EDTA-2Na 对磷酸二氢铵连续稳态结晶过程的影响

Influence of EDTA-2Na on continuous steady state crystallization of monoammonium phosphate(MAP)

针对目前工业上湿法磷酸生产高纯度磷酸二氢铵(MAP)过程中磷收率低、结晶母液利用困难以及晶体中金属离子含量高等问题,本研究提出螯合法生产高纯度MAP新工艺。在MAP结晶过程中加入螯合剂EDTA-2Na,螯合杂质金属离子,从而降低MAP晶体中杂质含量,提高MAP纯度。采用聚焦光束反射测量仪(FBRM)在线颗粒监测技术以及OptiMax全自动反应器的精确控温模块测定了溶解度和介稳区宽度等数据,分析了EDTA-2Na对MAP晶体的弦长分布、形貌和晶胞参数等的影响,系统研究了在生产过程中EDTA-2Na对MAP连续稳态结晶过程的影响。

Aiming at the problems of the production of high-purity monoammonium phosphate(MAP)by wet process phosphoric acid,such as low yield of phosphorus,difficult utilization of mother liquor and high content of metal ions in crystal,this research put forward a new method of chelation for producing high-purity MAP.Chelator EDTA-2Na was introduced to chelate metal ions to reduce the impurities in crystal during the process of MAP crystallization.In this paper,Focus beam reflectance measurement(FBRM)on-line particle monitoring technology and OptiMax automatic reactor with accurate temperature control module were used to measure the solubility and metastable zone width data.Additionally,the influence of EDTA-2Na on the chord length distribution,morphology,cell parameters of MAP crystal was analyzed,and the effect of EDTA-2Na on the continuous steady state crystallization of MAP was systematically studied.