几种常用高岭土的烧结性能比较

Sintering Properties of Several Common Kaolins

以龙岩高岭土、临沧高岭土和星子高岭土为原料,研究了煅烧温度对高岭土白度和烧结性能的影响。结果表明,高岭土的白度随煅烧温度的升高均呈现先降低后升高再降低的趋势,600℃下白度最低,龙岩、临沧和星子高岭土分别在1100℃、1200℃和1300℃白度达到最大值。星子高岭土因含有较高的Fe2O3,白度最低,且在1400℃由于会形成更多的铁着色化合物白度降低明显。龙岩高岭土因含有较高的K2O,促进烧结,1400℃煅烧后吸水率为0.29%,耐火度最低,达到白度最大值的温度也最低。1200℃之前临沧岭土因烧失量最大,烧成收缩率最大,1300℃下龙岩高岭土因烧结程度高,烧成收缩率反而大于临沧岭土。星子高岭土因耐火度最高且颗粒较粗致使其烧成收缩率最小。

The influences of the calcining temperature on the whiteness and sintering properties were studied using Longyan,Lincang and Xingzi kaolins as materials.The results show that the whiteness of the three kaolins decreased slightly when calcined at 200～600 ℃; when calcined at 600～1400℃,their whiteness increased to the highest value （the optimal calcining temperatures for Longyan,Lincang and Xingzi kaolins were respectively 1 100 ℃,1200 ℃ and 1300 ℃） and then decreased.The whiteness of Xingzi kaolin was much lower than those of Longyan and Lincang due to its high content of Fe2O3 and its whiteness reduced obviously due to the formation of more iron colored compounds.Longyan kaolin had the lowest refractoriness due to its high content of K2O,which led to the lowest temperature for reaching the maximum whiteness,and its water absorption was only 0.29％ when calcined at 1400 ℃.Up until 1200 ℃,Lincang kaolin had the maximum firing shrinkage due to its high loss on ignition.At 1300 ℃,the firing shrinkage of Longyan kaolin,with its good sintering degree,was bigger than that of Lincang kaolin.Xingzi kaolin had the least firing shrinkage due to its highest refractoriness and coarse particles.