二氧化硅制备水溶性硅钾肥的研究

采用二氧化硅和碳酸钾为原料，通过高温煅烧活化二氧化硅制备水溶性硅钾肥。研究了煅烧温度、煅烧时间、氧化钾与二氧化硅物质的量比、二氧化硅粒径等条件对制备水溶性硅钾肥的影响，并通过热重-差示扫描量热法（TG-DSC）、X射线衍射（XRD）和扫描电镜（SEM）等对样品进行了表征。最佳工艺条件：煅烧温度为900 ℃，煅烧时间为30 min，氧化钾与二氧化硅物质的量比为0.85，二氧化硅平均粒径为160 μm。在此条件下制得的硅钾肥具有全水溶性，硅活化率为99.34%，有效硅（以二氧化硅计）质量分数为39.55%，氧化钾质量分数为53.23%。在高温下二氧化硅与碳酸钾的化学反应可抑制碳酸钾的挥发，反应产物的组成不仅含有硅酸钾（K₂SiO₃），可能还存在二硅酸钾（K₂Si₂O₅）和四硅酸钾（K₂Si₄O₉）。

Study on preparation of water-soluble silicon-potassium fertilizer by silicon dioxide

Silicon dioxide and potassium carbonate were used as raw materials，water-soluble silicon-potassium fertilizer was prepared by calcining activated silicon dioxide at high temperature.The effects of calcination temperature，calcination time，n（K₂O）/n（SiO₂），and particle size of silicon dioxide on preparation process of water-soluble silicon potassium fertilizer were studied.And the product was characterized by thermogravimetric-differential scanning calorimetry（TG-DSC），X-ray diffraction（XRD） and scanning electron microscope（SEM）.The optimal process conditions were calcination temperature of 900 ℃，calcination time of 30 min，n（K₂O）/n（SiO₂） of 0.85，the average particle size of 160 μm.The silicon-potassium fertilizer prepared under this condition was fully water-soluble with silicon activation rate of 99.34%，effective silicon（SiO₂） content of 39.55 % and K₂O content of 53.23 %.The chemical reaction between silicon dioxide and potassium carbonate at high temperature could inhibit the volatilization of potassium carbonate.The composition of the reaction product may not only contain K₂SiO₃，but also contain K₂Si₂O₅ and K₂Si₄O₉.