δ-层状结晶二硅酸钠的制备

Three-step process of manufacturing δ-crystalline layered sodium disilicate

为了寻求三步法制备δ-层状结晶二硅酸钠的最佳工艺参数,以速溶粉状二硅酸钠为原料,探讨了干燥温度、干燥时间、调质粉水分含量、结晶温度和结晶时间对试样Ca^2＋交换能力的影响.实验结果表明：最佳工艺条件为干燥温度300℃,调质粉水分质量分数为8%～10%,结晶温度720℃,结晶时间30 min,此时试样的Ca^2＋交换能力均值为338 mg/g,Mg^2＋交换能力均值为392 mg/g,X射线衍射分析亦表明试样的δ相含量较高.

The process for producing δ-crystalline layered sodium disilicate with the three-step process is a new one. The three-step means the three process of spray-drying, re-drying and calcining. Amorphous sodium disilicate was used as a raw material. The influence of drying temperature, drying time, water content of dried powder, crystallization temperature, and crystallization time on the product calcium ion exchange capacity was discussed to obtain the best process parameters. The test data showed that the product calcium ion exchange capacity was in optimum when it was dried at 300 ℃ for several minutes, the water content of dried powder to 8% - 10% and calcined at 720 ℃ for 30 minutes. Under the optimum conditions the product calcium ion exchange capacity reached 338 mg·g^-1 and the magnesium ion capacity 392 mg·g^-1 on average. The result was verified by XRD analyses. exchange