大颗粒元明粉的制备研究

Research on preparation of large grained anhydrous sodium sulfate

大颗粒元明粉具有粉尘少、不易结块、流动性好等优点,并且价格比普通元明粉高出70-80元/t,利润空间较大,因此,大颗粒元明粉具有广阔的市场前景。在元明粉生产中,蒸发是一种结晶过程。根据结晶学理论,影响产品颗粒长大的因素很多。结合生产实际,对各种因素（如：硫酸钠清液的pH,钙、镁离子含量,透明度,晶种和添加剂A的加入量）做了实验研究,确定了制备大颗粒元明粉的最佳工艺条件：1 m^3硫酸钠清液加入晶种10 kg、添加剂A 0.05 kg;另外生产中应尽量提高硫酸钠清液的透明度。制备出了粒度均匀、符合用户需求的大颗粒元明粉产品：〉180μm粒子的质量分数达到95%,〉250μm粒子质量分数达到91%,为目前工业化大批量生产大颗粒元明粉提供了技术条件。

Large grained anhydrous sodium sulfate not only has many advantages, such as less dust, difficult to lump and good fluidity etc. ,but also has more profit space because its ton -price is 70 - 80 yuan higher than the ordinary anhydrous sodium sulfate. Therefore, it has broad market prospect. In the production of anhydrous sodium sulfate, evaporation is a crystallization process. According to crystallography theory, there are many factors can influence the growing -up of product＇ s particle size. Combined with the actuality of production, various factom, such as pH value, contents of Ca^2＋ and Mg^2 ＋ , transparence and addition amounts of seed crystal and additive A were studied. The optimum conditions to prepare large grained anhydrous sodium sulfate were confirmed as follows ：add seed crystal 10 kg and additive A 0.05 kg per 1 m^3 clear sodium sulfate solution, and try to enhance the transparence of clear sodium sulfate solution as much as possible：the epigranular large- grained anhydrous sodium sulfate was prepared,which can meet the costumer＇s requirements. The mass fraction of the particles above 180 μm reached 95% and the mass fraction of the particles above 250μm reached 91%. This research provides the technical conditions for the industrial bulk production of large grained anhydrous sodium sulfate.