焦作高岭土烧制白炭黑研究

Study on Amorphous Silica from Jiaozuo Kaolin by Calcination

通过煅烧硬质高岭土和硫酸铵的混合物,利用硫酸铵分解产物硫酸氢铵的高反应活性,将高岭土结构中的晶格铝脱去,转化为硫酸铝,使高岭土转变为非晶质二氧化硅。以白炭黑的白度作为衡量指标,讨论了煅烧温度、时间、混合物浓度对产物的影响。结果表明,最佳煅烧温度为500℃,煅烧时间不宜过长,否则无定形二氧化硅会部分转化为晶形二氧化硅。硫酸铵用量为高岭土质量的3.5倍时,产物白炭黑已达到较高白度,再提高用量效果不明显。

In this paper, Amorphous silica was generated through calcining the mixture of hard kaolin and ammonium sulfate, high activity of ammonium bisulphate which was the intermediate production of ammonium sulfate was used to make crystal aluminum in kaolin translating into soluble sulfate, then Amorphous silica was generated from kaolin. The effect of calcining temperature, time and mixture concentration was studied by White Degree indicator. The results showed that the best calcining temperature was 500~C, Amorphous silica could become crystal silica if it calcined for long time. The dose of ammonium sulfate was 3.5 times of kaolin could archive the best White Degree, increasing the dose had no obvious effect.