得到的最优实验条件为：结晶液中NaOH浓度200~250 g/L，NaNO3浓度200 g/L左右，搅拌转速200 r/min，80~40℃自然降温，添加晶种量1%(w)，该条件下Na3VO4结晶率为61%，晶体纯度可达95%，且晶体颗粒大(147 mm)，沉降分离速度快(<10 min).

关键词: NaOH, NaNO3, Na3VO4, 结晶, 钒渣