摘要
采用CaHPO_4·2H_2O-H_2SO_4-H_3PO_4-H_2O体系模拟湿法磷酸生产过程,以磷矿浆成分为依据,在单因素条件下分别研究Al^(3+)、Na^+和Mg^(2+)对结晶和CaSO_4·2H_2O水洗速率的影响。研究发现:添加Al^(3+)有利于CaSO_4·2H_2O晶体粒径增加;添加Na^+使得0.9%Na_2O含量的Na^+引起CaSO_4·2H_2O晶体团聚,有利于水洗;Mg^(2+)增加溶液黏度,严重影响晶体生长和水洗速率。通过X射线衍射、扫描电子显微镜对CaSO_4·2H_2O进行表征,发现其晶体生长符合非完整光滑突变界面模型,杂质离子影响反应速率和晶面生长速度。
The system,including CaHPO_4·2H_2O-H_2SO_4-H_3PO_4-H_2O,is utilized to simulate wet process for phosphoric acid production.Based upon the slurry composition of phosphate mineral analysis,according to single factor experimental demands,the influence of Al^(3+),Na^+ and Mg^(2+) on crystallization and washing rate of CaSO_4·2H_2O were investigated.The result indicated that,it is beneficial for the size of CaSO_4·2H2O crystals when adding Al^(3+) into the system.Na+as the form of 0.9%(mass)Na_2O in the slurry also caused agglomeration of CaSO_4 ·2H2O crystals.We also found that it is helpful for the washing rate.But when Mg^(2+) was added into the system,the unfavorable impact such as increasing the viscosity of solution,seriously influencing crystal growth and washing rate.For our target production,CaSO_4·2H_2O crystal,XRD,SEM were adopted to characterize the products during the process.The results showed that crystal growth conforms to Burton-Cabrera-Frank model.The impurity ions change the reaction rate and crystal plane growth rate.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2016年第S1期296-301,共6页
CIESC Journal
关键词
反应
结晶
离子
制备
二水硫酸钙
reaction
crystallization
ions
preparation
calcium sulfate dihydrate
