温度梯度下湿法磷酸合成工业磷酸一铵研究

以湿法磷酸净化连续生产工业级磷酸一铵新工艺为背景，以五氧化二磷质量分数为20%的湿法磷酸为原料，钡盐为脱硫剂，碳酸钾为脱氟剂，二氧化硅为助剂，采用化学沉淀法一次性除硫脱氟预处理，脱硫率及脱氟率分别为83%和87.82%，再通过连续2次的氨中和、连续双效浓缩、连续结晶，制备得到工业级磷酸一铵。合成的工业磷酸一铵的化学组成（质量分数）：N，11.85%、P2O5，59.62%、NH4H2PO4，96.68%、F-，0.17%、SO42-，0.64%，达到了工业级磷酸一铵优等品标准（GB 10205-2009《磷酸一铵、磷酸二铵》）。

Study on production of industrial MAP by purification of wet-process phosphoric acid at temperature gradient

Taking the new continuous production technology of  industrial monoammonium phosphate（MAP） by the purification of wet-process phosphoric acid as the background，with 20%（mass fraction） P2O5 wet-process phosphoric acid as raw material，barium salt as desulfurizing agent，potassium carbonate as defluorination agent，and silica as additive， one-time pretreatment was made for desulfurization and defluorination by chemical precipitation method.The rates of desulfurization and defluorination were 83% and 87.82%，respectively.Then industrial grade MAP was obtained by the ammonia neutralization for two times in a row，twice concentration in consecutive double-effect，and by continuous crystallization.The prepared industrial MAP′s chemical composition（mass fraction） was as follows：N（11.85%），P2O5 （59.62%），NH4H2PO4 （96.68%），F-（0.17%），and  SO42- （0.64%），which reached the requirements of Industrial Grade MAP Standard（GB 10205-2009）.