硅微粉的提纯及其在建筑结构胶中的应用研究

Silica powder purifing and appling in the building structural adhesive

硅微粉是工业冶炼硅铁生产过程的副产物,因其含有微量铁氧化物、炭等杂质影响其应用范围的拓展。本研究采用盐酸溶液酸洗方法可有效地去除原粉中的铁氧化物,实验发现随盐酸用量增加,铁的脱除率增大,当盐酸用量大于10g原粉/150mL（20%盐酸）后,脱除铁的反应基本达到平衡。采用煅烧方法可有效地脱除炭,并随煅烧温度增加炭脱除率增大,样品颜色从深灰色逐渐变成浅灰色,直至白色。当温度大于400℃、煅烧时间大于3h后,炭的燃烧反应基本平衡,可以获得满意的脱色效果。实验发现随煅烧温度升高,颗粒直径逐渐增大,因为在煅烧过程中颗粒发生了融合聚并现象;实验发现在建筑结构胶中加入适量硅微粉可有效地提高拉伸和弯曲强度。本研究最佳煅烧温度范围在400~500℃,硅微粉的最佳添加量在6%左右。

Silica powder is by-products from the ferrosilicon smelting industry.The material contains some of trace amounts of iron oxide and carbon and other impurities,so the scope of its application has been blocked.Hydrochloric acid pickling can remove the iron oxide of original powder effectively.It was found that iron removal ratio increased with increaseing of the amount of hydrochloric acid,when hydrochloric acid was more than original powder 10g / 150ml（20% hydrochloric acid）,removal iron reaction was basic balance.The carbon can be effectively removed by calcination,and carbon removal ratio increased with increaseing of calcination temperature,the sample color from dark gray turned to light gray,until white.When the temperature was higher than 400℃,the calcination time was greater than 3h carbon combustion reaction was basic balance,which can achieve satisfactory bleaching effect.It was found that particle diameter increased with increaseing of calcination temperature,because in the calcination process particles occurred fusion and copolymerization phenomenon;it was found that the adding amount of silicon powder appropriately can improve the tensile and bending strength of structural adhesive.The optimum calcination temperature range was between 400℃and 500℃,the optimum addition of silicon powder was about 6%.